Flash butt welding process for high-pressure boiler pipeline

Abstract

The invention provides a flash butt welding process for a high-pressure boiler pipeline. The flash butt welding process comprises the steps of 1) selecting a pipeline material, namely #20 carbon steel, having the diameter of 219mm and the wall thickness of 14-16mm, 2) pretreatment before pipeline welding, 3) pipeline clamping, 4) setting welding parameters, namely extension length of 75-85mm, flash allowance of 21-24mm, upset allowance of 4-7.5mm, flash starting speed of 0.16-0.30mm / s, flash stopping speed of 1.15-1.55mm / s, flash current of 4.8-7.2kA, upset speed of 30-35mm / s, upset force of 9.5-11MPa, charged upset time of 0.1-0.5s and clamping force of 11-12MPa, 5) weld joint burr removal. The flash butt welding process for the high-pressure boiler pipeline is short in welding time and high in welding efficiency; the joint quality is satisfied; the erection welding of the boiler pipeline is developed into more efficient flash butt welding technique from argon arc welding plus gas shield welding; in short, the flash butt welding process has wide application prospect.

Description

technical field [0001] The invention relates to a welding process method, in particular to a flash butt welding process method for high-pressure boiler pipes. Background technique [0002] In the butt joint construction of high-pressure boiler pipes, the main welding method currently used is "argon arc welding + gas shielded welding". When this method welds large-diameter and thick-walled pipes for high-pressure boilers, it is required that the pipes be evenly aligned throughout the circumference; the groove type needs to be a composite or U-shaped groove, which increases the welding construction procedure, low production efficiency, and high production costs. However, the advanced flash butt welding technology has very low requirements on the pipe groove, and can be welded and formed at one time without welding consumables. The welding time is short, the production efficiency is high, and the production cost is greatly reduced. [0003] In foreign countries, especially the...

AI Technical Summary

Problems solved by technology

However, flash welding process parameters include extension length, flash allowance, upsetting allowance, flash current, flash speed, upsetting speed, upsetting pressure, clamping pressure, secondary no-load voltage, etc. The parameters are complex and changeable , every time the material is changed or the cross-sectional area of ​​the butt joint changes, the welding process parameters need to be re-selected and optimized

The pipeline flash welding process disclosed above is either aimed at large-diameter and thick-walled pipelines for long-distance oil and gas transportation, or for small-diameter thin-walled pipelines for low-pressure boilers, and cannot be used for large-capacity high-pressure boilers. No. carbon steel pipe flash butt welding, the process needs to be redeveloped, but no relevant reports have been seen so far

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