Production method of low-temperature-resistant mine car bottom plate wear-resistant steel with thickness of 12-19mm

Abstract

The invention discloses a production method of low-temperature-resistant mine car bottom plate wear-resistant steel with the thickness of 12-19 mm. The low-temperature-resistant mine car bottom plate wear-resistant steel comprises the following chemical components in percentage by weight: 0.17%-0.18% of C, 0.32%-0.38% of Si, 1.00%-1.20% of Mn, less than or equal to 0.015% of P, less than or equal to 0.008% of S, 0.010%-0.020% of Ti, 0.10%-0.15% of Cr, 0.30%-0.40% of Mo, 0.012%-0.018% of Nb, 0.04%-0.07% of V, 0.0008%-0.0020% of Ce, 0.020%-0.028% of Als, 0.0015%-0.0020% of B and the balance of Fe and inevitable impurities, and technological parameters the low-temperature-resistant mine car bottom plate wear-resistant steel with-40 impact KV2 larger than or equal to 85 J is obtained.

Description

Technical Field

[0001] The invention belongs to the technical field of wear-resistant steel, and in particular relates to a method for producing low-temperature-resistant mine car bottom plate wear-resistant steel with a thickness of 12 to 19 mm. Background Art

[0002] Wear-resistant steel is a key consumable steel material for mining vehicle floorpans. Low-alloy wear-resistant steel offers excellent wear resistance and toughness, making it a highly cost-effective wear-resistant material for mining vehicle floorpans. The use of high-strength wear-resistant steel in mining vehicles not only improves strength, toughness, and wear resistance, but also effectively reduces material thickness, resulting in significant weight reduction and economic benefits. Lightweighting is imperative. Mining vehicles operate primarily under the abrasion and impact of minerals, making hardness and toughness crucial. Assuming the hardness meets the required standards, increasing the toughness of the steel plate significantly extends its lifespan. Summary of the Invention

[0003] The present invention aims to provide a wear-resistant steel for the bottom plate of a mining vehicle with a thickness of 12 to 19 mm. The steel adopts a low-cost design and has extremely high low-temperature impact toughness while ensuring surface hardness. This reduces production costs and extends the service life of the bottom plate of the mining vehicle, reduces social cost consumption, and makes a great contribution to green environmental protection and carbon reduction.

[0004] The specific technical solutions of the present invention are as follows.

[0005] One aspect of the present invention provides a method for producing low-temperature resistant mine car bottom plate wear-resistant steel with a thickness of 12 to 19 mm, wherein the low-temperature resistant mine car bottom plate wear-resistant steel has a -40 impact KV2 ≥ 85J;

[0006] The production method comprises the following process steps: smelting and casting - heating and rolling - heat treatment, wherein:

[0007] In the smelting and casting process, the chemical composition of the low-temperature resistant mine car bottom plate wear-resistant steel is controlled to be C: 0.17-0.18%, Si: 0.32-0.38%, Mn: 1.00-1.20%, P≤0.015%, S≤0.008%, Ti: 0.010-0.020%, Cr: 0.10-0.15%, Mo: 0.30-0.40%, Nb: 0.012-0.018%, V: 0.04-0.07%, Ce: 0.0008-0.0020%, Als: 0.020-0.028%, B: 0.0015-0.0020%, and the balance is Fe and unavoidable impurities;

[0008] In the heating and rolling process, the temperature of the cast slab out of the furnace is controlled to be 1160±15°C, the steel plate is rolled in two stages, the starting rolling temperature of the rough rolling stage is ≥1100°C, and the finishing rolling temperature is 820±15°C;

[0009] The heat treatment process includes a quenching process and a tempering process. In the quenching process, the holding temperature is controlled to be 870±15°C, and the plate is kept at the holding temperature for 15±5 minutes before quenching. In the tempering process, the holding temperature is controlled to be 205±10°C, and the plate is taken out of the furnace after being kept for 75±10 minutes. After being taken out of the furnace, it is cooled slowly away from wind.

[0010] In some embodiments, the surface hardness of the low-temperature resistant mine car bottom plate wear-resistant steel is ≥410 HBW.

[0011] In some embodiments, the yield strength of the low-temperature resistant mine car bottom plate wear-resistant steel is ≥1110MPa, the tensile strength is ≥1230MPa, and the elongation A 50 ≥23%.

[0012] In some embodiments, in the smelting and casting process, the scrap steel added to the converter smelting step is low-sulfur scrap steel, the refining step ensures that the molten steel composition meets design requirements, the RH vacuum treatment time is greater than 20 minutes, and after the vacuum treatment, the soft blowing state is entered, with a soft blowing time of greater than 10 minutes. After the vacuum treatment in the RH furnace, the molten steel reaches [N] ≤ 45 ppm. Continuous casting is performed using a continuous casting machine, with full protection during the casting process. Electromagnetic stirring and soft reduction are used to ensure slab quality. After the continuous cast slab is produced, it is stacked and slowly cooled.

