40CrNi2Si2MoVA钢的大气应力腐蚀行为

用单轴拉伸试样和预制裂纹试样研究40CrNi2Si2MoVA高强度钢在典型大气环境下的抗应力腐蚀性能.施加应力后的试样分别暴露于北京、青岛、万宁3个不同的大气试验站.研究表明:40CrNi2Si2MoVA钢的抗应力腐蚀性能取决于环境,在海洋性环境下应力腐蚀性较高.扫描电子显微镜微观分析表明裂纹起始于表面的腐蚀点,并向试样内部扩展,为沿晶开裂,有二次裂纹存在.随着应力水平的增大,二次裂纹明显增加.

ATMOSPHERIC STRESS CORROSION OF 40CrNi2Si2MoVA STEEL

An investigation of the stress corrosion cracking resistance of 40CrNi2Si2MoVA high strength steel in typical atmospheric environment is presented. Direct tension and pre - cracked stress - corrosion specimens were used The direct tension stress - corrosion specimens were taken from the longitudinal direction of stick and stress level was 65, 75, 85 and 95 percent of the a0.2, respectively. The pre- cracked specimens were taken from the forging and applied constant load. The samples were exposed in Beijing, Qingdao, and Wanning atmospheric test station. The results showed that SCC performance of 40CrNi2Si2MoVA steel depend on the environments. High SCC sensitivity was expressed in marine environment. The SEM showed that the crack initiated from pitting corrosion on the surface and developed to inner of the samples. It was intergranular mode of cracking, secondary cracking existed on the fracture surface. Large size secondary cracking increased obviously with the higher stress level. Serious corrosion was observed on the samples exposed in marine environment.