The large-scale production of high-Ti steels is limited by the formation of Ti-containing oxides or nitrides in steel-slag reactions during continuous casting.These processes degrade mold flux properties,clog submerge...The large-scale production of high-Ti steels is limited by the formation of Ti-containing oxides or nitrides in steel-slag reactions during continuous casting.These processes degrade mold flux properties,clog submerged entry nozzles,form floaters in the molds,and produce various surface defects on the cast slabs.This review summarizes the effects of nonmetallic inclusions on traditional CaO-SiO_(2)-based(CS)mold fluxes and novel CaO-Al_(2)O_(3)-based(CA)low-or non-reactive fluxes containing TiO_(2),BaO,and B_(2)O_(3)additives to avoid undesirable steel,slag,and inclusion reactions,with the aim of providing a new perspective for research and practice related to balancing the lubrication and heat transfer of mold fluxes to promote smooth operation and reduce surface defects on cast slabs.For traditional CS mold flux,although the addition of solvents such as Na_(2)O,Li_(2)O,and B_(2)O_(3)can enhance flowability,steel-slag reactions persist,limiting the effectiveness of CS mold fluxes in high-Ti steel casting.Low-or non-reactive CA mold fluxes with reduced SiO_(2)content are a research focus,where adding other components can significantly change flux characteristics.Replacing CaO with BaO can lower the melting point and inhibit crystallization,allowing the flux to maintain good flowability at low temperatures.Replacing SiO_(2)with TiO_(2)can stabilize the viscosity and enhance heat transfer.To reduce the environmental impact,fluorides are replaced with components such as TiO_(2),B_(2)O_(3),BaO,Li_(2)O,and Na_(2)O for F-frce mold fluxes with similar lubrication,crystallization,and heat-transfer effects.When TiO_(2)replaces CaF_(2),it stabilizes the viscosity and enhances the heat conductivity,forming CaTiO_(3)and CaSiTiO_(5)phases instead of cuspidine to control crystallization.B_(2)O_(3)lowers the melting point and suppresses crystallization,forming phases such as Ca_(3)B_(2)O_(6)and Ca_(11)Si_(4)B_(2)O_(22).BaO introduces non-bridging oxygen to reduce viscosity and ensure flux flowability at low temperatures.However,further studies are required to determine the optimal mold flux compositions corresponding to the steel grades and the interactions between the various components of the mold flux.In the future,the practical application of new mold fluxes for high-Ti steel will become the focus of further verification to achieve a balance between lubrication and heat transfer,which is expected to minimize the occurrence of casting problems and slab defects.展开更多
Journal of Iron and Steel Research International(中文刊名:钢铁研究学报(英文版),下文简称JISRI)是由中国钢铁工业协会主管、中国钢研科技集团有限公司主办的冶金领域学术期刊(CN 11-3678/TF,ISSN 1006-706X)。JISRI于1994年创刊,月...Journal of Iron and Steel Research International(中文刊名:钢铁研究学报(英文版),下文简称JISRI)是由中国钢铁工业协会主管、中国钢研科技集团有限公司主办的冶金领域学术期刊(CN 11-3678/TF,ISSN 1006-706X)。JISRI于1994年创刊,月刊,主编为赵栋梁教授和Hongbiao Dong教授。展开更多
Laser powder bed fusion(LPBF)is highly suitable for forming 18Ni300 mold steel,thanks to its excellent capability in manufacturing complex shapes and outstanding capacity for regulating microstructures.It is widely us...Laser powder bed fusion(LPBF)is highly suitable for forming 18Ni300 mold steel,thanks to its excellent capability in manufacturing complex shapes and outstanding capacity for regulating microstructures.It is widely used in fields such as injection molding,die casting,and stamping dies.Adding reinforcing particles into steel is an effective means to improve its performance.Nb/18Ni300 composites were fabricated by LPBF using two kinds of Nb powders with different particle sizes,and their microstructures and properties were studied.The results show that the unmelted Nb particles are uniformly distributed in the 18Ni300 matrix and the grains are refined,which is particularly pronounced with fine Nb particles.In addition,element diffusion occurs between the particles and the matrix.The main phases of the base alloy are α-Fe and a small amount of γ-Fe.With the addition of Nb,part of the α-Fe is transformed into γ-Fe,and unmelted Nb phases appear.The addition of Nb also enhances the hardness and wear resistance of the composites but slightly reduces their tensile properties.After aging treatment,the molten pools and grain boundaries become blurred,grains are further refined,and the interfaces around the particles are thinned.The aging treatment also promotes the formation of reverted austenite.The hardness,ultimate tensile strength,and volumetric wear rate of the base alloy reach 51.9 HRC,1704 MPa,and 17.8×10^(-6) mm^(3)/(N·m),respectively.In contrast,the sample added with fine Nb particles has the highest hardness(56.1 HRC),ultimate tensile strength(1892 MPa)and yield strength(1842 MPa),and the volume wear rate of the sample added with coarse Nb particles is reduced by 90%to 1.7×10^(-6) mm^(3)/(N·m).展开更多
The iron and steel industry is one of the largest contributors to U.S.and global greenhouse gas emissions.Hydrogen can act as a promising reducing agent and clean energy carrier to decarbonize this sector,and has rece...The iron and steel industry is one of the largest contributors to U.S.and global greenhouse gas emissions.Hydrogen can act as a promising reducing agent and clean energy carrier to decarbonize this sector,and has received significant attention in terms of process modelling,techno-economic analysis,and life cycle assessment in recent years.Policy incentives,hydrogen storage and transportation,and water stress levels are key factors that require significantly more consideration in order to realize hydrogen's potential to decarbonize this industry.This review demonstrates the need for a systematic understanding and critical assessment of these areas,and their profound impacts on the decarbonization of the iron and steel sector.Furthermore,hydrogen and water supply face competition from other hard-to-decarbonize sectors,which should be considered on national and regional levels.Lastly,future research should also consider the impact of other environmental factors and hydrogen leak when deploying hydrogen at scale for industrial decarbonization.展开更多
Industrial trials and thermodynamic calculations were carried out to investigate the effect of steel cleanliness on the composition of inclusions both in the molten steel and in the solidified steel of Al-killed Ca-tr...Industrial trials and thermodynamic calculations were carried out to investigate the effect of steel cleanliness on the composition of inclusions both in the molten steel and in the solidified steel of Al-killed Ca-treated low-sulfur steels.The composition of inclusions changed significantly at the Ca treatment stage with the modification of Al_(2)O_(3) into calcium aluminate and a slight decrease in the inclusion size and at the casting stage with the transformation of CaO into CaS with an increase in the inclusion size.Based on experimental results and thermodynamic calculations,the Al_(2)O_(3) content in inclusions in the molten steel showed a nearly linear inverse relationship with the total calcium(TCa)/total oxygen(TO)in the steel when TCa/TO<3 and kept less than 10 wt.%under TCa/TO>3.The CaO content in inclusions firstly increased until the TCa/TO reached 1-2 and then slightly decreased with the increase in TCa/TO.The CaS content in inclusions was less than 10 wt.%when TCa/TO<1.5 and increased with the increase in the TCa/TO and total sulfur(TS)content in the steel.After solidification and cooling,the CaO/CaS in inclusions increased with the increase in the TO/TS and TCa contents in the steel;however,the CaO/CaS was less than 1.0 regardless of the TCa content when TO/TS<1.Accordingly,the composition of inclusions after solidification could be adjusted by controlling the cleanliness and calcium content of the steel,thereby adjusting the property of inclusions.展开更多
