Rolling production method capable of reducing hardness of 42CrMo

A production method and hardness technology, applied in the direction of metal rolling, metal rolling, temperature control, etc., can solve the problems of increasing the labor intensity of slow cooling operators, increasing the construction cost of slow cooling pits, and high production costs, so as to reduce post-sequence Heat treatment process, easy on-line automatic control, and the effect of reducing the labor intensity of operation

Active Publication Date: 2016-12-14
DAYE SPECIAL STEEL CO LTD
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0007] (1) In order to control the hardness value of 42CrMo steel, some iron and steel enterprises adopt a heat treatment process (annealing process) to solve the problem, but this process has high production costs, long turnaround time, and wastes energy, which is not conducive to environmental protection
[0008] (2) In order to control the hardness value of 42CrMo steel, the domestic iron and steel industry mainly ensures the hardness value of 42CrMo steel through high-temperature off-line high-temperature sawing, and timely slow cooling in the slow cooling pit. Although this method has certain effects, there are The following disadvantages: 1) This method increases the construction cost of the slow cooling pit; 2) Increases th

Method used

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  • Rolling production method capable of reducing hardness of 42CrMo
  • Rolling production method capable of reducing hardness of 42CrMo
  • Rolling production method capable of reducing hardness of 42CrMo

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0049] A kind of rolling production technology that reduces 42CrMo hardness comprises the following steps:

[0050] 1) Billet heating: heat the billet in a four-stage walking heating furnace. The temperatures of the four stages are: preheating section: 700°C; heating stage: 1050°C; heating stage two: 1230°C; soaking section: 1220°C; The total heating time is 4h, and the soaking time is 40min;

[0051] 2) Billet descaling: the heated billet is descaled by high-pressure water to remove scale, and the pressure of high-pressure water descaling is 28MPa;

[0052] 3) Rough rolling billet: Send the descaled steel billet into 6 high-rigidity roughing mills for rough rolling to obtain a rough rolling billet. The rough rolling inlet temperature is 1070°C, and the rough rolling exit temperature is 1030°C;

[0053] 4) Cooling on the head-off roller table: the rough slab obtained in step 3) is cooled by a water tank spray ring in the head-off roller table area, the cooling rate is 7°C / s, ...

Embodiment 2

[0063] A kind of rolling production technology that reduces 42CrMo hardness comprises the following steps:

[0064] 1) Billet heating: heat the billet in a four-stage walking heating furnace. The temperatures of the four stages are: preheating section: 750°C; heating stage: 1080°C; heating stage two: 1240°C; soaking section: 1230°C; The heating time is 4.5h, and the soaking time is 50min;

[0065] 2) Billet descaling: the heated billet is descaled with high-pressure water to remove scale, and the pressure of high-pressure water descaling is 29MPa;

[0066] 3) Rough rolling billet: send the descaled steel billet into 6 high-rigidity roughing mills for rough rolling to obtain a rough rolling billet, the rough rolling inlet temperature is 1080°C, and the rough rolling exit temperature is 1025°C;

[0067] 4) Head-off roller table: the rough slab obtained in step 3) is cooled by a water tank spray ring in the head-off roller table area, the cooling rate is 8°C / s, and the surface t...

Embodiment 3

[0076] A kind of rolling production technology that reduces 42CrMo hardness comprises the following steps:

[0077] 1) Billet heating: heat the billet in a four-stage walking heating furnace. The temperatures of the four stages are: preheating section: 800°C; heating stage: 1150°C; heating stage two: 1200°C; soaking section: 1210°C; The total heating time is 4h, and the soaking time is 40min;

[0078] 2) Billet descaling: the heated billet is descaled by high-pressure water to remove scale, and the pressure of high-pressure water descaling is 28MPa;

[0079] 3) Rough rolling billet: send the descaled steel billet into 6 high-rigidity roughing mills for rough rolling to obtain a rough rolling billet, the rough rolling inlet temperature is 1100°C, and the rough rolling exit temperature is 1045°C;

[0080] 4) Cooling on the head-off roller table: the rough slab obtained in step 3) is cooled by a water tank spray ring in the head-off roller table area, the cooling rate is 9°C / s, ...

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Abstract

The invention belongs to the field of production machining of special steel of the metallurgical industry, and relates to a rolling production method capable of reducing hardness of 42CrMo. A 42CrMo casting blank serves as a raw material, and the method sequentially comprises following working procedures of heating, descaling, a rough rolling, cooling after rough rolling, continuous rolling, through water cooling, bar reducing sizing mill finish rolling, cooling bed cooling and finally obtaining a finished product bar; by the adoption of the technology, the site operation is simple, online automatic control is easily achieved, and operation labor intensity of a worker is reduced; through the online controlled rolling controlled cold technology, straightness of the 42CrMo steel grade is greatly improved; the subsequent heat treatment technology (annealing technology) is reduced, production cost is saved, the production period is shortened, and the steel market competitiveness is improved; the hardness value range of the obtained 42CrMo steel ranges from 220 HBW to 260 HBW; a metallographic structure comprises ferrite and pearlite; the banded structure is smaller than or equal to 2 levels; the grain size is larger than or equal to 8 levels; and the mechanical property can meet the national standard and user needs.

Description

technical field [0001] The invention belongs to the field of special steel production and processing in the metallurgical industry, and relates to a rolling process, in particular to a rolling production method for reducing the hardness of 42CrMo. Background technique [0002] In recent years, with the rapid development of my country's economy, my country's automobile manufacturing industry and machinery manufacturing industry have developed rapidly. Under this background, it is particularly important to accelerate the research and development of automobile steel. Due to its high strength, good hardenability, good plasticity and toughness, small deformation during quenching, high creep strength and durable strength at high temperature, 42CrMo steel is widely used in auto parts, such as automobile engine crankshafts, front axles, steering knuckle etc. However, with the development of deep processing technology of steel, in order to improve the processing efficiency, the user...

Claims

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Application Information

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IPC IPC(8): B21B1/16B21B37/74B21B45/08B21B45/02B21B43/00
CPCB21B1/16B21B37/74B21B43/00B21B45/0224B21B45/08
Inventor 李小龙周敦世周立新程卫国柳萍张光鸿邹晖黄国飘
Owner DAYE SPECIAL STEEL CO LTD
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