奥氏体不锈钢复合板采用SAW焊接基层的焊接工艺研究

通过对S30408+Q245R复合板基层进行SAW焊接接头显微硬度测量、铁素体含量测量、金相显微镜观察等研究,探讨焊接线能量、冷却速度对复合板基层焊缝组织和母材覆层析出σ相的影响。研究结果表明,基层使用SAW焊接时,焊缝硬度比使用SMAW焊接时略低;母材覆层铁素体含量、焊缝过渡层/覆层铁素体含量均比基层使用SMAW焊接时所测含量略低;两种焊接方法的焊缝基层显微组织基本相同。但焊缝覆层/过渡层采用SMAW和GTAW焊接时金相组织有所不同,使用SAW焊接基层时焊缝组织无明显晶粒粗大特征,且母材覆层和焊缝过渡层/覆层均不会析出σ相。

Study on welding technology of austenitic stainless steelcomposite plate by submerged arc welding

The microhardness measurement, the ferrite content measurement and the metallographic microscopic observation of SAW (submerged arc welding) welding joint of S30408 + Q245R composite board were carried out. Through these studies, the influence of welding line energy and the cooling rate on the microstructure of welding in the composite board base layer and the precipitation of the σ phase in the parent metal coating was discussed.Results showed that when using SAW welding in the base layer, the weld hardness was slightly lower than that of welding with SMAW (shielded metal arc welding) and the ferrite content in the base metal coating and that in the weld transition layer/coating were both slightly lower than those measured by SMAW in the base layer. The metallurgical structures of the weld layer of the two welding methods were basically the same. But the microstructure of weld coating/transition layer were different when using SMAW and GTAW (gas tungsten arc welding）. when using SAW in weld base layer, the weld microstructure has no obvious coarse grain characteristics, and neither parent metal coating nor the weld transition layer/coating would make the precipitation of σ phase happen.