摘要
在碳中和背景下,采用全废钢-电炉短流程炼钢工艺已成为钢铁行业实现低碳转型的重要路径之一,使用短流程炼钢技术可以有效降低钢铁行业的碳排放。但由于再生钢铁原料来源复杂、成分波动较大,其中含有难以在冶炼过程中去除的残余元素,会对成品钢的综合性能产生不利影响。本文以再生钢铁原料制备的34CrMo4C钢为研究对象,结合扫描电子显微镜(SEM)和电子背散射衍射(EBSD)表征手段,研究了调质处理(900℃淬火、560℃回火)工艺下基础钢与铌(Nb)改性钢的显微组织及力学性能,对比分析Nb微合金化对钢组织与性能的调控机制。结果表明,在相同的热处理制度下,两者均为典型回火索氏体组织,等效马氏体晶粒尺寸分别为2.0μm和2.2μm,沿原马氏体板条界面析出的大量球状或棒状的回火碳化物。Nb合金化试样在保持室温拉伸性能与基础钢相当的前提下,其-50℃横向冲击功吸收能量由26.7 J显著提升至49.9 J,增幅达86.9%;Nb在位错的偏聚以及回火碳化物的细化是低温冲击韧性显著改善的关键原因。
Under the background of carbon neutrality,the adoption of the all-scrap-based electric arc furnace(EAF)short-process steelmaking technology has become one of the key pathways for the steel industry to achieve low-carbon transformation.This short-process route can significantly reduce carbon emissions.However,due to the complex sources and fluctuating compositions of recycled steel scrap,residual elements that are difficult to remove during the smelting process are often introduced,which can adversely affect the overall properties of the final steel products.In this study,34CrMo4 steel produced from recycled steel scrap was used as the research object.The microstructure and mechanical properties of the base steel and Nb-modified steel under a quenching and tempering treatment(quenching at 900℃and tempering at 560℃)were investigated using scanning electron microscopy(SEM)and electron backscatter diffraction(EBSD).The regulation mechanism of Nb microalloying on steel microstructure and performance was comparatively analyzed.The results showed that,under the same heat treatment conditions,both steels exhibited a typical tempered sorbite(tempered martensite)microstructure with equivalent martensitic grain sizes of 2.0μm and 2.2μm,respectively,and a large number of spherical or rod-like tempering carbides precipitated along the original martensite lath boundaries.The Nb-alloyed sample maintained tensile properties comparable to the base steel at room temperature,while the transverse impact energy at-50℃increased significantly from 26.7 J to 49.9 J-an improvement of 86.9%.The pronounced enhancement in low-temperature impact toughness was mainly attributed to the segregation of Nb at dislocations and the refinement of tempering carbides.
作者
蔡纪升
王翠亮
虞鑫宁
吴宏辉
吴桂林
Cai Jisheng;Wang Cuiliang;Yu Xinning;Wu Honghui;Wu Guilin(Shijiazhuang Iron and Steel Co.Ltd.,Shijiazhuang 050031,Hebei;Institute for Carbon Neutrality,University of Science and Technology Beijing,Beijing 100083,China)
出处
《河北冶金》
2025年第12期54-60,共7页
Hebei Metallurgy
基金
国家自然科学基金(52474397)
河钢集团重点科技计划项目(HG2023234)。
