Carburizing and quenching process for cutter made of alloy steel

Abstract

The invention discloses a carburizing and quenching process for a cutter made of alloy steel, and belongs to the technical field of heat treatment of alloy steel tools. A carburizing and quenching process for a cutter made of alloy steel specifically comprises the steps that alloy steel raw materials with specific components are selected, ultrasonic cleaning, annealing, high-temperature quenching, subcritical quenching, subzero treatment, low-temperature tempering and other procedures are conducted, and finally carburizing treatment is conducted in a gas carburizing mode. The key of the process is that the cutter has high hardness and excellent wear resistance and keeps good toughness by controlling the cooling rate of high-temperature quenching and the conditions of subcritical quenching and subzero treatment. Particularly, in the gas carburizing process, methane gas is used for treating the tool, the uniformity and depth of a carburized layer are ensured, and therefore the service life of the tool is prolonged. By means of the technology, the surface hardness, fatigue resistance and corrosion resistance of the tool can be effectively improved, and it is ensured that the tool is stable in performance under harsh working conditions such as high loads and high-speed cutting.

Description

Technical Field

[0001] The present invention relates to the technical field of heat treatment of alloy steel tools, and more particularly to a carburizing and quenching process for a tool made of alloy steel. Background Art

[0002] In the tool manufacturing industry, alloy steels are widely used due to their excellent mechanical properties and wear resistance. In the field of high-hardness and wear-resistant tools, carburizing and quenching are particularly important for improving tool performance. Carburizing and quenching technology involves carburizing steel at high temperatures, combined with quenching and tempering processes. This technology achieves high hardness on the tool surface while maintaining excellent toughness and wear resistance, thereby extending the tool's service life.

[0003] Currently, the carburizing and quenching process for alloy steel cutting tools has been widely adopted in various fields, particularly in the automotive manufacturing, precision machining, and cutting tool industries. These industries place high demands on cutting tool performance, and therefore carburizing and quenching technology is considered a key means of improving tool performance. However, existing carburizing and quenching processes still present certain challenges, such as complex processes, demanding equipment requirements, and high costs. Furthermore, the thickness, uniformity, and hardness of the carburized layer directly impact tool performance.

[0004] With the continuous advancement of industrial technology, carburizing and quenching processes will develop towards greater efficiency, environmental friendliness, and energy conservation. For example, gas carburizing offers significant advantages in improving carburizing uniformity and reducing pollution, and is likely to become mainstream in the future. Furthermore, the combination of advanced heat treatment techniques and intelligent control systems can further enhance tool performance and reduce production costs. Furthermore, the emergence of new alloy materials will drive the development of carburizing and quenching technology, bringing more innovative possibilities to the tool industry. Summary of the Invention

[0005] The object of the present invention is to provide a carburizing and quenching process for a cutting tool made of alloy steel, which has excellent surface hardness, fatigue resistance, wear resistance and service life.

[0006] A carburizing and quenching process for a tool made of alloy steel, characterized by comprising the following steps: (1) Alloy steel is selected as the raw material, and its chemical composition includes: carbon: 0.45-0.55%, manganese: 0.6-1.0%, chromium: 1.2-1.6%, molybdenum: 0.3-0.5%, silicon: 0.15-0.35%, vanadium: 0.1-0.2%, and the rest is iron and inevitable impurities; (2) Processing the alloy steel material in step (1) into the shape of a tool, and then pre-treating it, the pre-treatment comprising: first ultrasonically cleaning it with anhydrous ethanol for 10-18 minutes, then washing it with deionized water, drying it with compressed air, and then annealing it at 760-800°C for 60-120 minutes, and then naturally cooling it to room temperature; (3) High-temperature quenching the tool in step (2) at 850-950°C for 30-60 minutes using quenching oil as the quenching medium, and rapidly cooling to room temperature; (4) subjecting the tool that has been subjected to high-temperature quenching in step (3) to a sub-temperature quenching treatment, using water as the quenching medium, and then subjecting it to a deep cooling treatment to return it to room temperature; (5) subjecting the tool subjected to cryogenic treatment in step (4) to low-temperature tempering treatment and naturally cooling to room temperature; (6) The tool that has been subjected to low-temperature tempering treatment in step (5) is subjected to conventional grinding and polishing, ultrasonically cleaned in ethanol, dried, and then carburized to obtain a finished product.

