Method for carbonitriding heat treatment of screws

A heat treatment method, carbonitriding technology, applied in the direction of coating, metal material coating process, solid-state diffusion coating, etc., can solve the problems such as the hardness of the shallow surface of the infiltration layer, and achieve high toughness, wear resistance and fatigue strength The effect of improving and reducing the risk of hydrogen embrittlement in electroplating

Active Publication Date: 2015-12-30
佳兴紧固件工业(苏州)有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Heat treatment is a common process to improve the mechanical properties of screws, but the current carbonitriding process used in screw processing has the dis

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Example Embodiment

[0021] Example 1

[0022] The screws to be heat treated are cleaned with warm water and high pressure spray to remove the residual oil and diesel in the screw threading process, reduce the pollution of the equipment, and ensure even carburization of the parts. The water pressure during the cleaning process is controlled to 1kgf / cm 2 .

[0023] The feeder speed is adjusted to 30Hz / rpm, the feeder transports the screws to the continuous furnace for continuous preheating and carbonitriding treatment, adjusts the main speed of the continuous furnace for continuous preheating, and the preheating is a two-stage type Preheating, the first stage of preheating temperature is 600℃, and the holding time is 10 minutes to reduce the internal stress caused by screw heading and threading, reduce the temperature difference between the inside and outside of the screw, and eliminate the cracking and cracking caused by work hardening. Deformation, the second stage of preheating temperature is 860℃, a...

Example Embodiment

[0026] Example 2

[0027] The screws to be heat treated are cleaned with warm water and high pressure spray to remove the residual oil and diesel in the screw threading process, reduce the pollution of the equipment, and ensure even carburization of the parts. The water pressure during the cleaning process is controlled to 1.2kgf / cm 2 .

[0028] The feeder speed is adjusted to 45Hz / rpm, the feeder transports the screws to the continuous furnace for continuous preheating and carbonitriding treatment, adjusts the main speed of the continuous furnace for continuous preheating, and the preheating is a two-stage type Preheating, the first stage of preheating temperature is 600℃, and the holding time is 13 minutes to reduce the internal stress caused by screw heading and threading, reduce the temperature difference between the inside and outside of the screw, and eliminate the cracking and cracking caused by work hardening. Deformation, the second stage of preheating temperature is 870℃,...

Example Embodiment

[0031] Example 3

[0032] The screws to be heat treated are cleaned with warm water and high pressure spray to remove the residual oil and diesel in the screw threading process, reduce the pollution of the equipment, and ensure even carburization of the parts. The water pressure during the cleaning process is controlled to 1.5kgf / cm 2 .

[0033] The feeder speed is adjusted to 60Hz / rpm, the feeder transports the screws to the continuous furnace for continuous preheating and carbonitriding treatment, adjusts the main speed of the continuous furnace for continuous preheating, and the preheating is a two-stage type Preheating, the first stage of preheating temperature is 600℃, and the holding time is 15 minutes to reduce the internal stress caused by the screw heading and threading, reduce the temperature difference between the inside and outside of the screw, and eliminate the cracking and cracking caused by the work hardening of the screw. Deformation, the second stage of preheating...

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PUM

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Abstract

The invention discloses a method for carbonitriding heat treatment of screws. The method comprises the following steps of: (1) cleaning the screws needing heat treatment; (2) adjusting the speed of a feeding machine; (3) adjusting the main speed of a continuous furnace to carry out continuous preheating, and carrying out carbonitriding heat treatment on the preheated screws, wherein the preheating temperature is controlled at 860-890DEG C, the carbon potential is 1%-1.2%, and the ammonia gas flow is 0.2-0.5nm<3>/h; (4) carrying out primary quenching; (5) carrying out secondary quenching by adopting quick brightening oil; (6) cleaning the surfaces of the screws; and (7) tempering at 370-420 DEG C for 70-90min. The surface hardness of the screws processed by adopting the method is larger than 450HV0.3, the core hardness is 280-350HV0.3, the toughness is high, the electroplating hydrogen embrittlement risk is low, and the wear resistance and fatigue strength are improved.

Description

technical field [0001] The invention relates to the field of screw processing, in particular to a heat treatment method for carbonitriding of screws. Background technique [0002] Screws are commonly used parts in equipment. With the development of modern industrial level, higher requirements are put forward for screw hardness, wear resistance, corrosion resistance, bending strength and contact fatigue strength. Heat treatment is a common process to improve the mechanical properties of screws, but the current carbonitriding process used in screw processing has the disadvantages of high hardness of the nitriding layer but shallow carburizing layer or a large hardening depth of the carburizing layer but low surface hardness. Contents of the invention [0003] In order to solve the above technical problems, the object of the present invention is to provide a heat treatment method for carbonitriding of screws. In order to realize the foregoing invention object, the technical ...

Claims

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Application Information

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IPC IPC(8): C21D1/18C23C8/32
Inventor 庄英树
Owner 佳兴紧固件工业(苏州)有限公司
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