Quenching process for forged round steel

Abstract

The invention relates to the technical field of round steel forging, and discloses a forged round steel quenching process which comprises the following specific steps: S1, preheating treatment; s2, quenching heating; s3, quenching and cooling; s4, low-temperature tempering; s5, cleaning and anti-rust treatment; according to the scheme, the product quality is improved, specifically, through preheating treatment, thermal stress and structural stress are reduced, the risks of cracks and deformation of round steel in the subsequent heating process are reduced, the qualified rate and quality stability of products are improved, and the structure performance is improved; the austenitizing of the round steel is more sufficient and uniform, so that a finer and more uniform martensite structure is obtained, the hardness, the strength and the wear resistance of the round steel are improved, and deformation and cracking are reduced: rapid quenching oil is adopted for cooling, and the temperature and the stirring speed of the quenching oil are controlled, so that the cooling speed of the round steel is more uniform; and the phenomena of deformation and cracking of the round steel in the quenching process are effectively reduced.

Description

Technical Field

[0001] The invention relates to the technical field of round steel forging, in particular to a quenching process for forged round steel. Background Art

[0002] In modern industrial production, forged round steel is widely used in machinery manufacturing, automobile industry, aerospace and other fields. However, the traditional quenching process often has some problems in practical applications, such as uneven heating leading to unstable performance of round steel, deformation and cracking caused by improper control of quenching cooling rate, and excessive residual stress caused by insufficient tempering. These problems not only affect the quality and service life of round steel, but also increase production costs and production cycles. Therefore, in order to improve the performance and quality of forged round steel and reduce production costs, it is necessary to improve and optimize the traditional quenching process to meet the needs of modern industrial production for high-quality forged round steel. Summary of the invention

[0003] 1. Technical issues to be resolved In view of the deficiencies in the prior art, the present invention provides a quenching process for forged round steel, which has the advantages of reducing deformation and cracking, and solves the problem of excessive residual stress caused by insufficient tempering.

[0004] (II) Technical solution To achieve the above object, the present invention provides the following technical solution: A quenching process for forged round steel, comprising the following specific steps: S1 preheating treatment: placing the forged round steel in a heating furnace at 500-600°C for preheating, and keeping the temperature for 1-2 hours to reduce thermal stress and tissue stress, and prevent the round steel from cracking and deforming during the subsequent heating process; S2 quenching heating: the preheated round steel is quickly transferred to a salt bath furnace or a controlled atmosphere furnace at 840-860°C for heating. The heating time is calculated according to the diameter and thickness of the round steel, and is generally calculated according to a heating coefficient of 1.0-1.5min / mm. S3 Quenching and cooling: After the round steel is heated, it is quickly immersed in rapid quenching oil for cooling. The temperature of the quenching oil is controlled between 40-80℃; S4 low temperature tempering: put the quenched round steel into the tempering furnace at 180-200℃ for low temperature tempering immediately, and keep it warm for 2-3 hours; S5 cleaning and anti-rust treatment: After the tempered round steel is taken out of the furnace, it is naturally cooled to room temperature, and then the oil stains on its surface are cleaned with a cleaning agent; After cleaning, apply anti-rust oil on the surface of the round steel or carry out anti-rust packaging to prevent the round steel from rusting during storage and transportation; S6 Quality Control: During the quenching process, the temperature, viscosity and flash point performance indicators of the quenching oil should be regularly tested and adjusted to ensure the cooling performance and stability of the quenching oil.

[0005] Preferably, the S2 quenching heating: in order to ensure uniform heating of the round steel, appropriate stirring or turning measures should be adopted during the heating process.

[0006] Preferably, the S3 quenching cooling: after the round steel enters the quenching oil, an appropriate stirring speed should be maintained to ensure cooling uniformity. The cooling time is determined according to the size and shape of the round steel, generally 3-10 minutes, until the surface temperature of the round steel drops to 150-200°C.

[0007] Preferably, the S4 low temperature tempering: low temperature tempering can reduce the internal stress of the round steel and improve its toughness and fatigue strength.

