摘要
Abstract
Defects such as deformation,porosity,cracks,incomplete penetration,etc.are easy to occur in the welding of alu-minum plate on the ceiling of LNG storage tank.Especially the fillet weld between the thirteenth ring stiffener and the ceil-ing bottom plate.According to the design structure of the aluminum ceiling of 220 000 m3 LNG storage tank,the key points of quality control in the welding process of the aluminum ceiling are elaborated in detail:using argon gas shielded metal arc welding,the gas should be supplied in advance when starting and closing the arc,and continue to supply gas after closing the arc to prevent the molten metal from oxidation and avoid repeated arc starting at the same time;When the welding cur-rent is 160～170 A and the welding speed is 38～40 cm/min.When the wire filling speed is 38～40 cm/min and the shielding gas flow rate is 20～25 L/min,the weld of aluminum ceiling is well formed.At least two passes shall be welded at the over-lapping position,and the sectional withdrawal welding or symmetrical welding method shall be adopted,and the load bear-ing on both sides of the pass shall be appropriately increased to achieve the purpose of controlling welding deformation.The quality control measures of aluminum ceiling welding are optimized from the aspects of"man,machine,material,method and environment".关键词
LNG储罐/铝吊顶/焊接缺陷/质量控制Key words
LNG storage tanks/aluminum ceiling/welding defects/welding quality分类
矿业与冶金
