LNG船用超低温阀门密封面堆焊工艺

LNG船用超低温阀门因其特殊的使用环境,需要在阀门密封面上堆焊钴基合金。通过2种材料、4种规格的工艺评定,提供1种GTAW堆焊和4种PTA堆焊工艺,对比发现GTAW比PTA焊接变形大、耗时长,但稀释率更低,两者焊后焊缝熔合区硬度测试值均与焊材相近,化学成分与焊材差别不大。该研究对实现LNG船用超低温阀门的国内自主化、批量化生产具有实践意义。

Surfacing Welding Process for Sealing Surface of LNG Marine Cryogenic Valve

Due to the special service environment of LNG marine cryogenic valve, it is necessary to surface the cobalt-base alloys on the sealing surface. Through the process qualification of two kinds of materials and four kinds of specifications, one kind of GTAW surfacing welding process and four kinds of PTA surfacing welding processes are provided. By comparison, GTAW welding deformation is larger than PTA, and GTAW welding time-consumption is longer, but GTAW welding dilution rate is lower; the hardness test values in weld fusion zone of GTAW welding and PTA welding after welding are similar to that of welding material, and their chemical composition is not much different from that of welding material. This research is of the practical significance for realizing the domestic independent and mass production of LNG marine cryogenic valve.