Lately,the implementation of China’s carbon peaking and carbon neutrality strategy has advanced the rapid development of the new energy industry.The cylindrical battery is extensively used due to its excellent con-si...Lately,the implementation of China’s carbon peaking and carbon neutrality strategy has advanced the rapid development of the new energy industry.The cylindrical battery is extensively used due to its excellent con-sistency,production efficiency,and high safety.Additionally,the cylindrical battery has been recognized as a major form of the future power battery by the series of benchmark car companies such as Tesla and BMW.Nickel-preplated steel(NPS),as the primary structural material for large cylindrical battery,is expected to see rapidly expanding market demand over the next three years.This study systematically introduces the continuous production of NPS for battery shell in Baosteel,including the control of substrate purity,the alloying treatment of the nickel coating layer,and the evaluation of key characteristics of products at the steel shell and battery.Moreover,this study presents the prospects for the application of NPS in square battery shells to foster the low-carbon transformation of new energy battery packaging materials.In conclusion,this study aims to provide a complete set of solutions for material selection,forming,and application technology of NPS products in diverse forms of battery shells.展开更多
High-quality steel production requires superior-performance refractories.To meet the requirements of quality enhancement and efficiency improvement in the steelmaking industry,the application of the novel microporous ...High-quality steel production requires superior-performance refractories.To meet the requirements of quality enhancement and efficiency improvement in the steelmaking industry,the application of the novel microporous magnesia with high strength,remarkable slag resistance,and excellent thermal insulation is promoted.The interface reaction between H13 steel and novel microporous magnesia castable was investigated by using the crucible method,to elucidate the molten steel purification mechanism.The interface microstructure was observed by scanning electron microscopy,and the composition,size,and amount of inclusions were statistically analyzed.A thermal calculation was conducted to gain a deeper understanding of the modification process of inclusions.Fused magnesia castables were used as the blank control.The results show that the average number density and size of inclusions were reduced by 5.99 mm^(−2) and 0.28μm respectively after the same reaction time because the micropores enhanced the inclusion adsorption.The size of inclusions caused by erosion decreased.Also,more[Mg]dissolved into molten steel over 60 min reaction time and resulted in a 0.49 wt.%increase in inclusion Mg content,which modified the inclusion by decreasing their melting point.Therefore,applying novel microporous magnesia was beneficial for purifying H13 steel.展开更多
Rare earth elements are widely used in steel production due to their unique metallurgical properties,which can modify inclusions,improve the cleanliness of molten steel,and optimize steel properties.However,high activ...Rare earth elements are widely used in steel production due to their unique metallurgical properties,which can modify inclusions,improve the cleanliness of molten steel,and optimize steel properties.However,high activity also makes rare earth elements prone to intense chemical reactions with refractories during the smelting process,which can not only accelerate the erosion and failure of refractories,but also reduce the cleanliness of molten steel owing to the formation of secondary inclusions.Therefore,it is essential to understand the interaction mechanisms between rare earth steels and refractories.Herein,the research progress on the interactions between rare earth steels and refractories is systematically reviewed.Based on both laboratory studies and industrial applications,emphasis is placed on the reaction mechanisms and their effects on the stability of refractories and the cleanliness of molten steel.At the same time,the prevention methods are summarized,including the refractory optimization,protective coatings for nozzles,argon blowing,and the application of external electric fields.Furthermore,the applicability and limitations of these methods are analyzed.Finally,future research directions are discussed to address the limitations of current studies,focusing on the development of novel refractories,non-contact control methods,and digitally intelligent process control.展开更多
This study utilizes wet/dry cyclic corrosion testing combined with corrosion big data technology to investigate the mechanism by which chloride ions(Cl^(-))influence the corrosion behavior of 650 MPa high-strength low...This study utilizes wet/dry cyclic corrosion testing combined with corrosion big data technology to investigate the mechanism by which chloride ions(Cl^(-))influence the corrosion behavior of 650 MPa high-strength low-alloy(HSLA)steel in industrially polluted environments.The corrosion process of 650 MPa HSLA steel occurred in two distinct stages:an initial corrosion stage and a stable corrosion stage.During the initial phase,the weight loss rate increased rapidly owing to the instability of the rust layer.Notably,this study demonstrated that 650 MPa HSLA steel exhibited superior corrosion resistance in Cl-containing environments.The formation of a corrosion-product film eventually reduced the weight-loss rate.However,the intrusion of Cl^(-)at increasing concentrations gradually destabilized theα/γ^(*)phases of the rust layer,leading to a looser structure and lower polarization resistance(R_(p)).The application of corrosion big data technology in this study facilitated the validation and analysis of the experimental results,offering new insights into the corrosion mechanisms of HSLA steel in chloride-rich environments.展开更多
