Large-gap argon arc welding bottom sealing repair method for carbon steel pipeline and container

Abstract

The invention discloses a large-gap argon arc welding bottom sealing repair method for a carbon steel pipeline and a container. The method comprises the steps of welding defect positioning, defect excavation, groove grinding, groove penetration flaw detection, welding seam fixing, pre-welding preheating, argon arc welding bottom sealing, electrode arc welding filling, capping, post-welding heat treatment and nondestructive testing. According to the welding method, a welding process is combined with two different welding methods including argon arc welding and manual arc welding, and a specialwelding bottom sealing mode is adopted, so that high-quality welding seams can be obtained even facing extremely difficult-to-be-treated large-gap welding seams at the root of the pipeline and the container in the welding repair; and due to the fact that a metallographic structure is fine, the welding seam, a fusion area and a heat affected area are high in impact toughness, the crack tendency issmall, and the service life of a welding joint is prolonged.

Description

technical field [0001] The invention relates to a large-gap argon-arc welding bottom-sealing process, which is applicable to the fields of pipeline, container welding, etc., and in particular relates to a method for repairing the bottom-sealing of carbon steel pipelines and containers by large-gap argon-arc welding. [0002] technical background [0003] During the construction and installation of carbon steel pipes and containers, due to assembly errors, sometimes the phenomenon of excessive gaps occurs, resulting in increased root gaps; after welding, the welds of carbon steel pipes and containers are detected to have excessive defects at the root, and repairs are carried out. tend to be wider. [0004] For carbon steel and large-gap argon-arc welding bottom-sealing welding with penetrating defects in container pipes, the two sides of the root of the groove are generally used as the base point for swing welding. In the affected area, the grains are coarse, the plasticity a...

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Problems solved by technology

[0003] During the construction and installation of carbon steel pipes and containers, due to assembly errors, sometimes there is a phenomenon that the gap is out of tolerance, resulting in an increase in the root gap; tend to be wider

[0004] For carbon steel and large-gap argon-arc welding bottom-sealing welding with penetrating defects in container pipes, the two sides of the root of the groove are generally used as the base point for swing welding. In the affected area, the grains are coarse, the plasticity and toughness are poor, and cracks are easy to occur; the upper back of the weld is easy to form welding nodules, and the lower back is easy to form concave, and the geometric shape of the inner wall changes suddenly, which has an adverse effect on the flow of the internal medium.

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