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A kind of preparation method of steel hot-rolled round wire rod for 10.9 high-strength bolts

A technology of high-strength bolts and discs, applied in the field of iron and steel metallurgy and ferrous metal pressure processing, can solve the problems of suboptimal microstructure and proportion, low plastic toughness and section shrinkage rate, and limited processing deformation capacity. , to achieve the effect of reducing processing procedures and energy consumption, improving the deformation capacity of upsetting and high cleanliness

Active Publication Date: 2018-09-14
WUKUN STEEL
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

At present, the hot-rolled round wire rod of high-strength bolt steel produced by the existing domestic technology has low cleanliness, relatively high content of inclusions, and most of the non-metallic inclusions are above grade 1.0; Production is difficult; in addition, the microstructure and proportion of steel have not been optimized, resulting in poor matching of strength and toughness of steel, limited processing deformation capacity, and low pass rate of 1 / 3 cold upsetting of wire rod, which restricts Application of the product in the production of 10.9 grade high strength bolts
[0004] At present, there are patents and paper research reports on steel for high-strength bolts in China, but the plasticity, toughness and section shrinkage of steel are low, and most of the products are only used for the production of 8.8 high-strength bolts

Method used

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  • A kind of preparation method of steel hot-rolled round wire rod for 10.9 high-strength bolts
  • A kind of preparation method of steel hot-rolled round wire rod for 10.9 high-strength bolts
  • A kind of preparation method of steel hot-rolled round wire rod for 10.9 high-strength bolts

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Effect test

preparation example Construction

[0019] The preparation method of the 10.9-grade high-strength bolt steel hot-rolled round wire rod of the present invention, described preparation method 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, the insertion depth of the stirring head is controlled at 1800~2000mm, and the amount of steel is 10.0~12.0 kg / t, and CaO desulfurizer is added for desulfurization For processing, the stirring time is controlled to 5 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 ≥ 3 / 4, and the desulfurization slag is removed to obtain the pretreated molten iron;

[0021] B. Molten steel smelting: Put the molten iron and high-quality steel scrap pretreated in step A into the LD converter, and carry out conventional top-bottom composite blowing. Adding amount ...

Embodiment 1

[0043] A, hot metal pretreatment desulfurization: blast furnace hot metal (chemical composition C 4.0wt%, Si 0.25wt%, Mn 0.60wt%, P0.105wt%, S 0.030wt%, 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 1800mm. According to the amount of 10.0 kg / t steel, add conventional CaO desulfurization agent for desulfurization treatment. The stirring time is controlled at 5 minutes; After the slag operation, ensure that the molten iron surface in the ladle is exposed ≥ 3 / 4, and remove the desulfurization slag; the composition of the molten iron after pretreatment is controlled as follows: C 4.0wt%, Si 0.25wt%, Mn 0.60wt%, P 0.105wt%, S 0.005 wt%, the rest is Fe and unavoidable impurities.

[0044] B, molten steel smelting: the molten iron after the pretreatment of step A (chemical composition C 4.0wt%, Si 0.25wt%, Mn0.60wt%, P 0.105wt%, S 0.030wt...

Embodiment 2

[0056] A. Hot metal pretreatment desulfurization: blast furnace hot metal (chemical composition C 4.2wt%, Si 0.35wt%, Mn 0.75wt%, P0.095wt%, S 0.024wt%, 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 1900mm, according to 11.0 kg / t 钢 Add the conventional CaO-based desulfurizer for desulfurization treatment, and control the stirring time to 5 minutes; after the stirring, carry out the slag removal operation to ensure that the molten iron surface in the ladle is exposed ≥ 3 / 4, and remove the desulfurization slag; the molten iron composition after pretreatment The control is: C 4.2wt%, Si 0.35wt%, Mn 0.75wt%, P 0.095wt%, S 0.004wt%, the rest is Fe and unavoidable impurities.

[0057] B, molten steel smelting: the molten iron after the pretreatment of step A (chemical composition C 4.2wt%, Si 0.35wt%, Mn0.75wt%, P 0.095wt%, S 0.004wt%, the ...

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Abstract

The invention discloses a preparation method of a hot-rolled steel coil rod for a 10.9-level high-strength bolt. The preparation method comprises the following steps of A, pretreatment and desulfurization of molten iron; B, smelting of molten steel; C, deoxygenation alloying; D, LF furnace refining of the molten steel; E, casting of the molten steel; F, billet heating; and G, controlled rolling and controlled cooling. According to the preparation method of the hot-rolled steel coil rod for the 10.9-level high-strength bolt, the prepared hot-rolled steel coil rod is high in cleanliness and good in hardenability and has proper strength and hardness as well as excellent plastic toughness and cold heading machining deformation capacity, the 10.9-level high-strength bolt can be produced through cold heading machining directly without spheroidizing annealing, manufacturing procedures and energy consumption are reduced, and production cost is 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 hot-rolled round wire rod of grade 10.9 high-strength bolt steel. Background technique [0002] Steel hot-rolled wire rods for high-strength fasteners are formed by metal plastic processing at room temperature. The internal structure of the material is tight, the mechanical properties of the product are good, the loss of processed materials is small, the production efficiency is high, the product's dimensional accuracy is high, and the surface finish is good. It is widely used in the production of high-strength bolt fasteners formed by cold heading. [0003] In recent years, with the adjustment of the product structure of the bolt fastener industry, the development of bolts from low strength to high strength, from high energy consumption to resource-saving development has become an inevit...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C21C1/02C21C5/35C21C5/36C21C7/06C21C7/072C21C7/076C21D8/06C22C38/02C22C38/04C22C38/32C22C33/04
CPCC21C1/025C21C5/35C21C5/36C21C7/0006C21C7/06C21C7/072C21C7/076C21D8/065C22C33/04C22C38/02C22C38/04C22C38/32Y02P10/20
Inventor 陈伟赵宇张卫强王卫东刘红兵李金柱苏灿东杨春雷邓家木汪涛马松
Owner WUKUN STEEL
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