摘要
采用Gleeble-3800热模拟试验机测定了Mn-S、Mn-V-S两种非调质钢不同高温条件下的热塑性,并分析了不同温度区间两种钢的断裂失效机制。结果表明,两种钢在800~850℃温度区间均出现了抗拉强度下降幅度最小的现象,主要原因为800~850℃温度区间处于部分再结晶区,温度升高再结晶程度升高,晶粒得到进一步细化,强度得到补充。Mn-S钢在850~1200℃温度区间平均每升高100℃,抗拉强度降低53.9 MPa。Mn-V-S钢的抗拉强度变化总体较为均匀,平均每升高100℃,抗拉强度降低53.9 MPa。Mn-V-S钢中V元素在950℃以下析出第二相粒子,减少了固溶C含量,抗拉强度低于Mn-S钢,在950℃以上V发生回溶,两者强度趋于相近。两种非调质钢断面收缩率变化可分为线性上升和平台期两部分,以1000℃为分界线,Mn-S钢750~850℃温度区间断面收缩率随温度升高增长幅度较小,850~950℃温度区间塑性得到较大幅度提升,900~1200℃范围内钢断面收缩率均超过90%。Mn-V-S钢750~1000℃温度区间断面收缩率随温度升高增长幅度较为均匀,在900℃后断面收缩率均在90%以上,1200℃达到最高,最高值为99.4%。750~850℃温度区间两种钢的断面收缩率低于80%,主要原因是先共析铁素体沿晶界呈网状分布,导致拉伸时产生应力集中,建议实际生产中避开该温度范围变形。
The hot ductility of Mn-S and Mn-V-S microalloyed medium carbon steel under different high temperature conditions was measured by Gleeble-3800 thermal simulation test machine,and the fracture failure mechanism of the two steels in different temperature ranges was analyzed.The results show that the tensile strength of the two kinds of steel decreases the least in the temperature range of 800~850℃.The main reason is that the temperature range of 800~850℃is in the partial recrystallization zone,the recrystallization degree increases with the increase of temperature,the grain is further refined and the strength is supplemented.In the temperature range of 850~1200℃,the average tensile strength of Mn-S steel decreases by 53.9 MPa for every 100℃increase.The change of tensile strength of Mn-V-S steel is generally uniform,and the average tensile strength decreases by 53.9 MPa every 100℃.In Mn-V-S steel,the second phase particles of vanadium are precipitated below 950℃,which reduces the content of C in solid solution,and the tensile strength is lower than that of Mn-S steel,and the re-dissolution of V occurs above 950℃,and the strength of the two tends to be similar.The change of section shrinkage of the two non-tempered steels can be divided into two parts:linear rise and plateau period.Taking 1000℃as the dividing line,the section shrinkage of Mn-S steel increases slightly with the increase of temperature in the temperature range of 750~850℃,while the plasticity increases significantly in the temperature range of 850~950℃.The shrinkage rate of steel section is more than 90%in the range of 900~1200℃.The section shrinkage of Mn-V-S steel in the temperature range of 750~1000℃increases with the temperature more evenly,and the section shrinkage rate is above 90%at 900℃,and reaches the highest at 1200℃,with the highest value of 99.4%.The section shrinkage rate of the two steels in the temperature range of 750~850℃is lower than 80%,mainly because the proeutectoid ferrite is distributed in a network along the grain boundary,resulting in stress concentration during stretching.It is recommended to avoid deformation in this temperature range in actual production.
作者
刘献达
孙万利
郝彦英
刘运娜
张晓辉
张朝磊
Liu Xianda;Sun Wanli;Hao Yanying;Liu Yunna;Zhang Xiaohui;Zhang Chaolei(Shijiazhuang Iron and Steel Co.,Ltd.,Shijiazhuang 050031,Hebei;Institute for Carbon Neutrality,University of Science and Technology Beijing,Beijing 100083)
出处
《河北冶金》
2024年第9期29-33,68,共6页
Hebei Metallurgy
基金
河北省科技重大专项项目(22281004Z)。
关键词
非调质钢
热塑性
再结晶
断裂失效
先共析铁素体
变形温度
microalloyed medium carbon steel
thermoplasticity
recrystallization zone
fracture failure
proeutectoid ferrite
deformation temperature
