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Carbonitriding process for medium-large thin-wall bearing in high-carbon chromium bearing steel

A high-carbon chromium bearing steel, carbonitriding technology, applied in the direction of metal material coating process, manufacturing tools, furnace types, etc., can solve problems such as large heat treatment deformation, achieve small deformation, reduce grinding amount, The effect of prolonging the service life

Inactive Publication Date: 2021-01-08
CHENGDU TIANMA RAILWAY BEARING
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] In order to improve the defect of large heat treatment deformation of medium and large thin-walled bearings, the purpose of the present invention is to provide a carbonitriding process for medium and large-scale thin-walled bearings of high-carbon chromium bearing steel

Method used

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  • Carbonitriding process for medium-large thin-wall bearing in high-carbon chromium bearing steel
  • Carbonitriding process for medium-large thin-wall bearing in high-carbon chromium bearing steel
  • Carbonitriding process for medium-large thin-wall bearing in high-carbon chromium bearing steel

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0044] s1. Carbonitriding: Put a batch of 25 bearing outer ring products in 25 stations of the rotary hearth furnace at the same time, set the pushing cycle to 504s, heat to 820°C, set the methanol flow rate to 2.5L / h, Nitrogen flow rate 2.0m 3 / h, natural gas flow rate 0.3m 3 / h, ammonia gas flow rate 0.2m 3 / h, carbon potential 1.05%.

[0045] s2. Die quenching: After the carbonitriding heating of the product, the furnace door is automatically pushed out and transferred to the lower mold 1, then the upper mold 2 is pressed down by the cylinder, and the upper mold 2 presses the inner chamfer of the upper end surface of the product 3 and enters the oil tank for quenching ,Such as image 3 shown. The upper mold 2 has a taper of 45° and a size of 280mm, and the lower mold 1 has a taper of 45° and a size of 260mm. The controlled quenching pressure is 0.50MPa, the quenching oil temperature is 60°C, and the quenching time is 180s.

[0046] s3. Tempering: Control the tempering ...

Embodiment 2

[0048] The difference from Example 1 is: s1, carbonitriding: set the pushing cycle to 648s, and heat to 830°C, the methanol flow rate is 3L / h, and the nitrogen flow rate is 2.5m 3 / h, natural gas flow rate 0.5m 3 / h, ammonia gas flow rate 0.3m 3 / h, carbon potential 1.15%.

[0049] s3. Tempering: Control the tempering temperature to 220°C and the tempering time to 4h.

[0050] get as figure 1 Bearing outer ring products shown.

Embodiment 3

[0052] The difference from Example 2 is that the taper of the upper mold is 45°, the size of the upper mold is 210mm, the taper of the lower mold is 30°, and the size of the lower mold is 210mm.

[0053] get as figure 2 Bearing inner ring products shown.

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Abstract

The invention discloses a carbonitriding process for a medium-large thin-wall bearing in high-carbon chromium bearing steel. The process comprises the following steps: s1, carbonitriding; s2, pressingdie quenching; and s3, tempering is conducted, wherein the outer diameter of a medium-large thin-wall bearing ring is 100-450 mm, the effective wall thickness is 5-20 mm, a die for pressure quenchingadopts an upper die and a lower die which are in a circular truncated cone shape, and the small ends of the upper die and the lower die are oppositely arranged, so that during pressure quenching, theupper die presses and connects the bearing ring on the circumferential outer surface of the lower die through the circumferential outer surface. The process has the advantages that the earlier-stagecarburization time can be shortened, and the problems that medium -large thin-wall bearing rings are large in carbonitriding heat treatment deformation and uneven in hardness and structure distribution are solved.

Description

technical field [0001] The invention relates to the field of bearings, and more specifically relates to a carbonitriding process for medium and large thin-walled bearings in high-carbon chromium bearing steel. Background technique [0002] At present, high-carbon chromium bearing steel GCr15 is mostly used for bearing rings. High-carbon chromium bearing steel GCr15 has good comprehensive performance. After carbonitriding treatment process, bearing rings can have higher surface strength and the surface of bearing rings is wear-resistant. The resistance and contact fatigue strength are significantly enhanced, effectively improving the service life of the bearing. The carbonitriding treatment process of high carbon chromium bearing steel GCr15 is carbonitriding + free quenching + tempering. This process is mainly used in small, high-speed bearings, because small bearing rings are small in size, with an outer diameter of less than 55mm, and heat treatment deformation is small, ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C23C8/32C21D1/673C21D9/40
CPCC23C8/32C21D1/673C21D9/40
Inventor 杨群浩邹勇李力新
Owner CHENGDU TIANMA RAILWAY BEARING
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