[0013] In some embodiments, the microstructure of the low-temperature resistant mine car bottom plate wear-resistant steel after heat treatment is a tempered martensite structure plus a small amount of bainite.

[0014] In some embodiments, in the smelting and casting process, the chemical composition of the low-temperature resistant mine car bottom plate wear-resistant steel is controlled to be C: 0.175-0.177%, Si: 0.32-0.38%, Mn: 1.00-1.19%, P≤0.015%, S≤0.002%, Ti: 0.012-0.019%, Cr: 0.10-0.15%, Mo: 0.31-0.36%, Nb: 0.012-0.018%, V: 0.04~0.07%, Ce: 0.0008-0.0017%, Als: 0.020-0.028%, B: 0.0015-0.0017%, and the balance is Fe and unavoidable impurities.

[0015] Another aspect of the present invention provides a low-temperature resistant mine car bottom plate wear-resistant steel with a thickness of 12 to 19 mm, which is obtained by the above-mentioned production method. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a metallographic photograph of the low-temperature-resistant mine car bottom plate wear-resistant steel obtained in Example 1.

[0017] Figure 2 This is a metallographic photograph of the low-temperature-resistant mine car bottom plate wear-resistant steel obtained in Example 2.

[0018] Figure 3 This is a metallographic photograph of the low-temperature-resistant mine car bottom plate wear-resistant steel obtained in Example 3. DETAILED DESCRIPTION

[0019] The present invention is described in detail below through specific examples. The examples are intended to help understand the present invention but are not intended to limit the present invention.

[0020] The present invention aims to provide a method for producing low-temperature resistant mine car bottom plate wear-resistant steel, which comprises the following steps:

[0021] 1. Smelting and casting

[0022] The scrap steel added to the converter smelting process must be low-sulfur scrap. The refining process must ensure that the molten steel composition meets the design requirements. The RH vacuum treatment time must be greater than 20 minutes. After the vacuum treatment, the soft blowing state is entered, and the soft blowing time must be greater than 10 minutes. During smelting, the chemical composition is controlled by weight as follows: C: 0.17-0.18%, Si: 0.32-0.38%, Mn: 1.00-1.20%, P≤0.015%, S≤0.008%, Ti: 0.010-0.020%, Cr: 0.10-0.15%, Mo: 0.30-0.40%, Nb: 0.012-0.018%, V: 0.04-0.07%, Ce: 0.0008-0.0020%, Als: 0.020-0.028%, B: 0.0015-0.0020%, and the balance is Fe and unavoidable impurities.

[0023] Continuous casting is carried out using a continuous casting machine, with full protection during the pouring process. Electromagnetic stirring and soft reduction are used to ensure slab quality. After the continuous casting slab comes off the line, it is stacked and slowly cooled.

[0024] 2. Heating and rolling

[0025] All products are produced from cold slabs. The slab temperature out of the furnace is 1160±15℃. The steel plate is rolled in two stages, with the starting rolling temperature of the rough rolling stage ≥1100℃ and the finishing rolling temperature of the fine rolling stage being 820±15℃.

[0026] 3. Heat treatment

[0027] The heat treatment process is quenching + low temperature tempering process.

[0028] Quenching process: The holding temperature of the steel plate is 870±15℃. After the steel plate reaches this temperature, it is kept warm for 15±5 minutes and then quenched.

[0029] Tempering process: The steel plate is kept at a temperature of 205±10℃ for 75±10min before being taken out of the furnace. After being taken out of the furnace, it is kept away from wind and cooled slowly.

[0030] Example 1

[0031] The chemical composition weight percentage of the steel plate is shown in Table 1. The slab heating furnace temperature is 1174℃. The starting temperature of the rough rolling is 1105℃, the finishing temperature of the fine rolling is 833℃, and the steel plate is stacked and slowly cooled after rolling. Quenching process: the steel plate is heated to 860℃, kept warm for 15 minutes, and then quenched. Tempering process: 195℃, kept warm for 65 minutes, and then slowly cooled after being taken out of the furnace. The steel plate is obtained. The properties of the steel plate are shown in Table 2, and the metallographic structure is shown in Figure 1 , the structure is tempered martensite plus tempered bainite.

[0032] Example 2

[0033] The chemical composition weight percentage of the steel plate is shown in Table 1. The slab heating furnace temperature is 1162℃. The starting temperature of the rough rolling is 1105℃, the finishing temperature of the fine rolling is 824℃, and the steel plate is stacked and slowly cooled after rolling. Quenching process: the steel plate is heated to 870℃, kept warm for 20 minutes, and then quenched. Tempering process: 210℃, kept warm for 75 minutes, and then slowly cooled after being taken out of the furnace. The steel plate is obtained. The properties of the steel plate are shown in Table 2, and the metallographic structure is shown in Figure 2 , the structure is tempered martensite plus tempered bainite.