[0007] Preferably, the cooling rate of the high temperature quenching in step (3) is controlled at 110-150°C / s.

[0008] Preferably, the sub-temperature quenching condition in step (4) is to keep the temperature at 450-550° C. for 30-60 minutes.

[0009] Preferably, the cryogenic treatment in step (4) is carried out at -90°C to -70°C for 40-80 minutes.

[0010] Preferably, the low-temperature tempering condition in step (5) is to keep the temperature at 150-200°C for 2-3 hours.

[0011] Preferably, the carburizing treatment in step (6) is performed by using gas carburizing, heating the tool to 880-940°C, using methane gas for carburizing for 3-5 hours, and naturally cooling to room temperature.

[0012] Compared with the prior art, the advantages of the present invention are: (1) Selection of raw materials and alloy steel composition in the present invention: Alloy steel with a carbon content of 0.45-0.55% is used as the raw material, which has good hardness and wear resistance and can meet the use requirements of the tool in high temperature and high pressure working environment.

[0013] The combination of appropriate amounts of elements such as manganese, chromium, molybdenum, silicon, and vanadium improves the corrosion resistance, strength, and thermal stability of the steel, ensuring the long service life of the tool under complex working conditions.

[0014] This composition ratio also optimizes the heat treatment performance of the tool and ensures the uniformity and depth of the tool surface hardness after carburizing.

[0015] (2) Pretreatment process of the tool according to the present invention: By using anhydrous ethanol ultrasonic cleaning and deionized water washing, impurities and oxides on the surface of the alloy steel are removed, ensuring quality stability during the subsequent heat treatment process.

[0016] Annealing treatment effectively releases the internal stress of the material, improves the organizational structure of the steel, provides a better foundation for subsequent high-temperature quenching, and avoids deformation or cracking caused by stress concentration.

[0017] (3) The present invention adopts high temperature quenching process: High-temperature quenching is carried out in the range of 850-950℃, which ensures that the surface hardness of the tool is significantly improved. The quenching cooling rate is controlled within 110-150℃ / s, which prevents cracks caused by thermal stress and ensures uniform hardening of the tool.

[0018] Using quenching oil as the medium can effectively and quickly cool the tool, further improving the hardness and wear resistance of the tool.

[0019] (4) The present invention adopts sub-temperature quenching and cryogenic treatment: The sub-temperature quenching process (450-550℃) can effectively improve the internal structure of the tool, reduce internal stress, further enhance the toughness of the tool, and avoid the problem of tool brittleness.

[0020] Cryogenic treatment is carried out in the range of -90℃ to -70℃, which helps to enhance the wear resistance of the tool and further refine the grain structure, thereby improving the strength and wear resistance of the tool.

[0021] (5) The present invention adopts a low-temperature tempering process: Low temperature tempering treatment (150-200℃) can further eliminate the internal stress during the quenching process, while improving the toughness of the tool and reducing the brittleness that may occur due to high temperature tempering.

[0022] The tempered tool has better comprehensive mechanical properties, can adapt to high load, high speed cutting and other working conditions, and improve the service life of the tool.

[0023] (6) The present invention adopts carburizing treatment: The gas carburizing process uses methane gas for carburizing at a temperature of 880-940°C, which can significantly increase the surface hardness of the tool without affecting the toughness of the tool inside.

[0024] The uniformity and depth of the carburized layer are controlled, ensuring the wear resistance and corrosion resistance of the tool during long-term use.

