Study On Welding Technology Of Independent C Semi-ref. Tank

LPG Vessels are used specially to transport liquefied petroleum gas, whose tanks are important equipments. In recent years, the market demand of LPG Vessels is increasing and the ability of tanks building becomes competition focus. Until now, there are only a few countries that are able to make these special tanks in the world such as America, German, Japan, South Korea, and so on. In our country, Jiangnan Heave Industry company has mastered the whole set of techniques of tanks building, but product methods are far behind of other countries. Therefore, it is important to study how to improve welding efficiency and quality in tank building when our country takes part in the market competition.A C Semi-ref. Tank was studied in this paper which is equipped on the 6500 m3 LPG Vessel. There are two tanks, of which 1# tank is a cylinder type single tank and 2# is a double-ear type tank. The lowest operation temperature of the tanks is -104℃, and the steel material of the structure is X12Ni5. The main behaviors of this kind low temperature steel are that it can keep enough strength, plastic and impact-resistant under low temperature. When welding, However, some flaws may produced in the low temperature steel such as large crystalloids, thermal cracks, more often included slag and not fuse. By analyzing the behavior and weldablity of low temperature steel, and traditional manual welding and semi-automatic/automatic high efficiency gas protect welding and test study of other welding methods, it complete the arts and crafts assessment of welding and is certificated by classification society. The semi-automatic/automatic high efficiency gas protecting welding and transverse submerged arc automatic welding methods are developed to apply in the practical production The successful application of the welding technique in tanks made of low temperature steel material represents that the tanks building lever of our country improves a lot.