Control method of boron content in narrow hardenability gear steel

A control method and gear steel technology, applied in the field of metallurgy, can solve problems affecting gear heat treatment deformation and bending fatigue life, adverse effects on hardenability, and effects on hardenability value, achieving significant economic and social benefits, and reducing hardenability The effect of wide bandwidth and lower boron content

Active Publication Date: 2022-08-02
ZENITH STEEL GROUP CORP CO LTD +1
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  • Abstract
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  • Claims
  • Application Information

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Problems solved by technology

[0004] The Chinese patent (application number 201810829537.7) discloses a method for reducing the boron content in 20CrMnTiH gear steel. By optimizing the composition of the slag system, the boron content is controlled at 2 ppm, and every time the boron content is increased by 1 ppm, the J9 point hardenability value of 20CrMnTiH steel is reduced. It affects 2.1HRC, and then affects the heat treatment deformation and bending fatigue life of the gear. This invention cannot control the boron content within 1ppm, and it will still have an adverse effect on the hardenability of the demanding narrow hardenability gear steel. Further reducing the boron in narrow hardenability gear steel is the problem to be solved by the present invention

Method used

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  • Control method of boron content in narrow hardenability gear steel
  • Control method of boron content in narrow hardenability gear steel

Examples

Experimental program
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Effect test

Embodiment 1

[0034] (1) The electric furnace uses high-speed molten steel raw materials for stirring and smelting with a large amount of oxygen, and the oxygen flow rate of the oxygen lance is 2800-3200Nm 3 / h, scrap steel accounts for 13% of the total weight of steelmaking raw materials, molten iron accounts for 87% of the total weight of steelmaking raw materials, the total loading is 111t / furnace, tapping [C] 0.04%, tapping [P]≤0.008%, The tapping temperature is 1620°C, and the steel slag retention operation is adopted. The amount of steel slag retained is 45t. The ladle adopts a thermal turnover ladle. Add low titanium and low aluminum ferrosilicon (B≤70ppm) 2.6kg / t, low carbon ferromanganese (B≤30ppm) 13.0kg / t, low carbon ferrochromium (B≤10ppm) 19.0kg / t, along with the steel flow. Deoxidizer aluminum block 60kg / furnace, low carbon recarburizer and slag lime 550kg / furnace, low boron (B≤20ppm) furnace protecting agent 300kg / furnace, it is strictly forbidden to use silicon manganese and...

Embodiment 2

[0040] Tapping [C] in the electric furnace process: 0.05%, tapping temperature 1632℃, feeding silicon calcium wire 80m / furnace in the VD vacuum treatment process, hanging bag temperature after soft blowing, continuous casting furnace time 1565℃, in the continuous casting process The superheat degree was 25°C, and other operations were the same as in Example 1.

Embodiment 3

[0042] The temperature in the soaking section is 1173°C, the rolling temperature is 1088°C, and the final rolling temperature is 849°C, and the rest of the operations are the same as those in Example 2.

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Abstract

The invention belongs to the technical field of metallurgy and discloses a method for controlling boron content of narrow hardenability gear steel. The invention optimizes the types of alloys used, strictly prohibits the addition of silicon manganese and high-carbon alloys, strictly controls the boron content in the alloys and raw and auxiliary materials, adopts a large amount of oxygen to stir low carbon in electric furnace smelting, and retains steel and slag. The boron content and the electric furnace tapping deoxidation process, the LF refining process adopts feeding an appropriate amount of aluminum wire to replace the deoxidation of aluminum particles, the VD vacuum refining process appropriately adjusts the argon flow rate, and the large ladle adopts measures such as leaving steel slag to reduce the narrow hardenability. The boron content in the gear steel can control the boron content in the gear steel to be less than or equal to 1ppm, which stabilizes the bandwidth of the narrow hardenability gear steel. With the narrow composition control process, the bandwidth of the hardenability gear steel can be controlled within the range of ≤3HRC, satisfying the It meets the requirements of users of high-grade gear steel, and has significant economic and social benefits.

Description

technical field [0001] The invention belongs to the technical field of metallurgy, and in particular relates to a method for controlling the boron content of narrow hardenability gear steel. Background technique [0002] Gear is one of the most critical components in automobiles. During the operation of transmitting power and changing speed, there are both rolling and sliding between the meshing tooth surfaces, and the root of the tooth is also subjected to pulsation and alternating bending stress. Therefore, the quality requirements for gears are very strict. With the rapid development of the gear industry, narrow hardenability gear steel is one of the development directions of high-end gear steel. The control of hardenability and hardenability bandwidth of gear steel mainly depends on the rational control of various chemical elements, narrow composition control and residual boron content control in the smelting process. Among them, the control of residual boron element is ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C22C33/06C22C38/02C22C38/04C22C38/06C22C38/28C21C7/00C21C7/06C21C7/072
CPCC22C33/06C21C7/06C21C7/072C21C7/0056C22C38/02C22C38/04C22C38/06C22C38/28Y02P10/20
Inventor 豆乃远李辉成于飞张建斌蒋鲤平王立涛张正林
Owner ZENITH STEEL GROUP CORP CO LTD
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