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Metal surface salt bath nitrocarburizing method

A technology of nitrocarburizing and metal surface application in the direction of metal material coating process, coating, solid-state diffusion coating, etc., which can solve the problems of low efficiency, inability to guarantee the quality of nitrocarburizing of parts, and failure to keep up with the increase of cyanide Speed ​​and other issues to achieve the effect of reducing pollution and improving regeneration capacity

Active Publication Date: 2013-01-30
CRRC QISHUYAN INSTITUTE CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0020] For cyanide treatment, if the CN - Combining with other cations will produce highly toxic substances, and then the method of removing slag and ventilating air into the salt bath can reduce the CN - content, but this method is inefficient and cannot keep up with the increasing rate of cyanide, nor can it guarantee the quality of nitrocarburizing of parts

Method used

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  • Metal surface salt bath nitrocarburizing method
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  • Metal surface salt bath nitrocarburizing method

Examples

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Effect test

Embodiment 1）

[0046] The method for the metal surface salt bath nitrocarburizing of the present embodiment comprises the following steps:

[0047] ① Cleaning of the workpiece. First check the surface of the workpiece to be infiltrated. If there is a decarburized layer, rust spots, sharp corners or sharp edges, it must be polished first, and then cleaned if there is no such situation by visual inspection.

[0048] When the workpiece is cleaned, first remove the oil stain on the surface by alkali washing, soak in clean water after alkali washing, rinse to remove the surface cleaning solution, and then dry it at 100°C to check the cleanliness of the workpiece surface and complete the cleaning to be processed.

[0049] During the cleaning process, for workpieces with blind holes or internal and external threads, the blind holes or threads need to be carefully inspected and cleaned.

[0050] ②Clamping of the workpiece. Install the cleaned workpiece obtained in step ① on the fixture to ensure t...

Embodiment 2）

[0084] The rest of the method of the metal surface salt bath nitrocarburizing of the present embodiment is the same as that of embodiment 1, the difference is: in the nitrocarburizing process of step ④, the sulfur-containing compound added in the salt bath furnace is The dosage of potassium sulfate and potassium sulfite is 2×10 of the quality of the salt bath in the salt bath furnace -2 %~4×10 -2 %.

[0085] S-3700N electron scanning microscope (voltage 20Kv, current 102μA, working distance 10mm) carried out elemental analysis on the nitrided layer of the co-infiltrated parts after adding sulfur-containing compounds, and there was no infiltration of sulfur element.

Embodiment 3 to Embodiment 6）

[0087] The rest of the method of salt-bath nitrocarburizing of metal surfaces in Examples 3 to 6 is the same as in Example 1, except that the corresponding sulfur-containing compounds and corresponding dosages listed in the following table are used.

[0088]

[0089] S-3700N electron scanning microscope (voltage 20Kv, current 102μA, working distance 10mm) carried out elemental analysis on the nitriding layer of the co-infiltrated parts after adding sulfur-containing compounds in the above-mentioned embodiments, and found no infiltration of sulfur element.

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Abstract

The invention discloses a metal surface salt bath nitrocarburizing method which comprises the following steps: (1) workpiece cleaning; (2) workpiece clamping; (3) workpiece preheating; (4) nitrocarburizing: transferring the workpieces preheated by the step (3) into a salt bath furnace, immersing the workpieces in the salt bath, and keeping the workpieces in the 535-585 DEG C salt bath for 30-180 minutes to complete nitrocarburizing, wherein when starting from the treatment of the first batch of workpieces to be nitrocarburized, taking salt samples from the salt bath furnace every 12-24 hours, determining the concentrations of cyanides and cyanates in the salt bath, and adding sulfur-containing compounds for lowering the cyanide content and regenerated salt into the salt bath furnace when the mass percent of the cyanides in the salt bath exceeds 3 wt%; and after completing the nitrocarburizing, cooling the workpieces, cleaning, drying, and carrying out oil immersion. According to the metal surface salt bath nitrocarburizing method disclosed by the invention, the sulfur-containing compounds are added into the salt bath composition in the nitrocarburizing process to lower the content of cyanides and enhance the regeneration capacity of the regenerated salt.

Description

technical field [0001] The invention relates to a method for heat treatment of metal surfaces, in particular to a method for salt bath nitrocarburizing of metal surfaces. Background technique [0002] With the continuous advancement of science and technology, the service conditions of workpieces become more and more harsh, so the requirements for the surface properties of metal parts are getting higher and higher. For metal parts, wear resistance, high strength and beautiful appearance are the basic requirements for the surface of metal parts. [0003] Nitrocarburizing is to infiltrate nitrogen and carbon elements into the surface of the workpiece at the same time, thereby changing the structure of the steel material, and thus changing the strength, friction, formability and corrosion resistance of the steel material under static load and alternating stress. After the workpiece is nitrocarburized, the surface obtains a co-infiltrated structure. In all industrial fields, th...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C23C8/54
Inventor 黄俊徐宁
Owner CRRC QISHUYAN INSTITUTE CO LTD
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