[0008] Preferably, the hardness of the round steel after quenching is tested, and the hardness should meet the product design requirements. If the hardness is unqualified, the cause should be analyzed and corresponding measures should be taken to adjust it, such as re-tempering or additional quenching.

[0009] Preferably, the temperature uniformity of the heating furnace and the tempering furnace is regularly tested and calibrated to ensure that the temperature uniformity of the round steel during the heating and tempering process meets the process requirements.

[0010] Preferably, the process is suitable for materials. This quenching process is suitable for medium carbon alloy structural steel, such as 42CrMo and 40Cr forged round steel.

[0011] (III) Beneficial effects Compared with the prior art, the present invention provides a quenching process for forged round steel, which has the following beneficial effects: 1. The quenching process of the forged round steel improves product quality: through preheating treatment, thermal stress and organizational stress are reduced, the risk of cracking and deformation of the round steel in the subsequent heating process is reduced, the qualified rate and quality stability of the product are improved, and the organizational performance is improved: the quenching heating temperature and time are accurately controlled to make the austenitization of the round steel more sufficient and uniform, so as to obtain a finer and more uniform martensitic structure, improve the hardness, strength and wear resistance of the round steel, and reduce deformation and cracking: rapid quenching oil is used for cooling, and the temperature and stirring speed of the quenching oil are controlled to make the cooling speed of the round steel more uniform, effectively reducing the deformation and cracking of the round steel during the quenching process, and improving the dimensional accuracy and appearance quality of the product.

[0012] 2. The quenching process of the forged round steel reduces the residual stress: the reasonable low-temperature tempering process can effectively reduce the residual stress inside the round steel, improve the toughness and fatigue strength of the round steel, extend the service life of the product, and improve production efficiency: the optimized quenching process shortens the production cycle, improves production efficiency, reduces production costs, and is conducive to the improvement of the company's market competitiveness and economic benefits. DETAILED DESCRIPTION

[0013] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0014] A quenching process for forged round steel comprises the following specific steps: S1 Preheating treatment: Place the forged round steel in a heating furnace at 500-600℃ for preheating and keep it warm for 1-2 hours to reduce thermal stress and structural stress and prevent cracks and deformation of the round steel during subsequent heating; S2 quenching heating: the preheated round steel is quickly transferred to a salt bath furnace or a controlled atmosphere furnace at 840-860°C for heating. The heating time is calculated according to the diameter and thickness of the round steel, and is generally calculated according to a heating coefficient of 1.0-1.5min / mm. Among them, in order to ensure uniform heating of the round steel, appropriate stirring or turning measures should be adopted during the heating process; S3 Quenching and cooling: After the round steel is heated, it is quickly immersed in rapid quenching oil for cooling. The temperature of the quenching oil is controlled between 40-80℃; Among them, after the round steel enters the quenching oil, the stirring speed should be maintained appropriately to ensure the cooling uniformity. The cooling time is determined according to the size and shape of the round steel, generally 3-10 minutes, until the surface temperature of the round steel drops to 150-200℃; S4 low temperature tempering: put the quenched round steel into the tempering furnace at 180-200℃ for low temperature tempering immediately, and keep it warm for 2-3 hours; Among them, low temperature tempering can reduce the internal stress of round steel and improve its toughness and fatigue strength; S5 cleaning and anti-rust treatment: After the tempered round steel is taken out of the furnace, it is naturally cooled to room temperature, and then the oil stains on its surface are cleaned with a cleaning agent; After cleaning, apply anti-rust oil on the surface of the round steel or carry out anti-rust packaging to prevent the round steel from rusting during storage and transportation; S6 Quality Control: During the quenching process, the temperature, viscosity and flash point performance indicators of the quenching oil should be regularly tested and adjusted to ensure the cooling performance and stability of the quenching oil; Among them, the hardness of the round steel after quenching is tested. The hardness should meet the product design requirements. If the hardness is unqualified, the cause should be analyzed and corresponding measures should be taken to adjust it, such as re-tempering or additional quenching; Among them, the temperature uniformity of the heating furnace and tempering furnace is regularly tested and calibrated to ensure that the temperature uniformity of the round steel during the heating and tempering process meets the process requirements.

