Heat treatment method for 35CrMo steel

A heat treatment method and water cooling technology, applied in the field of alloy steel processing, can solve the problems of uneven internal structure, poor weldability, high hardenability, etc., and achieve the effect of avoiding sudden cooling of the workpiece surface, green and environmental protection during the operation process, and stable crystal structure

Inactive Publication Date: 2018-12-21
SICHUAN YIHENG MACHINERY MFG CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0002] 35CrMo alloy structural steel has high static strength, impact toughness and high fatigue limit. Its hardenability is higher than that of 40Cr. It has high creep strength and durable strength at high temperature. Moderate plasticity during deformation, poor weldability
[0004] It can be seen that 35CrMo steel is widely used, but due to certain problems in certain process operations in the traditional heat treatment process, the surface of the workpiece is prone to stress concentration after quenching, the hardness is too large, the integrity of the workpiece is relatively poor, and the internal structure Inhomogeneous shape, easy cracking of steel, etc. In actual operation, the operational problems in the process are mainly reflected in the high quenching temperature, natural cooling in the open space after normalizing process, resulting in relatively low cooling efficiency, etc.

Method used

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  • Heat treatment method for 35CrMo steel

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0033] The heat treatment method of 35CrMo steel is carried out according to the following process steps:

[0034] (1) Put the 35CrMo steel piece into the heating furnace first, raise the temperature of the heating furnace, heat it to 800-850 ° C, and pass a certain amount of protective gas for 2 hours, then cool it with water for 40 seconds and put it in the oil cool down;

[0035] (2) Put the steel piece into the box-type heating furnace, raise the temperature of the heating furnace, control the furnace temperature at 600°C for 30h, heat preservation and tempering after quenching;

[0036] (3) After tempering is completed, let it cool at natural temperature, and it will be ready.

Embodiment 2

[0038] The heat treatment method of 35CrMo steel is carried out according to the following process steps:

[0039] (1) Put the 35CrMo steel piece into the heating furnace first, raise the temperature of the heating furnace, heat it to 800-850 ° C, and pass a certain amount of protective gas for 5 hours, then cool it with water for 60 seconds and put it in the oil Cool for 30s, add polyethylene glycol, polyacrylamide and sodium chloride to the water, the amount of the above three substances added is 6wt% of the water amount;

[0040] (2) Put the steel piece into a box-type heating furnace, raise the temperature of the heating furnace, control the furnace temperature at 650°C for 4 hours, keep warm and temper after quenching, and protect it with inert gas;

[0041] (3) After the tempering is completed, cool at natural temperature. When the temperature drops below 100°C, put the steel plate into water for further cooling. Add 3wt% sodium hydroxide to the water and cool it to room t...

Embodiment 3

[0043] The heat treatment method of 35CrMo steel is carried out according to the following process steps:

[0044] (1) Put the 35CrMo steel piece into the heating furnace first, raise the temperature of the heating furnace, heat it to 800-850 ° C, and pass a certain amount of protective gas for 4 hours, then cool it with water for 50 seconds and put it in the oil Cool for 20s, add polyethylene glycol, polyacrylamide, sodium chloride and a random copolymer of ethylene oxide and propylene oxide with a number average molecular weight of 30,000 in the water, and the amount of the above four substances added is 5wt% of the water amount ;

[0045] Polyethylene glycol, polyacrylamide, sodium chloride, ethylene oxide and propylene oxide random copolymer are measured in parts by mass, 4 parts of polyethylene glycol, 3 parts of polyacrylamide, chlorinated 2 parts of sodium, 4 parts of random copolymer of ethylene oxide and propylene oxide;

[0046] (2) Put the steel piece into a box-t...

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Abstract

The invention provides a heat treatment method for 35CrMo steel. The method comprises steps as follows: (A) an alloy is subjected to heat treatment between 800 DEG C and 850 DEG C for 2-5 h, is subjected to water cooling for 40-60 s and is immersed in oil for cooling; (B) the alloy is subjected to heat treatment between 600 DEG C and 650 DEG C for 4-30 h and is subjected to natural air cooling, and then heat treatment is completed. By the aid of the heat treatment method for the 35CrMo steel, the traditional heat treatment technology is optimized, the quenching temperature is adjusted, the cooling manner after normalization and quenching is optimized, the stress inside a workpiece is eliminated with the heat treatment method, the crystal structure inside the workpiece is stable, the hardness is moderate, the problem that the steel is prone to cracking is solved thoroughly, the method is easy to operate, the operation process is environment-friendly, the two steps are closely connected,the referable specific method is provided for subsequent operation, and the heat treatment method is relatively excellent.

Description

technical field [0001] The invention relates to the field of alloy steel processing, in particular to a heat treatment method for 35CrMo steel. Background technique [0002] 35CrMo alloy structural steel has high static strength, impact toughness and high fatigue limit. Its hardenability is higher than that of 40Cr. It has high creep strength and durable strength at high temperature. Moderate plasticity during deformation, poor weldability. Low temperature to -110 ℃, and has high static strength, impact toughness and high fatigue strength, good hardenability, no overheating tendency, small quenching deformation, acceptable plasticity during cold deformation, medium machinability, but The first type of tempering brittleness, poor weldability, preheating before welding, heat treatment after welding to eliminate stress, generally used after quenching and tempering, and can also be used after high-frequency surface quenching or quenching and low- and medium-temperature temperin...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C21D6/00C21D1/18C21D1/58C21D1/60C21D1/74
CPCC21D1/18C21D1/58C21D1/60C21D1/74C21D6/002
Inventor 李银芳李川何微琦
Owner SICHUAN YIHENG MACHINERY MFG CO LTD
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