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Process method for controlling non-martensite depth of carburized workpiece

A non-martensitic and process technology, which is applied in the direction of metal material coating process, coating, solid-state diffusion coating, etc., can solve the problem of not effectively reducing the depth of non-martensite on the surface of deep carburized workpieces and reducing the surface of workpieces. Hardness, wear resistance, affecting the contact fatigue strength of the workpiece and other issues, to achieve the effect of improving comprehensive mechanical properties, increasing stability, and increasing hardenability

Active Publication Date: 2016-12-14
CRRC QISHUYAN INSTITUTE CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Non-martensitic structure is a common carburizing quality defect, which reduces the surface hardness and wear resistance of the workpiece, affects the contact fatigue strength of the workpiece, and reduces the life of the workpiece
The existing heat treatment methods have few control methods for the depth of non-martensite, and cannot effectively reduce the depth of non-martensite on the surface of deep carburized workpieces

Method used

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  • Process method for controlling non-martensite depth of carburized workpiece
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  • Process method for controlling non-martensite depth of carburized workpiece

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Embodiment 1

[0036] The invention discloses a process method for controlling the non-martensitic depth of a carburized workpiece, which comprises the following steps:

[0037] Clean the workpiece to be carburized in advance, especially to ensure that there is no oil and other impurities on the surface of the tooth profile, and at the same time, do anti-seepage treatment on the part of the workpiece that does not need to be carburized.

[0038]S1. Carburizing: The carburizing includes a pretreatment step and a carburizing step, and the carburizing step includes a strong infiltration stage and a diffusion stage.

[0039] S1-1 Pretreatment step: Clamp the cleaned workpiece on the heat treatment tool, and put it into the box-type carburizing furnace as a whole. The selected box-type carburizing furnace has a volume of 1.2m 3 . Turn on the power to raise the temperature, and turn on a large flow of nitrogen to replace the atmosphere in the furnace to reduce the content of oxygen and other oxid...

Embodiment 2

[0051] The invention discloses a process method for controlling the non-martensitic depth of a carburized workpiece, which comprises the following steps:

[0052] Clean the workpiece to be carburized in advance, especially to ensure that there is no oil and other impurities on the surface of the tooth profile, and at the same time, do anti-seepage treatment on the part of the workpiece that does not need to be carburized.

[0053] S1. Carburizing: The carburizing includes a pretreatment step and a carburizing step, and the carburizing step includes a strong infiltration stage and a diffusion stage.

[0054] S1-1 Pretreatment step: Clamp the cleaned workpiece on the heat treatment tool, and put it into the box-type carburizing furnace as a whole. The selected box-type carburizing furnace has a volume of 1.2m 3 . Turn on the power to raise the temperature, and turn on a large flow of nitrogen to replace the atmosphere in the furnace to reduce the content of oxygen and other oxi...

Embodiment 3

[0066] The invention discloses a process method for controlling the non-martensitic depth of a carburized workpiece, which comprises the following steps:

[0067] Clean the workpiece to be carburized in advance, especially to ensure that the surface to be carburized is free of any oil and other impurities, and at the same time, do anti-seepage treatment on the parts of the workpiece that do not need to be carburized.

[0068] S1. Carburizing: The carburizing includes a pretreatment step and a carburizing step, and the carburizing step includes a strong infiltration stage and a diffusion stage.

[0069] S1-1 Pretreatment step: Clamp the cleaned workpiece on the heat treatment tool, and put it into the box-type carburizing furnace as a whole. The selected box-type carburizing furnace has a volume of 1.2m 3 . Turn on the power to raise the temperature, and turn on a large flow of nitrogen to replace the atmosphere in the furnace to reduce the content of oxygen and other oxidizin...

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Abstract

The invention discloses a process method for controlling the non-martensite depth of a carburized workpiece. The process method comprises the steps of carburizing, ammonia introducing, primary quenching, high-temperature tempering, secondary quenching and low-temperature tempering for two times. According to the process method for controlling the non-martensite depth of the carburized workpiece, the carbon potential during carburizing is improved, and the proportion of the strong carburizing stage in the total carburizing time is increased, so that the internal oxidation depth in the carburizing atmosphere is decreased; in addition, a certain amount of ammonia is introduced in the final stage of carburizing and heat preservation, N atoms permeate into the surface of the workpiece, the hardenability of a workpiece carburized layer is improved, and hence formation of a non-martensite structure is effectively prevented; and meanwhile, after carburizing is conducted, the high-temperature tempering process is added between the two times of quenching processes, and the subsequent two times of low-temperature tempering processes are conducted, so that the content of surface layer residual austenite is effectively decreased, and the situation that the residual austenite does not meet the technical requirement is avoided.

Description

technical field [0001] The invention relates to the technical field of carburizing and quenching heat treatment of workpieces, in particular to a process method for controlling the non-martensitic depth of carburized workpieces. Background technique [0002] In recent years, railway locomotives are developing towards high-speed and heavy-duty directions, and the requirements for the performance of locomotive traction workpieces are getting higher and higher. The workpieces are required to have high contact fatigue strength and bending fatigue strength to ensure sufficient service life and reliability of the workpiece. sex. At present, the locomotive traction workpiece is generally made of low-carbon alloy steel and strengthened by carburizing and quenching heat treatment. [0003] Carburizing is a common heat treatment process for metal materials. It refers to the process of carbon atoms infiltrating into the surface layer of steel. The specific method is to place the workp...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C23C8/22C21D1/18C23C8/26
CPCC21D1/18C23C8/22C23C8/26
Inventor 陈金龙吴国庆吴刚樊洋
Owner CRRC QISHUYAN INSTITUTE CO LTD
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