A method of regulating and controlling the hardness of alloy structural steel 50crva

A technology for alloy structural steel and hardness, which is applied in the field of adjusting and controlling the hardness of alloy structural steel 50CrVA, which can solve the problems of low overall material utilization rate and high processing difficulty, and achieve the effects of eliminating annealing process, improving utilization rate and reducing use cost

Active Publication Date: 2020-04-21
DAYE SPECIAL STEEL CO LTD
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

According to statistics, the annealing cost of one ton of 50CrVA round steel is about 400 yuan. Otherwise, when the factory hardness is greater than 270HBW, the damage rate of cutting tools of many downstream customers has exceeded the user's own tolerance for material processing costs, especially for cutting ends. The remainder of the material is more difficult to process, resulting in lower overall material usage

Method used

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  • A method of regulating and controlling the hardness of alloy structural steel 50crva

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Experimental program
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Effect test

Embodiment 1

[0042] The concrete composition of the 50CrVA steel that present embodiment provides is as follows:

[0043] C: 0.49, Si: 0.26, Mn: 0.7, P: 0.015, S: 0.003, Cr: 1.00, Ni: 0.04, Cu: 0.09, V: 0.152.

[0044] The phase transition points measured by DIL805L static phase transition instrument are: Ac1: 766°C, Ac3: 786°C, Ar1: 648°C, Ar3: 680°C.

[0045] In the above-mentioned embodiment, the above-mentioned material is firstly heated by a heating furnace, and then rolled by a step-by-step 26-stand continuous rolling mill.

[0046] Specifically, the above materials are used to make three round steel billets of the same specification, which are respectively rolled and tested on the upper cooling bed. At the same position of the three billets, water cooling before final rolling and water cooling before entering the cooling bed are carried out respectively. The final test results are as follows:

[0047] Specifications / mm P3 / ℃ P4 / ℃ P5 / ℃ P6 / ℃ Hardness / HBW 50 825 ...

Embodiment 2

[0049] C: 0.5, Si: 0.29, Mn: 0.74, P: 0.015, S: 0.004, Cr: 1.02, Ni: 0.05, Cu: 0.12, V: 0.144.

[0050] The phase transition points measured by DIL805L static phase transition instrument are: Ac1: 770°C, Ac3: 789°C, Ar1: 652°C, Ar3: 683°C.

[0051] In the above-mentioned embodiment, the above-mentioned material is firstly heated by a heating furnace, and then rolled by a step-by-step 26-stand continuous rolling mill.

[0052] Specifically, the above materials are used to make three round steel billets of the same specification, which are respectively rolled and tested on the upper cooling bed. At the same position of the three billets, water cooling before final rolling and water cooling before entering the cooling bed are carried out respectively. The final test results are as follows:

[0053] Specifications / mm P3 / ℃ P4 / ℃ P5 / ℃ P6 / ℃ Hardness / HBW 50 827 794 880 683 310 50 847 814 900 718 268 50 876 825 889 741 268 50 874 825 88...

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Abstract

The invention provides a method for regulating and controlling the hardness of alloy structural steel 50CrVA. The method is especially suitable for the hardness regulation and control of 50CrVA rolledround steel with the specification being equal to and less than 60 mm and includes the steps that the temperature of steel billet entering a cold bed after rolling is controlled to be 10-60 DEG C higher than the Ar3 phase change point, and the fact that the hardness of the 50CrVA steel in a factory delivery state is equal to and less than 270 HBW is achieved. By means of the method, the fact thatthe factory delivery hardness is equal to and less than 270 HBW can be achieved, the utilization rate of downstream customers for the whole material is improved, the annealing process of the 50CrVA rolled round steel in existing processes is eliminated, and the use cost of the material is reduced.

Description

technical field [0001] The invention belongs to the technical field of alloy structural steel production, in particular to a method for regulating and controlling the hardness of alloy structural steel 50CrVA. Background technique [0002] Alloy structural steel 50CrVA is also called 50CrVA spring steel. Strong carbides, and the added vanadium V can form strong carbides, refine the grains of steel, reduce overheating sensitivity, and improve strength and toughness, so 50CrVA spring steel has higher strength, and its maximum hardness can be Reached 321HBW. [0003] In actual production, the delivery state of alloy structural steel is hot-rolled bar. For medium-carbon CrV series alloy structural steel, the content of C, Cr, Mn, V is high, the specification is small, and the hardness of hot-rolled state is too high , The hardness of raw materials directly affects the user's cutting efficiency, saw blade loss, and material utilization. [0004] At present, the 50CrVA round st...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C21D8/06
CPCC21D8/065
Inventor 史啸峰鲁强倪艳红
Owner DAYE SPECIAL STEEL CO LTD
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