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A kind of narrow hardenability gear steel and its preparation method

A technology of hardenability and gear steel, applied in the field of steel, can solve problems such as surface pits, increase production costs, and affect descaling effects

Active Publication Date: 2022-03-08
BAOSTEEL SPECIAL STEEL SHAOGUAN CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0002] In the actual production process, the narrow hardenability gear steel is prone to cracking, and because the narrow hardenability gear steel series steel is Ni-containing steel, when it is heated in the heating furnace, there is an oxidative atmosphere in the furnace, resulting in continuous casting billet A deep oxide layer is formed on the surface, while the oxide of Ni-containing steel has a relatively high viscosity and is relatively dense. figure 1 as shown, figure 1 The middle gray part is the residual oxide layer after descaling by high pressure water
The iron oxide scale remaining on the surface of the billet is pressed into the surface of the round steel during the rolling process, causing pits on the surface, such as figure 2 As shown, the round steel needs to be peeled. When the pitting is serious, if the diameter tolerance cannot meet the requirements after peeling, it will be scrapped, which increases the production cost.

Method used

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  • A kind of narrow hardenability gear steel and its preparation method
  • A kind of narrow hardenability gear steel and its preparation method
  • A kind of narrow hardenability gear steel and its preparation method

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preparation example Construction

[0024] In view of this, the present application also provides a preparation method of the aforementioned narrow hardenability gear steel, which includes the following steps:

[0025] S1, converter smelting.

[0026] S2, refining outside the furnace.

[0027] Wherein, step S2 includes degassing and soft blowing processes, specifically, degassing and soft blowing processes include:

[0028] Carry out vacuum degassing treatment on the molten steel, use nitrogen as the circulation lifting gas throughout the process, the N content range before RH treatment is required to be 40-60ppm, the treatment time is ≥10min under the vacuum degree of less than 0.266kPa, and use 0.8MPa nitrogen circulation for more than 15min after the pump is withdrawn , the N content is controlled at 80-120ppm, and after the RH treatment is completed, argon soft blowing is carried out at the bottom to promote the floating of inclusions.

[0029] S3, billet continuous casting.

[0030] In order to improve t...

Embodiment 1

[0053] A preparation method of narrow hardenability gear steel, which comprises the following steps:

[0054] S1, converter smelting.

[0055] S2. Refining outside the furnace: Carry out vacuum degassing treatment on the molten steel, use nitrogen as the circulation lifting gas throughout the process, the N content range before RH treatment is required to be 40-60ppm, the treatment time is ≥10min under the vacuum degree of less than 0.266kPa, and 0.8 is used after the pump is withdrawn. The MPa nitrogen circulation is more than 15min, and the N content is controlled at 80-120ppm. After the RH treatment, the bottom blowing argon soft blowing is carried out to promote the floating of inclusions.

[0056] S3. Billet continuous casting: the size of the billet section is 280mm*280mm, and the electromagnetic stirring of the mold is weakly stirred. The electromagnetic stirring parameter of the mold is 100A±5A / 2.5Hz, and the electromagnetic stirring parameter of the end is 250A±10A / 3....

Embodiment 2-4 and comparative example 1-6

[0063] Embodiment 2-4 and comparative example 1-6 are set, wherein the chemical composition of the narrow hardenability gear steel of embodiment 2-4 and comparative example 1-6 is as shown in table 1, wherein, embodiment 2-4 and comparative example The preparation method of the narrow hardenability gear steel of proportions 1-6 is similar to that of Example 1, the difference is only some parameters in step S4 and step S5 as shown in Table 2.

[0064] Among them, the properties, surface quality, and pass rate of magnetic flux leakage flaw detection of the round steel produced in Examples 1-4 and Comparative Examples 1-6 are shown in Table 3.

[0065] The chemical composition (wt%) of table 1 gear steel

[0066] Smelting ingredients C Si mn Cr Mo Ni Al N Al / N Example 1 0.20 0.24 0.85 0.56 0.20 0.53 0.032 0.0092 3.48 Example 2 0.20 0.25 0.85 0.54 0.20 0.51 0.033 0.00956 3.45 Example 3 0.19 0.25 0.86 0.52 0.19 0.50 0....

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Abstract

The application provides a narrow hardenability gear steel and a preparation method thereof, which relate to the field of iron and steel. Narrow hardenability gear steel by mass percentage, including: C: 0.19%‑0.21%, Si: 0.22%‑0.28%, Mn: 0.82%‑0.87%, Cr: 0.52%‑0.58%, Ni: 0.50%‑ 0.55%, Mo: 0.19%-0.21%, Al: 0.025%-0.035%, N: 0.0080%-0.0120%, and the balance of Fe and unavoidable impurities, wherein, Al / N=3-3.6, the obtained narrow The hardenable gear steel not only meets the hardenability requirements of the steel grade, but also reduces the influence tendency of the steel composition on the surface quality, effectively improving the surface quality of the narrow hardenable gear steel.

Description

technical field [0001] The present application relates to the field of iron and steel, in particular, to a gear steel with narrow hardenability and a preparation method thereof. Background technique [0002] In the actual production process, the narrow hardenability gear steel is prone to cracking, and because the narrow hardenability gear steel series steel is Ni-containing steel, when it is heated in the heating furnace, there is an oxidative atmosphere in the furnace, resulting in continuous casting billet A deep oxide layer is formed on the surface, while the oxide of Ni-containing steel has a relatively high viscosity and is relatively dense. figure 1 as shown, figure 1 The middle gray part is the residual oxide layer after descaling by high pressure water. The iron oxide scale remaining on the surface of the billet is pressed into the surface of the round steel during the rolling process, causing pits on the surface, such as figure 2 As shown, it is necessary to pe...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C22C38/02C22C38/04C22C38/06C22C38/44C21D8/06B22D11/115
CPCC22C38/02C22C38/04C22C38/06C22C38/44C21D8/065B22D11/115
Inventor 刘年富吴学兴钟寿军黄铸铭钟芳华杨伟光周成宏钟凡赵贺楠张正波
Owner BAOSTEEL SPECIAL STEEL SHAOGUAN CO LTD