Method for heat treatment of an alloy material and engineering machine part

Abstract

The application discloses a heat treatment method of alloy material and an engineering machinery accessory, and relates to the technical field of engineering machinery accessories. The heat treatment method of alloy material comprises the following steps: firstly, heating the alloy material to 680-730 DEG C, and keeping the temperature for 1-3 hours; secondly, heating the alloy material to 850-880 DEG C, and keeping the temperature for 2-4 hours; and thirdly, quenching and cooling the alloy material in a quenching liquid containing 5-10% PAG. The heat treatment method of alloy material and the engineering machinery accessory are suitable for engineering machinery accessories.

Description

Technical Field

[0001] This invention belongs to the field of heat treatment technology, and particularly relates to a heat treatment method for alloy materials and engineering machinery parts. Background Technology

[0002] Construction machinery is an important component of the equipment manufacturing industry. In general terms, construction machinery refers to the mechanical equipment necessary for comprehensive mechanized construction projects, including earthwork construction, road construction and maintenance, mobile lifting and loading operations, and various building projects.

[0003] Current construction machinery parts not only fail to meet manufacturing requirements during installation and use, but also lack sufficient installation space and structure. This increases the number of parts, raises assembly costs, and fails to provide adequate strength, reliability, and replaceability, thus hindering the optimization of the overall machine performance after assembly. Therefore, there is an urgent need for construction machinery parts with high hardness, strength, and reliability.

[0004] In the existing technology, the steel used for construction machinery parts is usually ordinary low-carbon alloy material. Since these construction machinery parts are generally frequently moving parts in their function, they have a high wear rate and require frequent replacement, which increases maintenance costs. Therefore, it is very important to find an alloy material with strong comprehensive mechanical properties, that is, excellent hardness and strength.

[0005] To improve the overall performance of alloy materials used in engineering machinery parts, their microstructure can be controlled through heat treatment. A key factor in heat treatment is the quenching and cooling process, making the quenching and cooling of alloy materials particularly important. Currently, the heat treatment method for alloy materials generally involves normalizing, quenching, and tempering. The quenching medium is quenching oil, used in a 1:10 weight ratio (1 ton of alloy material to 10 tons of quenching oil) to ensure quenching effectiveness. However, after a period of use, the oxidation of the alloy material and the carbonization of the medium oil increase the viscosity and reduce the oil volume, necessitating the addition of new quenching oil, leading to high oil quenching costs. Furthermore, oil quenching is prone to ignition, posing safety hazards, and generates large amounts of harmful substances, causing environmental pollution. Simultaneously, existing heat treatment methods result in low-carbon alloy materials with poor hardness and strength, failing to meet the requirements for high comprehensive mechanical properties. Summary of the Invention

[0006] Based on the above-mentioned technical problems, the present invention proposes a heat treatment method for alloy materials and engineering machinery parts. The alloy materials after heat treatment have excellent hardness and strength properties, thus making them suitable for use in engineering machinery parts.

[0007] The present invention proposes a heat treatment method for alloy materials, comprising: first heating the alloy material to 680-730℃ and holding it for 1-3 hours, then heating it to 850-880℃ and holding it for 2-4 hours, and then immersing it in a quenching liquid containing 5-10% PAG for quenching and cooling.

[0008] In this invention, after the alloy material is heated to its austenitizing temperature in a stepped manner, it is then quenched and cooled in a PAG quenching liquid. This process transforms the microstructure of the alloy material into a three-phase structure of austenite, ferrite, and martensite, ensuring that the resulting alloy material has high strength and hardness. At the same time, the quenching liquid containing 5-10% PAG has a suitable cooling rate for quenching the alloy material, ensuring that the quenched alloy material has sufficient hardness, a uniform internal microstructure, and is less prone to cracking.

[0009] Preferably, the quenching fluid further contains a hydrophilic regulator;

[0010] Preferably, the hydrophilicity regulator is sodium polyvinyl ester sulfonate.

