淬火温度对不同铬含量的低碳马氏体不锈钢组织和性能的影响

摘要：为研究淬火温度对不同铬含量的马氏体不锈钢组织和性能的影响，采用高温共聚焦显微镜(CLSM)、光镜(OM)、扫描电镜(SEM)、万能拉伸机、显微硬度计等方法对材料组织和性能进行了测试及表征。随着淬火温度的升高，不锈钢淬火后的晶粒尺寸都变大，计算确定了13%Cr和14%Cr不锈钢的晶界迁移能分别为113.62和125.92J/mol。13%Cr不锈钢经过淬火后显微组织为板条马氏体，回火后的组织为回火马氏体。但是，14%Cr不锈钢在1200℃淬火后生成了板条马氏体和少量的高温铁素体，并且在回火后高温铁素体并未消失，会对后续性能产生影响。淬火温度对不锈钢的强度影响不大。不锈钢中的铬质量分数从13%增加至14%，马氏体不锈钢强度增加，但伸长率有所降低。马氏体不锈钢的硬度随淬火温度的升高而下降，这主要与晶粒尺寸有关。

Effect of quenching temperature on microstructure and property of low carbon martensitic stainless steels with different Cr content

Abstract： To study the effect of the quenching temperature on the microstructure and property of low-carbon martensitic stainless steels with different Cr contents, confocal laser scanning microscope, optical microscope, scanning electron microscope, universal tensile machine, and microhardness tester were used to the test and characterize the microstructure and property of steel. With the increase of the quenching temperature, the grain size of the stainless steel increased, and the grain boundary migration energy of 13% Cr stainless steel and 14% Cr stainless steels was 113.62 and 125.92J/mol, respectively. The microstructure of 13% Cr martensitic stainless steel after quenching was the lath martensite, and it was the tempered martensite after tempering. However, the microstructure of 14% Cr martensitic stainless steel after quenching from 1200℃ was the lath martensite and a small amount of high temperature ferrite. The high-temperature ferrite was hardly disappeared after tempering, which was detrimental to steel properties. The quenching temperature had little effect on the strength of stainless steel. With the increase of the Cr content from 13% to 14%, the strength of the stainless steel increased, while the elongation decreased. The hardness of the martensitic stainless steel decreased with a higher quenching temperature, which was mainly related to the grain size.