Medium and low-carbon alloy constructional steel surface pressurization gas-nitridation method

A technology of low-carbon alloy and pressurized gas, which is applied in the direction of metal material coating process, coating, solid-state diffusion coating, etc., can solve the limitation of heavy-duty large curvature radius parts bearing and impact resistance, long time, irreplaceable Deep carburization and other problems, to achieve the effect of enhancing the process effect, promoting adsorption and reducing the decomposition rate

Inactive Publication Date: 2013-06-19
YANSHAN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The conventional gas nitriding process takes a long time, generally tens or even hundreds of hours, and the nitrided layer is relatively shallow, which limits the load-bearing and impact resistance of some heavy-duty and large-radius-of-curvature parts.
At present, conventional nitriding still cannot replace deep carburizing

Method used

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  • Medium and low-carbon alloy constructional steel surface pressurization gas-nitridation method
  • Medium and low-carbon alloy constructional steel surface pressurization gas-nitridation method
  • Medium and low-carbon alloy constructional steel surface pressurization gas-nitridation method

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Experimental program
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Effect test

Embodiment 1

[0014] Process 31CrMoV9 steel into a test piece and hang it in a solid solution nitriding furnace with the patent name "A pressurized high-temperature nitriding device with a double-pressure balance structure" and the patent number 201210530358.6. NH 3 The flow rate is 0.1L / min, the decomposition rate is 30-40%, and the nitriding treatment is carried out for 10 hours, and then NH is continuously fed 3 To the furnace, cooling to 100 ° C to end. Such as figure 1 As shown, the thickness of the infiltrated layer obtained by the test block is about 0.441mm.

Embodiment 2

[0016] Process 42CrMo steel into a test block and hang it in a solid solution nitriding furnace with the patent name "A pressurized high-temperature nitriding device with a double-pressure balance structure" and the patent number 201210530358.6. NH 3 The flow rate is 0.3L / min, the decomposition rate is 50-60%, nitriding treatment is carried out for 5 hours, and then NH is continuously fed 3 To the furnace, cooling to 100 ° C to end. Such as figure 2 As shown, the thickness of the infiltrated layer obtained by the specimen is 0.24mm.

Embodiment 3

[0018] The 20CrMnTi steel is processed into a test block and hung in the solid solution nitriding furnace with the patent name "A pressurized high-temperature nitriding device with a double-pressure balance structure" and the patent number is 201210530358.6. NH 3 The flow rate is 0.5L / min, the decomposition rate is 60% to 80%, the nitriding treatment is 20h, and then the NH is continuously fed 3 To the furnace, cooling to 100 ° C to end. Such as image 3 As shown, the thickness of the infiltrated layer obtained by the test block is about 0.692mm.

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Abstract

The invention discloses a medium and low-carbon alloy constructional steel surface pressurization gas-nitridation method. The medium and low-carbon alloy constructional steel surface pressurization gas-nitridation method comprises the following steps of putting a medium and low-carbon alloy constructional steel workpiece into a solid solution nitrogenation furnace which is shown in the patent having a patent name of pressurization high-temperature nitridation device with dual pressure equilibrium structure and having the patent number of 201210530358.6, improving the pressure to 0.1-0.5MPa at a temperature of 500-800 DEG C, feeding NH3 into the solid solution nitrogenation furnace at a flow rate of 0.1-0.5L/min, carrying out gas nitridation treatment at a decomposition rate of 30-80% for 5-20 hours, sequentially feeding NH3 into the solid solution nitrogenation furnace, cooling to a temperature below 150 DEG C, and taking out the workpiece. The medium and low-carbon alloy constructional steel surface pressurization gas-nitridation method can effectively promote adsorption of N atoms on the part surface, improve N activity, an interface reaction rate and a hole and slit nitridation capability, reduce an NH3 decomposition rate, improve nitrogen potential, obviously reduce an NH3 consumption amount in nitridation, greatly improve process effects and realize short-term deep nitridation.

Description

technical field [0001] The invention belongs to the field of metal surface chemical heat treatment, and relates to a surface nitriding method of medium and low carbon alloy structural steel. Background technique [0002] Commonly used structural parts such as shafts and gears usually require nitriding treatment to improve their surface hardness, wear resistance and fatigue resistance. The conventional gas nitriding process takes a long time, generally tens or even hundreds of hours, and the nitrided layer is shallow, which limits the load-bearing and impact resistance of some heavy-duty and large-radius-of-curvature parts. At present, conventional nitriding still cannot replace deep carburizing. Contents of the invention [0003] The purpose of the present invention is to provide a pressurized gas nitriding method on the surface of medium and low carbon alloy structural steels which can realize short-term deep nitriding. The present invention mainly introduces pressure p...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C23C8/26
Inventor 傅万堂郭明伟王博曲明贵赵品郑炀曾吕知清
Owner YANSHAN UNIV
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