Three-layer drainage cover for underwater local dry type low-pressure welding and method for obtaining low pressure

Abstract

The invention provides a three-layer drainage cover for underwater local dry type low-pressure welding and a method for obtaining low pressure. The three-layer drainage cover for underwater local drytype low-pressure welding comprises the three-layer water drainage cover body, a welding system, a drainage system, an exhaust system, a cooling circulation system and a preheating system. By the adoption of the designed three-layer water drainage cover body, under the jointed action of multiple grades of pressurizing water pumps and pressurizing air pumps which are in full-automatic unified intelligent control, water in a welding local space and preheating space are forced to be discharged, forced air exhaust and forced smoke exhaust are conducted at the same time, and therefore a dry type normal pressure or low pressure area is formed in the welding local space; an electric arc stably combusts in the dry type normal pressure or low pressure area, the welding process is stable, the problems of weld joint metal hardening, high hydrogen content and the like are avoided, a connector or additive manufacturing product with the welding quality similar with the welding quality on the land oreven reaching high quality in a low pressure environment are formed. The three-layer drainage cover can be used for severe underwater environments of low visibility, large water flow velocity, industrial reaction solutions nuclear radiation and the like, can be used for butt welding, angle welding, groove welding, overlaying welding, spray welding, thermal spraying and additive manufacturing.

Description

technical field [0001] The invention relates to the fields of welding and thermal spraying, and relates to a three-layer drainage cover for underwater local dry low-pressure welding and a method for obtaining low pressure; in particular, it relates to a three-layer drainage for underwater local dry low-pressure welding / additive manufacturing Hood device and method for obtaining low pressure for welding, thermal spraying, additive manufacturing process by reducing the pressure of the underwater environment of welding, thermal spraying, additive manufacturing to normal pressure or low pressure, and in a dry environment The stability of the welding metallurgical process is optimized, and the quality of welded joints and additively manufactured parts is improved. Background technique [0002] The development of offshore oil and natural gas resources has developed from small-scale mining on the western coast of the United States before World War II to large-scale development on a...

AI Technical Summary

Problems solved by technology

[0004] At present, the underwater local dry welding method still has some shortcomings: (1) The welding area is in a high-pressure state, it is difficult to start the arc, and the arc is easy to extinguish; (2) The cooling speed of the weld pool is too fast, and it is easy to produce hardened structures , high hydrogen content; (3) welding droplet transfer is difficult, resulting in arc instability

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