[0011] In this invention, adding sodium polyvinyl ester sulfonate to the quenching liquid can adjust the viscosity of the quenching liquid, making the cooling parameters and cooling rate of the resulting quenching liquid more excellent, meeting the requirements of alloy materials for heat treatment, and obtaining alloy materials with stronger hardenability and higher hardness.

[0012] Preferably, the content of sodium polyvinyl ester sulfonate is 0.1-0.5% of the weight of the quenching fluid.

[0013] Preferably, the temperature of the quenching fluid is 20-50℃.

[0014] Preferably, the surface temperature of the alloy material when it is removed from the quenching liquid is 200-260℃.

[0015] Preferably, the heat treatment method for the alloy material used in automotive parts further includes: heating the quenched and cooled alloy material to 280-400℃ and tempering it for 1-2 hours.

[0016] Preferably, the chemical composition of the alloy material, by weight percentage, includes: C 0.22-0.33%, Si 0.3-0.4%, Mn 0.3-0.9%, Cr 1.0-2.6%, Ti 0.25-0.51%, Ni 0.18-0.35%, Mo 0.25-0.46%, Mg 0.05-0.1%, W 0.02-0.06%, S < 0.06%, P < 0.1%, with the balance being Fe.

[0017] In this invention, the principle of low carbon is adopted, and manganese, chromium, nickel, titanium, molybdenum and tungsten alloy material elements are added to the formula, so that the alloy material formula is reasonable and has good comprehensive mechanical properties, especially high strength and hardness, and good wear resistance.

[0018] Preferably, 0.5≤[Ti]+[Ni]+0.2×[Mo]≤0.8, where [Ti], [Ni], and [Mo] are the mass percentages of Ti, Ni, and Mo, respectively.

[0019] In this invention, when the mass percentages of Ti, Ni, and Mo satisfy the above equation, the overall mechanical properties of the alloy material are more superior.

[0020] The present invention also proposes an alloy material for automotive parts, which is obtained by the above-mentioned heat treatment method.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] The alloy material for engineering machinery parts of the present invention undergoes a stepped heating process combined with quenching to alter the microstructure of the alloy material, enabling a complete transformation of the alloy material's structure. Furthermore, through reasonable control of the chemical element content, its mechanical properties and wear resistance are effectively improved. Detailed Implementation

[0023] The present invention will now be described in detail through specific embodiments. However, these embodiments are clearly provided for illustrative purposes and are not intended to limit the scope of the present invention.

[0024] Example 1

[0025] An alloy material for engineering machinery parts comprises the following chemical composition by weight percentage: C 0.27%, Si 0.35%, Mn 0.6%, Cr 1.7%, Ti 0.36%, Ni 0.26%, Mo 0.37%, Mg 0.08%, W 0.04%, S 0.03%, P 0.06%, with the balance being Fe; wherein, [Ti]+[Ni]+0.2×[Mo]=0.69.

[0026] The heat treatment methods for the alloy materials used in the above-mentioned engineering machinery parts include:

[0027] The alloy material is heated to 700℃ and held for 2 hours, then heated to 870℃ and held for 3 hours. After that, it is immersed in a quenching liquid of 7% PAG at 30℃ for quenching and cooling. The weight ratio of the alloy material to the quenching liquid is 1:10. After holding for a period of time, the alloy material is removed from the quenching liquid. The surface temperature of the alloy material is 230℃. After air cooling to room temperature, the alloy material is placed in an isothermal furnace at 340℃ and held for 1.5 hours. After being removed from the furnace and air cooled to room temperature, the alloy material for engineering machinery parts is obtained.

[0028] Example 2

[0029] An alloy material for engineering machinery parts comprises the following chemical composition by weight percentage: C 0.27%, Si 0.35%, Mn 0.6%, Cr 1.7%, Ti 0.36%, Ni 0.26%, Mo 0.37%, Mg 0.08%, W 0.04%, S 0.03%, P 0.06%, with the balance being Fe; wherein, [Ti]+[Ni]+0.2×[Mo]=0.69.

