Primary and secondary induction heating local heat treatment method

Abstract

The invention relates to the technical field of heat treatment, and provides a primary and secondary induction heating local heat treatment method. This method combines the main and auxiliary heating with induction heating. By welding thermocouples, laying insulation blankets and induction cables in the main and auxiliary heating areas, the induction power is used to heat the main and auxiliary heating areas. According to the main heating process curve, the main Heat treatment in the heating zone. After the main heating zone cools down to room temperature, remove the induction cable and insulation blanket in the main heating zone, heat up the secondary heating zone, and perform heat treatment on the secondary heating zone according to the secondary heating process curve to realize the local heat treatment of the primary and secondary induction heating. The invention not only improves the mechanical properties and microstructure of the weld area, but also greatly reduces the welding residual stress, and generates smaller tensile stress or even compressive stress on the inner surface of the heat treatment object, and realizes the quantitative control of the residual stress level of the heat treatment object , which effectively solves the problem of poor local heating uniformity and difficulty in precise temperature control of heavy equipment with super-diameter and super-thickness.

Description

technical field [0001] The invention relates to the technical field of heat treatment, in particular to a local heat treatment method for primary and secondary induction heating. Background technique [0002] Heavy-duty hydrogenation reactors and over-limit towers are the core equipment of the petrochemical industry, and their successful manufacture reflects the overall technical level of the country in a certain sense, and is a symbol of my country's "big country heavy equipment". For such core equipment, domestic and foreign standards require the use of heat treatment to eliminate welding residual stress. At present, with the development of large-scale pressure vessels, due to the limitation of the diameter and length of the pressure vessel itself, it is impossible to perform overall heat treatment. Welding seams are produced during the assembly process, and only partial heat treatment can be performed. After a large number of tests and calculations, it was found that th...

AI Technical Summary

Problems solved by technology

[0003] Aiming at the problem that it is difficult to eliminate the residual stress on the inner wall of the container by the local heat treatment recommended by the current standards and it is difficult to achieve temperature uniformity when locally heating the ultra-large diameter and ultra-thick container, the present invention proposes a primary and secondary induction heating local heat treatment method. Combination of auxiliary heating and induction heating, using primary and auxiliary heating to improve the mechanical properties and microstructure of the weld area, greatly reducing the residual stress of the weld, and generating small tensile stress or even compressive stress on the inner surface of the heat treatment object, which is realized by induction heating Heating and precise temperature control of ultra-thick containers

Images