Back chipping-free butt plate submerged-arc welding method

Abstract

The invention relates to the field of steel plate flat butt welding, and particularly discloses a back chipping-free butt plate submerged-arc welding method for a medium plate of 14-35 mm. The back chipping-free butt plate submerged-arc welding method comprises the following steps: designing grooves with less weld passes; performing positioned welding according to requirements; adopting an ultralow frequency pulse submerged-arc welding method to control a current, a voltage and a wire feeding rate; combined with the specific technological parameters and technical parameters to realize the back chipping-free submerged-arc welding of the I-shaped grooves in the plate thickness of 10-25 mm and back chipping-free large truncated edge (15-18 mm) welding for the plate thickness of 25 mm above, so as to realize the automatic submerged arc welding technology for the front and the reverse side of the plate within the plate thickness range. According to the back chipping-free butt plate submerged-arc welding method disclosed by the invention, the pulse parameters of the welding current and the welding voltage are provided, the variable speed wire feeding of a wire feeding motor is combined, the arc is directly acted on the metal at the bottom of the molten bath, the convection of the metal in the large molten bath is enhanced, the impurities are facilitated to be separated out, and the molding of the root of weld can be ensured; the back chipping-free butt plate submerged-arc welding method is favorable to reduction of welding heat input, improvement on the welding quality and reduction of welding deformation.

Description

technical field [0001] The invention relates to the field of flat butt welding of steel plates, in particular to a method for submerged arc welding of 14-35mm medium and thick plates without root cleaning. Background technique [0002] In the welding of ships and steel structures, the following processes are generally used in the welding of the centering plate: V-shaped grooves without blunt edges or small blunt edges, or asymmetric double V-shaped grooves with small blunt edges , after the front side is grounded by gas shielded arc welding, the cover surface is filled by submerged arc welding, and then the back is gouged to clear the root, the bottom is sealed by gas shielded arc welding, and the submerged arc welding is used to fill and cover the surface. The disadvantage of this process is that the filling metal of the V-shaped groove is relatively heavy Many; the process is cumbersome, multi-layer multi-pass welding increases the occurrence of defects; the reverse root c...

AI Technical Summary

Problems solved by technology

However, this kind of process requires high equipment, and the ceramic liner is added on the reverse side. It is necessary to place special tooling to place the steel plate to be welded before the ceramic liner can be pasted. The deformation of the steel plate in this process is relatively large.

[0004] The current submerged arc welding of the butt plate is free of bottoming and root cleaning, and the process of less weld bead adopts the process of suspended double-sided welding, leaving a gap of 4-5mm, and adding flux pads on the reverse side. This process can also expand the clean-free process of the butt plate. The plate thickness range of the submerged arc welding process is basically free, but this process inevitably has the following disadvantages. First, such a 4-5mm gap is difficult to control. After spot welding, the steel plate cannot turn over, so during the welding process, the point The quality of the welding position is unstable, and adding flux pads on the reverse side requires special tooling, and consumes a lot of flux; due to the large gap on the reverse side, the molten pool is held by the flux during the welding process, thus forming a molten layer at the root of the front weld seam that is not easy to remove. Slag, which increases the difficulty of melting the root of the front weld bead, and also increases the possibility of non-fusion defects

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