Welding method for marine low-temperature steel

Abstract

The invention relates to a welding method for marine low-temperature steel. The welding method comprises the following steps of: step 1, manufacturing two welding base materials made of the marine low-temperature steel, wherein a joint is in a butt welding form, and a groove is a V-shaped groove with an angle of 40-50 degrees; step 2, removing oil stains, rust and pollutants on the surface of the V-shaped groove and in a range, which is at least 20mm away from the edge of the V-shaped groove, of the upper surface and the lower surface of the welding base materials, and polishing to expose metal luster; step 3, fixing a horse plate at the lower end of the V-shaped groove, and arranging an end tab at each of the two ends of the V-shaped groove; step 4, adopting multi-layer and multi-pass welding, wherein the thickness of each layer of welding pass is 3-5mm, and the width of single-pass welding does not exceed 25mm; step 5, adopting a carbon dioxide gas shielded welding method, setting welding parameters, then welding by using the welding base materials, wherein the interlayer temperature difference is smaller than 150 DEG C, and the single-pass welding is not stopped in the midway; step 6, checking the surface quality of a welding seam, wherein the surface of the welding seam cannot have welding defects; and step 7, carrying out internal quality flaw detection on the welding seam 48 hours after the welding is ended.

Description

Technical field [0001] The present invention relates to the technical field of welding steel, particularly to a method of welding low temperature steel ship. Background technique [0002] LPG (Liquefied Petroleum Gas) ships, of LEG (liquefied ethylene gas) vessel, the LNG (liquefied natural gas) ship, service minimum temperature is about -55 deg.] C, and the tanks of the ship close to the part of the hull structure of the tank, the performance requirements for the material very harsh, often with expensive nickel alloy steel was produced as a low temperature; the use of new low carbon-manganese steel ship instead of nickel alloy steel as a low temperature can improve performance reduce construction costs; temperature steel welding processes may be from Chinese Patent application No. 200610135088.3 the invention discloses a low temperature steel weld welding process gain insight housing. The main problem is low carbon steel welding base material is generally low, and the toughness ...

AI Technical Summary

Problems solved by technology

[0003] The purpose of the present invention is to overcome the current low-temperature steel welding process for the welding of carbon-manganese series marine low-temperature steel. There is a low-temperature steel welding process for the welding of carbon-manganese series marine low-temperature steel. Low temperature, poor toughness and cold crack resistance, provide a welding method for marine low-temperature steel with low welding heat input, high welding strength, good toughness and cold crack resistance

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