冷加工塑性硬化对304不锈钢力学参数的影响

Effects of cold working plastic hardening on mechanical parameters of 304 stainless steel

准确的材料力学参数是结构完整性分析与评价的重要基础,冷加工硬化现象会造成材料力学性能参数的改变,而受冷加工硬化作用力学性能发生变化的局部区域往往是需要进行结构完整性分析的关键部位。为获取不同冷加工硬化量下材料的力学性能,文中采用数值模拟和力学试验相结合的方法,以常用的金属材料304奥氏体不锈钢为研究对象,通过单轴拉伸试验获得了10%,20%,30%,40%等4种不同冷加工条件下的工程应力应变数据;利用线弹塑性硬化模型,结合ABAQUS软件建立了获取冷加工硬化后材料力学性能的数值模拟方法,分析了不同冷加工硬化量下304奥氏体不锈钢力学性能的变化规律。结果表明,线弹塑性硬化模型在一定范围内能够较好地反映304奥氏体不锈钢受冷加工硬化作用后的力学行为,随着冷加工硬化量的不断增大,304奥氏体不锈钢的屈服应力大幅度升高,同时,冷加工硬化对304奥氏体不锈钢折减系数的影响相对较小。提出的方法可以用于重要工程结构中关键部位的结构完整性分析。

The accurate mechanical parameters of materials are of great significance to analyze and evaluate the structural integrity analysis and evaluation.The cold work hardening phenomenon will cause the change of the material mechanical property parameters,and the local areas where the mechanical properties are changed by the cold work hardening are often the key part for the structural integrity analysis.In order to obtain the mechanical properties of materials under different cold working conditions,the numerical simulation and mechanical testing methods were comparatively used in this paper.The 304 austenitic stainless steel was used in this research,and engineering stress and strain data under 10%,20%,30% and 40% cold worked conditions were obtained through the uniaxial tensile test.Combining the linear elastoplastic hardening model and the ABAQUS software,a numerical simulation method for obtaining the mechanical properties of the cold worked materials was established.The variation of the mechanical properties of the 304 austenitic stainless steel under different cold work conditions was analyzed.The results show that the linear elastic plastic hardening model can better reflect the mechanical behavior of the material after cold working.With the increase of the amount of cold work hardening,the yield stress of 304 austenitic stainless steel increased greatly while the effect of cold work hardening on the reduction factor of 304 austenitic stainless steel is relatively small.The method proposed in this paper can be used to analyze the structural integrity of key parts of important engineering structures.