压力容器D类焊缝的焊接工艺评定

Welding Process Evaluation of D-type Weld for Pressure Vessels

为了评价压力容器D类焊缝的焊接工艺,采用钨极氩弧焊(TIG)和手工电弧焊(SMAW)对厚度32 mm的Q345R钢板进行焊接工艺试验,通过外观检查、无损探伤、拉伸试验、弯曲试验、冲击试验等方法检测了Q345R钢的焊接接头的性能。结果显示:在制定的焊接工艺参数下,焊接接头射线探伤为I级;在焊后620℃保温3 h消应力热处理后,焊接接头抗拉强度高于Q345R钢抗拉强度的下限值(500 MPa);焊缝和热影响区-20℃冲击功达到95 J以上,满足标准要求;侧弯试样弯曲面焊缝和热影响区没有萌生裂纹,满足NB/T 47014—2011标准要求;焊缝组织为块状铁素体+少量珠光体,珠光体均匀分布于铁素体的晶界处。评定结果表明,TIG+SMAW焊接工艺合理,可满足该压力容器D类焊缝的焊接质量要求。

In order to evaluate the welding technology of D-type weld of pressure vessel, TIG welding and SMAW were used to test the welding technology of 32 mm Q345R steel plate. The performance of the welded joint of Q345R steel was tested by means of appearance inspection, nondestructive testing, tensile test, bending test and impact test. The results show that the radiographic inspection of welded joints is grade I under the specified welding process parameters.After thermal treatment at620 ℃ for 3 h, the tensile strength of the welded joint is higher than the lower limit(500 MPa) of the tensile strength of Q345R steel. Impact energy of weld and HAZ at-20 ℃ reaches more than 95 J meeting the standard requirements. There is no crack initiation in the weld and heat affected zone of the bending surface of the lateral bending sample, which meets the requirements of NB/T 47014—2011. The weld is composed of massive ferrite and a small amount of pearlite, and the pearlite is evenly distributed at the grain boundary of ferrite. The results show that the welding process of TIG welding+SMAW is reasonable and can meet the welding quality requirements of D-type welds of pressure vessels.