Position determining method for postweld heat treatment temperature equivalent points of inner walls of steel pipes with 9 percent of Cr

Abstract

The invention relates to a position determining method for postweld heat treatment temperature equivalent points of inner walls of steel pipes with 9 percent of Cr. According to the method, T groups of data of postweld heat treatment temperature equivalent points of the inner walls of pipelines with different sizes under the conditions of different heating widths, different heat preservation widths and different heat treatment ambient temperatures are calculated, and the influences of the sizes of the pipelines, the heating widths, the heat preservation widths, the heat treatment ambient temperatures and controlled temperature on positions of the equivalent points are comprehensively considered, a nerve network based on error back propagation is built, trained and tested; and trained and tested network output thresholds are revised to obtain a method for determining postweld heat treatment temperature equivalent points of the inner walls of the novel martensite heat-resistant thick-walled steel pipelines with 9 percent of Cr according to the actual measurement data of the positions of the equivalent points. By the method, the positions of the temperature equivalent points of the inner walls can be quickly determined to help guiding and opitmizing a heat treatment process, so that the heat treatment quality is improved.

Description

technical field [0001] The invention relates to a method for determining the position of the equivalent point of the temperature of the inner wall of a 9% Cr steel pipe after welding heat treatment. Background technique [0002] 9%Cr new martensitic heat-resistant steel mainly includes three new martensitic heat-resistant steels: T / P92, T / P91 and E911, which are widely used in ultra-supercritical boiler main steam pipes, headers and other thick-walled pipes and other components , low weld toughness is a major problem in the installation process of this series of steel pipeline welds. In order to improve the toughness of the weld, local heat treatment must be carried out on the weld. Researches at home and abroad have shown that the post-weld heat treatment temperature (that is, the temperature control temperature mentioned later) has a great influence on the weld. It is difficult to further improve), after a short time of constant temperature treatment, the impact energy o...

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Problems solved by technology

[0007] Another object of the present invention is to solve the existing problems in the prior art; provide a kind of 9% solution that solves the problem of wasting time and increasing costs when using experimental methods to determine the position of the equivalent point in engineering, and the experimental results do not have universal applicability. Determination Method of Equivalent Point of Inner Wall Temperature in Post-weld Heat Treatment of Cr New Martensitic Heat-resistant Steel Pipeline

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