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Heat treatment process for reducing sensitization degree of austenitic stainless steel

A technology of austenitic stainless steel and sensitization degree, applied in the field of heat treatment of stainless steel materials and austenitic stainless steel heat treatment process, can solve the problems of immature research, improve the resistance to intergranular corrosion, reduce the residence time, and improve the operability. strong effect

Inactive Publication Date: 2017-06-16
SHANGHAI UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

The first two methods are not suitable for a certain austenitic stainless steel that has been produced, and the research on the latter two methods is not mature enough, which will have a negative impact on the large-scale use of austenitic stainless steel in industrial production.

Method used

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  • Heat treatment process for reducing sensitization degree of austenitic stainless steel

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Embodiment 1

[0023] In this embodiment, a heat treatment process for reducing the sensitization degree of austenitic stainless steel, the steps are as follows:

[0024] a. Take a 304 austenitic stainless steel sample with a size of 80×10×4mm, and carry out segmental annealing treatment on the austenitic stainless steel sample under the protection of reducing atmosphere, and the reducing protective atmosphere adopts N 2 :H 2 The mixed gas whose molar ratio is 2:3, specifically adopts the four-stage annealing process, and the control conditions of the staged annealing process are as follows:

[0025] The first stage of annealing process: the annealing furnace is raised to 300°C at a rate of 5°C / min, and held for 0.5h;

[0026] The second stage of annealing process: the annealing furnace is raised to 1350°C at a heating rate of 10°C / min, and held for 0.5h;

[0027] The third stage annealing process: cooling to 1200°C with the furnace, holding for 12 hours;

[0028] The fourth stage anneal...

Embodiment 2

[0032] This embodiment is basically the same as Embodiment 1, especially in that:

[0033] In this embodiment, a heat treatment process for reducing the sensitization degree of austenitic stainless steel, the steps are as follows:

[0034] a. A 304 austenitic stainless steel sample with a size of 80×10×4mm was taken, and the austenitic stainless steel sample was annealed in stages under the protection of a reducing atmosphere. The reducing atmosphere was pure H 2 , specifically using a four-stage annealing process, the control conditions of the staged annealing process are as follows:

[0035] The first stage of annealing process: the annealing furnace is raised to 400°C at a rate of 10°C / min, and kept for 5 hours;

[0036] The second stage annealing process: the annealing furnace is raised to 1450°C at a heating rate of 30°C / min, and kept for 5 hours;

[0037] The third-stage annealing process: cooling to 1000°C with the furnace and holding for 24 hours;

[0038] The four...

Embodiment 3

[0042] This embodiment is basically the same as the previous embodiment, and the special features are:

[0043] In this embodiment, a heat treatment process for reducing the sensitization degree of austenitic stainless steel, the steps are as follows:

[0044] a. Take a 304 austenitic stainless steel sample with a size of 80×10×4mm, and carry out segmental annealing treatment on the austenitic stainless steel sample under the protection of reducing atmosphere, and the reducing protective atmosphere adopts N 2 :H 2 The mixed gas whose molar ratio is 3:7, specifically adopts the four-stage annealing process, and the control conditions of the staged annealing process are as follows:

[0045] The first stage of annealing process: the annealing furnace is raised to 350°C at a rate of 5°C / min, and kept for 2 hours;

[0046] The second stage annealing process: the annealing furnace is raised to 1450°C at a heating rate of 20°C / min, and kept for 2 hours;

[0047] The third stage ann...

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Abstract

The present invention discloses a heat treatment process for reducing the sensitization degree of an austenitic stainless steel, wherein an austenitic stainless steel is subjected to segmented annealing treatment under a reduced protection atmosphere, and then water cooling is performed to achieve a room temperature. According to the present invention, with the heat treatment process, the residence time of the austenitic stainless steel in the sensitization temperature zone during the austenitic stainless steel heat treatment process can be reduced, the formation of the partial chromium carbide can be effectively inhibited, the carbide formed at the grain boundary position can be re-dissolved into the austenite to form the appropriate amount of the delta-ferrite, the sensitization degree of the austenitic stainless steel can be reduced, and the intergranular corrosion resistance can be improved; and the heat treatment process has advantages of simple process, remarkable effect and strong operability, and can be used for large-scale industrial production.

Description

technical field [0001] The invention relates to a heat treatment method for stainless steel materials, in particular to a heat treatment process for austenitic stainless steel, which is applied in the technical field of material corrosion protection. Background technique [0002] Austenitic stainless steel is an important stainless steel, which has an austenitic structure at room temperature. When the steel contains about 18% Cr, 8%~10% Ni, and about 0.1% C, it has a stable austenite structure. Austenitic stainless steel has high corrosion resistance, mainly due to the addition of Cr and Ni. The added Cr and Ni react with oxygen in the air to form a dense oxide film on the surface. This oxide film has high stability in many corrosive media, thus preventing the steel itself from being corroded by corrosive media. But under certain conditions, it will also be corroded. Intergranular corrosion is one of the corrosion forms, which is a selective corrosion phenomenon that occu...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C21D1/26C21D1/74
CPCC21D1/26C21D1/74C21D2211/001
Inventor 钟庆东任帅东李辉孙金虎王永东
Owner SHANGHAI UNIV
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