[0030] The heat treatment methods for the alloy materials used in the above-mentioned engineering machinery parts include:

[0031] The alloy material is heated to 680℃ and held for 3 hours, then heated to 850℃ and held for 4 hours. After that, it is immersed in a quenching liquid of 10% PAG at 20℃ for quenching and cooling. The weight ratio of the alloy material to the quenching liquid is 1:10. After holding for a period of time, the alloy material is removed from the quenching liquid. The surface temperature of the alloy material is 200℃. After air cooling to room temperature, the alloy material is placed in an isothermal furnace at 400℃ and held for 1 hour. After being removed from the furnace and air cooled to room temperature, the alloy material for engineering machinery parts is obtained.

[0032] Example 3

[0033] An alloy material for engineering machinery parts comprises the following chemical composition by weight percentage: C 0.27%, Si 0.35%, Mn 0.6%, Cr 1.7%, Ti 0.36%, Ni 0.26%, Mo 0.37%, Mg 0.08%, W 0.04%, S 0.03%, P 0.06%, with the balance being Fe; wherein, [Ti]+[Ni]+0.2×[Mo]=0.69.

[0034] The heat treatment methods for the alloy materials used in the above-mentioned engineering machinery parts include:

[0035] The alloy material is heated to 730°C and held for 1 hour, then heated to 880°C and held for 2 hours. After that, it is immersed in a quenching liquid of 5% PAG at 50°C for quenching and cooling. The weight ratio of the alloy material to the quenching liquid is 1:10. After holding for a period of time, the alloy material is removed from the quenching liquid. The surface temperature of the alloy material is 260°C. After air cooling to room temperature, the alloy material is placed in an isothermal furnace at 280°C and held for 2 hours. After being removed from the furnace and air cooled to room temperature, the alloy material for engineering machinery parts is obtained.

[0036] Example 4

[0037] An alloy material for engineering machinery parts comprises the following chemical composition by weight percentage: C 0.23%, Si 0.37%, Mn 0.82%, Cr 1.1%, Ti 0.46%, Ni 0.29%, Mo 0.42%, Mg 0.07%, W 0.05%, S 0.03%, P 0.06%, with the balance being Fe; [Ti]+[Ni]+0.2×[Mo]=0.83.

[0038] The heat treatment methods for the alloy materials used in the above-mentioned engineering machinery parts include:

[0039] The alloy material is heated to 700℃ and held for 2 hours, then heated to 870℃ and held for 3 hours. After that, it is immersed in a quenching liquid of 7% PAG at 30℃ for quenching and cooling. The weight ratio of the alloy material to the quenching liquid is 1:10. After holding for a period of time, the alloy material is removed from the quenching liquid. The surface temperature of the alloy material is 230℃. After air cooling to room temperature, the alloy material is placed in an isothermal furnace at 340℃ and held for 1.5 hours. After being removed from the furnace and air cooled to room temperature, the alloy material for engineering machinery parts is obtained.

[0040] Example 5

[0041] An alloy material for engineering machinery parts comprises the following chemical composition by weight percentage: C 0.27%, Si 0.35%, Mn 0.6%, Cr 1.7%, Ti 0.36%, Ni 0.26%, Mo 0.37%, Mg 0.08%, W 0.04%, S 0.03%, P 0.06%, with the balance being Fe; wherein, [Ti]+[Ni]+0.2×[Mo]=0.69.

[0042] The heat treatment methods for the alloy materials used in the above-mentioned engineering machinery parts include:

[0043] The alloy material is heated to 700℃ and held for 2 hours, then heated to 870℃ and held for 3 hours. After that, it is immersed in a quenching liquid containing 7% PAG and 0.3% sodium polyvinyl ester sulfonate at 30℃ for quenching and cooling. The weight ratio of the alloy material to the quenching liquid is 1:10. After holding for a period of time, the alloy material is removed from the quenching liquid. The surface temperature of the alloy material is 230℃. After air cooling to room temperature, the alloy material is placed in an isothermal furnace at 340℃ and held for 1.5 hours. After being removed from the furnace and air cooled to room temperature, the alloy material for the engineering machinery parts is obtained.

