Y-shaped groove back-chipping-free submerged-arc welding technology for moderately thick plate in boiler and pressure container

Abstract

The invention relates to a Y-shaped groove back-chipping-free submerged-arc welding technology for a moderately thick plate in a boiler and a pressure container. The technology comprises the steps that cutting and assembling are carried out before welding, particularly, a Y-shaped groove is cut in a moderately thick plate barrel through machining or flame cutting according to the plate thickness, wherein the groove gap is 0-1 mm, the root face size is 4-6 mm, and the groove angle is (60-80)+ / -5 degrees; Y-shaped groove front face submerged-arc welding bottoming is carried out, particularly, submerged-arc welding is directly adopted for carrying out welding on the front face of the Y-shaped groove, and the fusion depth is larger than 1 / 2 of the root face size in the welding process; the Y-shaped groove front face submerged-arc welding filling and facing are carried out, particularly, conventional current submerged-arc welding is used for carrying out repeated welding on the front face of the Y-shaped groove for groove front face filling and facing; and Y-shaped groove back face submerged-arc welding is carried out, particularly, submerged-arc welding is directly adopted for carrying out welding on the back face of the Y-shaped groove under the condition that back chipping is not carried out, and selection of welding parameters pays attention to control over the Y-shaped groove back face seam surplus height.

Description

technical field [0001] The invention relates to a welding process for a longitudinal circumferential seam of a medium-thick plate cylinder, in particular to a submerged arc welding process in which the longitudinal circumferential seam of a medium-thick plate cylinder of a boiler and a pressure vessel is unclear, and belongs to the field of welding technology. Background technique [0002] In the field of boilers and pressure vessels, the welding of the longitudinal circumferential seam of the medium-thick plate cylinder is an important part of product manufacturing. The traditional welding method of the medium-thick plate cylinder generally adopts the following two processes: 1) Open Y-type (or X-type ) groove, the front of the groove is welded by submerged arc welding, and the back of the groove is welded by carbon arc gouging and grinding. High; 2) Open Y-shaped (or X-shaped) grooves, the front of the grooves is welded by electrode arc welding or semi-automatic gas shield...

AI Technical Summary

Problems solved by technology

[0002] In the field of boilers and pressure vessels, the welding of the longitudinal circumferential seam of the medium-thick plate cylinder is an important part of product manufacturing. The traditional welding method of the medium-thick plate cylinder generally adopts the following two processes: 1) Open Y-type (or X-type ) groove, the front of the groove is welded by submerged arc welding, and the back of the groove is welded by carbon arc gouging and grinding. High; 2) Open Y-shaped (or X-shaped) grooves, the front of the grooves is welded by electrode arc welding or semi-automatic gas shielded welding, and then submerged arc welding is used to fill the cover, and the back does not need carbon arc gouging. Submerged arc welding is directly used for welding. Although this process does not require carbon arc gouging, it still needs to use electrode arc welding or semi-automatic gas shielded welding for bottom welding, and the efficiency is relatively low; therefore, it is urgent to develop efficient medium-thickness welding. A New Technology of Submerged Arc Welding for Unclear Root Welding

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