The failure of zinc pot hardware in continuous hot-dip galvanizing lines （CGLs） is due to zinc corrosion, abrasion ,and dross build-up. Enhancing the life of pot hardware will not only upgrade the quality of the she...The failure of zinc pot hardware in continuous hot-dip galvanizing lines （CGLs） is due to zinc corrosion, abrasion ,and dross build-up. Enhancing the life of pot hardware will not only upgrade the quality of the sheet products but also will increase the efficiency of CGLs, with decreasing cost and increasing energy savings. This paper introduces the current research and development for thermal spray coatings for pot rolls, sleeves, and bushings, and analyses the thermal spray and surface treatment technique details of dross adhesion prevention. It provides the potential applications and developing trends in thermal spray coatings and surface treatment techniques for pot hardware.展开更多
This paper employs a combined experimental and numerical approach to investigate the influence of airflow characteristics-specifically air velocityν_(a)and air densityρ_(a)-on the evolution of water-entry cavities a...This paper employs a combined experimental and numerical approach to investigate the influence of airflow characteristics-specifically air velocityν_(a)and air densityρ_(a)-on the evolution of water-entry cavities at low Froude numbers(Fr<13).A custom-designed test platform enables control over air densityρ_(a)and water-entry initial velocity V_(0).The velocity V_(0)influences the cavity expansion rate,which in turn determines the air inflow velocityνa into the cavity.Based on the experimental results,a critical condition for surface seal is proposed:ρ^(*)·Fr_(c)^(2.62)=315,whereρ^(*)=ρ_(a)/ρ_(0),ρ_(0)is the ambient density.For constant air density,deep seal dynamics exhibit negligible direct sensitivity to airflow when the Fr<Fr_(c),aligning with classical inertial theories and a 1/2-power scaling law during radial collapse.Asρ^(*)or Fr increases beyond the critical threshold,the cavity closure mode transitions from deep seal to surface seal.Numerical simulations,based on finite volume method,reveals that when the flow field is approximately uniform,the ratio of air flow velocityνa to projectile velocityνis~1.5.Furthermore,the airflow-induced pressure difference basically satisfiesΔp=ρ_(a)u_(a)^(2)/2,driving inward splash motion.Neglecting the change in projectile velocity,there isΔp∝ρ_(a)V_(0)^(2)/2.When the splash is about to close,the flow field distribution is relatively complex,and the pressure relationship no longer holds consistently.Surface seal blocks the connection between the cavity and the external atmosphere,directly impacting the internal pressure dynamics and further influencing the deep seal characteristics.展开更多
Ultra-precision machining technology received relatively little attention in the machining of key components for semiconductor equipment,such as the seal surfaces of mass flow controller(MFC).The machining quality of ...Ultra-precision machining technology received relatively little attention in the machining of key components for semiconductor equipment,such as the seal surfaces of mass flow controller(MFC).The machining quality of these features is vital to the corrosion resistance of MFC valve body.Currently,the processing of these features still relies on conventional manual polishing,which will lead to uncertainty in surface quality.Therefore,this article employs a special fabricated sinter pouring polyurethane(SPPU)grind-polishing tool to conduct two-dimensional ultrasonic vibration-assisted polishing experiments,with a focus on the tool's performance.The machining mechanism of the tool was analyzed.Taking into account the ultrasonic cavitation effect,the penetration depth of a single grain was calculated,and established a surface roughness model.Through experiments,it was found that as the amplitude increased,the surface roughness showed a decreasing trend,reaching as low as 0.003μm,but the change in polishing force exhibited an opposite trend.Additionally,the material removal efficiency significantly improves with the increase of amplitude.The processed surface had a reduced carbon content and no oxygen element,indicating the stable machining performance of the tool.This article provides effective reference for the automated processing of MFC valve body features.展开更多
文摘The failure of zinc pot hardware in continuous hot-dip galvanizing lines （CGLs） is due to zinc corrosion, abrasion ,and dross build-up. Enhancing the life of pot hardware will not only upgrade the quality of the sheet products but also will increase the efficiency of CGLs, with decreasing cost and increasing energy savings. This paper introduces the current research and development for thermal spray coatings for pot rolls, sleeves, and bushings, and analyses the thermal spray and surface treatment technique details of dross adhesion prevention. It provides the potential applications and developing trends in thermal spray coatings and surface treatment techniques for pot hardware.
基金supported by the National Natural Science Foundation of China(Grant Nos.12372239,12572284)supported by the National Key Laboratory of Ship Structural Safety(Grant No.Naklas2024ZZ004-J)the Key Research and Development Program of Heilongjiang Province(Grant No.JD24A002).
文摘This paper employs a combined experimental and numerical approach to investigate the influence of airflow characteristics-specifically air velocityν_(a)and air densityρ_(a)-on the evolution of water-entry cavities at low Froude numbers(Fr<13).A custom-designed test platform enables control over air densityρ_(a)and water-entry initial velocity V_(0).The velocity V_(0)influences the cavity expansion rate,which in turn determines the air inflow velocityνa into the cavity.Based on the experimental results,a critical condition for surface seal is proposed:ρ^(*)·Fr_(c)^(2.62)=315,whereρ^(*)=ρ_(a)/ρ_(0),ρ_(0)is the ambient density.For constant air density,deep seal dynamics exhibit negligible direct sensitivity to airflow when the Fr<Fr_(c),aligning with classical inertial theories and a 1/2-power scaling law during radial collapse.Asρ^(*)or Fr increases beyond the critical threshold,the cavity closure mode transitions from deep seal to surface seal.Numerical simulations,based on finite volume method,reveals that when the flow field is approximately uniform,the ratio of air flow velocityνa to projectile velocityνis~1.5.Furthermore,the airflow-induced pressure difference basically satisfiesΔp=ρ_(a)u_(a)^(2)/2,driving inward splash motion.Neglecting the change in projectile velocity,there isΔp∝ρ_(a)V_(0)^(2)/2.When the splash is about to close,the flow field distribution is relatively complex,and the pressure relationship no longer holds consistently.Surface seal blocks the connection between the cavity and the external atmosphere,directly impacting the internal pressure dynamics and further influencing the deep seal characteristics.
基金supported by the Key Research and Development Projects of Shenyang City(grant No.2021020900047)Huanqi Technology(Shenyang)Co.,Ltd,China,and Dongguan Senyong Diamond Technology Co.,Ltd,China.
文摘Ultra-precision machining technology received relatively little attention in the machining of key components for semiconductor equipment,such as the seal surfaces of mass flow controller(MFC).The machining quality of these features is vital to the corrosion resistance of MFC valve body.Currently,the processing of these features still relies on conventional manual polishing,which will lead to uncertainty in surface quality.Therefore,this article employs a special fabricated sinter pouring polyurethane(SPPU)grind-polishing tool to conduct two-dimensional ultrasonic vibration-assisted polishing experiments,with a focus on the tool's performance.The machining mechanism of the tool was analyzed.Taking into account the ultrasonic cavitation effect,the penetration depth of a single grain was calculated,and established a surface roughness model.Through experiments,it was found that as the amplitude increased,the surface roughness showed a decreasing trend,reaching as low as 0.003μm,but the change in polishing force exhibited an opposite trend.Additionally,the material removal efficiency significantly improves with the increase of amplitude.The processed surface had a reduced carbon content and no oxygen element,indicating the stable machining performance of the tool.This article provides effective reference for the automated processing of MFC valve body features.
