Submerged arc welding method for K-shaped groove of 80mm extra-thick steel plate with excellent plate shape after welding

Abstract

The invention discloses a submerged arc welding method for a K-shaped groove of an 80mm extra-thick steel plate with an excellent plate shape after welding. The method comprises the following steps of: taking a K-shaped symmetrical groove machined by machinery as the groove type, wherein a truncated edge is not remained at the root, and the assembling clearance of the groove is 2-3mm; performing backing welding on a front root weld pass of a K-shaped groove test plate by adopting a solid gas shield welding wire during backing welding, so that partial weld metal penetrates through the reverse side of the groove after the root weld pass is penetrated, the backing welding is finished, and employing mixed gas protection of argon and carbon dioxide during welding; performing positive submerged arc welding after backing welding is finished, turning over and performing back chipping while welding to 2 / 3 depth of the groove, performing reverse submerged arc welding until the reverse welding line is totally filled, and finishing welding of the residual 1 / 3 depth on the positive side after the welding on the reverse side is completely finished. The method is easy and convenient to operate, the turn-over frequency is reduced, the labor intensity is reduced, the working efficiency is improved, the residual deformation of a soldering block is small, and the welding quality is high.

Description

technical field [0001] The invention relates to a welding process technology of an extra-thick steel plate, in particular to a submerged arc welding method for a K-shaped groove of an 80mm extra-thick steel plate with excellent plate shape after welding. Background technique [0002] The extra-thick plate is welded by submerged arc automatic welding, which can not only improve labor efficiency, reduce labor intensity, improve the working environment, save resources, but also reduce labor costs. However, submerged arc automatic welding of extra-thick plates is prone to defects such as pores, cracks, slag inclusions, incomplete fusion, and incomplete penetration. The most important disadvantage is that the welding deformation is not easy to control, and the main cause of the welding deformation is the welding residual stress caused by the uneven temperature field generated by welding. There are two main factors affecting welding stress and deformation, one is the range and de...

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Problems solved by technology

[0003] Due to the high rigidity of the extra-thick steel plate structure, the cooling speed after welding is fast, and the weld seam is subject to greater restraint, so the residual stress on the weld seam is also large, which is prone to large deformation, resulting in poor plate shape after welding

[0004] The Chinese patent application number is 201110435335.2, and the patent publication number is 102554416A describes a submerged arc welding method for thick plates with asymmetric K-groove, but the thickness of the plate is only 60mm, and the asymmetric K-groove is prone to welding out of shape

The Chinese patent application number is 201010579763.8, and the patent publication number is 102000901A describes the submerged arc welding method of 100mm thick E36 steel plate, but the X-shaped groove is used, and the machining of the groove is more complicated than that of the K-shaped groove, and the patent directly Submerged arc welding is used to make the bottom, but the blunt edge of the groove is too small, and it is very easy to weld through when directly performing submerged arc welding with a large heat input. It is not suitable for K-shaped grooves without blunt edges. The method described in the patent needs to turn over the plate at least 4 times for submerged arc welding, and the labor intensity is high

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