[0015] Among them, this process is suitable for materials. This quenching process is suitable for medium carbon alloy structural steel, such as 42CrMo and 40Cr forged round steel.

[0016] Furthermore, the solution improves product quality: through preheating treatment, thermal stress and structural stress are reduced, the risk of cracking and deformation of round steel in the subsequent heating process is reduced, the product qualification rate and quality stability are improved, and the structural performance is improved: the quenching heating temperature and time are accurately controlled to make the austenitization of the round steel more complete and uniform, thereby obtaining a finer and more uniform martensitic structure, improving the hardness, strength and wear resistance of the round steel, and reducing deformation and cracking: rapid quenching oil is used for cooling, and the temperature and stirring speed of the quenching oil are controlled to make the cooling speed of the round steel more uniform, effectively reducing the deformation and cracking of the round steel in the quenching process, and improving the dimensional accuracy and appearance quality of the product.

[0017] Furthermore, the solution reduces residual stress: a reasonable low-temperature tempering process can effectively reduce the residual stress inside the round steel, improve the toughness and fatigue strength of the round steel, extend the service life of the product, and improve production efficiency: the optimized quenching process shortens the production cycle, improves production efficiency, reduces production costs, and is beneficial to the improvement of the company's market competitiveness and economic benefits.

[0018] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A quenching process for forged round steel, characterized in that: The specific steps include: S1 preheating treatment: the forged round steel is placed in a heating furnace at 500-600°C for preheating and kept warm for 1-2 hours to reduce thermal stress and structural stress and prevent the round steel from cracking and deforming during the subsequent heating process; S2 quenching heating: the preheated round steel is quickly transferred to a salt bath furnace or a controlled atmosphere furnace at 840-860°C for heating. The heating time is calculated according to the diameter and thickness of the round steel, and is generally calculated according to a heating coefficient of 1.0-1.5min / mm. S3 Quenching and cooling: After the round steel is heated, it is quickly immersed in rapid quenching oil for cooling. The temperature of the quenching oil is controlled between 40-80℃; S4 low temperature tempering: put the quenched round steel into the tempering furnace at 180-200℃ for low temperature tempering immediately, and keep it warm for 2-3 hours; S5 cleaning and anti-rust treatment: After the tempered round steel is taken out of the furnace, it is naturally cooled to room temperature, and then the oil stains on its surface are cleaned with a cleaning agent; After cleaning, apply anti-rust oil on the surface of the round steel or carry out anti-rust packaging to prevent the round steel from rusting during storage and transportation; S6 Quality Control: During the quenching process, the temperature, viscosity and flash point performance indicators of the quenching oil should be regularly tested and adjusted to ensure the cooling performance and stability of the quenching oil.

2. The quenching process for forged round steel according to claim 1, characterized in that: S2 quenching heating: In order to ensure uniform heating of the round steel, appropriate stirring or turning measures should be adopted during the heating process.

3. The quenching process of forged round steel according to claim 1, characterized in that: The S3 quenching cooling: After the round steel enters the quenching oil, an appropriate stirring speed should be maintained to ensure cooling uniformity. The cooling time is determined according to the size and shape of the round steel, generally 3-10 minutes, until the surface temperature of the round steel drops to 150-200°C.

4. The quenching process for forged round steel according to claim 1, characterized in that: The S4 low temperature tempering: Low temperature tempering can reduce the internal stress of round steel and improve its toughness and fatigue strength.

5. The quenching process of forged round steel according to claim 1, characterized in that: The hardness of the round steel after quenching should be tested. The hardness should meet the product design requirements. If the hardness is unqualified, the cause should be analyzed and appropriate measures should be taken to adjust it, such as re-tempering or additional quenching.

6. The quenching process for forged round steel according to claim 1, characterized in that: The temperature uniformity of the heating furnace and tempering furnace should be tested and calibrated regularly to ensure that the temperature uniformity of the round steel during the heating and tempering process meets the process requirements.

7. The quenching process for forged round steel according to claim 1, characterized in that: Applicable materials: This quenching process is suitable for medium carbon alloy structural steel, such as 42CrMo and 40Cr forged round steel.