[0034] Example 3

[0035] The chemical composition weight percentage of the steel plate is shown in Table 1. The slab heating furnace temperature is 1155℃. The rough rolling start temperature is 1105℃, the finishing rolling temperature is 815℃, and the steel plate is stacked and slowly cooled after rolling. Quenching process: heat the steel plate to 885℃, keep it warm for 20 minutes, and then quench it. Tempering process: 200℃, keep it warm for 80 minutes, and then take it out of the furnace and slowly cool it. The steel plate is obtained. The steel plate properties are shown in Table 2, and the metallographic structure is shown in Figure 3 , the structure is tempered martensite plus tempered bainite.

[0036] Table 1: Chemical composition of steel plate (wt%)

[0037] C Si Mn P S Cr Mo Nb V Ti B Als Ce 0.176 0.32 1.00 0.014 0.002 0.10 0.36 0.012 0.07 0.012 0.0017 0.020 0.0008 0.177 0.37 1.12 0.014 0.002 0.12 0.31 0.013 0.06 0.014 0.0016 0.025 0.0009 0.175 0.38 1.19 0.012 0.002 0.15 0.34 0.018 0.04 0.019 0.0015 0.028 0.0017

[0038] Table 2: Steel plate properties

[0039]

[0040] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art will be able to modify the technical solutions described in the aforementioned embodiments or substitute equivalents for some of the technical features. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A method for producing low-temperature-resistant mine car bottom plate wear-resistant steel with a thickness of 12 to 19 mm, characterized in that: The -40 impact KV2 of the low-temperature resistant mine car bottom plate wear-resistant steel is ≥85J; The production method comprises the following process steps: smelting and casting - heating and rolling - heat treatment, wherein: In the smelting and casting process, the chemical composition of the low-temperature resistant mine car bottom plate wear-resistant steel is controlled to be C: 0.17-0.18%, Si: 0.32-0.38%, Mn: 1.00-1.20%, P≤0.015%, S≤0.008%, Ti: 0.010-0.020%, Cr: 0.10-0.15%, Mo: 0.30-0.40%, Nb: 0.012-0.018%, V: 0.04-0.07%, Ce: 0.0008-0.0020%, Als: 0.020-0.028%, B: 0.0015-0.0020%, and the balance is Fe and unavoidable impurities; In the heating and rolling process, the temperature of the cast billet out of the furnace is controlled to be 1160±15°C, the steel plate rolling adopts two-stage rolling, the starting rolling temperature of the rough rolling stage is ≥1100°C, and the finishing rolling temperature is 820±15°C; The heat treatment process includes a quenching process and a tempering process. In the quenching process, the insulation temperature is controlled to be 870±15°C, and the plate is kept at the insulation temperature for 15±5 minutes before quenching. In the tempering process, the insulation temperature is controlled to be 205±10°C, and the plate is taken out of the furnace after being kept for 75±10 minutes, and then cooled slowly away from wind after being taken out of the furnace.

2. The production method according to claim 1, wherein the surface hardness of the low-temperature resistant mine car bottom plate wear-resistant steel is ≥410HBW.

3. The production method according to claim 2, wherein the yield strength of the wear-resistant steel for the bottom plate of the low-temperature mine car is ≥1110MPa, the tensile strength is ≥1230MPa, and the elongation A 50 ≥23%.

4. The production method according to any one of claims 1 to 3, wherein in the smelting and casting process, the scrap steel added to the converter smelting process is low-sulfur scrap steel, the refining process ensures that the molten steel composition meets the design requirements, the RH vacuum treatment time is greater than 20 minutes, the vacuum treatment is completed and the soft blowing state is entered, the soft blowing time is greater than 10 minutes, and the molten steel after vacuum treatment in the RH furnace reaches [N] ≤ 45ppm; a continuous casting machine is used for continuous casting, the casting is protected throughout the process, and electromagnetic stirring and light pressure are used to ensure the quality of the slab. After the continuous casting slab is off the line, it is stacked and slowly cooled.

5. The production method according to any one of claims 1 to 4, wherein the microstructure of the low-temperature resistant mine car bottom plate wear-resistant steel after heat treatment is a tempered martensite microstructure plus a small amount of bainite.

6. The production method according to any one of claims 1 to 5, in the smelting and casting process, the chemical composition of the low-temperature resistant mine car bottom plate wear-resistant steel is controlled in weight percentage to be C: 0.175-0.177%, Si: 0.32-0.38%, Mn: 1.00-1.19%, P≤0.015%, S≤0.002%, Ti: 0.012-0.019%, Cr: 0.10-0.15%, Mo: 0.31-0.36%, Nb: 0.012-0.018%, V: 0.04-0.07%, Ce: 0.0008-0.0017%, Als: 0.020-0.028%, B: 0.0015-0.0017%, and the balance is Fe and unavoidable impurities.

7. A low-temperature-resistant mine car bottom plate wear-resistant steel with a thickness of 12 to 19 mm, obtained by the production method according to any one of claims 1 to 6.

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