不锈钢焊接工字形截面残余应力分布试验研究

Experimental study on residual stress distributions in fabricated stainless steel I-sections

通过焊接加工10个不锈钢工字形截面试件(选材包括奥氏体型S30408和双相型S22253两种),采用分割法将试件截面切分成条带,量测释放的残余应变,计算得出截面的残余应力大小与分布形态。结果表明:试件截面的残余拉应力峰值低于材料的名义屈服强度,对于奥氏体型S30408和双相型S22253两种不锈钢试件的截面残余拉应力峰值分别约为其名义屈服强度的80%和60%。基于试验结果对现有简化分布模型的评估表明其应用的局限性,提出可以较准确描述不锈钢焊接工字形截面残余应力分布的建议简化模型,结合现有的其他试验数据,对建议简化分布模型的适用范围进行了验证和推广,可以为不锈钢结构构件的稳定性研究和设计提供参考。

A total of ten stainless steel I-section specimens were fabricated by welding and prepared for this experimental study,including austenitic grade S30408 and duplex grade S22253. All the test specimens were cut into small strips by means of the sectioning method. The magnitudes and distributions of residual stresses were obtained by the measured relieved residual strains. It is revealed that the measured peak tensile residual stresses are lower than the nominal yield strengths. Specifically,the peak values of tensile residual stresses in S30408 and S22253 test specimens reach 80% and 60% of the corresponding yield strengths,respectively. Based on the obtained test results,existing distribution models were evaluated and proved to be improper for fabricated stainless steel I-sections. Newly proposed distribution models were presented and further validated by all available test data,extending their scope of application to other stainless steel alloys. The test data and the proposed distribution models can be used in research and design of structural stainless steel members.