[0044] The sodium polyvinyl alcohol ester sulfonate is prepared by the following method: polyvinyl alcohol is dissolved in DMF, 25 wt% sodium metal flakes of polyvinyl alcohol are added, and the mixture is stirred at room temperature for 1 hour. Then, a DMF solution containing 1.5 times the mass of polyvinyl alcohol sulfonyl propionic anhydride is added dropwise, and the mixture is stirred and reacted for 1 hour. The temperature is then raised to 70°C and stirred and reacted for 3 hours. After washing with water, the mixture is concentrated to obtain the sodium polyvinyl alcohol ester sulfonate.

[0045] Comparative Example 1

[0046] An alloy material for engineering machinery parts comprises the following chemical composition by weight percentage: C 0.27%, Si 0.35%, Mn 0.6%, Cr 1.7%, Ti 0.36%, Ni 0.26%, Mo 0.37%, Mg 0.08%, W 0.04%, S 0.03%, P 0.06%, with the balance being Fe; wherein, [Ti]+[Ni]+0.2×[Mo]=0.69.

[0047] The heat treatment methods for the alloy materials used in the above-mentioned engineering machinery parts include:

[0048] The alloy material is heated to 700℃ and held for 2 hours, then heated to 870℃ and held for 3 hours. After that, it is immersed in No. 100 machine oil at 30℃ for quenching and cooling. The weight ratio of the alloy material to the quenching liquid is 1:10. After holding for a period of time, the alloy material is removed from the quenching liquid. The surface temperature of the alloy material is 230℃. After air cooling to room temperature, the alloy material is placed in an isothermal furnace at 340℃ and held for 1.5 hours. After being removed from the furnace and air cooled to room temperature, the alloy material for engineering machinery parts is obtained.

[0049] Experimental test:

[0050] The engineering machinery parts obtained in the above embodiments and comparative examples were tested after being polished with alloy materials. The test results are shown in Table 1 below.

[0051] Table 1. Properties of alloy materials for engineering machinery parts obtained from the examples and comparative examples.

[0052]

[0053] As can be seen from the table above, compared with the traditional quenching method, the alloy material quenched by the method of the present invention has better strength and hardness, thus making it suitable for use in engineering machinery parts; and by further adjusting the chemical composition of the alloy material and the added components of the quenching liquid, the strength and hardness of the alloy material after quenching can be further improved.

[0054] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A heat treatment process for an alloy steel for automotive parts, characterized by, include: The alloy steel is first heated to 680-730℃ and held for 1-3 hours, then heated to 850-880℃ and held for 2-4 hours, and then immersed in a quenching liquid containing 5-10% PAG for quenching and cooling. The quenching fluid also contains a hydrophilic regulator; the hydrophilic regulator is sodium polyvinyl ester sulfonate. The chemical composition of the alloy steel, by weight percentage, includes: C 0.22-0.33%, Si 0.3-0.4%, Mn 0.3-0.9%, Cr 1.0-2.6%, Ti 0.25-0.51%, Ni 0.18-0.35%, Mo 0.25-0.46%, Mg 0.05-0.1%, W 0.02-0.06%, S < 0.06%, P < 0.1%, with the balance being Fe; 0.5≤[Ti]+[Ni]+0.2×[Mo]≤0.8, where [Ti], [Ni], and [Mo] are the mass percentages of Ti, Ni, and Mo, respectively. The content of sodium polyvinyl ester sulfonate is 0.1-0.5% of the weight of the quenching fluid.

2. The heat treatment process for alloy steel for automotive parts according to claim 1, characterized in that, The temperature of the quenching fluid is 20-50℃.

3. The heat treatment process for alloy steel for automotive parts according to claim 1 or 2, characterized in that, The surface temperature of the alloy steel when it is removed from the quenching liquid is 200-260℃.

4. The heat treatment process for alloy steel for automotive parts according to claim 1 or 2, characterized in that, Also includes: The quenched and cooled alloy steel is heated to 280-400℃ and tempered for 1-2 hours.

5. An alloy steel for automotive parts, characterized in that, It is obtained by heat treatment process according to any one of claims 1-4.

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