The synergistic effects of corrosion and impact loading on the microstructure evolution and dynamic mechanical properties of ultrahigh-strength AerMet 100 steel are investigated.Through integrated experiments and mode...The synergistic effects of corrosion and impact loading on the microstructure evolution and dynamic mechanical properties of ultrahigh-strength AerMet 100 steel are investigated.Through integrated experiments and modeling,the result reveals that the corrosion leads to grain refinement and a reduction in the proportion of low-angle grain boundaries.Notably,corrosion promotes austenite enrichment(increasing from 1.8%to 13.9%)through selective dissolution of the martensitic matrix,while repetitive impacts reverse this trend(reducing to 0.1%)through stress-induced martensitic transformation.Fracture analysis demonstrates corrosion-induced ductile-to-brittle transition,with quasi-cleavage features dominating after prolonged corrosion.A physics-based dynamic yield strength model with<3%prediction error relative to impact tests is developed.These findings establish microstructure-property relationships of AerMet 100 steel under multi-field coupling,providing critical guidance for designing corrosion-resistant ultrahigh-strength steels in marine-impact environments.展开更多
Considering the Hamaker constant,inclusion size,and distance between inclusions on the surface of the molten steel,a new collision model of the inclusions on the surface of the molten steel was established based on in...Considering the Hamaker constant,inclusion size,and distance between inclusions on the surface of the molten steel,a new collision model of the inclusions on the surface of the molten steel was established based on in-situ observed results of the collision process of different types of inclusions on the surface of the molten steel.The developed model can be used to calculate the attraction of inclusions on the surface of the molten steel including Al_(2)O_(3)MgO,SiO_(2),etc.展开更多
The high-temperature compressive deformation behavior of medium manganese steel using a four-roll reversible rolling mill is investigated,revealing the effects of different Mn contents on the thermal deformation behav...The high-temperature compressive deformation behavior of medium manganese steel using a four-roll reversible rolling mill is investigated,revealing the effects of different Mn contents on the thermal deformation behavior of oxidation products in the alloy.It is found that within the experimental temperature range,the higher the deformation temperature,the better the plasticity of the oxidation products.It was observed that increasing the Mn content refines the grains,enhances the deformation ability of the oxidation products,and improves the flatness of the interfaces.Since(Fe,Mn)O has a similar crystal structure to FeO,the addition of Mn refines the grains of(Fe,Mn)O,causing the deformation to be distributed across more grains under the same deformation amount,and thereby improving its plasticity.At the interface between Fe-Mn alloy oxidation products and the matrix,there exists a spinel-phase solid solution,which can deform together with the oxidation products and the matrix at high temperatures.It was found that with increasing the Mn content,the size and number of pores between the spinel phases increased.First-principles simulation calculations were used to verify this,showing that Mn promotes the generation of vacancies.The greater number of pores in the spinel phase can effectively relieve the compressive stress caused by rolling deformation,thereby improving the deformation capability of the oxidation products at the interface.展开更多
To reveal the influence mechanism of Nb/Ti microalloying on the mechanical property of ferritic stainless steel,the grain size,phase composition,microhardness,mechanical properties and fracture morphology are characte...To reveal the influence mechanism of Nb/Ti microalloying on the mechanical property of ferritic stainless steel,the grain size,phase composition,microhardness,mechanical properties and fracture morphology are characterized and analyzed for ferritic stainless steel with single addition of Ti stabilizing element and composite addition of Nb and Ti stabilizing elements.The influence mechanism of Ti and Nb stabilizing elements is elucidated on microstructure and mechanical properties of ferritic stainless steel.Results indicate that the grains are bigger(20-60µm)for ferritic stainless steel containing 0.09 wt.%Ti(F-Ti-ss).The average grain size is about 43.9µm.Meanwhile,there are many granular TiN precipitates with big size.For ferritic stainless steel with Nb and Ti stabilizing elements(F-Nb-Ti-ss),the grains are small(8-22µm),and average grain size is about 17.3µm.There are a few granular TiN precipitates with small size.Furthermore,many nanoscale(Fe,Cr,Nb)C phases precipitate at grain boundary,which plays a role in refining grain size.Compared with mechanical properties of F-Ti-ss(506 MPa and 28.2%),both the ultimate tensile strength and elongation are improved for F-Nb-Ti-ss(573 MPa and 30.5%).The ultimate tensile strength is increased by 13.2%.The main reason is that grains are obviously refined and a large number of nanoscale phases precipitate at grain boundary for F-Nb-Ti-ss.Therefore,strengthening effect is obvious and grain deformation is more uniform during tensile test.展开更多
In this study,a 1400 MPa-grade ultra-high-strength steel thin-plate butt-welded joint was selected as the research object,and the joint was fabricated using the metal inert gas(MIG)welding process with ER307Si filler ...In this study,a 1400 MPa-grade ultra-high-strength steel thin-plate butt-welded joint was selected as the research object,and the joint was fabricated using the metal inert gas(MIG)welding process with ER307Si filler wire.Residual stress distributions were measured via the hole-drilling method,while micro-hardness was assessed using a micro-hardness tester.Simultaneously,both transverse shrinkage and angular distortion of the welded joint were experimentally determined.According to the hardness distribution of the joint,a thermalmetallurgical-mechanical finite element model was developed based on SYSWELD software platform.This model incorporates solid-state phase transformations(SSPT)and softening effect in the HAZ,as well as strain hardening and annealing behaviors in the weld metal.The temperature field,residual stress distribution,and welding deformation of single-pass butt-welded joint were simulated by the developed computational method.The simulation results were validated against experimental measurements,confirming the accuracy and reliability of the proposed computational approach.Furthermore,based on the numerical results,the influence mechanisms of SSPT and material softening on residual stress and deformation were analyzed.The findings indicate that SSPT exhibits considerable influences on the magnitude and distribution of welding residual stress.It reduces the peak longitudinal residual stress from 1620 MPa to 1350 MPa and increases the peak transverse residual stress from 350 MPa to 402 MPa.The results also manifest that the softening effect further reduces the peak longitudinal residual stress by 300 MPa,while exhibits minor effect on transverse residual stress.However,the results show that neither the SSPT nor the softening effect presents obvious influence on welding deformation.展开更多
