Residual Stresses in Multilayer Welds with Different Martensitic Transformation Temperatures Analyzed by High-Energy Synchrotron Diffraction
Residual Stresses in Multilayer Welds with Different Martensitic Transformation Temperatures Analyzed by High-Energy Synchrotron Diffraction
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高能同步辐射分析不同马氏体相变温度多层焊缝的残余应力
DOI：
10.4028/www.scientific.net/msf.681.37
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发表时间：
2011
期刊：
影响因子：
--
通讯作者：
J. Gibmeier
中科院分区：
文献类型：
--
作者：
A. Kromm;T. Kannengiesser;J. Altenkirch;J. Gibmeier
开发低转变温度（LTT）合金是为了控制焊缝金属冷却过程中马氏体相变产生的残余应力。这种 LTT 合金对减轻焊接过程中有害的残余拉伸应力的积极作用已经在各个实验室测试的基础上得到证实。在当前项目中，通过实验研究了在由于较厚样品的多道焊接而增加的约束下相变机制是否有效。使用能量色散同步加速器 X 射线衍射 (EDXRD) 对电弧焊加工的 V 型焊缝的局部残余应力深度分布进行非破坏性分析。使用高能（20 keV 至 150 keV）EDXRD 可以评估包含所有贡献相信息的衍射光谱。由于所研究的 LTT 合金在焊接后含有残余奥氏体，因此应力分析也考虑了该相。结果特别显示了焊接板厚度增加和附加熔敷焊缝金属的约束效应如何影响靠近焊缝表面区域的残余应力水平。虽然纵向残余应力总体上有所降低，但在从焊缝到热影响区 (HAZ) 的过渡区中发现了残余压应力。
Low Transformation Temperature (LTT) alloys were developed in order to control the residual stress development by the martensitic phase transformation already during cooling of the weld metal. The positive effect of such LTT alloys on the mitigation of detrimental tensile residual stresses during welding has already been confirmed on the basis of individual laboratory tests. Within the current project it was experimentally investigated whether the phase transformation mechanisms are effective under increased restraint due to multi-pass welding of thicker specimens. The local residual stress depth distribution was analyzed non-destructively for V-type welds processed by arc welding using energy dispersive synchrotron X-ray diffraction (EDXRD). The use of high energy (20 keV to 150 keV) EDXRD allowed for the evaluation of diffraction spectra containing information of all contributing phases. As the investigated LTT alloy contains retained austenite after welding, this phase was also considered for stress analysis. The results show in particular how the constraining effect of increased thickness of the welded plates and additional deposited weld metal influences the level of the residual stresses in near weld surface areas. While the longitudinal residual stresses were reduced in general, in the transition zone from the weld to the heat-affected zone (HAZ) compressive residual stresses were found.