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测试了各种焊接工艺参数对SA335P91炉管全位置打底焊左右焊道交汇时小孔闭合处的热循环曲线的影响。分析结果表明,电弧在闭合小孔处停留时间thole对小孔闭合处的焊接热循环曲线主参数峰值温度Tmax和高温停留时间Δt800的影响最为显著,其次是焊接电流I,再其次是焊接速度v,而预热温度T0 的影响不明显。过长的thole和过大的焊接电流I都会导致该处结晶组织粗大,方向性强是产生结晶裂纹的主要原因。
The influence of various welding process parameters on the thermal cycling curve of the hole closed at the intersection of left and right weld of SA335P91 furnace tube with all-position backing welding was tested. The analysis results show that the influence of the residence time thole of the arc at the closed orifice on the main parameter peak temperature Tmax and the high temperature residence time Δt800 of the closed curve of the orifice is the most significant, followed by the welding current I and then the welding speed v , But the effect of preheating temperature T0 is not obvious. Excessively long thole and too large welding current I will cause the crystal structure to be coarse and the directionality is the main reason for the crystal crack.