[0025] The natural cooling process to room temperature reduces thermal shock, further protects the surface quality of the tool and ensures the performance of the final product. DETAILED DESCRIPTION

[0026] Example 1: (1) Alloy steel is selected as the raw material, and its chemical composition includes: carbon: 0.45%, manganese: 0.6%, chromium: 1.2%, molybdenum: 0.3%, silicon: 0.15%, vanadium: 0.1%, and the rest is iron and inevitable impurities; (2) Processing the alloy steel material in step (1) into the shape of a tool, and then pre-treating it, the pre-treatment comprising: first ultrasonically cleaning it with anhydrous ethanol for 10 minutes, then washing it with deionized water, drying it with compressed air, and then annealing it at 760°C for 60 minutes, and then naturally cooling it to room temperature; (3) High-temperature quenching the tool in step (2) at 850°C for 30 minutes using quenching oil as the quenching medium and rapidly cooling to room temperature at a cooling rate of 110°C / s; (4) The tool that has been high-temperature quenched in step (3) is subjected to a sub-temperature quenching treatment, which is kept at 450°C for 30 minutes, with the quenching medium being water, and then subjected to a cryogenic treatment, which is kept at -90°C for 40 minutes, and then returned to room temperature; (5) The tool that has been cryogenically treated in step (4) is subjected to low-temperature tempering treatment, kept at 150°C for 2 hours, and naturally cooled to room temperature; (6) The tool that has been subjected to low-temperature tempering treatment in step (5) is subjected to conventional grinding and polishing, then ultrasonically cleaned in ethanol, dried, and carburized using gas carburizing. The tool is heated to 880°C and carburized using methane gas for 3 hours. The tool is naturally cooled to room temperature to obtain a finished product.

[0027] Example 2: (1) Alloy steel is selected as the raw material, and its chemical composition includes: carbon: 0.475%, manganese: 0.7%, chromium: 1.3%, molybdenum: 0.35%, silicon: 0.2%, vanadium: 0.125%, and the rest is iron and inevitable impurities; (2) Processing the alloy steel material in step (1) into the shape of a tool, and then pre-treating it, the pre-treatment comprising: first ultrasonically cleaning it with anhydrous ethanol for 12 minutes, then washing it with deionized water, drying it with compressed air, and then annealing it at 770°C for 75 minutes, and then naturally cooling it to room temperature; (3) High-temperature quenching the tool in step (2) at 875°C for 37 minutes using quenching oil as the quenching medium and rapidly cooling to room temperature at a cooling rate of 120°C / s; (4) The tool that has been high-temperature quenched in step (3) is subjected to a sub-temperature quenching treatment, which is kept at 475°C for 37 minutes, with the quenching medium being water, and then subjected to a cryogenic treatment, which is kept at -85°C for 50 minutes, and then returned to room temperature; (5) The tool subjected to cryogenic treatment in step (4) is subjected to low-temperature tempering treatment, kept at 162°C for 2.25 hours, and naturally cooled to room temperature; (6) The tool that has been subjected to low-temperature tempering treatment in step (5) is subjected to conventional grinding and polishing, then ultrasonically cleaned in ethanol, dried, and carburized using gas carburizing. The tool is heated to 895°C and carburized using methane gas for 3.5 hours. The tool is naturally cooled to room temperature to obtain the finished product.

