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Preparation method for high-quality 40Cr alloy structural steel hot rolled coil rod

A kind of alloy structural steel, high-quality technology, applied in the field of iron and steel metallurgy and ferrous metal pressure processing, can solve the problem that the microstructure and proportion are not optimized, restrict the application of 40Cr alloy structural steel, the reduction of area rate and the qualified rate of upsetting Low-level problems, to achieve excellent plasticity and toughness, cold heading deformation ability, less inclusions, and improved upsetting deformation ability

Active Publication Date: 2017-07-07
WUKUN STEEL
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

At present, domestic 40Cr alloy structural steel hot-rolled round wire rods are mostly produced by "converter + LF furnace + continuous casting + high-speed wire rolling mill". The gas content and inclusions in the steel are relatively high, with oxygen content > 35ppm, nitrogen content > content>2ppm, most of the non-metallic inclusions are 0.5-1.5; in addition, the microstructure and proportion of the steel have not been optimized, resulting in limited plastic and ductile processing deformation ability of the steel, which restricts the use of 40Cr alloy structural steel in high-grade Applications in the field of fasteners
[0003] At present, there are patents and paper research reports on the production of 40Cr alloy structural steel in China, but the content of harmful elements, inclusions and gases in the steel is relatively high, the reduction of area and the pass rate of 1 / 3 upsetting are low, which restricts the structure of 40Cr alloy Application of steel in the field of high-grade fasteners

Method used

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  • Preparation method for high-quality 40Cr alloy structural steel hot rolled coil rod
  • Preparation method for high-quality 40Cr alloy structural steel hot rolled coil rod
  • Preparation method for high-quality 40Cr alloy structural steel hot rolled coil rod

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preparation example Construction

[0019] The preparation method of the hot-rolled round wire rod of high-quality 40Cr alloy structural steel of the present invention comprises the following steps:

[0020] A. Hot metal pretreatment desulfurization: transport the blast furnace hot metal to the KR method hot metal pretreatment device for desulfurization treatment, the insertion depth of the stirring head is controlled at 2000~2200mm, and the amount of steel is 12.0~14.0 kg / t, and CaO desulfurizer is added for desulfurization Treatment, the stirring time is controlled to 6 minutes; after the stirring is completed, the slag removal operation is carried out to ensure that the molten iron surface in the ladle is exposed ≥ 4 / 5, and the desulfurization slag is removed to obtain the pretreated molten iron;

[0021] B. Molten steel smelting: Add the pretreated molten iron and high-quality steel scrap obtained in step A into the LD converter, and carry out top-bottom compound blowing. The amount of steel added is 3.0kg / t...

Embodiment 1

[0045] A. Hot metal pretreatment desulfurization: blast furnace hot metal (chemical composition C 4.0wt%, Si 0.25wt%, Mn 0.50wt%, P0.100wt%, S 0.025wt%, the rest is Fe and unavoidable impurities) transport Go to the KR method molten iron pretreatment device for desulfurization treatment. The insertion depth of the stirring head is controlled at 2000mm. According to the amount of 12.0 kg / t steel, add conventional CaO desulfurization agent for desulfurization treatment. The stirring time is controlled at 6 minutes; After the slag operation, ensure that the molten iron surface in the ladle is exposed ≥ 4 / 5, and remove the desulfurization slag; the composition of the molten iron after pretreatment is controlled as follows: C 4.0wt%, Si 0.25wt%, Mn 0.50wt%, P 0.100wt%, S 0.005 wt%, the rest is Fe and unavoidable impurities.

[0046] B, molten steel smelting: the pretreatment desulfurization hot metal of step A (chemical composition C 4.0wt%, Si 0.25wt%, Mn0.50wt%, P 0.100wt%, S 0.0...

Embodiment 2

[0059] A, molten iron pretreatment desulfurization: blast furnace molten iron (chemical composition C 4.1wt%, Si 0.37wt%, Mn 0.65wt%, P0.090wt%, S 0.020wt%, the rest is Fe and unavoidable impurities) transport To the KR method molten iron pretreatment device for desulfurization treatment, the insertion depth of the stirring head is controlled at 2100mm, according to 13.0 kg / t 钢 Add the conventional CaO-based desulfurizer for desulfurization treatment, and control the stirring time to 6 minutes; after the stirring, carry out the slag removal operation to ensure that the molten iron surface in the ladle is exposed ≥ 4 / 5, and remove the desulfurization slag; the molten iron composition after pretreatment The control is: C 4.1wt%, Si 0.37wt%, Mn 0.65wt%, P 0.090wt%, S 0.003wt%, the rest is Fe and unavoidable impurities.

[0060] B, molten steel smelting: the pretreatment desulfurized hot metal of step A (chemical composition C 4.1wt%, Si 0.37wt%, Mn0.65wt%, P 0.090wt%, S 0.020wt%,...

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Abstract

The invention discloses a preparation method for a high-quality 40Cr alloy structural steel hot rolled coil rod. The preparation method comprises the following steps of A, hot metal pretreatment desulfurization, B, molten steel smelting, C, deoxygenation alloying, D, molten steel LF furnace refining, E, molten steel VD furnace vacuum refining, F, molten steel casting, G, billet heating, and H, controlled rolling and controlled cooling. The high-quality 40Cr alloy structural steel hot rolled coil rod produced through the method is high in steel cleanliness and fewer in occluded foreign substance and has high-strength as well as excellent plastic toughness and cold heading machining deformation capacity, the production requirement of a high-level fastener is met, and steel gas content and the occluded foreign are greatly reduced.

Description

technical field [0001] The invention belongs to the technical field of iron and steel metallurgy and ferrous metal pressure processing, and in particular relates to a method for preparing a high-quality 40Cr alloy structural steel hot-rolled round wire rod. Background technique [0002] 40Cr alloy structural steel is one of the most widely used steel types in the machinery manufacturing industry. It has good processability and mechanical properties, and has good low-temperature impact toughness, plasticity, wear resistance and low notch sensitivity. It is widely used in the production of household appliances , office supplies, gears, main shafts, crankshafts, eccentric shafts, oil pump rotors, sliders, worms, collars, sleeves, pins, connecting rods, screws, nuts, intake valves of equipment such as automobiles, motorcycles and machine tools Manufacture of other parts. The processing and manufacturing process of parts made of 40Cr is complicated, and they are generally import...

Claims

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Application Information

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IPC IPC(8): C21C1/02C21C7/064C21C5/35C21C7/06C21C7/076C21C7/10C21D8/06C22C38/02C22C38/04C22C38/18C21D6/00C22C33/04
CPCC21C1/025C21C5/35C21C7/0006C21C7/06C21C7/0645C21C7/076C21C7/10C21D6/002C21D6/005C21D6/008C21D8/065C21D2211/005C21D2211/009C22C33/04C22C38/02C22C38/04C22C38/18Y02P10/20
Inventor 陈伟张卫强杨银辉王文峰吴光耀王卫东张瑜张志波赵卫东速国武马松
Owner WUKUN STEEL
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