T23/P23钢高强匹配焊缝金属接头再热裂纹表征

Characterization of Reheat-caused Crack of T23/P23 Steel Hi-strength-matched Weld Metal Joint

综述了T23/P23钢高强匹配焊缝金属接头再热裂纹的特征。结果表明,T23/P23耐热钢高强匹配接头再热裂纹倾向明显,焊后状态高强匹配接头具有较高的强度和可以接受的塑性和韧性。接头显微组织中的HAZ粗晶区碳化物析出、晶界的滑移及晶界的脆化是再热裂纹产生的必要条件;影响HAZ组织的主要因素是母材中碳化物形成元素和残留元素的种类及含量。随接头拘束应力增大,再热温度升高时再热裂纹倾向增大。T23/P23钢接头中氢的行为是产生再热裂纹不可忽视的影响因素。生产中常用低应力化和低氢化综合工艺及参数,以及新型专用焊接材料等措施,使接头中的应力水平降低,氢含量最小化,控制再热裂纹形成条件,并获得了较满意的效果。

The characteristics of reheat-caused cracks in the high strength-matched weld metal joint of T23/P23 steel are summarized.The results show that the tendency of reheat-caused crack is obvious for the high strength matched joint of T23/P23 heat resistant steel,and the high strength matched joint in post-welded state has higher strength,acceptable plasticity and toughness.Carbide precipitation in HAZ coarse grain zone,grain boundary slip and grain boundary embrittlement in the microstructure of the joint are the necessary conditions for the generation of reheat-caused cracking;The main factors affecting the microstructure of HAZ are the types and contents of the carbide forming elements and the residual elements in the base metal.As the constraint stress of the joint increases,the tendency for reheat-caused cracks increases along with the increase of the reheat temperature.minimize the hydrogen content,the conditions for occurrence of the reheat-caused crack are properly controlled,The behavior of hydrogen in the T23/P23 steel joint as a factor affecting the occurrence of the reheat-caused crack can not be neglected.Thanks to taking actions such as adoption of low stress and low hydrogen combined process and parameters,and use of the new type specialized welding material,etc.to lower the stress level of the joint and resulting in satisfactory effect.