[0028] Example 3: (1) Alloy steel is selected as the raw material, and its chemical composition includes: carbon: 0.5%, manganese: 0.8%, chromium: 1.4%, molybdenum: 0.4%, silicon: 0.2%, vanadium: 0.15%, and the rest is iron and inevitable impurities; (2) Processing the alloy steel material in step (1) into the shape of a tool, and then pre-treating it, the pre-treatment comprising: first ultrasonically cleaning it with anhydrous ethanol for 14 minutes, then washing it with deionized water, drying it with compressed air, and then annealing it at 780°C for 90 minutes, and then naturally cooling it to room temperature; (3) subjecting the tool in step (2) to high temperature quenching, keeping the temperature at 900°C for 45 minutes, using quenching oil as the quenching medium, and rapidly cooling it to room temperature at a cooling rate of 130°C / s; (4) The tool that has been high-temperature quenched in step (3) is subjected to a sub-temperature quenching treatment, which is kept at 500°C for 45 minutes, with the quenching medium being water, and then subjected to a cryogenic treatment, which is kept at -80°C for 60 minutes, and then returned to room temperature; (5) The tool subjected to cryogenic treatment in step (4) is subjected to low-temperature tempering treatment, kept at 175°C for 2.5 hours, and naturally cooled to room temperature; (6) The tool that has been subjected to low-temperature tempering treatment in step (5) is subjected to conventional grinding and polishing, and then ultrasonically cleaned in ethanol. After drying, it is carburized using gas carburizing. The tool is heated to 910°C and carburized using methane gas for 4 hours. It is then naturally cooled to room temperature to obtain the finished product.

[0029] Example 4: (1) Alloy steel is selected as the raw material, and its chemical composition includes: carbon: 0.5%, manganese: 0.9%, chromium: 1.5%, molybdenum: 0.45%, silicon: 0.3%, vanadium: 0.175%, and the rest is iron and inevitable impurities; (2) Processing the alloy steel material in step (1) into the shape of a tool, and then pre-treating it, the pre-treatment comprising: first ultrasonically cleaning it with anhydrous ethanol for 16 minutes, then washing it with deionized water, drying it with compressed air, and then annealing it at 790°C for 105 minutes, and then naturally cooling it to room temperature; (3) High-temperature quenching the tool in step (2) at 925°C for 52 minutes using quenching oil as the quenching medium and rapidly cooling to room temperature at a cooling rate of 140°C / s; (4) The tool that has been high-temperature quenched in step (3) is subjected to a sub-temperature quenching treatment, which is kept at 525°C for 52 minutes, with the quenching medium being water, and then subjected to a cryogenic treatment, which is kept at -75°C for 70 minutes, and then returned to room temperature; (5) The tool subjected to cryogenic treatment in step (4) is subjected to low-temperature tempering treatment, kept at 187°C for 2.75 hours, and naturally cooled to room temperature; (6) The tool that has been subjected to low-temperature tempering treatment in step (5) is subjected to conventional grinding and polishing, then ultrasonically cleaned in ethanol, dried, and carburized using gas carburizing. The tool is heated to 925°C and carburized using methane gas for 4.5 hours. The tool is naturally cooled to room temperature to obtain the finished product.

[0030] Example 5: (1) Alloy steel is selected as the raw material, and its chemical composition includes: carbon: 0.55%, manganese: 1.0%, chromium: 1.6%, molybdenum: 0.5%, silicon: 0.35%, vanadium: 0.2%, and the rest is iron and inevitable impurities; (2) Processing the alloy steel material in step (1) into the shape of a tool, and then pre-treating it, the pre-treatment comprising: first ultrasonically cleaning it with anhydrous ethanol for 18 minutes, then washing it with deionized water, drying it with compressed air, and then annealing it at 800°C for 120 minutes, and then naturally cooling it to room temperature; (3) High-temperature quenching the tool in step (2) at 950°C for 60 minutes using quenching oil as the quenching medium and rapidly cooling to room temperature at a cooling rate of 150°C / s; (4) The tool that has been subjected to high-temperature quenching in step (3) is subjected to a sub-temperature quenching treatment, which is kept at 550°C for 60 minutes, with the quenching medium being water, and then subjected to a cryogenic treatment, which is kept at -70°C for 80 minutes, and then returned to room temperature; (5) The tool that has been cryogenically treated in step (4) is subjected to low-temperature tempering treatment, kept at 200°C for 3 hours, and naturally cooled to room temperature; (6) The tool that has been subjected to low-temperature tempering treatment in step (5) is subjected to conventional grinding and polishing, ultrasonically cleaned in ethanol, dried, and carburized using gas carburizing. The tool is heated to 940°C and carburized using methane gas for 5 hours. The tool is naturally cooled to room temperature to obtain a finished product.

