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Refining method for controlling brittle inclusions in bearing steel

A technology of brittle inclusions and bearing steel, applied in the field of iron and steel metallurgy, can solve the problems of difficulty and effective control, achieve good desulfurization ability, good melting performance, and solve the effect of difficult slag removal

Active Publication Date: 2017-02-15
XINGTAI IRON & STEEL
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  • Application Information

AI Technical Summary

Problems solved by technology

This process has good desulfurization and deoxidation effects, and at the same time, through strict control of the Al content of the molten steel and the CaO / Al content in the slag 2 o 3 Control the content of D-type inclusions in steel; but this process is similar to that of Sanyo Special Steel in Japan, without strict control and RH vacuum chamber slag-free operation, it is difficult to effectively control brittle non-metallic inclusions in steel

Method used

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  • Refining method for controlling brittle inclusions in bearing steel

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Embodiment 1

[0021] Embodiment 1: The refining method for controlling brittle inclusions in bearing steel adopts the following specific processes.

[0022] 1. LF refining process: including tapping alloying to LF treatment position pre-deoxidation slagging process and LF treatment process.

[0023] (1) The process of tapping alloying to LF treatment position pre-deoxidation and slag formation: the temperature of molten steel at the end of converter smelting is 1600°C, and 7kg / t steel is added in the later stage of tapping. The main components of refining slag are: CaO 45%, SiO 2 2%, Al 2 o 3 45%; the flow rate of ladle bottom blowing during tapping is controlled at 3.5L / min•t -1 At the end of tapping, the sliding plate is used to stop the slag to control the amount of slag ≤ 3kg / t of steel, and 20kg of aluminum particles are added to the molten steel to deoxidize the slag to reduce the oxidation of the slag; after tapping, the bottom blowing flow rate of the ladle is controlled to 0.35...

Embodiment 2

[0027] Embodiment 2: The refining method for controlling brittle inclusions in bearing steel adopts the following specific processes.

[0028] 1. LF refining process: including tapping alloying to LF treatment position pre-deoxidation slagging process and LF treatment process.

[0029] (1) The process of tapping alloying to LF treatment position pre-deoxidation and slag formation: the temperature of molten steel at the end of converter smelting is 1650°C, and 10kg / t steel is added in the later stage of tapping. The main components of refining slag are: CaO 60%, SiO 2 1.5%, Al 2 o 3 35%; the flow rate of ladle bottom blowing during tapping is controlled at 3.2NL / min•t -1 At the end of tapping, the sliding plate is used to stop the slag to control the amount of slag ≤ 3kg / t of steel, and 40kg of aluminum particles are added to the molten steel to deoxidize the slag to reduce the oxidation of the slag; after tapping, the bottom blowing flow rate of the ladle is controlled to ...

Embodiment 3

[0033] Embodiment 3: The refining method for controlling brittle inclusions in bearing steel adopts the following specific processes.

[0034] 1. LF refining process: including the pre-deoxidation slagging process to the LF treatment position and the LF treatment process.

[0035] (1) The process of tapping alloying to LF treatment position pre-deoxidation and slag formation: the temperature of molten steel at the end of converter smelting is 1620°C, and 8kg / t of refining slag is added in the later stage of tapping. The main components of refining slag are: CaO 50%, SiO 2 3%, Al 2 o 3 45%; the flow rate of ladle bottom blowing during tapping is controlled at 3.0L / min•t -1 At the end of tapping, the sliding plate is used to stop the slag to control the amount of slag ≤ 3kg / t of steel, and 30kg of aluminum particles are added to the molten steel to strongly deoxidize the slag and reduce the oxidation of the slag; after tapping, the bottom blowing flow rate of the ladle is co...

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Abstract

The invention discloses a refining method for controlling brittle inclusions in bearing steel, comprising an LF refining procedure and an RH refining procedure; the LF refining procedure comprises a process from steel tapping and alloying to pre-deoxidation slag formation on an LF treatment position and an LF treatment process; the process from steel tapping and alloying to pre-deoxidation slag formation on the LF treatment position comprises the steps of controlling the molten steel temperature at a converter smelting end point at 1600-1650 DEG C; adding 7-10kg / t of refining slag at the later stage of steel tapping, wherein the refining slag has high alkalinity and a low melting point; controlling the flow of argon blown to a steel ladle in the steel tapping process at 2.5-3.5NL / min.t<-1>; carrying out slag stopping operation at the last stage of steel tapping, and adding 20-40kg of aluminum particles; and controlling the flow of argon blown to the steel ladle at 0.15-0.35L / min.t<-1> in the process from steel tapping ending to LF refining; and the LF treatment process comprises the steps of controlling the flow of argon blown to the steel ladle at 2.5-5.0L / min.t<-1> in the LF treatment process; adding 30-50kg of aluminum particles at the earlier stage of LF smelting; and in the middle stage of LF smelting, adding 30-50kg of quartz and 200-400kg of lime, and adopting refining slag with medium-lower alkalinity. By using the method, the brittle inclusions in the steel can be effectively prevented and removed.

Description

technical field [0001] The invention belongs to the technical field of iron and steel metallurgy, in particular to a refining method for controlling brittle inclusions in bearing steel. Background technique [0002] High-carbon chromium bearing steel is often used to manufacture balls, rollers and bearing rings and other components. With the development of modern science and technology, higher requirements are put forward for the life, stability and reliability of bearings. However, in bearing steel The inclusions destroy the continuity of the matrix and produce stress concentration, which becomes the source of cracks for bearing spalling, which has a great impact on the performance of the bearing, especially the contact fatigue life. [0003] According to GB / T 10561-2005 "Determination Standard Grading Chart Microscopic Examination Method of Non-metallic Inclusion Content in Steel", common inclusions in steel are divided into five categories: A, B, C, D, and Ds according to...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C21C7/10C21C7/06
CPCC21C7/06C21C7/10
Inventor 逯志方张治广马富平苏庆林赵铮铮修建军姬旦旦黄翠环王秋坤李富伟刘志勇阎丽珍
Owner XINGTAI IRON & STEEL
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