A kind of induction heating device and method for welding preheating of thick-walled oil pipe

Abstract

The invention provides an induction heating device and method for welding preheating of thick-walled petroleum pipes. The induction heating device comprises a control assembly, multistage heating devices, a support, a supporting base, a lifting device, a plurality of temperature sensors, a transmission device, a driving motor, a linear push rod and a tail mounting disk. The control assembly is incommunication connection with the temperature sensors and the multistage heating devices. The method is implemented through the steps of starting the motor; adjusting the positions of the multistage heating devices; starting the first-stage heating device; starting the second-stage heating device; measuring the temperature value of points A, B, C, D, E, F and G in the wall thickness measuring direction through the temperature sensors after completion of heating; conducting data comparison between the temperature values of the seven points and the preset preheating temperature of a system to judge whether the temperature values of the seven points reach the preheating temperature; and starting the third-stage heating device to conduct heat compensation on workpieces. Through the induction heating device and method, induction heating at different frequencies of current is realized, and the preheating temperature is controlled to distribute uniformly on the edges of pipe billets to prevent generation of a too large temperature gradient.

Description

technical field [0001] The invention relates to the field of heat treatment, in particular to an induction heating device and method for welding preheating of thick-walled oil pipes. Background technique [0002] When using induction heating to realize butt welding of pipe ends, the temperature distribution gradient in the welding seam welding area is relatively large, and large residual stress is generated during the cooling process, which affects the quality of the welded pipe. In order to reduce the shrinkage stress between the weld seam and the adjacent base metal, slow down The cooling rate in the critical temperature range during the cooling process prevents excessive hardening and reduces the ductility of the weld and heat-affected zone, so that hydrogen has more time to escape from the weld and adjacent base metal, avoiding hydrogen-induced cracks, and improving Welding quality of welded pipes, in the welding process of welded pipes, it is often necessary to preheat ...

AI Technical Summary

Problems solved by technology

Flame heating with propane is a commonly used technical method in the actual production of welded pipe preheating. However, for thick-walled petroleum pipes, although the flame heating method heats evenly, it has high energy consumption, large pollution, and low heating efficiency. Started to use induction heating technology to preheat before welding

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