The dissolution of MgO-refractory into the slag had an obvious influence on the steel-slag reaction and the slag property,especially for high-aluminum steels.The dissolution behavior of MgO-refractory was investigated...The dissolution of MgO-refractory into the slag had an obvious influence on the steel-slag reaction and the slag property,especially for high-aluminum steels.The dissolution behavior of MgO-refractory was investigated under various conditions,including the temperature,the initial steel composition,and the initial slag composition.A steel-slag-refractory kinetic model for high-aluminum steel was developed,which incorporated the process of MgO-refractory dissolution.The dependence of the MgO mass transfer coefficient k_(MgO)^(r)on temperature T during MgO-refractory dissolution process was established,as described by ln k_(MgO)^(r)=63,754/T+24.38524.It was indicated that the MgO dissolution rate was significantly influenced by the temperature.A higher temperature increased the dissolution rate of MgO.The initial steel composition had a slight impact on the MgO dissolution rate.Additionally,the initial slag composition strongly impacted the MgO saturation concentration and the dissolution rate.A lower initial Al_(2)O_(3)/SiO_(2)ratio increased the MgO dissolution rate.The steel-slag-refractory kinetic model accurately predicted the dissolution of MgO-refractory and the influence of dissolved MgO on the viscosity and composition change during steel-slag-refractory reactions.It was suggested that a higher temperature can hardly reduce the viscosity due to the dissolution of the MgO-refractory.展开更多
This study investigates the microstructure and co-precipitation behavior of multicomponent(Ni(Al,Mn)and Cu)nanoparticles in the weld heat-affected zones of high-strength low-carbon steel.Through thermal simulations,th...This study investigates the microstructure and co-precipitation behavior of multicomponent(Ni(Al,Mn)and Cu)nanoparticles in the weld heat-affected zones of high-strength low-carbon steel.Through thermal simulations,the intercritical,fine-grained,and coarsegrained heat-affected zones were systematically characterized to elucidate the interplay between the microstructure,precipitation,and mechanical properties.At a heat input of 30 kJ·cm^(−1),Ni(Al,Mn)nanoparticles dissolve in the intercritical heat-affected zone,followed by dense reprecipitation coupled with significant coarsening of Cu particles during cooling,thereby retaining high strength but reducing impact toughness to(142±10)J(compared to(205±8)J of the base metal).The fine-grained heat-affected zone,under the same heat input,exhibits a refined ferritic-bainite matrix with a few fine Ni(Al,Mn)and slightly coarsened Cu particles,thus enhancing plastic deformation capacity and resulting in superior impact toughness of(196±7)J.Despite complete dissolution of original precipitates at peak temperatures in the coarse-grained heat-affected zone,re-precipitated nanoparticles provide effective strengthening effect,compensating for grain coarsening and dislocation recovery and resulting in an impressive impact toughness of(186±6)J.The toughening mechanism is primarily attributed to the synergistic actions of the matrix,precipitates,and deformation twins.These findings provide mechanistic and quantitative insights for developing processing-microstructure-property relationships in different welding heat-affected zones,and this framework can be further utilized to optimize welding parameters for tailored applications.展开更多
The detection and characterization of non-metallic inclusions are essential for clean steel production.Recently,imaging analysis combined with high-dimensional data processing of metallic materials using artificial in...The detection and characterization of non-metallic inclusions are essential for clean steel production.Recently,imaging analysis combined with high-dimensional data processing of metallic materials using artificial intelligence(AI)-based machine learning(ML)has developed rapidly.This technique has achieved impressive results in the field of inclusion classification in process metallurgy.The present study surveys the ML modeling of inclusion prediction in advanced steels,including the detection,classification,and feature prediction of inclusions in different steel grades.Studies on clean steel with different features based on data and image analysis via ML are summarized.Regarding the data analysis,the inclusion prediction methodology based on ML establishes a connection between the experimental parameters and inclusion characteristics and analyzes the importance of the experimental parameters.Regarding the image analysis,the focus is placed on the classification of different types of inclusions via deep learning,in comparison with data analysis.Finally,further development of inclusion analyses using ML-based methods is recommended.This work paves the way for the application of AIbased methodologies for ultraclean-steel studies from a sustainable metallurgy perspective.展开更多
To solve the false detection and missed detection problems caused by various types and sizes of defects in the detection of steel surface defects,similar defects and background features,and similarities between differ...To solve the false detection and missed detection problems caused by various types and sizes of defects in the detection of steel surface defects,similar defects and background features,and similarities between different defects,this paper proposes a lightweight detection model named multiscale edge and squeeze-and-excitation attention detection network(MSESE),which is built upon the You Only Look Once version 11 nano(YOLOv11n).To address the difficulty of locating defect edges,we first propose an edge enhancement module(EEM),apply it to the process of multiscale feature extraction,and then propose a multiscale edge enhancement module(MSEEM).By obtaining defect features from different scales and enhancing their edge contours,the module uses the dual-domain selection mechanism to effectively focus on the important areas in the image to ensure that the feature images have richer information and clearer contour features.By fusing the squeeze-and-excitation attention mechanism with the EEM,we obtain a lighter module that can enhance the representation of edge features,which is named the edge enhancement module with squeeze-and-excitation attention(EEMSE).This module was subsequently integrated into the detection head.The enhanced detection head achieves improved edge feature enhancement with reduced computational overhead,while effectively adjusting channel-wise importance and further refining feature representation.Experiments on the NEU-DET dataset show that,compared with the original YOLOv11n,the improved model achieves improvements of 4.1%and 2.2%in terms of mAP@0.5 and mAP@0.5:0.95,respectively,and the GFLOPs value decreases from the original value of 6.4 to 6.2.Furthermore,when compared to current mainstream models,Mamba-YOLOT and RTDETR-R34,our method achieves superior performance with 6.5%and 8.9%higher mAP@0.5,respectively,while maintaining a more compact parameter footprint.These results collectively validate the effectiveness and efficiency of our proposed approach.展开更多
