Quenching liquid for carburizing and quenching

Abstract

The invention discloses quenching liquid for carburizing and quenching. The quenching liquid for carburizing and quenching comprises the following components in parts by weight: 1-3% of a surfactant; 1%-3% of an antirust agent; 0.5%-2% of a bactericide; and 5%-40% of at least one of a polyacrylic acid and polyvinylpyrrolidone copolymer, a polyacrylic acid polymer and a polyvinylpyrrolidone polymer, wherein the relative molecular mass range of the copolymer is 50,000-300,000; and the balance of deionized water.

Description

Technical Field

[0001] The present invention relates to a mechanical device for printing, and particularly to a quenching liquid for carburizing and quenching. Background Art

[0002] Carburizing and quenching is a common heat treatment process for metal materials, which can make the surface of the carburized workpiece obtain high hardness and improve its wear resistance.

[0003] Most of the materials using the carburizing process are low-carbon steel or low-alloy carbon steel (carbon content less than 0.25%). The specific method is to place the workpiece in an active carburizing medium, heat it to the single-phase austenite region of 900 - 950 degrees Celsius, keep it for a sufficient time, so that the active carbon atoms decomposed from the carburizing medium penetrate into the surface layer of the steel workpiece. Then, through quenching and low-temperature tempering, the surface layer of the workpiece has high hardness, high wear resistance and fatigue strength. The chemical composition of its surface can be close to that of high-carbon steel, while the central part of the workpiece still maintains the strength, toughness and plasticity of low-carbon steel, enabling the workpiece to withstand impact loads.

[0004] The carburizing process is widely used in mechanical parts of airplanes, automobiles and tractors, such as gears, shafts, camshafts, etc.

[0005] The quenching process of the carburizing process is to make the supercooled austenite undergo martensite or bainite transformation to obtain martensite or bainite structure, and then cooperate with tempering at different temperatures to greatly improve the strength, hardness, wear resistance, fatigue strength and toughness of the steel, so as to meet the different use requirements of various mechanical parts and tools. It can also meet the special physical and chemical properties such as ferromagnetic property and corrosion resistance of some special steel materials through quenching. It is widely used in various tools, dies, measuring tools and parts requiring surface wear resistance (such as gears, rolls, carburized parts, etc.).

[0006] In the prior art, quenching oil and water-soluble quenching liquid are commonly used as the cooling medium for carburizing and quenching. There are relevant literatures on the use of quenching oil for carburizing and quenching, such as: [1] He Yongjun, He Jiasheng, He Jiaxian, etc. A hot working method for carburizing and quenching of a variable-speed gear: CN201510207346.3[P][2024-10-17]; there are also relevant articles introducing the influence of different quenching oils on the carburizing and quenching structure and deformation, such as: [2] Fan Pengyu, Zhai Pengyuan, Liu Ke, etc. Numerical simulation of the influence law of different quenching oils on the carburizing and quenching structure and deformation of 18Cr2Ni2MoVNbA steel [J]. Heat Treatment of Metals, 2024, 49(4): 229-236, and the workpiece deformation is controlled by selecting a suitable quenching oil, such as: [3] Wang Peizhong, Zuo Yongping, Sun Qingru. How to select quenching oil to control the deformation of carburized gears [J]. Heat Treatment Technology and Equipment, 2011, 32(1): 5. DOI: 10.3969 / j.issn.1673-4971.2011.01.016.In addition, there are also relevant literatures on the use of water-soluble quenching fluids for carburizing quenching, such as: [4] Zhou Wenju. Machining process of a hydraulic pump worm: CN201710642324.9[P]. CN107236847A[2024-10-17]; and [5] Li Jiangui, Sun Wei, Kang Fengbo. Application research of aqueous medium in the first-stage quenching of G20Cr2Ni4A carburizing [J]. Metalworking (Hot Working), 2017, 19(No.790): 28-30. DOI: CNKI:SUN:JXRG.0.2017-19-008; and there are reports on inorganic water-soluble quenching fluids, see [6] Yuan Xinghui, Wang Guiji, Li Weixing, etc. Quenching process of a carburized bearing steel: CN 201410327216[P][2024-10-16]; and [7] Yan Yixiao, Fan Xinyu, Wang Yuanqi, etc. Research on the quenching process of inorganic polymer water-soluble quenching fluid for GCr15SiMn bearing steel [J]. Bearing, 2020(8): 4. DOI: 10.19533 / j.issn1000-3762.2020.08.007; in addition, there are also relevant reports on water-soluble high-molecular polymers, [8] Shi Juyan, Wang Baocheng, Yu Jing, etc. A carbide-precipitating rare-earth carburized steel [2024-10-17]. DOI: CN101967605 A; and [9] Anonymous. HT series of polymer organic synthetic water-based quenching fluids [J]. Modern Manufacturing, 2018(025): 000; and

