Low-temperature gas nitriding method for high-strength austenitic stainless steel

A technology of austenitic stainless steel and low-temperature gas, which is applied in workpiece surface treatment equipment, coating, metal rolling, etc., can solve the problems of gas nitriding process difficulty and diffusion difficulty, and improve the difficulty and effect of low-temperature gas nitriding Obvious effect of improving mechanical properties

Pending Publication Date: 2021-09-28
YANSHAN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

In order to further improve the strength, corrosion resistance, wear resistance and other properties of austenitic stainless steel, many scholars have devoted themselves to the surface strengthening research of austenitic stainless steel in recent years, but compared with the traditional nitrided steel (38CrMoAl, 40Cr), Due to the different structure of austenitic stainless steel (face-centered cubic structure), the diffusion of N atoms in austenitic stainless steel is much more difficult than that of commonly used nitriding steel, and because the high-strength austenitic stainless steel matrix itself contains a large amount of nitrogen, which makes the gas nitriding process more difficult

Method used

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  • Low-temperature gas nitriding method for high-strength austenitic stainless steel
  • Low-temperature gas nitriding method for high-strength austenitic stainless steel
  • Low-temperature gas nitriding method for high-strength austenitic stainless steel

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Experimental program
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Effect test

Embodiment 1

[0071] In terms of mass percentage, the chemical composition of the high-strength austenitic stainless steel used in this embodiment is: Cr 18.9%, Mn 19.3%, Ni 2.0%, C 0.11%, and the balance is iron.

[0072] The high-strength austenitic stainless steel is subjected to solution treatment by water cooling after heat preservation at 1150°C for 1 hour to obtain steel for testing;

[0073] The test steel with a thickness of 10 mm is rolled on a rolling mill for multiple passes, the reduction of each pass is 5%, and the final reduction after rolling is 50%, to obtain rolled steel;

[0074] Put the rolled steel into ultrasonically oscillating absolute ethanol, and clean it for 2 minutes at an ultrasonic power of 80 kHz; Take it out after washing for 3 minutes, and dry the surface of the sample to obtain activated steel;

[0075] Put the activated steel in the nitriding furnace, evacuate the inner tank of the nitriding furnace, fill it with ammonia gas at a rate of 1L / min, fill the ...

Embodiment 2

[0080] The preparation method is basically the same as in Example 1, except that the nitriding time is adjusted from "6h" to "12h".

Embodiment 3

[0094] In terms of mass percentage, the chemical composition of the high-strength austenitic stainless steel used in this embodiment is: C 0.013%, Mn 24.86%, Cr 17.26%, N 0.008%, and the balance is iron.

[0095] The high-strength austenitic stainless steel is subjected to solution treatment by water cooling after heat preservation at 1150°C for 1 hour to obtain steel for testing;

[0096] The test steel with a thickness of 10 mm is rolled on a rolling mill for multiple passes, the reduction of each pass is 5%, and the final reduction after rolling is 50%, to obtain rolled steel;

[0097] Put the rolled steel into ultrasonically oscillating absolute ethanol, and clean it for 2 minutes under the condition of ultrasonic power of 80 kHz; then put it into 2wt% phosphorous acid + 4wt% hydrochloric acid solution at 50°C for pickling for 3 minutes and take it out. Dry the surface of the sample to obtain activated steel;

[0098] Put the activated steel in the nitriding furnace, evac...

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Abstract

The invention provides a low-temperature gas nitriding method for high-strength austenitic stainless steel, and relates to the technical field of material surface treatment. The low-temperature gas nitriding method for the high-strength austenitic stainless steel comprises the following steps that the high-strength austenitic stainless steel is subjected to solution treatment, and test steel is obtained; cold rolling deformation treatment is conducted on the test steel to obtain rolled steel; the rolled steel is subjected to surface activating treatment, and activated steel is obtained; the activated steel is subjected to low-temperature gas nitriding treatment, a nitriding layer is formed, and nitrided high-strength austenitic stainless steel is obtained; the temperature of the low-temperature gas nitriding treatment is 300-600 DEG C; and the nitriding time is 6-12 h. Gas nitriding of the high-strength austenitic stainless steel can be achieved under the low-temperature condition, and meanwhile, the nitriding efficiency can be improved; and the thickness of the nitriding layer is increased within a short time, and the mechanical property of the austenitic stainless steel is improved.

Description

technical field [0001] The invention relates to the technical field of material surface treatment, in particular to a low-temperature gas nitriding method for high-strength austenitic stainless steel. Background technique [0002] Gas nitriding is a chemical heat treatment technology that puts steel parts in a nitrogen-containing atmosphere at a certain temperature for a certain period of time, so that nitrogen atoms can penetrate into the surface of the parts. Gas nitriding technology can significantly improve the hardness, fatigue strength, corrosion resistance and wear resistance of the surface of parts. The conventional gas nitriding method has the disadvantages of long process cycle (20-80h), low production efficiency and high energy consumption (processing temperature is above 800°C), and the surface layer of nitriding parts is brittle and easy to peel off. [0003] High-strength austenitic stainless steel has been widely used in national equipment fields such as aero...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C23C8/26C23C8/02C22C38/38C22C38/58C23G1/08B21B45/02B21B1/00
CPCC23C8/26C23C8/02C22C38/58C22C38/001C22C38/38C23G1/08B21B45/0278B21B1/00
Inventor 吕知清李瑞鑫周冰娆臧志伟刘天宇刘浩楠傅万堂
Owner YANSHAN UNIV
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