X7Ni9钢制LNG运输船液货舱焊接工艺及应用

Welding Process and Application of Cargo Tank for X7Ni9 Steel LNG Carrier

比较了国内外标准中9%Ni钢的化学成分和性能要求,分别采用Ni-Cr-Mo系焊条和Ni-Cr-Fe系焊条匹配国产低温调质钢X7Ni9,对焊接工艺试验结果进行分析,选定了X7Ni9同种钢以及X7Ni9与S30408异种钢相焊的焊接材料,并制定相应的焊接工艺,有效克服了X7Ni9钢焊接过程中易出现的磁偏吹、热裂纹等难点。该焊接工艺应用于国内首艘双燃料30 000 m^3LNG运输船的液货舱焊接,取得良好的效果。

The chemical composition and performance requirements of 9%Ni steel in domestic and international standards were compared,the Ni-Cr-Mo system electrodes and Ni-Cr-Fe system electrodes were used to match the domestic low-temperature quenched and tempered nickel steel X7Ni9.The welding process test results were analyzed,the welding consumables were selected for welding between same X7Ni9 steel and welding between X7Ni9 and S30408 stainless steel,and the corresponding welding process was formulated,which effectively overcame the difficulties such as magnetic blow and hot crack prone to occur in the welding process of X7Ni9 steel.This welding process was applied to the cargo tank welding of the first dual-fuel 30 000 m^3 LNG carrier in China,and achieved good results.