G115 steel,co-developed by China Iron and Steel Research Institute and Baosteel,is suitable for use in 600650℃ultra-supercritical boilers.Creep tests were carried out on a G115 hot extrusion tube at 625℃and a stress...G115 steel,co-developed by China Iron and Steel Research Institute and Baosteel,is suitable for use in 600650℃ultra-supercritical boilers.Creep tests were carried out on a G115 hot extrusion tube at 625℃and a stress of 130 MPa.Microstructure observation samples were obtained at different creep stages.The creep curve showed that the creep rate of G115 steel increased continuously after the creep test entered the steady-state stage,whereas fracture did not occur for an extended period of time.The scanning electron microscopy observation showed that the martensite lath did not appear to degenerate during the creep test,and its width increased.The transmission electron microscopy observation showed that the size and quantity of M 23 C 6 and the Laves phase increased;however,the increase in size was not obvious.The precipitation mainly gathered at the grain boundaries and the martensite lath boundaries,strengthening them.展开更多
基金financially supported by the National Natural Science Foundation of China(Nos.52204345 and 52474361)the Scientific Research Innovation Projects of Graduate Student of Jiangsu province,China(No.KYCX24_4184)。
文摘The large-scale production of high-Ti steels is limited by the formation of Ti-containing oxides or nitrides in steel-slag reactions during continuous casting.These processes degrade mold flux properties,clog submerged entry nozzles,form floaters in the molds,and produce various surface defects on the cast slabs.This review summarizes the effects of nonmetallic inclusions on traditional CaO-SiO_(2)-based(CS)mold fluxes and novel CaO-Al_(2)O_(3)-based(CA)low-or non-reactive fluxes containing TiO_(2),BaO,and B_(2)O_(3)additives to avoid undesirable steel,slag,and inclusion reactions,with the aim of providing a new perspective for research and practice related to balancing the lubrication and heat transfer of mold fluxes to promote smooth operation and reduce surface defects on cast slabs.For traditional CS mold flux,although the addition of solvents such as Na_(2)O,Li_(2)O,and B_(2)O_(3)can enhance flowability,steel-slag reactions persist,limiting the effectiveness of CS mold fluxes in high-Ti steel casting.Low-or non-reactive CA mold fluxes with reduced SiO_(2)content are a research focus,where adding other components can significantly change flux characteristics.Replacing CaO with BaO can lower the melting point and inhibit crystallization,allowing the flux to maintain good flowability at low temperatures.Replacing SiO_(2)with TiO_(2)can stabilize the viscosity and enhance heat transfer.To reduce the environmental impact,fluorides are replaced with components such as TiO_(2),B_(2)O_(3),BaO,Li_(2)O,and Na_(2)O for F-frce mold fluxes with similar lubrication,crystallization,and heat-transfer effects.When TiO_(2)replaces CaF_(2),it stabilizes the viscosity and enhances the heat conductivity,forming CaTiO_(3)and CaSiTiO_(5)phases instead of cuspidine to control crystallization.B_(2)O_(3)lowers the melting point and suppresses crystallization,forming phases such as Ca_(3)B_(2)O_(6)and Ca_(11)Si_(4)B_(2)O_(22).BaO introduces non-bridging oxygen to reduce viscosity and ensure flux flowability at low temperatures.However,further studies are required to determine the optimal mold flux compositions corresponding to the steel grades and the interactions between the various components of the mold flux.In the future,the practical application of new mold fluxes for high-Ti steel will become the focus of further verification to achieve a balance between lubrication and heat transfer,which is expected to minimize the occurrence of casting problems and slab defects.
文摘Journal of Iron and Steel Research International(中文刊名:钢铁研究学报(英文版),下文简称JISRI)是由中国钢铁工业协会主管、中国钢研科技集团有限公司主办的冶金领域学术期刊(CN 11-3678/TF,ISSN 1006-706X)。JISRI于1994年创刊,月刊,主编为赵栋梁教授和Hongbiao Dong教授。
基金Key-Area Research and Development Program of Guangdong Province(2023B0909020004)Project of Innovation Research Team in Zhongshan(CXTD2023006)+1 种基金Natural Science Foundation of Guangdong Province(2023A1515011573)Zhongshan Social Welfare Science and Technology Research Project(2024B2022)。
文摘Laser powder bed fusion(LPBF)is highly suitable for forming 18Ni300 mold steel,thanks to its excellent capability in manufacturing complex shapes and outstanding capacity for regulating microstructures.It is widely used in fields such as injection molding,die casting,and stamping dies.Adding reinforcing particles into steel is an effective means to improve its performance.Nb/18Ni300 composites were fabricated by LPBF using two kinds of Nb powders with different particle sizes,and their microstructures and properties were studied.The results show that the unmelted Nb particles are uniformly distributed in the 18Ni300 matrix and the grains are refined,which is particularly pronounced with fine Nb particles.In addition,element diffusion occurs between the particles and the matrix.The main phases of the base alloy are α-Fe and a small amount of γ-Fe.With the addition of Nb,part of the α-Fe is transformed into γ-Fe,and unmelted Nb phases appear.The addition of Nb also enhances the hardness and wear resistance of the composites but slightly reduces their tensile properties.After aging treatment,the molten pools and grain boundaries become blurred,grains are further refined,and the interfaces around the particles are thinned.The aging treatment also promotes the formation of reverted austenite.The hardness,ultimate tensile strength,and volumetric wear rate of the base alloy reach 51.9 HRC,1704 MPa,and 17.8×10^(-6) mm^(3)/(N·m),respectively.In contrast,the sample added with fine Nb particles has the highest hardness(56.1 HRC),ultimate tensile strength(1892 MPa)and yield strength(1842 MPa),and the volume wear rate of the sample added with coarse Nb particles is reduced by 90%to 1.7×10^(-6) mm^(3)/(N·m).
基金Lawrence Berkeley National Laboratory is supported by the Office of Science of the United States Department of Energy and operated under contract grant no. DE-AC02-05CH11231funded by the Industrial Efficiency & Decarbonization Office (IEDO) of United States Department of Energy
文摘The iron and steel industry is one of the largest contributors to U.S.and global greenhouse gas emissions.Hydrogen can act as a promising reducing agent and clean energy carrier to decarbonize this sector,and has received significant attention in terms of process modelling,techno-economic analysis,and life cycle assessment in recent years.Policy incentives,hydrogen storage and transportation,and water stress levels are key factors that require significantly more consideration in order to realize hydrogen's potential to decarbonize this industry.This review demonstrates the need for a systematic understanding and critical assessment of these areas,and their profound impacts on the decarbonization of the iron and steel sector.Furthermore,hydrogen and water supply face competition from other hard-to-decarbonize sectors,which should be considered on national and regional levels.Lastly,future research should also consider the impact of other environmental factors and hydrogen leak when deploying hydrogen at scale for industrial decarbonization.
基金support from the National Key Research and Development Program(Nos.2023YFB3506802 and 2023YFB3709900)the National Natural Science Foundation of China(Grant Nos.52174293 and U22A20171)+1 种基金and the Fundamental Research Funds for the Central Universities(Grant No.FRF-BD-20-04A)the High Steel Center(HSC)at North China University of Technology and University of Science and Technology Beijing.
