Heat treatment method for normalizing type nuclear power pressure vessel equipment bearing steel plate

Abstract

The invention discloses a heat treatment method for a normalizing type nuclear power pressure vessel equipment bearing steel plate. The procedures of normalizing heat treatment and cooling are included. A radiation pipe heated roller bottom type heat treatment furnace is adopted, nitrogen protection is adopted in the whole process, and the proportion of oxygen and nitrogen in the furnace is reasonably and strictly controlled to be lower than 1 / 20000; through optimization adjustment of the normalizing heat preservation temperature, the total heating time and the cooling red return temperature,steel plate toughness matching is reasonable, the comprehensive performance is excellent, a uniform and refined bainite + ferrite structure is obtained in the through-thickness direction, the grain size is at the level from 8.5-9.5, the steel plate yield strength is larger than or equal to 355 MPa, the tensile strength is 510-680 MPa, ductility A50 is larger than or equal to 20%, the lamellar tearing resisting performance value is larger than or equal to 45%, the 0 DEG C low temperature impact toughness average value is larger than or equal to 220 J, the lateral swell increment is larger thanor equal to 1.55 mm, and roughness is smaller than or equal to 6.3 microns. The characteristics that the production procedure is simple, the product quality is stable, and batched production can be achieved are achieved.

Description

technical field [0001] The invention belongs to the technical field of metallurgy, and in particular relates to a heat treatment method for a steel plate used for supporting equipment of normalized nuclear power pressure vessels. Background technique [0002] In order to achieve sustainable development, it is necessary to speed up the implementation of energy conservation and emission reduction, vigorously develop clean energy, and ensure the rapid and sound development of the national economy. The practice of the development and operation of nuclear power technology in the world has proved that nuclear energy has the advantages of being clean, safe and capable of providing stable power on a large scale, and is increasingly favored. [0003] As the pillar of pressure vessels in nuclear power plants, pressure vessel support steel plates have high requirements on the performance and surface quality of the steel plates used, and special heat treatment methods are required to me...

AI Technical Summary

Problems solved by technology

Aiming at the reasons affecting the surface of the steel plate, the invention effectively solves the problem of nodules on the roll surface by optimizing and strictly controlling the nitrogen and oxygen content in the furnace, effectively reduces the probability of quality defects such as pits on the lower surface of the steel plate, and ensures heat treatment. After the stability of steel plate properties and the surface at high temperature to reduce the bonding of layered iron scale

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