Method for calculating position of highest temperature point of postweld heat treatment of 9-12% Cr martensitic heat-resistant steel vertical arrangement pipeline

Abstract

The invention relates to a method for calculating position of highest temperature point of postweld heat treatment of a 9-12% Cr martensitic heat-resistant steel vertical arrangement pipeline. The method provided by the invention is characterized by comprising the following steps that 1, a theoretical highest temperature point calculation module is used for establishing T groups of calculation models of postweld heat treatment temperature fields of the 9-12% Cr martensitic heat-resistant steel vertical arrangement pipelines with different sizes under different heating widths, different heat preservation widths, different heat treatment environment temperatures and different heat treatment temperatures on the basis of a heat transfer theory, and calculating the position of the highest temperature point of heat treatment under corresponding conditions through a finite element analysis method; 2, a BP neural network model module; 3, a prediction model creating module; 4, a model correcting module; 5, a highest temperature point determining module. The method provided by the invention can be used for conveniently and quickly calculating the position of the highest temperature point of the post weld heat treatment of the 9-12% Cr martensitic heat-resistant steel vertical arrangement pipeline.

Description

technical field [0001] The invention relates to a calculation method for the position of the highest temperature point of post-weld heat treatment of pipelines, in particular to a calculation method for the position of the highest temperature point of post-weld heat treatment of pipelines vertically arranged in 9-12% Cr martensitic heat-resistant steel, which can be convenient and fast Calculate the position of the highest temperature point of post-weld heat treatment for vertically arranged pipes of 9-12% Cr martensitic heat-resistant steel. Background technique [0002] 9-12%Cr martensitic heat-resistant steel is widely used in ultra-supercritical boiler main steam pipes, headers and other thick-walled pipes. The low weld toughness is a problem that occurs during the installation of welds in this series of steel pipes. main problem. 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 show...

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Problems solved by technology

Therefore, during on-site construction, the local temperature may exceed the Ac1 point and the heat treatment effect cannot be achieved.

Although the center of the heating zone can be offset to the lower side of the center of the heating zone in order to compensate for the inconsistent energy loss caused by the internal air flow during construction, there is still no standard specification for how to select the offset of the heating zone. It is mostly selected based on experience, and the site construction urgently needs to know the position of the highest temperature point of heat treatment, so that it is convenient to install thermocouples for temperature monitoring

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