[0031] Performance Testing Hardness test The cutting tools in Examples 1-5 were cut into 10 mm long samples, polished and cleaned, and then hardness tested using a BuehlerWilson 2000 Rockwell hardness tester, with reference to the national standard GB / T 230.1-2018. The test results are shown in the following table: Carburized layer thickness detection The cutting tool in Examples 1-5 was used to cut a 10 mm long sample, and the surface was polished using a grinder until the sample surface reached mirror-level flatness. The sample was then etched using a Nital solution, an acidic etchant. The depth of the carburized layer was measured using a FEI Quanta 250 scanning electron microscope, with reference to the national standard GB / T 6394-2002. The test results are shown in the following table: Wear resistance test 10 mm long samples were cut from the cutting tools in Examples 1-5, polished and cleaned, and then fixed in a wear tester. The wear resistance was tested using a Pin-on-Disk wear tester with a friction force of 5 N and a friction speed of 1 m / s, according to the national standard GB / T 11843-2008. The test results are shown in the following table: Fatigue resistance test 10 mm long samples were cut from the cutting tools in Examples 1-5, polished and cleaned, and then mounted on a fatigue testing machine for cyclic load testing. Fatigue resistance was tested using an Instron 8801 multifunctional fatigue testing machine, with reference to the national standard GB / T 528-2009. The test results are shown in the following table:

Claims

1. A carburizing and quenching process for a tool made of alloy steel, characterized in that: The steps include: (1) Alloy steel is selected as the raw material, and its chemical composition includes: carbon: 0.45-0.55%, manganese: 0.6-1.0%, chromium: 1.2-1.6%, molybdenum: 0.3-0.5%, silicon: 0.15-0.35%, vanadium: 0.1-0.2%, and the rest is iron and inevitable impurities; (2) Processing the alloy steel material in step (1) into the shape of a tool, and then pre-treating it, the pre-treatment comprising: first ultrasonically cleaning it with anhydrous ethanol for 10-18 minutes, then washing it with deionized water, drying it with compressed air, and then annealing it at 760-800°C for 60-120 minutes, and then naturally cooling it to room temperature; (3) High-temperature quenching the tool in step (2) at 850-950°C for 30-60 minutes using quenching oil as the quenching medium, and rapidly cooling to room temperature; (4) subjecting the tool that has been subjected to high-temperature quenching in step (3) to a sub-temperature quenching treatment, using water as the quenching medium, and then subjecting it to a deep cooling treatment to return it to room temperature; (5) subjecting the tool subjected to cryogenic treatment in step (4) to low-temperature tempering treatment and naturally cooling to room temperature; (6) The tool that has been subjected to low-temperature tempering treatment in step (5) is subjected to conventional grinding and polishing, ultrasonically cleaned in ethanol, dried, and then carburized to obtain a finished product.

2. The carburizing and quenching process for a tool made of alloy steel according to claim 1, characterized in that: The cooling rate of the high temperature quenching in step (3) is controlled at 110-150°C / s.

3. The carburizing and quenching process for a cutting tool made of alloy steel according to claim 1, characterized in that: The sub-temperature quenching condition in the step (4) is to keep the temperature at 450-550°C for 30-60 minutes.

4. The carburizing and quenching process for a tool made of alloy steel according to claim 3, characterized in that: The cryogenic treatment in step (4) is carried out at a temperature of -90°C to -70°C for 40 to 80 minutes.

5. The carburizing and quenching process for a tool made of alloy steel according to claim 1, characterized in that: The low-temperature tempering condition in step (5) is to keep the temperature at 150-200°C for 2-3 hours.

6. The carburizing and quenching process for a cutting tool made of alloy steel according to claim 1, characterized in that: The carburizing treatment in step (6) is as follows: carburizing is performed by gas carburizing, heating the tool to 880-940°C, carburizing the tool with methane gas for 3-5 hours, and then naturally cooling the tool to room temperature.

Images