Method for welding thick steel plates through single-wire electrogas welding machine

Abstract

The invention discloses a method for welding thick steel plates through a single-wire electrogas welding machine. The method is characterized by including the following steps of pre-welding preparation, welding and post-welding heat treatment. The post-welding heat treatment method includes the steps of placing workpieces in a furnace with the furnace temperature not higher than 300 DEG C, heating the workpieces to the temperature of 625+ / -20 DEG C at the heating rate of 65 DEG C / h, keeping the temperature of 625+ / -20 DEG C for six hours, then cooling the workpieces to below 300 DEG C at the rate of 65 DEG C / h, discharging the workpieces out of the furnace and cooling the workpieces in still air. At the macroscopic level, arc breaking does not occur in the welding process, smooth and attractive surfaces of weld joints are formed, and follow-up fusion transition of weld metal of the weld joints and wood has not defect except for incomplete fusion at arc striking ends. Cutting and sampling analysis on weld joints of test pieces for welding shows that mechanical properties of the weld joints are higher than those of parent metal, the hardness of the part, in the heat affected zone, of the parent metal is lower than that of the weld joints and slightly higher than that of the part, outside the heat affected zone, of the parent metal; the front weld joints and the back weld joints have the same forming width.

Description

technical field [0001] The invention belongs to the field of welding technology, in particular to a method for welding thick steel plates using a single-wire gas-electric vertical welding machine. Background technique [0002] With the rapid development of my country's economic construction, thick steel plate steel structure welding has appeared in large numbers in metallurgy, shipbuilding, petrochemical, water conservancy and other industries. For the vertical seam welding of steel plates with a thickness of 60-100 mm (or even thicker), there is no high-quality and efficient welding method and related equipment. It is difficult to solve this problem with electrode arc welding, although electroslag welding can solve this problem. , for example, the application number is 201010180014.8, and the invention name is the patent of the welding method of the thick plate butt joint. One step, pre-welding preparation: add a variety of iron alloy elements to the tube coating formula t...

AI Technical Summary

Problems solved by technology

[0005] The purpose of the present invention is to provide a thick steel plate vertical seam welding method for the vertical seam welding of thick steel plate steel structures. Difficulty in welding