基于预充氢拉伸法的焊接接头氢致裂纹敏感性评价
Hydrogen induced cracking sensibility of welded joint based on tensile test with hydrogen pre-charging
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摘要: 提出了焊接接头预充氢拉伸法评价焊接接头氢致裂纹敏感性的新方法,以30CrMnSiNi2钢TIG焊接接头为研究对象,对此方法进行了试验验证. 结果表明,预充氢后的拉伸试样断裂位置由未充氢时的母材区转变为HAZ粗晶区,预充氢电流对屈服强度影响不大,随预充氢电流密度增加抗拉强度下降,断后伸长率和断面收缩率减小. 同时,随着预充氢电流的增加,断裂方式由准解理断裂和韧窝断裂组成的混合型断裂逐渐向穿晶准解理断裂和沿晶准解理混合断裂过渡. 预充氢拉伸试验结果表明该方法能够方便地确定焊接接头临氢环境时的薄弱环节,有效评价焊接接头氢致裂纹敏感性.Abstract: Focusing on the TIG welded joint of 30CrMn-SiNi2 steel, a new method of tensile test with hydrogen pre-charging is proposed to evaluate the hydrogen induced cracking sensibility, which was also provededby with experiment data. The results show that fracture path was changed from the parent metal area to heat effect zone after hydrogen pre-charging. The electric current of pre-charging hydrogen had less effect on the yield strength. With the increase of current density of pre-charging hydrogen, the tensile strength, elongation, and shrinkage on the cross section of sample was decreased. Meanwhile, the joint fracture mode varied from a mixed-rupture consisting of quasi-cleavage and dimples to a quasi-cleavage fracture containing transgranular fracture and intergranularfracture. The results of pre-charging tensile test shows this method can simply identify the weak zone of the welded joint in hydrogen environment. It also can effectively evaluate the hydrogen induced cracking sensibility of welded joint.