屈服点不明的20MnSi热轧带肋钢筋金相组织分析

对 2 0 Mn Si热轧带肋钢筋在拉伸试验中屈服点不明显 (亦称无屈服点 )的试样进行了化学成分测定、断口观察及金相组织检验 ,并与机械性能正常的试样做了对比分析。结果表明 :2 0 Mn Si热轧带肋钢筋中出现的魏氏组织、上贝氏体及马氏体组织是使屈服点消失的主要原因。并指出应通过适当控制加热温度、终轧温度及冷却速度防止异常组织的出现

Microstructure Analysis of 20MnSi HRB of non-Yield Point in Tension

In order to find out the reason of 20MnSi HRB of non yield point in tension, the chemical composition analysis, the fracture observation and the microstructure examination of the tensile sample are carried out, and the comparison and analyses of the samples with normal mechanical properties are made as well. The results show that the appearance of Widmanstatten structure,upper bainite and martensite in the structure of 20MnSi HRB is the main cause making the yield point disappear. And it is pointed out that these abnormal microstructures should be prevented by properly controlling heating temperature, end rolling temperature, and the cooling rate in the production.