Continuous spheroidizing annealing method for high-carbon chromium bearing steel round steel

A technology of high carbon chromium bearing steel and continuous annealing furnace, which is applied in the field of heat treatment of steel materials, can solve the problems of uneven spheroidized structure, long annealing process time, poor treatment effect, etc., so as to promote spheroidization transformation and shorten spheroidization. Annealing cycle, the effect of improving continuity

Pending Publication Date: 2022-03-01
LIANFENG STEEL (ZHANGJIAGANG) CO LTD
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AI Technical Summary

Benefits of technology

This patented technology describes methods used during manufacturing processes involving carbon steels that are subjected to heat treatments such as rolling reduction (Reduction) Anneals). These techniques help improve their properties by converting them into pure forms called martensitic structures like bainless iron, which helps reduce defects caused by impurities present inside the material. Additionally, these technical improvements result in better control over how well they work when exposed to certain environments without losing strength due to corrosion damage.

Problems solved by technology

This patented technical problem addressed by this patents relates to improving the performance of high-Carbon chrome bearings during manufacturing due to their poor machine tooling ability or requiring expensive equipment after being cut into small pieces that are then treated through conventional methods like acid pickling or electrolytic polishing techniques.

Method used

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  • Continuous spheroidizing annealing method for high-carbon chromium bearing steel round steel

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Embodiment 1

[0026] Ф25mm high carbon chromium bearing steel round bar annealed production;

[0027] Invention composition: C: 0.97%, Mn: 0.34%, Si: 0.25%, Cr: 1.45%, P: 0.009%, S: 0.004%, Ni: 0.02%, Cu: 0.06%, Mo: 0.01%, Al : 0.010%, Ti: 0.0015%, [O]: 0.0006%, Ca: 0.0001%, As: 0.004%, Pb: 0.0002%, Sn: 0.003%; the balance is Fe and unavoidable impurities.

[0028] The steps of the present invention include furnace loading, heating and heating, primary isothermal, cooling, secondary isothermal, cooling out of the furnace, finishing and inspection.

[0029] (1) Through high-temperature diffusion and controlled rolling and controlled cooling, the 25mm round steel in the hot-rolled state is obtained, and the 25mm high-carbon chromium bearing steel round steel in the hot-rolled state is loaded into the roller hearth type continuous annealing furnace; wherein the roller hearth type continuous annealing furnace Stove, the heating source is natural gas, the upper and lower rows of radiant tubes are

Embodiment 2

[0038] Ф70mm high carbon chromium bearing steel round steel annealed production;

[0039] Invention composition: C: 0.98%, Mn: 0.33%, Si: 0.26%, Cr: 1.48%, P: 0.010%, S: 0.003%, Ni: 0.02%, Cu: 0.05%, Mo: 0.01%, Al : 0.013%, Ti: 0.0015%, [O]: 0.0005%, Ca: 0.0001%, As: 0.004%, Pb: 0.0002%, Sn: 0.003%; the balance is Fe and unavoidable impurities.

[0040] The steps of the present invention include furnace loading, heating and heating, primary isothermal, cooling, secondary isothermal, cooling out of the furnace, finishing and inspection.

[0041] (1) Through high-temperature diffusion and controlled rolling and controlled cooling, the hot-rolled 70mm round steel is obtained, and the hot-rolled 70mm high-carbon chromium bearing steel round steel is loaded into the roller hearth type continuous annealing furnace; wherein the roller hearth type continuous annealing furnace Stove, the heating source is natural gas, the upper and lower rows of radiant tubes are used for radiant heating

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Abstract

The invention belongs to the technical field of heat treatment of steel and iron materials, and particularly relates to a continuous spheroidizing annealing method for high-carbon chromium bearing steel round steel. The method comprises the steps that high-carbon-chromium bearing steel round steel in a hot rolling state is loaded into a roller hearth type continuous annealing furnace to be heated, the heating time is 3-3.5 h, and the heating rate is 200-250 DEG C/h; after heating to 790-810 DEG C, keeping the temperature for 3.5-4 hours to finish primary isothermal treatment; cooling treatment is carried out, rapid cooling is carried out to 710-730 DEG C, heat preservation is carried out for 6.5-7 h, and then secondary isothermal treatment is carried out; after secondary isothermal treatment, furnace cooling is carried out to 600-650 DEG C, then furnace discharging and air cooling are carried out to room temperature, and continuous spheroidizing annealing treatment is completed; after annealing, the Brinell hardness of the high-carbon chromium bearing steel is 180-200 HBW, the total decarburized layer depth is smaller than or equal to 0.8% of the nominal diameter, the spheroidized structure is 2.0-3.0 grades, the uniformity is good, and necessary structure preparation is made for obtaining good comprehensive performance.

Description

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Claims

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Application Information

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Owner LIANFENG STEEL (ZHANGJIAGANG) CO LTD
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