Thermal treatment method for improving low-temperature impact toughness of austenite-ferrite stainless steel

A technology of low temperature impact toughness and heat treatment method, applied in heat treatment equipment, heat treatment process control, manufacturing tools, etc., can solve the problems of poor impact toughness, unable to meet the requirements of use, etc., and achieve the effect of reducing plasticity and toughness

Active Publication Date: 2014-07-09
HENAN ZHONGYUAN HEAVY FORGING
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

After heat treatment of austenitic-ferritic stainless steel products according to the conventional process, the strength can be guaranteed, but the low-temperature impact toughness is poor, which cannot meet the use requirements

Method used

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  • Thermal treatment method for improving low-temperature impact toughness of austenite-ferrite stainless steel

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Experimental program
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Effect test

Embodiment 1

[0017] A heat treatment method for improving low-temperature impact toughness of austenitic-ferritic stainless steel, the method is as follows:

[0018] 1) After the austenitic-ferritic stainless steel is forged, install the furnace under the condition that the furnace temperature is not higher than 350°C, and preheat twice;

[0019] 2) The temperature of the first preheating is 600°C, the heating rate is 0<50°C / h, and the temperature is kept for 1h; the temperature of the second preheating is 830°C, the temperature is kept for 1h, and then solid solution treatment is carried out;

[0020] 3) The solid solution temperature is 1040°C, the holding time is 0.8 hours / 100mm, and then cooled;

[0021] 4) Put it into clean water with an initial temperature of less than 10°C, and keep it for 20 minutes at a cooling rate of 4 seconds / mm.

[0022] In the step 4), in order to control the temperature of the clear water, the clear water is continuously injected at a speed of 38 tons / hour....

Embodiment 2

[0024] A heat treatment method for improving low-temperature impact toughness of austenitic-ferritic stainless steel, the method is as follows:

[0025] 1) After the austenitic-ferritic stainless steel is forged, install the furnace under the condition that the furnace temperature is not higher than 350°C, and preheat twice;

[0026] 2) The temperature of the first preheating is 660°C, the heating rate is 0<50°C / h, and the temperature is kept for 3 hours; the temperature of the second preheating is 900°C, the temperature is kept for 3 hours, and then solid solution treatment is carried out;

[0027] 3) The solid solution temperature is 1080°C, the holding time is 1.3 hours / 100mm, and then cooled;

[0028] 4) Put it into clean water with an initial temperature of less than 10°C, and keep it for 20 minutes at a cooling rate of 6 seconds / mm.

[0029] In the step 4), in order to control the temperature of the clear water, the clear water is continuously injected at a speed of 40 ...

Embodiment 3

[0031] A heat treatment method for improving low-temperature impact toughness of austenitic-ferritic stainless steel, the method is as follows:

[0032] 1) After the austenitic-ferritic stainless steel is forged, install the furnace under the condition that the furnace temperature is not higher than 350°C, and preheat twice;

[0033] 2) The temperature for the first preheating is 630°C, the heating rate is 0<50°C / h, and the temperature is kept for 2 hours; the temperature for the second preheating is 870°C, the temperature is kept for 1 hour, and then solid solution treatment is performed;

[0034] 3) The solid solution temperature is 1060°C, the holding time is 1 hour / 100mm, and then cooled;

[0035] 4) Put it into clean water with an initial temperature of less than 10°C, and keep it for 20 minutes at a cooling rate of 5 s / mm.

[0036] In the step 4), in order to control the temperature of the clear water, the clear water is continuously injected at a speed of 39 tons / hour....

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Abstract

The invention belongs to the technical field of production of duplex stainless steel products used at low temperature and particularly relates to a thermal treatment method for improving low-temperature impact toughness of austenite-ferrite stainless steel with high requirements for performance indexes. The thermal treatment method comprises the steps: feeding forged austenite-ferrite stainless steel into a furnace at the feeding temperature of not greater than 350 DEG C and performing twice preheating; performing solution treatment; performing cooling, feeding the austenite-ferrite stainless steel into clear water with the initial temperature smaller than 10 DEG C, and retaining the austenite-ferrite stainless steel for 20 minutes at the cooling speed of 4-6 seconds / mm. An austenite-ferrite stainless steel solution treatment process comprises the steps of (1) heating, namely controlling heating speed, preheating temperature, solid solution temperature and retaining time at a low-temperature section, reducing thermal stress and simultaneously obtaining good duplex structural proportion and (2) cooling, namely adopting a quick low-temperature long-time water-cooling mode to prevent precipitation due to fragility phase and remarkably reducing the plasticity and the toughness of the steel.

Description

technical field [0001] The invention belongs to the technical field of production of duplex stainless steel products used at low temperatures, and in particular relates to a heat treatment method for low-temperature impact toughness of austenitic-ferritic stainless steel with high requirements on various performance indexes. Background technique [0002] For steel forging products used at low temperature, due to the low temperature of the working environment, the brittleness of the product material will increase during long-term use. If the original steel forging material has high strength and poor low temperature impact toughness, it will be in a very short Failure forms such as fracture occur due to excessive brittleness within a certain period of time, reducing the service life. In order for this type of product to work normally without premature failure, in addition to having good strength, it is also necessary to ensure good low-temperature impact toughness under use. ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C21D6/00C21D11/00C22C38/44
Inventor 王济生
Owner HENAN ZHONGYUAN HEAVY FORGING
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