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Heat treatment process of AISI4340 steel forgings

A steel forging and process technology, which is applied in the field of heat treatment process of AISI4340 steel forging, can solve the problems of poor low temperature impact toughness and inability to meet the requirements of use.

Active Publication Date: 2010-07-28
HENAN ZHONGYUAN SPECIAL STEEL EQUIP MFG CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

AISI 4340 steel forgings are commonly used steel forgings at low temperature. When heat-treating AISI 4340 steel forgings according to the conventional process, air cooling is used after normalizing, and water quenching and oil cooling are used for quenching. The unit of effective section size is mm, and the unit of cooling time is Calculated in seconds, the water cooling temperature is 30°C, the water cooling time is 1 to 1.3 times the effective cross-sectional size of AISI 4340 steel forgings, the oil cooling temperature is 20-70°C, and the oil cooling time is 7-7 times the effective cross-sectional size of AISI 4340 steel forgings 9 times, although the strength of the AISI 4340 steel forgings treated in this way can be guaranteed, but the low-temperature impact toughness is poor, which cannot meet the use requirements

Method used

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  • Heat treatment process of AISI4340 steel forgings
  • Heat treatment process of AISI4340 steel forgings
  • Heat treatment process of AISI4340 steel forgings

Examples

Experimental program
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Effect test

Embodiment 1

[0021] As shown in the accompanying drawing, a heat treatment process of AISI 4340 steel forgings, the heat treatment process is:

[0022] (1) Normalizing treatment to complete austenite transformation: AISI 4340 steel forgings are put into the furnace at room temperature, preheated to 600°C, preheated and kept for 3 hours to eliminate internal stress, and then heated to normal at a rate of 20°C / h The fire temperature is 860°C, heat preservation (1h per 100mm AISI 4340 steel forging effective cross-sectional diameter) until the core of AISI 4340 steel forging reaches the normalizing temperature to complete the structure transformation and homogenization, and the axial flow fan is used for forced cooling when the furnace is released, and the blower is improved. The height of the base makes it aligned with the AISI 4340 steel forging, and four axial flow fans are placed on both sides of the upper and lower clamping platforms, blowing directly onto the AISI 4340 steel forging from...

Embodiment 2

[0028] As shown in the accompanying drawing, a heat treatment process of AISI 4340 steel forgings, the heat treatment process is:

[0029] (1) Normalizing treatment to complete austenite transformation: AISI 4340 steel forgings are put into the furnace at a temperature of 350°C, preheated to 640°C, preheated and kept for 4 hours to eliminate internal stress, and then heated at a rate of 50°C / h to The normalizing temperature is 890°C, heat preservation (effective cross-sectional diameter of 100mm AISI 4340 steel forgings is 0.9h) until the core of AISI 4340 steel forgings reaches the normalizing temperature to complete the structural transformation and homogenization, and the furnace is forced to cool by axial flow fan blasting. Raise the height of the base of the axial flow fan to align it with the AISI 4340 steel forging, place four blowers on both sides of the upper and lower clamping platforms, and blow directly onto the AISI 4340 steel forging from multiple directions, forc...

Embodiment 3

[0035] As shown in the accompanying drawing, a heat treatment process of AISI 4340 steel forgings, the heat treatment process is:

[0036] (1) Normalizing treatment to complete austenite transformation: AISI 4340 steel forgings are put into the furnace at a temperature of 650°C, preheated to 680°C, preheated and kept for 5 hours to eliminate internal stress, and then heated at a rate of 80°C / h to Normalizing temperature is 910°C, heat preservation (effective cross-sectional diameter of AISI 4340 steel forgings is 0.8h per 100mm) until the core of AISI 4340 steel forgings reaches the normalizing temperature to complete structural transformation and homogenization. Raise the height of the blower base so that it is aligned with the AISI 4340 steel forging, place four blowers on both sides of the upper and lower clamping platforms, and blow directly onto the AISI 4340 steel forging from multiple directions, forcing the entire AISI 4340 steel forging to cool evenly and rapidly to r...

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Abstract

The invention belongs to the technical field of the production technology of steel forging products used in low temperature and discloses a heat treatment process of AISI4340 steel forgings. In the heat treatment process, air cooling is performed after normalization; the temperature of water-cooling after quenching is 10-20 DEG C, the dimension unit of the effective cross-section is millimeter, the unit of cooling time is second, and the cooling time is 2-3 times of the effective cross-section dimension of AISI4340 steel forgings. By using the heat treatment process of the invention, the strength of the AISI4340 steel forgings can be enabled and the low-temperature impact toughness is effectively improved, thus the service life of forgings is prolonged.

Description

technical field [0001] The invention belongs to the technical field of production of steel forgings used at low temperatures, and in particular relates to a heat treatment process for AISI4340 steel forgings. 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 to make this type of product work normally and avoid early failure, it must have high hardness and good low-temperature impact toughness under use. AISI 4340 steel forgings are commonly used steel forgings at low temperature. When heat-treating AISI 4340 steel forgings according to the conventional proc...

Claims

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Application Information

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IPC IPC(8): C21D8/00C21D1/28C21D1/18
Inventor 李守杰赵颖
Owner HENAN ZHONGYUAN SPECIAL STEEL EQUIP MFG CO LTD
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