Bainite isothermal quenching thermal treatment process method for medium-carbon bearing steel

A technology of austempering and medium carbon bearings, which is applied in heat treatment equipment, quenching agents, manufacturing tools, etc., can solve the problems of long production cycle, peeling of seepage layer, long time, etc., and achieve bearing manufacturing cost reduction, high contact fatigue life, Good wear resistance effect

Active Publication Date: 2013-12-18
LAIWU IRON & STEEL GRP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The disadvantage is that the heat treatment process is complicated, the time is long (tens of hours to more than a hundred hours), the cost is high, and sometimes the carburizing layer will peel off due to improper carburizing control or impact during use, which will affect the service life.
[0003] Judging from the steel types and heat treatment processes commonly used at present, there are different problems such as complex process, long production cycle, high cost and energy consumption, or unsatisfactory comprehensive performance.

Method used

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  • Bainite isothermal quenching thermal treatment process method for medium-carbon bearing steel
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  • Bainite isothermal quenching thermal treatment process method for medium-carbon bearing steel

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Embodiment 1

[0027] The bearing wall thickness is 40mm. The bainite austempering process includes the following steps:

[0028] The bearing steel after blanking is firstly forged and heated in a gas furnace at the bottom of the car. The heating temperature is 1140-1160°C, the holding time is 0.3-0.8min / mm, the initial forging temperature is 1090-1110°C, and the final forging temperature is controlled at 890~910℃. After forging, carry out normalizing + spheroidizing annealing; normalizing temperature is 860-890°C, keep warm for 20-40 minutes, leave the furnace and air-cool to form flaky pearlite structure; carry out spheroidizing annealing after normalizing, and the spheroidizing annealing temperature is 750-780°C , keep it warm for 4-6 hours, cool it to 600°C with the furnace, and then air-cool it to form a fine and uniform spheroidized structure. The steel parts after spheroidizing annealing are subjected to bainite isothermal quenching and low-temperature tempering treatment; the baini...

Embodiment 2

[0030] The bearing wall thickness is 30mm. The bainite austempering process includes the following steps:

[0031]The bearing steel after blanking is firstly forged and heated in a gas furnace at the bottom of the car. The heating temperature is 1140-1160°C, the holding time is 0.3-0.7min / mm, the initial forging temperature is 1090-1110°C, and the final forging temperature is controlled at 890~910℃. After forging, carry out normalizing + spheroidizing annealing; normalizing temperature is 860-890°C, keep warm for 20-40 minutes, leave the furnace and air-cool to form flaky pearlite structure; carry out spheroidizing annealing after normalizing, and the spheroidizing annealing temperature is 750-780°C , keep it warm for 4-6 hours, cool it to 600°C with the furnace, and then air-cool it to form a fine and uniform spheroidized structure. The steel parts after spheroidizing annealing are subjected to bainite isothermal quenching and low-temperature tempering treatment; the bainit...

Embodiment 3

[0033] The bearing wall thickness is 20mm. The bainite austempering process includes the following steps:

[0034] The bearing steel after blanking is firstly forged and heated in a bottom-mounted gas furnace at a heating temperature of 1140-1160°C, a holding time of 0.3-0.6min / mm, an initial forging temperature of 1090-1110°C, and a final forging temperature of 890~910℃. After forging, carry out normalizing + spheroidizing annealing; normalizing temperature is 860-890°C, keep warm for 20-40 minutes, leave the furnace and air-cool to form flaky pearlite structure; carry out spheroidizing annealing after normalizing, and the spheroidizing annealing temperature is 750-780°C , keep it warm for 4-6 hours, cool it to 600°C with the furnace, and then air-cool it to form a fine and uniform spheroidized structure. The steel parts after spheroidizing annealing are subjected to bainite isothermal quenching and low-temperature tempering treatment; the bainite isothermal quenching proce...

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Abstract

The invention relates to a bainite isothermal quenching thermal treatment process for medium-carbon bearing steel. The process comprises the following steps of: performing normalizing treatment to obtain a flaky pearlite structure; then performing spheroidizing annealing treatment to obtain a fine and uniform spheroidized structure; and performing bainite isothermal quenching and low-temperature tempering treatment on a spheroidized steel member. The bearing treated by the process method has high hardness, high impact toughness, high wear resistance and long fatigue life, meets the requirements of bearing performance of impact-resistant and heavy-load metallurgical mines, petroleum and the like well, and has better economic benefit.

Description

technical field [0001] The invention relates to a medium-carbon bearing steel heat treatment process suitable for impact-resistant and heavy-load working conditions, in particular to a medium-carbon bearing steel bainite austempering heat treatment process. Background technique [0002] At present, domestic production and manufacture of impact-resistant and heavy-duty bearings mostly adopt two manufacturing processes. One is to use high-carbon chromium bearing steels such as GCr18Mo, GCr15, and GCr15SiMn, and undergo conventional martensitic quenching processes to obtain a metallographic structure that is tempered. Martensite and evenly distributed fine-grained carbides. Since the martensite structure is hard and brittle, although the bearing has high hardness after heat treatment, the toughness is insufficient. The other is to use G20Cr2Ni4A carburizing steel, etc., after carburizing, quenching and low temperature tempering, the surface layer is hard and wear-resistant, an...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C21D1/20C21D1/60
Inventor 戈文英翟正龙敖青李泰田磊
Owner LAIWU IRON & STEEL GRP
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