[10] Chen Ru, Chen Yanrui. Application of AQ364 quenching fluid in parts of rock drilling machinery and pneumatic tools [J]. Rock Drilling Machinery & Pneumatic Tools, 1997(3): 4. DOI: CNKI:SUN:ZYJG.0.1997-03-013; and

[11] Song Congzhen, Hu Shaotao, Yang Xiucheng. Application of PAG quenching medium in gear carburizing quenching [J]. Heat Treatment Technology and Equipment, 2014, 35(2): 2. DOI: 10.3969 / j.issn.1673-4971.2014.02.017. Summary of the Invention

[0007] One advantage of the present invention is to provide a quenching fluid for carburizing quenching. Compared with oil-based quenching media, the water-soluble quenching fluid completely eliminates the environmental pollution caused by various fumes during oil quenching with quenching oil, is non-toxic, smokeless and flameless, is more environmentally friendly and safe, improves the working environment and eliminates fire hazards. It has higher economic efficiency than quenching oil and lower comprehensive cost. The carry-out amount is small. It has good thermal stability, can fully maintain stable performance, and has a long service life. It can be miscible with water in any proportion to adjust the concentration to meet different quenching requirements.

[0008] One advantage of the present invention is to provide a quenching liquid for carburizing and quenching. This application uses a new quenching medium for carburizing and quenching, a water-soluble polymer ACR / PVP-based quenching liquid. Its cooling capacity is faster than that of quenching oil at a cooling rate of 300 degrees, so that it can improve the core hardness of the material and the content of martensite structure, and make the structure more uniform and the nucleation rate higher.

[0009] One advantage of the present invention is to provide a quenching liquid for carburizing and quenching. The ACR / PVP-based quenching liquid not only has the common advantages of water-soluble quenching liquids such as safety and environmental protection, but also can achieve similar effects to PAG-based quenching liquids at a lower use concentration, thus further saving costs. At the same time, the ACR / PVP-based polymer has a higher thermal decomposition temperature and will be more stable during use, further extending the service life of the quenching liquid and maintaining good workpiece performance.

[0010] To achieve at least one of the above advantages of the present invention, the present invention provides a quenching liquid for carburizing and quenching. The quenching liquid for carburizing and quenching includes the following components in parts by weight:

[0011] Surfactant: 1% - 3%;

[0012] Rust inhibitor: 1% - 3%;

[0013] Bactericide: 0.5% - 2%; and

[0014] At least one of polyacrylic acid and polyvinylpyrrolidone copolymer polymer, polyacrylic acid polymer, and polyvinylpyrrolidone polymer: 5% - 40%, and its relative molecular mass ranges from 50,000 to 300,000; and

[0015] The balance is deionized water.

[0016] According to an embodiment of the present application, the surfactant is any one or two of polyglycerol fatty acid ester or glycerol polyoxyethylene ether substances.

[0017] According to an embodiment of the present application, the rust inhibitor is any one or two of methylbenzotriazole or benzotriazole derivatives.

[0018] According to an embodiment of the present application, the bactericide is a general bactericide or a fungicide. Detailed implementation

[0019] The following description is used to disclose the present invention so that those skilled in the art can implement the present invention. The preferred embodiments in the following description are only examples, and those skilled in the art can think of other obvious variations. The basic principles defined in the following description of the present invention can be applied to other embodiments, variants, improvements, equivalent schemes, and other technical solutions without departing from the spirit and scope of the present invention.

[0020] The quenching liquid for carburizing and quenching according to a preferred embodiment of the present application will be elaborated in detail below, wherein the quenching liquid for carburizing and quenching is a water-soluble polymer ACR / PVP type quenching liquid, which comprises the following components in parts by weight:

[0021] Surfactant: 1% - 3%;

[0022] Rust inhibitor: 1% - 3%;

[0023] Bactericide: 0.5% - 2%; and

[0024] At least one of polyacrylic acid and polyvinylpyrrolidone copolymer, polyacrylic acid polymer, and polyvinylpyrrolidone polymer: 5% - 40%, and its relative molecular mass ranges from 50,000 to 300,000; and

[0025] The balance of deionized water.

[0026] It is worth mentioning that if the content of the water-soluble polymer in the formula, that is, at least one of polyacrylic acid and polyvinylpyrrolidone copolymer, polyacrylic acid polymer, and polyvinylpyrrolidone polymer, is less than 5%, it will cause the cooling rate of the quenching liquid during use to be too fast, and the maximum cooling rate and the cooling rate at 300 degrees may be close to that of water, which is likely to cause deformation and cracking of the quenched workpiece, or reduce the impact resistance of the material; if the content of the water-soluble polymer in the formula is too large, such as greater than 40%, it will cause the quenching cooling rate to be too low, especially the maximum cooling rate is too low, resulting in insufficient hardness or uneven hardness of the workpiece after quenching, affecting the performance stability of the workpiece.

