高速冲击拉伸条件下低硅TRIP钢的延伸率特性

对低硅HSLA -TRIP钢在室温条件下 5 0 0s-1～ 1 70 0S-1应变率范围内的动态拉伸性能进行了研究。实验结果表明 ,随应变率增大 ,钢的均匀延伸率 (eu)下降、总延伸率(et)和能量吸收值增加 ,但强度 (σb)保持不变或略有提高 ,能量吸收的增幅随应变率增大而变缓。分析认为 :残余奥氏体在颈缩发生前的较完全转变有利于提高均匀延伸率 ;高应变率下能量吸收值的提高可能由两个原因造成 :一是大应变下的奥氏体相变推迟断裂的发生 ;二是动态拉伸中的绝热温升有利于总延伸率的提高。

ELONGATION PROPERTIES OF LOW Si HSLA TRIP STEEL UNDER DYNAMIC TENSILE TEST

A kind of low Si HSLA TRIP steel was tested at the high strain rates from 500 S -1 to 1700S -1 at room temperature. The results showed that the total elongation and the energy absorption value increased but the uniform elongation decreased with the strain rate elevated,the tensile strength just slightly rose, and the energy absorption value grew sluggishly at the higher strain rate. The retained austenite transformation prior to the necking of the example enhanced the uniform elongation rate. The phenomenon of higher strength plastic balance at higher strain rate might be caused by two factors: one was the retained austenite transformation delaying the fracture occurrence under large strain,another was the adiabatic heating softening the material in dynamic tensile test.