Composite heat treatment method

An ideal technology for composite heat treatment, which is applied in the field of improvement of composite heat treatment methods, can solve problems such as low hardness loose layers, achieve the effect of reducing workpiece deformation and increasing the depth of effective hardened layer

Inactive Publication Date: 2011-03-30
闫欧
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Problems solved by technology

But at the same time, there is still the problem of a low-hardness loose layer on the surface. These treatments can only be applied to thin stamped metal parts. In order to

Method used

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Examples

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Effect test

Embodiment

[0011] Example: The crankshaft of the machine tool, the material is 20Cr, the depth of the carburized layer is 0.4μm, the surface hardness is higher than 850HV, and the deformation of the workpiece has been treated by carburizing. With ferrite nitrocarburizing, the depth of the infiltrating layer cannot meet the requirements.

[0012] The heat treatment of the crankshaft is carried out in a TX-60 box furnace. First, carburize at 880°C, control the carbon potential concentration to 0.85% for 90 minutes, and use methanol decaacetone as the catalyst. After the carburized layer is checked, the temperature is reduced to 740°C. Human ammonia gas, ammonia decomposition rate is controlled at 85~90yo, time is 3 hours, the workpiece is processed to obtain a 0.23smm high nitrogen austenite layer, then quenched or water), and aged at 250 ℃ for 3 hours. After treatment, the surface hardness of the workpiece reaches 870HV, and the core hardness is 35HRC; the deformation is within the tolerance...

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Abstract

The invention provides a composite heat treatment method and relates to a metal material carburizing and nitriding composite heat treatment process method. By the composite heat treatment method provided by the invention, the depth of a metal heat treatment permeating layer is improved; deformation is reduced; advantages of various processes are organically combined and completely exerted; the defects of the processes are overcome; and high using performance of metal is achieved. The composite heat treatment method comprises the following steps of: heating a workpiece to an austenite state and performing carburizing or carbonitriding to obtain an ideal permeating layer; cooling the permeating layer in a furnace to the austenite nitriding temperature of between 640 and 720 DEG C and performing nitriding or carbonitriding, so that the nitrogen concentration of the austenite on the surface layer of the workpiece is increased to that of the austenite nitriding layer; and directly quenching at the temperature of about 800 DEG C and performing aging treatment in the range of 300 DGE C, or directly performing isothermal quenching at the temperature of between 200 and 240 DEG C, so that the high-nitrogen austenite is decomposed and ideal surface hardness and wear resistance of the meal are achieved.

Description

Technical field: [0001] The invention relates to an improvement of a composite heat treatment method, in particular to a composite heat treatment process method of carburizing and nitriding of metal materials. Background technique: [0002] At present, in the process of metal heat treatment, carburizing or nitriding is a commonly used heat treatment process to change the chemical composition and microstructure of the metal surface during the heat treatment process, so that the metal surface has high hardness and wear resistance. The maximum hardness is 58-62HRC, which is equivalent to 630-750HV. The core has low martensite (or bainite, sorbite) and other structures, which has certain toughness and impact resistance, so it has been widely used. However, this method has certain restrictions on the improvement of metal surface hardness and wear resistance. In addition, the metal processed by this heat treatment method requires high requirements on the carburizing furnace and some re...

Claims

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Application Information

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IPC IPC(8): C23F17/00C23C8/20C23C8/30C21D1/18C21D1/20C21D10/00
Inventor 闫欧
Owner 闫欧
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