[0027] Preferably, its relative molecular mass ranges from 50,000 to 100,000.

[0028] Preferably, the chemical structure of the polyacrylic acid and polyvinylpyrrolidone copolymer included in the water-soluble polymer ACR / PVP type quenching liquid for carburizing and quenching is shown in the following figure:

[0029]

[0030] Preferably, the surfactant is any one or two of polyglycerol fatty acid ester or glycerol polyoxyethylene ether substances.

[0031] Preferably, the rust inhibitor is any one or two of methylbenzotriazole or benzotriazole derivatives.

[0032] Preferably, the bactericide is a general bactericide or a fungicide; in a preferred embodiment, the bactericide is implemented as any one or two of BK, BIT, and BBIT and a combination of two or more thereof.

[0033] It is worth mentioning that compared with PAG quenching fluids, this quenching fluid has a higher thermal decomposition temperature and stronger stability during application. And it can achieve similar effects at a lower usage concentration. It can further reduce the usage temperature of the quenching fluid and shorten the carburizing time, which helps to save energy and improve work efficiency.

[0034] In addition, the surfactant used has high-temperature stability and can adjust the cooling rate at 300°C. All these enable this quenching fluid to have a longer service life and higher efficiency.

[0035] Example 1:

[0036] Surfactant: 1%;

[0037] Rust inhibitor: 1%;

[0038] Bactericide: 0.5%; and

[0039] Copolymer of polyacrylic acid and polyvinylpyrrolidone: 5%, with a relative molecular mass range of 50,000 to 150,000; and

[0040] The balance of deionized water.

[0041] In Example 1, at a 10% usage concentration, the cooling rate at 300°C is 35°C / s; at a 20% usage concentration, the cooling rate at 300°C is 22°C / s. The starting thermal decomposition temperature is 423°C.

[0042] Example 2:

[0043] Surfactant: 3%;

[0044] Rust inhibitor: 3%;

[0045] Bactericide: 2%; and

[0046] Polyacrylic acid polymer: 10%, with a relative molecular mass range of 5 to 150,000; and

[0047] The balance of deionized water.

[0048] In Example 2, at a 10% usage concentration, the cooling rate at 300°C is 35°C / s; at a 20% usage concentration, the cooling rate at 300°C is 18°C / s. The starting thermal decomposition temperature is 418°C.

[0049] Example 3:

[0050] Surfactant: 2%;

[0051] Rust inhibitor: 2%;

[0052] Bactericide: 1%; and

[0053] Polyvinylpyrrolidone polymer 40%, with a relative molecular mass ranging from 200,000 to 300,000; and

[0054] The balance is deionized water.

[0055] In Example 3, at a 10% use concentration, the cooling rate at 300 °C is 29 °C / s; at a 20% use concentration, the cooling rate at 300 °C is 16 °C / s. The initial thermal decomposition temperature is 420 °C.

[0056] For quenching oils in the prior art, different quenching oils will have differences. Generally, the cooling rate at 300 °C is between 4 and 15 °C / s.

[0057] In addition, it is worth mentioning that the initial thermal decomposition temperature of PAG-based quenching fluids is about 350 °C. In the embodiments of the present application, the thermal decomposition temperature of the ACR / PVP-based polymer is higher, which will be more stable during use, further extending the service life of the quenching fluid and also maintaining good workpiece performance.

[0058] Those skilled in the art should understand that the embodiments of the present invention described above and shown in the drawings are only examples and do not limit the present invention. The advantages of the present invention have been fully and effectively realized. The functions and structural principles of the present invention have been demonstrated and explained in the embodiments. Without departing from the said principles, the embodiments of the present invention can have any deformation or modification.

Claims

1. A quenching liquid for carburizing and quenching, characterized in that: The quenching liquid for carburizing and quenching comprises the following components in parts by weight: Surfactant: 1%~3%; Rust inhibitor: 1% to 3%; Fungicide: 0.5%~2%; as well as At least one of polyacrylic acid and polyvinyl pyrrolidone copolymers, polyacrylic acid polymers, and polyvinyl pyrrolidone polymers: 5% to 40%, with a relative molecular mass ranging from 50,000 to 300,000; and The balance is deionized water.

2. The quenching liquid for carburizing and quenching according to claim 1, characterized in that: The surfactant is any one or two of polyglycerol fatty acid esters or glycerol polyoxyethylene ether substances.

3. The quenching liquid for carburizing and quenching according to claim 1, characterized in that: The rust inhibitor is any one or two of tolutriazole and benzotriazole derivatives.

4. The quenching liquid for carburizing and quenching according to claim 1, characterized in that: The bactericide is a general bactericide or a fungicide.

5. The quenching liquid for carburizing and quenching according to claim 1, characterized in that: Its relative molecular mass ranges from 50,000 to 100,000.

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