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Low temperature gas carburizing method for realizing reinforcement and corrosion resistance of austenitic stainless steel

A technology of austenitic stainless steel and low-temperature gas, which is applied in the direction of coating, metal material coating process, solid-state diffusion coating, etc., and can solve problems such as corrosion resistance decline

Inactive Publication Date: 2012-12-19
WUHAN RES INST OF MATERIALS PROTECTION
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0010] The purpose of the present invention is to provide a low-temperature gas carburizing method for achieving corrosion resistance and strengthening of austenitic stainless steel, which can not only greatly improve the surface strength of austenitic stainless steel, but also maintain the good corrosion resistance of austenitic stainless steel, So as to solve the common problem of corrosion resistance decline in austenitic stainless steel strengthening treatment

Method used

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  • Low temperature gas carburizing method for realizing reinforcement and corrosion resistance of austenitic stainless steel
  • Low temperature gas carburizing method for realizing reinforcement and corrosion resistance of austenitic stainless steel

Examples

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Embodiment 1

[0026] Embodiment 1: Implement low-temperature carburizing treatment to 304 austenitic stainless steel according to the treatment method of the present invention

[0027] First, degrease and dry the surface of 304 austenitic stainless steel parts with a mass of 20Kg, put them into the carburizing furnace, weigh 200g of polytetrafluoroethylene according to the specified proportion, put them into the bottom of the carburizing furnace, and cover the carburizing furnace tightly cover; then pass in protective nitrogen gas, turn on the electric heating until the temperature of the furnace rises to 550°C, keep it warm for 30 minutes, polytetrafluoroethylene decomposes at 535°C, and the decomposed products activate the passivation film on the surface of austenitic stainless steel; cool down To 470°C, evacuate the gas in the furnace, and pass 35%CO+10%H into the carburizing furnace 2 +55%N 2 Mix carburizing gas, keep warm for 48 hours, take out the test piece, and complete the low-tem...

Embodiment 2

[0028] Embodiment 2: Implement low-temperature carburizing treatment to 316 austenitic stainless steel according to the treatment method of the present invention

[0029] First, degrease and dry the surface of 316 austenitic stainless steel parts with a mass of 15Kg, put them into the carburizing furnace, weigh 102g of polytetrafluoroethylene according to the specified proportion, put them into the bottom of the carburizing furnace, and cover the carburizing furnace tightly cover; then pass in protective nitrogen gas, turn on the electric heating until the temperature of the furnace rises to 550°C, keep it warm for 30 minutes, polytetrafluoroethylene decomposes at 535°C, and the decomposed products activate the passivation film on the surface of austenitic stainless steel; cool down To 470°C, evacuate the gas in the furnace, and feed 38%CO+10%H into the carburizing furnace 2 +52%N 2 Mix carburizing gas, keep warm for 48 hours, take out the test piece, and complete the low-tempe...

Embodiment 3

[0030] Embodiment 3: Implement low-temperature carburizing treatment to 321 austenitic stainless steel according to the treatment method of the present invention

[0031] First, degrease and dry the surface of 321 austenitic stainless steel parts with a mass of 18Kg, put them into the carburizing furnace, weigh 90g of polytetrafluoroethylene according to the specified proportion, put them into the bottom of the carburizing furnace, and cover the carburizing furnace tightly Cover; then pass in protective nitrogen gas, turn on the electric heating until the temperature of the furnace rises to 550°C, keep warm for 30 minutes, polytetrafluoroethylene decomposes at 535°C, and the decomposed products activate the passive film on the surface of the austenitic stainless steel; cool down To 470°C, evacuate the gas in the furnace, and feed 25%CO+10%H into the carburizing furnace 2 +65%N 2 Mix carburizing gas, keep warm for 48 hours, take out the sample, and complete the low-temperature...

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Abstract

The invention provides a low temperature gas carburizing method for realizing reinforcement and corrosion resistance of austenitic stainless steel, which belongs to the field of chemical heat treatment. The method comprises the following steps: disposing a clean and dry austenitic stainless steel part in a carburizing furnace which is filled with a PTFE activator with an amount in proportion to the mass of the austenitic stainless steel part and tightly covering the cover of the carburizing furnace; blowing in protective nitrogen, powering on and heating the carburizing furnace to a temperature of 550 DEG C so as to allow PTFE to undergo pyrolysis, and activating a passivation film on the surface of austenitic stainless steel in the furnace by using pyrolysis products of PTFE so as to form a conduction channel which is beneficial for diffusion of carbon atoms on the surface of the austenitic stainless steel; and then, pumping out gas in the furnace, blowing in mixed gas of CO, H2 and N2 into the carburizing furnace, carrying out carburizing at a temperature of 460 to 480 DEG C which is lower than the formation temperature of a chromium carbide and carrying out insulation for 48 to 72 hours to complete carburizing. According to the invention, the purpose of realizing reinforcement of the austenitic stainless steel through low temperature carburizing and maintaining excellent corrosion resistance of the austenitic stainless steel are achieved, and the method is simple to implement and has high production efficiency.

Description

technical field [0001] The invention relates to a low-temperature gas carburizing method for realizing strengthening and corrosion resistance of austenitic stainless steel, which belongs to the field of chemical heat treatment. Background technique [0002] Austenitic stainless steel is widely used in chemical industry, automobile, food industry, pharmaceutical machinery, electrical components, marine and marine components, decoration and daily necessities, etc. Typical parts are water pumps, gears, pipes, valve seats, utensils, tableware, etc.; More than half of all industrial fasteners are made of stainless steel. However, austenitic stainless steel has a very obvious weakness, that is, the surface strength is not high, which is directly manifested as low hardness, wear resistance and fatigue resistance, which seriously affects the application range of austenitic stainless steel, or greatly reduces the cost of components. Therefore, the surface strengthening of austenitic...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C23C8/22
CPCC23C8/02
Inventor 潘邻张良界李朋杨闽红朱云峰
Owner WUHAN RES INST OF MATERIALS PROTECTION
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