低合金高强度钢消除应力裂缝的研究

以应力松弛法对一组Cr—Ni—Mo—V 系钢的消除应力裂缝倾向进行了测定,并采用扫描电镜、能谱对晶界断面形态和晶面成分进行分析,从而对现行的二次沉淀硬化弱化晶界和回火脆性因素的说法提出了异议。指出:消除应力裂缝的产生,主要取决于晶界高温强度的下降和一次过热中的晶界脆化.

AN INVESTIGATION ON STRESS-RELIEF CRACKING IN LOW ALLOY HIGH STRENGTH STEELS

The susceptibility of Cr Ni-Mo-V steels to stress relief cracking was studied by the stress-relaxation test.The fracture surface was examined with a scanning electron microscope and the composition of grain boundayr face was analyzed by the energy dis-persion means.From the test data,the authors found the current conception that secondary precipitation hardening weakened the grain boundary and that reheat cracking was the result of embrittlement caused by tempering might be incorrect.Stress-relief cracking is mainly due to the lowering of grain boundary high temperature strength and to the embrittlement of grain boundary through overheating in welding.