Method and device for improving underwater wet welding joint structure property

Abstract

The invention relates to the technical field of welding, and particularly relates to a method and a device for improving an underwater wet welded joint structure property. The method comprises the step that a welded sample is welded underwater through a welding torch and the step that weld preheating before welding and / or heat treatment after welding is conducted on the welded surface of the welded sample. Corresponding devices comprise an underwater welding power supply, the welding torch connected with the underwater welding power supply, the welded sample and a welding water groove arranged outside the welded sample. An induction heating coil is arranged on the upper surface of the welded sample and is controlled by an induction heating power supply. By adopting the method and the device for improving the underwater wet welded joint structure property, when heat treatment is effectively conducted on the welded sample, weld joint cooling speeds can meanwhile be slowed down, and accordingly the effects of reducing wet welding defects such as the number of weld joints, quenched structures of heat affected zones and cold crack inclination. Therefore, the method and the device for improving the underwater wet welded joint structure property are convenient to operate.

Description

technical field [0001] The invention relates to the field of welding technology, in particular to a method and a device for improving the structure and performance of underwater wet welding joints. Background technique [0002] As an important construction technology of marine steel structure, underwater welding has become an indispensable engineering method for marine energy development, ship maintenance, marine engineering construction and repair. Over the past few years, with the country's vigorous development of water conservancy and hydropower projects and the deployment of dangerous reservoir reinforcement projects, the maintenance and repair of underwater steel structures are also in great need of this underwater welding technology. [0003] Compared with other underwater welding methods, wet underwater welding has the following advantages: ①It can be directly used in underwater welding environment. ② No other auxiliary equipment is needed, and the movement is conven...

AI Technical Summary

Problems solved by technology

Affected by the evaporation of water vapor, compared with land welding, the cooling rate of the welding pool is about 10-15 times that of land welding, so the crystallization speed of the welding pool is accelerated, and the content of diffusible hydrogen is higher, which will lead to pores The occurrence of welding defects such as cold cracks and cold cracks will reduce the serviceability and fatigue resistance of the welded structure; the influence of the oxidizing atmosphere will increase the burning loss of alloying elements and remain in the weld in the form of non-metallic inclusions, thus Reduce the mechanical properties of welded joints

This brings a series of adverse effects to underwater welding

[0005] In order to solve the problem of excessive cooling of the welding zone during underwater wet welding, researchers have used welding bead plus insulation layer, weld seam tempering technology (multi-layer multi-pass welding) or the method of using thermite electrode to carry out underwater welding. Wet welding, although it slows down the cooling rate of the weld to a certain extent, the effect is not obvious and the efficiency is not high

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