Welding method of large-thickness plate T-shaped joint welding

Abstract

The invention provides a welding method of a large-thickness plate T-shaped joint. The welding method is suitable for the plates with the thickness larger than 30 mm. The welding method comprises thefollowing steps: welding guns are placed on the two sides of a middle plate of the large-thickness plate T-shaped joint; double-sided asynchronous backing MAG welding is adopted during backing welding; the two welding guns maintain a certain arc distance; and full penetration of a root part is achieved by increasing the heat input of the welding guns and reducing the arc distance between the welding guns so that narrow gap welding without back gauging can be realized. Double-sided synchronous filling MAG welding is adopted during filling welding, the two welding guns are synchronous, on one hand, the welding speed is increased, and on the other hand, welding angle deformation and residual stress are reduced. Due to the facts that the back gauging is not required to be carried out on a backface through a carbon gouging, corner deformation does not exist and reserved gaps are reduced, the metal filling amount of a welding seam is reduced by more than 40% compared with that of traditional welding, the one-time qualified rate of the products is improved by 40%, and the production efficiency is improved by more than 5-10 times.

Description

technical field [0001] The invention relates to a welding method, in particular to a T-shaped joint welding method for large and thick plates. Background technique [0002] my country is a big welding country but not a strong welding country. The reason is that the welding automation level is low, the production efficiency is not high, and the quality of welding products is greatly affected by the welder's technical level. With the rapid development of industrial production and market demand, more and more expensive labor costs, extensive consumption of energy and materials, and rework and scrapping of workpieces due to welding quality problems have seriously restricted the development of my country's welding industry. Especially in the field of T-joint welding of large and thick plates, the traditional manual welding of large and thick plates generally adopts asymmetric grooves, and performs pre-welding preheating, front welding, back carbon planing, and back re-welding and...

AI Technical Summary

Problems solved by technology

However, this new process is only suitable for double V-shaped grooves. In K-shaped symmetrical grooves, it is difficult to completely penetrate the root in double-pulse TIG welding, and it is easy to produce welding defects such as root fusion, incomplete penetration, slag inclusions, and pores. At the same time, a gap of 2 to 3 mm needs to be reserved in this process, which will increase the workload of joint splicing in the early stage of welding, use a large amount of welding consumables, and the reserved gap may also become smaller, which will further aggravate the lack of fusion at the root. Welding defects such as penetration, slag inclusions, pores, etc.

[0005] For this reason, in view of the problems of low assembly precision, difficult gap control, low welding efficiency and many root defects of large and thick plate T-joint joints, a high-efficiency, energy-saving, and low-consumable T-joint welding method for large and thick plates has become the subject of this paper. Technical problems to be solved urgently in the field

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