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Electric arc plasma auxiliary low-voltage nitriding method for surface of hot-working die

A surface arc and plasma technology, applied in metal material coating process, coating, solid-state diffusion coating, etc.

Active Publication Date: 2015-12-23
SOUTH CHINA UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0007]The above scheme has developed the nitriding process to a certain extent, but the ionized nitriding layer is shallow, and it is difficult to ensure a uniform layer for metal parts with complex structures. Moreover, the equipment is complex and the initial investment is large, and its wide-scale promotion and application are limited.

Method used

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  • Electric arc plasma auxiliary low-voltage nitriding method for surface of hot-working die
  • Electric arc plasma auxiliary low-voltage nitriding method for surface of hot-working die
  • Electric arc plasma auxiliary low-voltage nitriding method for surface of hot-working die

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0057] Example 1— Sand blasting on workpiece surface

[0058] (1) The workpiece is H13 steel that has been sandblasted, with a sandblasting particle size of 80 mesh and a roughness of Ra1.4μm. The workpiece is ultrasonically cleaned with acetone solution for 20 minutes, taken out and dried with a hair dryer, and placed in an arc plasma assisted nitriding device Carry out nitriding treatment in the vacuum chamber, turn on the mechanical pump and the molecular turbo pump in turn to evacuate to the background vacuum, heat to 600°C, and remove the residue in the vacuum chamber.

[0059] (2) Keep the temperature in the furnace at 500°C, and the air pressure in the vacuum chamber is 4.0×10 -3 Pa, the workpiece transfer platform is connected to the negative pole of the pulse power supply, the negative bias voltage is 300V, the pulse frequency is 20kHz, and the duty cycle is 0.8. The arc is struck by an arc target. The arc target uses a Ti target. The target current is 85A. There i...

Embodiment 2

[0064] Example 2— Workpiece surface grinding wheel grinding

[0065] (1) The workpiece is H13 steel in the grinding state of the grinding wheel, the roughness is Ra0.8μm, the workpiece is ultrasonically cleaned with acetone solution for 20 minutes, after taking it out, it is dried with a hair dryer, and placed in an arc plasma assisted nitriding device for nitriding treatment, followed by Turn on the mechanical pump and the molecular turbo pump to evacuate to the background vacuum, heat to 600°C, and remove the residue in the vacuum chamber.

[0066] (2) Keep the temperature in the furnace at 500°C, and the air pressure in the vacuum chamber is 4.0×10 -3 Pa, the workpiece transfer platform is connected to the negative pole of the pulse power supply, the negative bias voltage is 300V, the pulse frequency is 20kHz, and the duty cycle is 0.8. The arc is struck by an arc target. The arc target uses a Ti target. The target current is 85A. There is a baffle in front of the target...

Embodiment 3

[0071] Example 3— Sandpaper grinding of workpiece surface

[0072] (1) The workpiece is sandpaper-polished (1000#) H13 steel, with a roughness of Ra0.35μm. The workpiece is ultrasonically cleaned with acetone solution for 20 minutes. After taking it out, it is dried with a hair dryer and placed in an arc plasma assisted nitriding device for nitriding For nitrogen treatment, turn on the mechanical pump and molecular turbo pump in turn to evacuate to the background vacuum, heat to 600°C, and remove the residue in the vacuum chamber.

[0073] (2) Keep the temperature in the furnace at 500°C, and the air pressure in the vacuum chamber is 4.0×10 -3 Pa, the workpiece transfer platform is connected to the negative pole of the pulse power supply, the negative bias voltage is 300V, the pulse frequency is 20kHz, and the duty cycle is 0.8. The arc is struck by an arc target. The arc target uses a Ti target. The target current is 85A. There is a baffle in front of the target, and the e...

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Abstract

The invention discloses an electric arc plasma auxiliary low-voltage nitriding method for the surface of a hot-working die. The method includes the steps that firstly, ion etching is performed on the surface of the hot-working die through Ar+ generated by electric arc-enhanced glow discharge, so that oxide on the surface of the material is removed; then a certain flow of high-purity N2, high-purity H2 and high-purity Ar are continuously introduced to a furnace, the temperature ranging from 300 DEG C to 600 DEG C and the air pressure ranging from 0.2 Pa to 1.0 Pa in the furnace are kept constant, a workpiece rotation platform is connected with the negative electrode of a pulse power source, and plasma nitridation is performed; the depth of a nitriding layer in 2h nitridation ranges from 15 micrometers to 40 micrometers, the thickness of a compound layer in the nitriding layer ranges from 0 to 3 micrometers, the hardness ranges from 1000 HV<0.1> to 1300 HV<0.1>, and the brittleness level and the looseness level are both smaller than 1. In addition, the surface of a workpiece is effectively bombarded and activated in real time through argon ions, so that nitrogen atomic diffusion channels are increased, the nitriding process is accelerated, and finally the high-strength and high-tenacity nitriding surface layer is obtained.

Description

technical field [0001] The invention belongs to the field of material surface modification, and in particular relates to a low-pressure nitriding method assisted by electric arc plasma on the surface of a hot work mold, which is suitable for surface strengthening of hard alloy cutters, molds and metal parts. Background technique [0002] Plasma nitriding is an important chemical heat treatment technology, which has the advantages of low treatment temperature, fast speed, no pollution, good process controllability, etc., and can significantly improve the surface hardness and wear resistance of metal materials. Nitriding methods are usually divided into gas nitriding, liquid nitriding, solid nitriding and ion nitriding. Among them, ion nitriding has been widely used because of its high efficiency, low pollution, easy control, and small deformation of workpieces. [0003] At present, the commonly used ion nitriding technologies include direct current ion nitriding, pulse direc...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C23C8/36
CPCC23C8/36
Inventor 匡同春蔡盼盼李雪萍谭超林邓阳周克崧
Owner SOUTH CHINA UNIV OF TECH
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