文摘Industrial trials and thermodynamic calculations were carried out to investigate the effect of steel cleanliness on the composition of inclusions both in the molten steel and in the solidified steel of Al-killed Ca-treated low-sulfur steels.The composition of inclusions changed significantly at the Ca treatment stage with the modification of Al_(2)O_(3) into calcium aluminate and a slight decrease in the inclusion size and at the casting stage with the transformation of CaO into CaS with an increase in the inclusion size.Based on experimental results and thermodynamic calculations,the Al_(2)O_(3) content in inclusions in the molten steel showed a nearly linear inverse relationship with the total calcium(TCa)/total oxygen(TO)in the steel when TCa/TO<3 and kept less than 10 wt.%under TCa/TO>3.The CaO content in inclusions firstly increased until the TCa/TO reached 1-2 and then slightly decreased with the increase in TCa/TO.The CaS content in inclusions was less than 10 wt.%when TCa/TO<1.5 and increased with the increase in the TCa/TO and total sulfur(TS)content in the steel.After solidification and cooling,the CaO/CaS in inclusions increased with the increase in the TO/TS and TCa contents in the steel;however,the CaO/CaS was less than 1.0 regardless of the TCa content when TO/TS<1.Accordingly,the composition of inclusions after solidification could be adjusted by controlling the cleanliness and calcium content of the steel,thereby adjusting the property of inclusions.
文摘Lately,the implementation of China’s carbon peaking and carbon neutrality strategy has advanced the rapid development of the new energy industry.The cylindrical battery is extensively used due to its excellent con-sistency,production efficiency,and high safety.Additionally,the cylindrical battery has been recognized as a major form of the future power battery by the series of benchmark car companies such as Tesla and BMW.Nickel-preplated steel(NPS),as the primary structural material for large cylindrical battery,is expected to see rapidly expanding market demand over the next three years.This study systematically introduces the continuous production of NPS for battery shell in Baosteel,including the control of substrate purity,the alloying treatment of the nickel coating layer,and the evaluation of key characteristics of products at the steel shell and battery.Moreover,this study presents the prospects for the application of NPS in square battery shells to foster the low-carbon transformation of new energy battery packaging materials.In conclusion,this study aims to provide a complete set of solutions for material selection,forming,and application technology of NPS products in diverse forms of battery shells.
基金support of this study by the National Natural Science Foundation of China(Grant Nos.U22A20173 and U21A2058).
文摘High-quality steel production requires superior-performance refractories.To meet the requirements of quality enhancement and efficiency improvement in the steelmaking industry,the application of the novel microporous magnesia with high strength,remarkable slag resistance,and excellent thermal insulation is promoted.The interface reaction between H13 steel and novel microporous magnesia castable was investigated by using the crucible method,to elucidate the molten steel purification mechanism.The interface microstructure was observed by scanning electron microscopy,and the composition,size,and amount of inclusions were statistically analyzed.A thermal calculation was conducted to gain a deeper understanding of the modification process of inclusions.Fused magnesia castables were used as the blank control.The results show that the average number density and size of inclusions were reduced by 5.99 mm^(−2) and 0.28μm respectively after the same reaction time because the micropores enhanced the inclusion adsorption.The size of inclusions caused by erosion decreased.Also,more[Mg]dissolved into molten steel over 60 min reaction time and resulted in a 0.49 wt.%increase in inclusion Mg content,which modified the inclusion by decreasing their melting point.Therefore,applying novel microporous magnesia was beneficial for purifying H13 steel.
基金supported by the National Natural Science Foundation of China(Nos.52450003,52025041,U2341267,and 52174294).
文摘Rare earth elements are widely used in steel production due to their unique metallurgical properties,which can modify inclusions,improve the cleanliness of molten steel,and optimize steel properties.However,high activity also makes rare earth elements prone to intense chemical reactions with refractories during the smelting process,which can not only accelerate the erosion and failure of refractories,but also reduce the cleanliness of molten steel owing to the formation of secondary inclusions.Therefore,it is essential to understand the interaction mechanisms between rare earth steels and refractories.Herein,the research progress on the interactions between rare earth steels and refractories is systematically reviewed.Based on both laboratory studies and industrial applications,emphasis is placed on the reaction mechanisms and their effects on the stability of refractories and the cleanliness of molten steel.At the same time,the prevention methods are summarized,including the refractory optimization,protective coatings for nozzles,argon blowing,and the application of external electric fields.Furthermore,the applicability and limitations of these methods are analyzed.Finally,future research directions are discussed to address the limitations of current studies,focusing on the development of novel refractories,non-contact control methods,and digitally intelligent process control.
基金financially supported by the National Natural Science Foundation of China(Nos.52104319 and 52374323)。
文摘This study utilizes wet/dry cyclic corrosion testing combined with corrosion big data technology to investigate the mechanism by which chloride ions(Cl^(-))influence the corrosion behavior of 650 MPa high-strength low-alloy(HSLA)steel in industrially polluted environments.The corrosion process of 650 MPa HSLA steel occurred in two distinct stages:an initial corrosion stage and a stable corrosion stage.During the initial phase,the weight loss rate increased rapidly owing to the instability of the rust layer.Notably,this study demonstrated that 650 MPa HSLA steel exhibited superior corrosion resistance in Cl-containing environments.The formation of a corrosion-product film eventually reduced the weight-loss rate.However,the intrusion of Cl^(-)at increasing concentrations gradually destabilized theα/γ^(*)phases of the rust layer,leading to a looser structure and lower polarization resistance(R_(p)).The application of corrosion big data technology in this study facilitated the validation and analysis of the experimental results,offering new insights into the corrosion mechanisms of HSLA steel in chloride-rich environments.
基金supported by the National Natural Science Foundation of China(12522203,12532003 and U2267252)National Technological Basic Research Program of China,the Development and Application Project of Ship CAE Softwarethe Science and Technology Innovation 2035 Major Project of Yongjiang under Grant(2025Z009).
文摘The synergistic effects of corrosion and impact loading on the microstructure evolution and dynamic mechanical properties of ultrahigh-strength AerMet 100 steel are investigated.Through integrated experiments and modeling,the result reveals that the corrosion leads to grain refinement and a reduction in the proportion of low-angle grain boundaries.Notably,corrosion promotes austenite enrichment(increasing from 1.8%to 13.9%)through selective dissolution of the martensitic matrix,while repetitive impacts reverse this trend(reducing to 0.1%)through stress-induced martensitic transformation.Fracture analysis demonstrates corrosion-induced ductile-to-brittle transition,with quasi-cleavage features dominating after prolonged corrosion.A physics-based dynamic yield strength model with<3%prediction error relative to impact tests is developed.These findings establish microstructure-property relationships of AerMet 100 steel under multi-field coupling,providing critical guidance for designing corrosion-resistant ultrahigh-strength steels in marine-impact environments.
