Method for heat treatment of low-activation steel

Abstract

The invention discloses a method for heat treatment of low-activation steel. The method comprises the following steps: (1) performing primary normalizing treatment on the low-activation steel, and then carrying out cooling; (2) performing secondary normalizing treatment on a cooled sample obtained in the step (1), and then carrying out cooling; and (3) performing tempering treatment on a cooled sample obtained in the step (2), and then carrying out cooling. Therefore, by adopting the method, uniform and fine original austenite grains and tempered martensite lath structures can be obtained, so that when the low-activation steel is subjected to impact stress, the stress is dispersed on a plurality of grains, the plastic deformation is relatively uniform, the stress concentration is relatively small, the grain boundaries generated by the fine grain structures are relatively large, cracks are not easy to expand, and the toughness of the low-activation steel can be improved. In addition, the method can be further applied to performance optimization of the low-activation steel and production of structural materials of commercial fusion power stations.

Description

technical field [0001] The invention belongs to the technical field of low-activation steel, and in particular relates to a method for heat-treating low-activation steel. Background technique [0002] As an important part of my country's strategic emerging industries, nuclear energy has the advantages of high energy density, low-carbon cleanliness, and stability. It is an important pillar of energy supply among non-fossil energy sources, and it is also an important means of smog control and energy security. my country has adjusted the policy of "moderately developing nuclear power" to "actively developing nuclear power", which is of great significance to solving the energy shortage crisis and environmental pollution problems that our country is currently facing. Nuclear energy includes fusion energy and fission energy. In view of the limitations of the small amount of nuclear fuel required for fission energy and the difficult-to-handle radioactive waste generated by fission...

AI Technical Summary

Problems solved by technology

[0004] 9% Cr low-activation steel belongs to the category of martensitic heat-resistant steel. Its strength is high, and its tensile strength is about 700-800MPa. However, its toughness is low, and its toughness is about 160J before service. Dislocations and fine precipitated phase particles can hinder the boundary migration of tempered martensite laths, ensuring good service performance of the material

However, with increasing service time, M 23 C 6 and Laves phase particles are easy to coarsen and gather at the grain boundary, and cannot effectively pin the lath boundary, resulting in the migration of the martensitic lath boundary, the coarsening of the lath, and the decrease in material strength and toughness, especially the rapid decline in toughness. Therefore, It is particularly important to change the organizational structure from the source to improve the toughness of materials

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