Submerged arc welding process

Abstract

The invention discloses a process for carrying out submerged arc welding on two plates with thicknesses of no more than 14 mm. The process comprises the following steps: after one part to be welded forms a groove, checking an assembling clearance between the two plates and making the assembling clearance satisfy requirements, fixing a gasket on the back face of an abutted part; enabling a variable speed submerged arc welding trolley to move along a welding joint at a constant speed; controlling a welding wire to swing backwards relative to the trolley in a reciprocating way at a constant speed in the direction of the welding joint when the welding wire on the trolley moves at the constant speed with the trolley; controlling the swinging amplitude of the welding wire, so that the swinging arc of the welding wire always falls within a range of a molten pool; and adjusting the height of the welding wire so as to guarantee that an electric arc can directly act upon the root of the groove when the welding wire is positioned at a swinging arc front point. According to the invention, the desired welding current is reduced, linear energy is also reduced, the expansion stress of the welding joint is reduced and cracks are uneasy to generate on a welding joint terminal; moreover, as the two sides of the side wall of the groove can be continuously heated by the electric arc, the deposition rate is increased, the production efficiency is increased, the electric quantity and the consumption of the welding material are reduced and the production cost is reduced.

Description

technical field [0001] The invention relates to a butt welding process for plate parts whose plate thickness is not greater than 14mm. Background technique [0002] In the process of ship construction, when carrying out butt welding of plates with a thickness of less than 14mm, the general shipyard mainly adopts the following two methods: 1. Semi-automatic CO2 shielded welding. CO2 shielded welding or semi-automatic CO2 shielded welding for the first two passes and submerged arc welding for the last two passes. The advantage is that there are few cracks at the end of the weld seam. The disadvantage is that the welding process is complicated and the production efficiency is low, and the arc cannot always be on the groove side. The two sides of the wall are heated, and the arc energy is insufficient, resulting in low deposition rate; second, the FCB high-efficiency welding method (that is, double arc double molten pool submerged arc welding) is adopted. This method has no arc ...

AI Technical Summary

Problems solved by technology

[0002] In the process of ship construction, when carrying out butt welding of plates with a thickness of less than 14mm, the general shipyard mainly adopts the following two methods: 1. Semi-automatic CO2 shielded welding. CO2 shielded welding or semi-automatic CO2 shielded welding for the first two passes and submerged arc welding for the last two passes. The advantage is that there are few cracks at the end of the weld seam. The disadvantage is that the welding process is complicated and the production efficiency is low, and the arc cannot always be on the groove side. The two sides of the wall are heated, and the arc energy is insufficient, resulting in low deposition rate; second, the FCB high-efficiency welding method (that is, double arc double molten pool submerged arc welding) is adopted. This method has no arc light, less smoke and dust, and high production efficiency during the welding process, but It must be powered by dual power supplies, and the current is relatively large. The increase in current and the heat preservation effect of the flux lead to an increase in line energy (line energy = current * voltage / welding speed), which in turn increases the expansion stress of the weld, and eventually leads to welding. Cracks are easy to occur at the end of the seam, and for a plate with a thickness of 14mm, because the length of the arc is generally 3mm, it cannot reach the entire depth of the weld (14mm) at one time, so this method uses four-layer welding, and the weld is divided into four layers. Welding to achieve the welding effect, in addition, a large increase in power consumption will also lead to an increase in production costs, which is not good for shipyards