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Preparation method of high-quality 40Cr alloy structure straight-bar round steel

A high-quality, alloy technology, applied in the manufacture of converters, etc., can solve the problems of unreasonable microstructure and proportion, low area reduction rate, low upsetting pass rate, high gas content and inclusions, etc., to achieve good display Microstructure, excellent plasticity and toughness and machinability, and high cleanliness

Active Publication Date: 2017-07-04
WUKUN STEEL
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  • Description
  • Claims
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Problems solved by technology

At present, most domestic 40Cr alloy structural round steel is produced by "converter + LF furnace + continuous casting + bar rolling mill". The gas content and inclusions in the steel are relatively high, with oxygen content > 35ppm, nitrogen content > 50ppm, and hydrogen content > 2ppm. Most of the non-metallic inclusions are 0.5~1.5; in addition, the microstructure and proportion of the steel are not reasonable, which leads to the limited processing and deformation ability of the steel, which restricts the application of 40Cr alloy structural steel in the field of high-end machinery manufacturing industry
[0003] At present, there are patents and 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 upsetting are low, which restricts its use in the high-end machinery manufacturing industry. field application

Method used

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  • Preparation method of high-quality 40Cr alloy structure straight-bar round steel
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  • Preparation method of high-quality 40Cr alloy structure straight-bar round steel

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preparation example Construction

[0020] The preparation method of high-quality 40Cr alloy structure straight bar round steel of the present invention comprises the following steps:

[0021] 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 2300~2500mm, and the amount of steel is 14.0~16.0 kg / t, and CaO desulfurizer is added for desulfurization For processing, the stirring time is controlled to be 8 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;

[0022] B. Molten steel smelting: Add the pretreated molten iron and high-quality steel scrap into the LD converter for top-bottom combined blowing, respectively, at 30.0-34.0kg / t steel, 20.0-24.0kg / t steel, 2.0- Adding am...

Embodiment 1

[0045] A, molten iron pretreatment desulfurization: blast furnace molten iron (chemical composition C 3.8wt%, Si 0.40wt%, Mn 0.30wt%, P0.110wt%, 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 2300mm, according to 14.0kg / t 钢 Add the conventional CaO-based desulfurizer for desulfurization treatment, and control the stirring time to 8 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; after pretreatment, the molten iron composition The control is: C 3.8wt%, Si 0.40wt%, Mn 0.30wt%, P 0.110wt%, S0.003wt%, the rest is Fe and unavoidable impurities.

[0046] B, molten steel smelting: the pretreatment deep desulfurization hot metal of A step (chemical composition C 3.8wt%, Si 0.40wt%, Mn0.30wt%, P 0.110wt%, S 0....

Embodiment 2

[0060] A, hot metal pretreatment desulfurization: blast furnace hot metal (chemical composition C 4.0wt%, Si 0.50wt%, Mn 0.40wt%, P0.100wt%, S0.018wt%, 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 2400mm. According to the amount of 15.0 kg / t steel, add conventional CaO desulfurization agent for desulfurization treatment. The stirring time is controlled at 8 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 0.50wt%, Mn 0.40wt%, P 0.100wt%, S0. 0.02wt%, the rest is Fe and unavoidable impurities.

[0061] B, molten steel smelting: the pretreatment deep desulfurization hot metal of step A (chemical composition C 4.0wt%, Si 0.50wt%, Mn0.40wt%, P 0.100wt%, S...

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Abstract

The invention discloses a preparation method of high-quality 40Cr alloy structure straight-bar round steel. The preparation method includes the following steps, namely, the step A of molten iron pretreatment and desulfuration, the step B of molten iron smelting, the step C of deoxidization alloying, the step D of molten iron LF furnace refining, the step E of molten iron VD furnace vacuum refining, the step F of molten iron casting, the step G of steel billet heating, the step H of rolling and the step I of steel finishing. The high-quality 40Cr alloy structure straight-bar round steel produced through the method is high in cleanliness and low in inclusion content and content of harmful elements P and S, has high strength, excellent ductility and toughness, excellent impact toughness and excellent upsetting deformation capacity, and can well meet the requirements of the field of high-end machine manufacturing industries.

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 preparation method of high-quality 40Cr alloy structure straight round steel. Background technique [0002] 40Cr alloy structural round steel is a kind of steel with a wide range of uses. With the rapid development of the machinery manufacturing industry, its demand is increasing. It is widely used in the production of quenched and tempered parts for important purposes, such as parts working under alternating loads, medium Parts with rotating speed and medium load, workpieces with high load and wear resistance requirements after surface quenching without great impact, such as gears, sleeves, crankshafts, etc.; due to the complicated manufacturing process of these parts, they are generally mechanical equipment The important parts of steel often need to bear the comprehensive effect of various loads, so there are...

Claims

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Application Information

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IPC IPC(8): C22C33/04C21C1/02C21C5/36C21C7/06C21C7/10C21D8/06C22C38/02C22C38/04C22C38/18
CPCC21C1/02C21C5/36C21C7/0006C21C7/0056C21C7/06C21C7/10C21D8/06C22C33/04C22C38/02C22C38/04C22C38/18
Inventor 陈伟赵宇李金柱邓家木张瑜苏灿东文玉兵张红斌段鹏杰黄静
Owner WUKUN STEEL
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