基金support from the National Natural Science Foundation of China(Grant No.U22A20171)the National Key Research and Development Program Project(2023YFB3709901)+3 种基金the China Baowu Low Carbon Metallurgical Innovation Fund(BWLCF202315)the Pangang-USTB Vanadium and Titanium Research Institute Research Projectthe High Steel Center(HSC)at North China University of TechnologyYanshan University and University of Science and Technology Beijing,China.
文摘Considering the Hamaker constant,inclusion size,and distance between inclusions on the surface of the molten steel,a new collision model of the inclusions on the surface of the molten steel was established based on in-situ observed results of the collision process of different types of inclusions on the surface of the molten steel.The developed model can be used to calculate the attraction of inclusions on the surface of the molten steel including Al_(2)O_(3)MgO,SiO_(2),etc.
基金supported by National Key Research and Development Program of China(Grant No.2022YFB3304800)the Reviving-Liaoning Excellence Plan(XLYC2203186).
文摘The high-temperature compressive deformation behavior of medium manganese steel using a four-roll reversible rolling mill is investigated,revealing the effects of different Mn contents on the thermal deformation behavior of oxidation products in the alloy.It is found that within the experimental temperature range,the higher the deformation temperature,the better the plasticity of the oxidation products.It was observed that increasing the Mn content refines the grains,enhances the deformation ability of the oxidation products,and improves the flatness of the interfaces.Since(Fe,Mn)O has a similar crystal structure to FeO,the addition of Mn refines the grains of(Fe,Mn)O,causing the deformation to be distributed across more grains under the same deformation amount,and thereby improving its plasticity.At the interface between Fe-Mn alloy oxidation products and the matrix,there exists a spinel-phase solid solution,which can deform together with the oxidation products and the matrix at high temperatures.It was found that with increasing the Mn content,the size and number of pores between the spinel phases increased.First-principles simulation calculations were used to verify this,showing that Mn promotes the generation of vacancies.The greater number of pores in the spinel phase can effectively relieve the compressive stress caused by rolling deformation,thereby improving the deformation capability of the oxidation products at the interface.
基金the National Key Research and Development Program of China(Grant No.2023YFB3712400)the National Natural Science Foundation of China(Grant Nos.52027805 and 52204381)Fundamental Research Funds for the Central Universities(Grant No.FRF-TP-24-002A).
文摘To reveal the influence mechanism of Nb/Ti microalloying on the mechanical property of ferritic stainless steel,the grain size,phase composition,microhardness,mechanical properties and fracture morphology are characterized and analyzed for ferritic stainless steel with single addition of Ti stabilizing element and composite addition of Nb and Ti stabilizing elements.The influence mechanism of Ti and Nb stabilizing elements is elucidated on microstructure and mechanical properties of ferritic stainless steel.Results indicate that the grains are bigger(20-60µm)for ferritic stainless steel containing 0.09 wt.%Ti(F-Ti-ss).The average grain size is about 43.9µm.Meanwhile,there are many granular TiN precipitates with big size.For ferritic stainless steel with Nb and Ti stabilizing elements(F-Nb-Ti-ss),the grains are small(8-22µm),and average grain size is about 17.3µm.There are a few granular TiN precipitates with small size.Furthermore,many nanoscale(Fe,Cr,Nb)C phases precipitate at grain boundary,which plays a role in refining grain size.Compared with mechanical properties of F-Ti-ss(506 MPa and 28.2%),both the ultimate tensile strength and elongation are improved for F-Nb-Ti-ss(573 MPa and 30.5%).The ultimate tensile strength is increased by 13.2%.The main reason is that grains are obviously refined and a large number of nanoscale phases precipitate at grain boundary for F-Nb-Ti-ss.Therefore,strengthening effect is obvious and grain deformation is more uniform during tensile test.
基金funded by the National Natural Science Foundation of China(Grant No.52471032).
文摘In this study,a 1400 MPa-grade ultra-high-strength steel thin-plate butt-welded joint was selected as the research object,and the joint was fabricated using the metal inert gas(MIG)welding process with ER307Si filler wire.Residual stress distributions were measured via the hole-drilling method,while micro-hardness was assessed using a micro-hardness tester.Simultaneously,both transverse shrinkage and angular distortion of the welded joint were experimentally determined.According to the hardness distribution of the joint,a thermalmetallurgical-mechanical finite element model was developed based on SYSWELD software platform.This model incorporates solid-state phase transformations(SSPT)and softening effect in the HAZ,as well as strain hardening and annealing behaviors in the weld metal.The temperature field,residual stress distribution,and welding deformation of single-pass butt-welded joint were simulated by the developed computational method.The simulation results were validated against experimental measurements,confirming the accuracy and reliability of the proposed computational approach.Furthermore,based on the numerical results,the influence mechanisms of SSPT and material softening on residual stress and deformation were analyzed.The findings indicate that SSPT exhibits considerable influences on the magnitude and distribution of welding residual stress.It reduces the peak longitudinal residual stress from 1620 MPa to 1350 MPa and increases the peak transverse residual stress from 350 MPa to 402 MPa.The results also manifest that the softening effect further reduces the peak longitudinal residual stress by 300 MPa,while exhibits minor effect on transverse residual stress.However,the results show that neither the SSPT nor the softening effect presents obvious influence on welding deformation.
基金support from the National Key R&D Program of China(Grant No.2023YFB3709901)the National Natural Science Foundation of China(Grant No.U22A20171)+1 种基金China Baowu Low Carbon Metallurgy Innovation Foundation(Grant No.BWLCF202315)the High Steel Center(HSC)at North China University of Technology and University of Science and Technology Beijing,China.
