屈强比是衡量金属材料均匀塑性变形能力的重要指标。本文对不同层间温度下690MPa级HSLA钢熔敷金属进行了室温拉伸,探讨组织对熔敷金属屈强比的影响规律。应用金相显微镜,透射电子显微镜对熔敷金属的显微组织进行了分析,并采用Lepera腐蚀法,对熔敷金属组织中M-A组元进行了观察。结果表明:层间温度的降低使熔敷金属的屈强比升高,层间温度从200℃降低到80℃,屈强比由0.781增加到0.82。进一步研究表明:随层温的降低,熔敷金属中M-A组元数量减少是造成屈强比升高的原因之一。
The yield ratio was a very important factor to evaluate plastictiy deformation of metal materials. The tensile properties of deposited metal of 690 MPa level HSLA steel at different interpass temperature was tested by tensile test machine at room temperature and the rule of yield ratio was analyzed. The M-A constituents were etched by Lepera reagent. The microstructure was observed by optical microscope, transmission electron microscope. The results indicate that with the decrease of interpass temperature, the yield ratio rises,interpass temperature decreases from 200℃ to 80℃ corresponding yield ratio increase from 0.781 to 0.82. With interpass temperature decreasing,the decrease of M-A constituents in number and the increase of large angle boundary among them are important reasons to the rise of yiled ratio.