Optimal calculation method for post-weld heat treatment heating rate of 9% cr heat-strength steel pipeline

Abstract

The invention discloses an optimization calculation method for the post-weld heat treatment heating rate of a 9% Cr hot-strength steel pipeline, including establishing a post-weld heat treatment temperature field model of the 9% Cr hot-strength steel pipeline; parameters; based on the obtained heat treatment parameters, a prediction model of the heating rate of the 9%Cr hot-strength steel pipe is established; based on the requirements of the radial temperature gradient of the pipe, the heating rate is selected through the prediction model of the heating rate of the 9%Cr hot-strength steel pipe. The invention can calculate the maximum heating rate of post-weld heat treatment of 9% Cr heat-strength steel pipes of different specifications according to the requirements of heater power and construction period, and can be used to guide P91, P92, E911, G115 and other 9% Cr heat-strength steel pipes The optimized selection of the post-weld heat treatment heating rate of the joint can meet the requirements of the post-weld heat treatment and at the same time reduce the heat treatment time to achieve the purpose of shortening the construction period.

Description

technical field [0001] The invention belongs to the technical field of heat-resistant steel welding, and in particular relates to an optimal calculation method for the heating rate of the post-weld heat treatment of a 9% Cr heat-strength steel pipeline. Background technique [0002] 9% Cr heat-strength steel is a martensitic heat-resistant steel widely used in super (super) critical thermal power units. It has excellent high-temperature creep resistance at high temperatures and is often used in the main steam pipes of units, Containers and other components. After welding of 9% Cr heat-strength steel pipes, the joints often have certain residual stress and low toughness. In order to solve this problem, post-weld heat treatment is generally adopted in engineering to eliminate residual stress and improve toughness. [0003] At present, the post-weld heat treatment of 9% Cr heat-strength steel pipes adopts the electric power standard DL / T819-2010 "Technical Regulations for Weld...

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Problems solved by technology

[0003] At present, the post-weld heat treatment of 9% Cr heat-strength steel pipes adopts the electric power standard DL / T819-2010 "Technical Regulations for Welding Heat Treatment in Thermal Power Plants", which recommends a heating rate selection method according to the difference in pipe wall thickness. However, in actual engineering, the power of the heater varies, and it is often necessary to shorten the construction period, reduce the heat treatment time, and often need to increase the heating rate

However, if the heating rate increases too much, the temperature gradient between the inner wall and the outer wall of the pipeline will increase, resulting in insufficient heat treatment time for the inner wall, which will affect the quality of heat treatment.

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