Heat treatment technology of low alloy steel casting

A technology for low-alloy steel and castings, which is applied in the field of heat treatment of low-alloy steel castings, can solve problems such as temper brittleness, poor toughness of low-alloy steel castings, and environmental pollution, so as to reduce environmental pollution and safety hazards, meet Requirements for strength and hardness, and the effect of reducing production costs

Inactive Publication Date: 2017-06-27
QINGDAO SANTONGDE METAL PROD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

At present, the heat treatment process of low-alloy steel castings generally adopts normalizing-quenching-tempering, in which quenching medium uses quenching oil, and its ratio is 1:10 by weight, that is, 1 ton of castings is put into 10 tons of quenching oil to ensure the quenching effect After the quenching oil has been used for a period of time, the oxidized powder of the casting and the carbonization of the medium oil will increase the viscosity of the quenching oil and reduce the oil volume, and new quenching oil must be added, resulting in high oil quenching costs; Fire will bring potential safety hazards, and a large amount of harmful substances will be produced during quenching, causing pollution to the environment
The tempering temperature of conventional low-alloy steel is 550-560°C, and the cooling method is to cool out of the furnace when the temperature is lower than 200°C. The low-alloy steel castings treated by the above heat treatment process have poor toughness, and the bending angle is lower than 80°, which cannot meet the requirements. The demand for high toughness, and the above cooling method, when the casting temperature is in the range of 200-400 ℃, it is easy to produce temper brittleness, which will reduce the mechanical properties of the casting

Method used

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  • Heat treatment technology of low alloy steel casting
  • Heat treatment technology of low alloy steel casting

Examples

Experimental program
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Effect test

Embodiment 1

[0016] Embodiment 1: The heat treatment process steps of the low-alloy steel casting of the present embodiment are as follows:

[0017] (1) Normalizing: Place the low-alloy steel casting in a normalizing furnace, raise the temperature to 870°C, keep it warm for 3 hours, and cool it to room temperature after taking it out of the furnace;

[0018] (2) Quenching: Place the low-alloy steel casting in a quenching furnace, raise the temperature to 850°C, keep it warm for 2.5 hours, and cool it to room temperature when it comes out of the furnace;

[0019] (3) Tempering: Place the low-alloy steel casting in a tempering furnace, raise the temperature to 700°C, keep it warm for 3 hours, and then take it out of the furnace and air-cool it to room temperature.

Embodiment 2

[0020] Embodiment 2: the heat treatment process steps of the low-alloy steel casting of the present embodiment are as follows:

[0021] (1) Normalizing: Place the low-alloy steel casting in a normalizing furnace, raise the temperature to 880°C, keep it warm for 2.5 hours, and cool it to room temperature after taking it out of the furnace;

[0022] (2) Quenching: Place the low-alloy steel casting in a quenching furnace, raise the temperature to 860°C, keep it warm for 3 hours, and cool it to room temperature when it comes out of the furnace;

[0023] (3) Tempering: Place the low-alloy steel casting in a tempering furnace, raise the temperature to 710°C, keep it warm for 3 hours, and then take it out of the furnace and air-cool it to room temperature.

Embodiment 3

[0024] Embodiment 3: the heat treatment process steps of the low-alloy steel casting of the present embodiment are as follows:

[0025] (1) Normalizing: Place the low-alloy steel casting in a normalizing furnace, raise the temperature to 890°C, keep it warm for 3 hours, and cool it to room temperature after taking it out of the furnace;

[0026] (2) Quenching: Place the low-alloy steel casting in a quenching furnace, raise the temperature to 870°C, keep it warm for 3 hours, and cool it to room temperature after taking it out of the furnace;

[0027] (3) Tempering: Place the low-alloy steel casting in a tempering furnace, raise the temperature to 710°C, keep it warm for 2.5 hours, and then take it out of the furnace and air-cool it to room temperature.

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Abstract

The invention relates to a heat treatment process for castings, in particular to a heat treatment process for low alloy steel castings, comprising the following steps: normalizing, water quenching, high temperature tempering and air cooling. The heat treatment process of the low-alloy steel castings of the present invention improves the tempering temperature of the low-alloy steel castings, and adopts a direct air-cooling method out of the furnace. The treated low-alloy steel castings not only meet the requirements for strength and hardness, but also improve the toughness of the castings; In the heat treatment process of the low-alloy steel casting of the present invention, water cooling is used in the quenching step, which reduces production costs, reduces environmental pollution, and reduces potential safety hazards.

Description

technical field [0001] The invention relates to a heat treatment process for castings, in particular to a heat treatment process for low alloy steel castings. Background technique [0002] Due to the advantages of high strength and high wear resistance, low-alloy steel castings gradually replace ordinary carbon steel and are widely used in the field of casting, especially ZG42CrMo, ZG35CrMo and other materials, whose strength is 2-3 times that of ordinary carbon steel. In practical application, the strength, hardness and toughness of low alloy steel need to be selected reasonably. At present, the heat treatment process of low-alloy steel castings generally adopts normalizing-quenching-tempering, in which quenching medium uses quenching oil, and its ratio is 1:10 by weight, that is, 1 ton of castings is put into 10 tons of quenching oil to ensure the quenching effect After the quenching oil has been used for a period of time, the oxidized powder of the casting and the carbon...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C22C38/18C22C38/04C22C38/12C22C38/02C21D6/00C21D1/18C21D1/28
CPCC22C38/18C21D1/18C21D1/28C21D6/002C21D6/005C22C38/02C22C38/04C22C38/12
Inventor 赵振荣
Owner QINGDAO SANTONGDE METAL PROD
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