文摘The dissolution of MgO-refractory into the slag had an obvious influence on the steel-slag reaction and the slag property,especially for high-aluminum steels.The dissolution behavior of MgO-refractory was investigated under various conditions,including the temperature,the initial steel composition,and the initial slag composition.A steel-slag-refractory kinetic model for high-aluminum steel was developed,which incorporated the process of MgO-refractory dissolution.The dependence of the MgO mass transfer coefficient k_(MgO)^(r)on temperature T during MgO-refractory dissolution process was established,as described by ln k_(MgO)^(r)=63,754/T+24.38524.It was indicated that the MgO dissolution rate was significantly influenced by the temperature.A higher temperature increased the dissolution rate of MgO.The initial steel composition had a slight impact on the MgO dissolution rate.Additionally,the initial slag composition strongly impacted the MgO saturation concentration and the dissolution rate.A lower initial Al_(2)O_(3)/SiO_(2)ratio increased the MgO dissolution rate.The steel-slag-refractory kinetic model accurately predicted the dissolution of MgO-refractory and the influence of dissolved MgO on the viscosity and composition change during steel-slag-refractory reactions.It was suggested that a higher temperature can hardly reduce the viscosity due to the dissolution of the MgO-refractory.
基金supported by the National Natural Science Foundation of China(No.U2330110)Youth Science Foundation Project(Category A)of Liaoning Province,China(No.2025JH6/101100006).
文摘This study investigates the microstructure and co-precipitation behavior of multicomponent(Ni(Al,Mn)and Cu)nanoparticles in the weld heat-affected zones of high-strength low-carbon steel.Through thermal simulations,the intercritical,fine-grained,and coarsegrained heat-affected zones were systematically characterized to elucidate the interplay between the microstructure,precipitation,and mechanical properties.At a heat input of 30 kJ·cm^(−1),Ni(Al,Mn)nanoparticles dissolve in the intercritical heat-affected zone,followed by dense reprecipitation coupled with significant coarsening of Cu particles during cooling,thereby retaining high strength but reducing impact toughness to(142±10)J(compared to(205±8)J of the base metal).The fine-grained heat-affected zone,under the same heat input,exhibits a refined ferritic-bainite matrix with a few fine Ni(Al,Mn)and slightly coarsened Cu particles,thus enhancing plastic deformation capacity and resulting in superior impact toughness of(196±7)J.Despite complete dissolution of original precipitates at peak temperatures in the coarse-grained heat-affected zone,re-precipitated nanoparticles provide effective strengthening effect,compensating for grain coarsening and dislocation recovery and resulting in an impressive impact toughness of(186±6)J.The toughening mechanism is primarily attributed to the synergistic actions of the matrix,precipitates,and deformation twins.These findings provide mechanistic and quantitative insights for developing processing-microstructure-property relationships in different welding heat-affected zones,and this framework can be further utilized to optimize welding parameters for tailored applications.
基金support from the National Key Research and Development Program of China(No.2024YFB3713705)is acknowledgedWangzhong Mu would like to acknowledge the Strategic Mobility,Sweden(SSF,No.SM22-0039)+1 种基金the Swedish Foundation for International Cooperation in Research and Higher Education(STINT,No.IB2022-9228)the Jernkontoret(Sweden)for supporting this clean steel research.Gonghao Lian would like to acknowledge China Scholarship Council(CSC,No.202306080032).
文摘The detection and characterization of non-metallic inclusions are essential for clean steel production.Recently,imaging analysis combined with high-dimensional data processing of metallic materials using artificial intelligence(AI)-based machine learning(ML)has developed rapidly.This technique has achieved impressive results in the field of inclusion classification in process metallurgy.The present study surveys the ML modeling of inclusion prediction in advanced steels,including the detection,classification,and feature prediction of inclusions in different steel grades.Studies on clean steel with different features based on data and image analysis via ML are summarized.Regarding the data analysis,the inclusion prediction methodology based on ML establishes a connection between the experimental parameters and inclusion characteristics and analyzes the importance of the experimental parameters.Regarding the image analysis,the focus is placed on the classification of different types of inclusions via deep learning,in comparison with data analysis.Finally,further development of inclusion analyses using ML-based methods is recommended.This work paves the way for the application of AIbased methodologies for ultraclean-steel studies from a sustainable metallurgy perspective.
基金funded by Ministry of Education Humanities and Social Science Research Project,grant number 23YJAZH034The Postgraduate Research and Practice Innovation Program of Jiangsu Province,grant number SJCX25_17National Computer Basic Education Research Project in Higher Education Institutions,grant number 2024-AFCEC-056,2024-AFCEC-057.
文摘To solve the false detection and missed detection problems caused by various types and sizes of defects in the detection of steel surface defects,similar defects and background features,and similarities between different defects,this paper proposes a lightweight detection model named multiscale edge and squeeze-and-excitation attention detection network(MSESE),which is built upon the You Only Look Once version 11 nano(YOLOv11n).To address the difficulty of locating defect edges,we first propose an edge enhancement module(EEM),apply it to the process of multiscale feature extraction,and then propose a multiscale edge enhancement module(MSEEM).By obtaining defect features from different scales and enhancing their edge contours,the module uses the dual-domain selection mechanism to effectively focus on the important areas in the image to ensure that the feature images have richer information and clearer contour features.By fusing the squeeze-and-excitation attention mechanism with the EEM,we obtain a lighter module that can enhance the representation of edge features,which is named the edge enhancement module with squeeze-and-excitation attention(EEMSE).This module was subsequently integrated into the detection head.The enhanced detection head achieves improved edge feature enhancement with reduced computational overhead,while effectively adjusting channel-wise importance and further refining feature representation.Experiments on the NEU-DET dataset show that,compared with the original YOLOv11n,the improved model achieves improvements of 4.1%and 2.2%in terms of mAP@0.5 and mAP@0.5:0.95,respectively,and the GFLOPs value decreases from the original value of 6.4 to 6.2.Furthermore,when compared to current mainstream models,Mamba-YOLOT and RTDETR-R34,our method achieves superior performance with 6.5%and 8.9%higher mAP@0.5,respectively,while maintaining a more compact parameter footprint.These results collectively validate the effectiveness and efficiency of our proposed approach.
文摘G115 steel,co-developed by China Iron and Steel Research Institute and Baosteel,is suitable for use in 600650℃ultra-supercritical boilers.Creep tests were carried out on a G115 hot extrusion tube at 625℃and a stress of 130 MPa.Microstructure observation samples were obtained at different creep stages.The creep curve showed that the creep rate of G115 steel increased continuously after the creep test entered the steady-state stage,whereas fracture did not occur for an extended period of time.The scanning electron microscopy observation showed that the martensite lath did not appear to degenerate during the creep test,and its width increased.The transmission electron microscopy observation showed that the size and quantity of M 23 C 6 and the Laves phase increased;however,the increase in size was not obvious.The precipitation mainly gathered at the grain boundaries and the martensite lath boundaries,strengthening them.
