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我单位在给山东某石化企业设计和制造管路补偿器时,考虑到其最高工作温度是380℃左右,工作压力为160MPa,因而设计的补偿器除波纹管用SUS304材料外,其它如法兰盘、端管等各零部件全部选用15CrMo这种耐热材料。15CrMo钢的合金成分较多,焊接工艺较复杂,并且所选用的R307焊条工艺性不好、表面成形较差、易咬边,特别是在角焊时,咬边现象更严重。针对以上情况,笔者根据实际工作经验制定了一种较简单的焊接工艺方法。1 软层焊接工艺 由于焊件体积较大（长约2m,管径为φ700mm）,整体预热较困难,为此我们采用了局部预热及焊后保温措施,并采用了一种新的焊接工艺——软层焊接工艺。所谓软层焊接就是内层采用与母材等强的焊条焊接,而表面2～6mm采用略低于母材强度（约达到母材强度的0.82）的焊条,以增加焊缝的塑性储备,降低拘束应力,从而提高了焊缝的抗裂性能。据此,我们采用R307作为内层焊条,A022作为盖面层焊条。2 焊接工艺 （1）选用R307焊条和A022焊条,直径均为φ4mm。焊条在焊前需经过（350～400）℃烘干,时间为1～2h,
When I was designing and manufacturing a pipe compensator for a petrochemical enterprise in Shandong, my unit considered that the maximum working temperature was about 380 ℃ and the working pressure was 160MPa. Therefore, the designed compensator except the SUS304 material for bellows, , The end of the pipe and other components all use 15CrMo this heat-resistant materials. 15CrMo steel alloy composition, the welding process is more complex, and the selected R307 electrode technology is not good, the surface forming poor, easy to undercut, especially in fillet welding, undercut phenomenon more serious. In view of the above, the author based on actual work experience developed a simpler welding process. A soft layer welding process Due to the large size of the weldment (about 2m, diameter φ700mm), the overall preheating is more difficult, for which we have adopted a partial preheating and post-weld insulation measures and the use of a new welding Process - Soft layer welding process. The so-called soft-layer welding is the inner layer with a base metal and other strong welding electrodes, and the surface of 2 ~ 6mm slightly lower than the base metal strength (about 0.82 base metal strength of the electrode) to increase the plastic weld reserves, lower Constrain the stress, thereby improving the weld crack resistance. Accordingly, we use R307 as the inner electrode, A022 as the cover electrode. 2 welding process (1) Selection of R307 electrode and A022 electrode, the diameter is φ4mm. Before welding electrode to be through (350 ~ 400) ℃ drying time is 1 ~ 2h,