Discussion on reheat crack tendency of heat-resistant steel joint based on slit type cranking test

基于铁研试验的耐热钢接头再热裂纹倾向探讨 Discussion on reheat crack tendency of heat-resistant steel joint based on slit type cranking test 孙咸 SUN Xian 1 first-author 太原理工大学焊接材料研究所 太原理工大学焊接材料研究所 Institute of Welding Consumables,Taiyuan University of Technology Institute of Welding Consumables,Taiyuan University of Technology 探讨了铁研试验中涉及的耐热钢接头再热裂纹倾向。结果表明,在消除应力热处理后BHW35钢的铁研试件中发现了启裂于接头根部应力集中处、沿HAZ过热区晶界扩展的、止裂于焊缝或HAZ细晶区的裂纹,其性质属于再热裂纹。接头HAZ粗晶区显微组织是再热裂纹产生的必要条件,而接头中的拘束应力和氢以及高温行为则是产生再热裂纹的充分条件。生产中常用低应力化和低氢化综合工艺及参数,以及专用焊接材料等措施,使接头中的应力水平降低,接头中的氢含量最小化,控制再热裂纹形成条件,并获得了较满意的效果。 The tendency of reheat cracks of heat-resistant steel joints involved in the slit type cracking test was discussed. The results show that the cracks which start at the stress concentration at the root of the joint,propagate along the grain boundary of HAZ overheated zone and stop at the weld or HAZ fine grain zone are found in the slit type cracking specimen of BHW35 steel after stress relief heat treatment,and their properties are reheat cracks. The microstructures of HAZ coarse-grained zone are the necessary conditions for the formation of reheat cracks,while the restraint stress,hydrogen and high temperature behavior in the joint are the sufficient conditions for the formation of reheat cracks. In order to reduce the stress level in the joint,minimize the hydrogen content in the joint,control the formation conditions of reheat cracks,the comprehensive processes such as low stress and low hydrogenation and special welding materials are commonly used in production,and more satisfactory results have been obtained. 再热裂纹 耐热钢 铁研试验 拘束应力 扩散氢 reheat crack heat-resistant steel slit type cracking test restraint stress diffused hydrogen TG457.11 2022-03-08 8 50