Low-back-pressure penetration electric arc welding device and method

Abstract

The invention relates to a low-back-pressure penetration electric arc welding device and method. The central negative-pressure cavity of a low-back-pressure protection device is subjected to air extraction treatment by using an air extracting device, tail flame of penetration electric arc positioned in the central negative-pressure cavity and the back side of a keyhole pool are in a negative-pressure state of an argon atmosphere, and a pressure gradient pointing from the front side to the back side of a keyhole pool is formed on the keyhole pool, so that the stiffness and electric arc stability of the penetrating electric arc on the front side of the keyhole pool are further enhanced, and the penetrating capability of the penetrating electric arc is improved on the premise of not changing the front side stress distribution and the temperature gradient of the keyhole pool. By adopting the welding device and the method, the weldable thickness of the conventional penetrating electric arc welding process is increased greatly, and the welding line back side shaping of penetration welding is improved by maintaining the negative-pressure state on the back side of the keyhole pool.

Description

technical field [0001] The invention relates to a low back pressure penetrating arc welding device and method, belonging to the field of welding technology. Background technique [0002] With the development of modern industry towards large-scale structures, the welding structure of medium and ultra-thick plates is more and more widely used. Therefore, the requirements for welding methods are also getting higher and higher. Traditional welding methods have been difficult to meet such requirements. welding requirements. For the manufacture of thick-walled metal structures such as pressure vessels, boilers, rails, ships, and large-scale engineering construction site operations, a large number of thick-plate joints generally use large-groove multi-layer multi-pass MAG / MIG welding or submerged arc welding. With the continuous increase of plate thickness, the above methods have shown great limitations and inapplicability. The most prominent performance is that due to the sharp ...

AI Technical Summary

Problems solved by technology

However, as the thickness of the welded plate increases, the requirements for the penetration ability of the plasma arc are also higher and higher, and the tendency of small hole instability increases. It is extremely important to find a better balance between heat input and stable forming of small holes. Difficult, when the thickness of the workpiece to be welded reaches a certain value, the plasma arc will not be able to penetrate the workpiece to be welded

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