16Mn钢解理断裂性质的局部方法分析

Analysis on a Local Approach of Cleavage Fracture Properties of 16Mn Steel

用断裂力学的局部方法对低合金钢16Mn的低温断裂韧性进行了分析和预测。结果表明,16Mn钢的材料常数σ_u约为2550MPa,m=16～18。由拉伸实验确定的这两个材料常数,可以看成16Mn钢的固有的解理性质,与温度无关。本文将无量钢系数C_m作为应变硬化指数H和温度的函数加以分析,并进一步给出了C_m值随m变化的趋势。本文表明,在分析金属材料的低温断裂性能时,局部方法简化了材料的特征描述,能评估带缺陷(含裂纹)结构的力学完整性。

A local approach of fracture mechanics is applied to analyze and to predict the fracture properties of a low alloy steel 16Mn. The results show that the material constants of 16Mn steel are σ_u=2550MPa and m=16～18. The two parameters determined by tensile tests can be considered as intrinsic cleavage properties of this metal, independantly of temperature. As a dimensionless function of the strain hardening exponent H and of temperature, the C_m values are analyzed and computed, and variations of C_m along with m values also given. This study shows that the local approach of fracture can be used to simplify the material characterization and to assess mechanical integrity of flawed structures in the analysis of fracture properties of material at low temperature.