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以10 mm的Q345B钢板为母材,开Y型坡口,使用等离子-MAG复合焊方法,进行单层单道焊接。对焊接接头进行无损检测,未发现裂纹、气孔、夹渣等缺陷。分析焊接接头的显微组织,焊缝区主要由铁素体和珠光体构成,先共析铁素体沿柱状晶界析出,晶内主要是针状铁素体和珠光体的混合物;焊接热影响区较窄,组织形态变化明显但晶粒尺寸有所改善。硬度试验显示,焊缝和热影响区的硬度高于母材。对焊接接头进行拉伸、弯曲和冲击等力学性能测试,结果表明,采用等离子-MAG复合焊接方法得到的接头强度和韧塑性良好。
A 10 mm Q345B steel plate as the base material, open the Y-groove, the use of plasma-MAG composite welding method for single-layer single-pass welding. Non-destructive testing of welded joints, found no cracks, pores, slag and other defects. The microstructure of welded joint was analyzed. The weld zone mainly consisted of ferrite and pearlite. Pre-eutectoid ferrite was precipitated along the columnar grain boundary. The intragranular mixed ferrite and pearlite were the main part. The welding heat The affected area is narrower and the morphological changes are obvious but the grain size is improved. Hardness tests show that the weld and HAZ have higher hardness than the base metal. The mechanical properties of the welded joints such as tensile, bending and impact tests were tested. The results show that the joint strength and toughness obtained by the plasma-MAG composite welding method are good.