深孔法测试Q345焊接试板热处理前后三维残余应力的可行性

Three-dimensional residual stress determination in Q345 weldment before and after PWHT by deep-hole drilling method

针对热处理前后的Q345焊接试板,采用深孔法测试焊缝位置厚度方向的应力分布特征,采用压痕应变法测量焊缝表面残余应力。测试结果表明,焊后原始状态的焊缝应力在厚度方向上呈M形状分布,应力峰值接近焊缝金属屈服强度的90%;消除应力热处理后的焊缝应力水平较低,基本维持在50~70 MPa。通过对比分析热处理前后的焊缝内部残余应力特征,说明采用深孔法可以很好地表征热处理前后的焊缝三维残余应力。

Taking low alloy steel Q345 welding plate as the research object,stress distribution characteristics in depth direction of weldment before and after PWHT was researched by deep-hole drilling method and indentation strain-gage method was adopted to surface stress.The research results showed that residual stress of weld in original state after welding was distributed in M shape along the thickness direction,and peak value of stress was close to 90%yield strength of weld metal.Stress level of weld after PWHT was relatively low,basically maintaining at 50~70 MPa.By comparing and analyzing characteristics of residual stress in weld before and after PWHT,it showed that deep-hole drilling method could well characterize three-dimensional residual stress in weld before and after PWHT.