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Hot processing method for removing decarbonizing of steel surface

A heat treatment method and technology of steel parts, applied in the field of heat treatment, can solve the problem of eliminating decarburization, etc., and achieve the effect of continuous seepage layer and internal structure state

Inactive Publication Date: 2007-02-14
SHANGHAI AUTOMOBILE GEAR WORKS +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The patent is how to prevent decarburization, and how to eliminate decarburization of steel parts that have been decarburized

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0014] Eliminate surface decarburization of an automobile shift fork steel part, material: SAE 8620H (material standard SAE J1268).

[0015] ①Precision forging of steel parts, the starting forging temperature is 1150°C-1200°C, and the final forging temperature is ≥900°C.

[0016] ②Normalizing treatment, controlled atmosphere (carbon potential 0.5-0.6% / c): After the steel is austenitized at 940°C / 2 hours, it is air-cooled or air-cooled to room temperature to obtain a uniform pearlite + ferrite balanced structure.

[0017] ③ Carburizing by heat treatment. Under the austenitization temperature and carbon potential, the maximum depth of decarburization layer is measured according to metallography. Before the final heat treatment, carburizing treatment is carried out to form a decarburization-free continuous The composition and metallographic structure of the steel are then slowly cooled to 300°C with the furnace, and then released from the furnace to avoid repeated oxidation and d...

Embodiment 2

[0023] Eliminate surface decarburization treatment of precision forged differential gear, material SAE / AISI4615.

[0024] ①Precision forging of steel parts, the starting forging temperature is 1150°C-1230°C, and the final forging temperature is ≥900°C.

[0025] ②Normalizing treatment, controlled atmosphere furnace (carbon potential 0.5-0.6%C), austenitizing the steel at 925°C / 2 hours, then air cooling or air cooling to room temperature to obtain a uniform pearlite + ferrite balance structure.

[0026] ③ Carburizing by heat treatment. Under the austenitization temperature and carbon potential, the maximum depth of decarburization layer is measured according to metallography. Before the final heat treatment, carburizing treatment is carried out to form a decarburization-free continuous The composition and metallographic structure of the steel are then slowly cooled to 300°C with the furnace, and then released from the furnace to avoid repeated oxidation and decarburization, and ...

Embodiment 3

[0032] Eliminate surface decarburization of an automobile shift fork steel part, material: SAE 8620H (material standard SAE J1268).

[0033] ①Steel parts are precision forged, with a starting forging temperature of 1200°C and a final forging temperature of 910°C.

[0034] ②Normalizing treatment, controlled atmosphere (carbon potential 0.5% / c): After the steel is austenitized at 940°C / 2 hours, it is air-cooled or air-cooled to room temperature to obtain a uniform pearlite + ferrite balanced structure.

[0035] ③Carburization by heat treatment, at the austenitization temperature and carbon potential, according to the maximum depth of the decarburization layer, before the final heat treatment, carburizing treatment is carried out first, and the surface with decarburization layer is formed to form a continuous composition without decarburization and The metallographic structure is then slowly cooled to 300°C with the furnace to avoid repeated oxidation and decarburization, and to ...

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PUM

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Abstract

The invention relates to a heat processing method used to remove steel parts surface decarburization. It includes the following steps: precision forging for the steel parts; heat treatment carbon complementing; normalizing treatment; machine tooled; carbonitriding quenching; backfire. The heat treatment carbon complementing is that the decarburized layer surface is processed cementation to form no decarburization continuous component and metallographic structure at austenitic temperature and carbon potential according to decarburized layer extreme depth before final heat treatment, then cooled to 300 degree centigrade to draw a charge. This can make the processed or unprocessed parts of the steel part have the same effective depth of hardening to improve steel part surface strength and control the deformation.

Description

technical field [0001] The invention relates to a method in the technical field of heat treatment, in particular to a heat treatment method for eliminating decarburization on the surface of a steel piece. Background technique [0002] During the forging process of steel parts at high temperature (1150°C-1250°C), under the action of oxygen in the air, the surface will be oxidized and decarburized (at 1 atmosphere, the oxidation temperature of steel is 520°C), the non-processed surface of steel parts , after the final carburizing or carbonitriding heat treatment, if the depth of the decarburized layer is greater than or equal to the depth requirement of the carburized layer or carbonitrided layer of the product, there will be a discontinuity of the carburized layer and the internal structure state, which will lead to Severe reduction in product functionality. [0003] After searching the prior art documents, it is found that the Chinese patent application number: CN03178373.2...

Claims

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Application Information

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IPC IPC(8): C23F17/00C23C8/20C21D1/18C21D11/00
Inventor 林德成归永康
Owner SHANGHAI AUTOMOBILE GEAR WORKS
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