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Chromizing nitriding surface treatment technology for austenitic stainless steel

A technology of austenitic stainless steel and surface treatment, which is applied in the direction of metal material coating process, coating, solid diffusion coating, etc., can solve the problems of no stable and reliable chromium nitriding surface treatment technology, etc., and achieve stable process quality Reliable, reduced workpiece deformation, and fewer types

Pending Publication Date: 2021-06-22
CNNC JIANZHONG NUCLEAR FUEL
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Problems solved by technology

[0007] Therefore, there is no stable and reliable chromium nitriding surface treatment technology in China at present.

Method used

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  • Chromizing nitriding surface treatment technology for austenitic stainless steel
  • Chromizing nitriding surface treatment technology for austenitic stainless steel

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Embodiment Construction

[0042] The present invention will be further described below by means of the accompanying drawings and specific embodiments.

[0043] Step 1. Chromizing treatment

[0044] Based on the principle of powder chromizing, the workpiece is buried in the chromizing agent (chrome powder, filler and catalyst according to the chemical composition), and then put into the chromizing tank together before entering the furnace. By controlling the holding time at the chromizing temperature, the workpiece A certain thickness of high-concentration chromizing layer is formed on the surface.

[0045] The chemical and physical principle of the powder chromizing process is: the infiltration agent NH 4 I decomposes under high temperature and reacts with high temperature chromium powder to generate chromous iodide. When the generated chromium iodide gas is in contact with the surface of the high-temperature workpiece, chromium atoms are deposited on the surface of the workpiece through reactions su...

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Abstract

The invention belongs to the field of nuclear fuel manufacturing, and particularly relates to a chromizing nitriding surface treatment technology for austenitic stainless steel, which comprises the following steps: burying a workpiece into a chromizing agent, filling the workpiece and the chromizing agent into a chromizing tank, putting the chromizing tank into a chromizing furnace for chromizing heat treatment, putting the workpiece into a high-pressure vacuum gas quenching furnace, and converting a chromizing layer into a chromizing and nitriding composite layer, wherein the chromizing agent comprises chromium powder, a filling agent and a catalyst, and chromizing heat treatment comprises chromizing powder pretreatment, loading and packaging and then heat treatment; the nitriding treatment comprises cleaning and drying a sample, the workpiece and a nitriding furnace, and then carrying out nitriding heat treatment on the nitriding furnace. By means of the formula of the chromizing agent, the hardening phenomenon is avoided, damage to the workpiece is not likely to be caused, the relation between the chromizing heat preservation time factor and the chromizing layer thickness is designed, the chromizing layer thickness is controlled, workpiece deformation is reduced, the solid solution nitriding technology can meet the nitriding requirement, and the adverse effect on the material performance in the powder chromizing process is eliminated.

Description

technical field [0001] The invention belongs to the field of nuclear fuel manufacture, and in particular relates to a stainless steel chromizing and nitriding surface treatment process. Background technique [0002] In the surface treatment technology of stainless steel parts of fuel assemblies and reactor internal components that are specifically required by sodium-cooled fast reactors, or in the surface hardening technology of stainless steel parts for civil use, it is often necessary to chromium-nitride the surface of eustenitic stainless steel parts. The purpose is to In order to avoid adhesion of some parts in the sodium-cooled fast neutron reactor during irradiation and operation, the technology is to chromize the surface of stainless steel and then nitriding to achieve a hardened layer with sufficient thickness and strength on the surface. A surface treatment process in which parts are hardened and strengthened. [0003] This technology used to be the technical bottl...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C23C10/42C23C8/26
CPCC23C10/42C23C8/26
Inventor 皇甫鸿宾何俊杰李林冲张塞柏王卫东肖永华张成余范绍华刘亮徐春刘兵
Owner CNNC JIANZHONG NUCLEAR FUEL
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