Low-stress 650HB-grade wear-resistant steel plate and production method thereof

Abstract

The invention discloses a low-stress 650HB-grade wear-resistant steel plate and a production method thereof. The steel plate comprises the following chemical components in percentage by mass: 0.43 to 0.45 percent of C, 0.61 to 0.70 percent of Si, 0.55 to 0.70 percent of Mn, less than or equal to 0.010 percent of P, less than or equal to 0.008 percent of S, 1.20 to 1.40 percent of Cr, 0.040 to 0.055 percent of Al, 0.0025 to 0.0035 percent of B and the balance of Fe and inevitable impurities. The production method comprises the working procedures of converter smelting, LF refining, VD refining, continuous casting, heating, rolling, quenching and self-tempering. In the self-tempering process, after the temperature of the quenched steel plate reaches 250-400 DEG C, the steel plate is directly off-line and subjected to stack cooling without intervals. According to the method, the production process is shortened, the energy is saved, and the efficiency is improved; the stress of the obtained steel plate is 20-60 Mpa, and the brinell hardness is 650-700 HBW.

Description

Technical Field

[0001] The present invention belongs to the technical field of wear-resistant steel, and particularly relates to a low-stress 650HB grade wear-resistant steel plate and a production method thereof. Background Art

[0002] Wear is the main form of material failure. Statistics show that 80% of material consumption is caused by wear, and among them, the consumption caused by abrasive wear accounts for about 50% of the total. Wear not only consumes materials, causing significant economic losses, but also seriously increases the equipment maintenance frequency, greatly reduces the production efficiency, and restricts the development of modern industry. Therefore, in order to reduce material wear, it is of great significance to develop high-grade new wear-resistant materials.

[0003] Low-alloy wear-resistant steel has low alloy cost, good machinability, and convenient and flexible production. By adjusting the chemical composition and heat treatment process, different types of microstructures can be obtained, and the matching of hardness and toughness can be reasonably controlled within a wide temperature range, improving the wear resistance and meeting the needs of different wear conditions. In the domestic market, the supply of low-end low-alloy wear-resistant steel exceeds the demand, but high-end wear-resistant steel needs to be imported. From the perspective of reducing imports and increasing domestic production, the market share of high-grade low-alloy wear-resistant steel will gradually increase. Summary of the Invention

[0004] The purpose of the present invention is to provide a low-stress 650HB grade wear-resistant steel plate and a production method thereof. By adopting the quenching + self-tempering process, not only the production process is shortened, energy is saved, and production efficiency is improved, but also the stress generated during the quenching process of the steel plate can be effectively removed. The obtained steel plate has a stress of 20 - 60 Mpa, a Brinell hardness of 650 - 700 HBW, and has the characteristics of low stress, high hardness, and good wear resistance.

[0005] To achieve the above purpose, the technical solution adopted by the present invention is: A low-stress 650HB grade wear-resistant steel plate, the chemical composition and its mass percentage content are: C: 0.43 - 0.45%, Si: 0.61 - 0.70%, Mn: 0.55 - 0.70%, P ≤ 0.010%, S ≤ 0.008%, Cr: 1.20 - 1.40%, Al: 0.040 - 0.055%, B: 0.0025 - 0.0035%, and the balance is Fe and unavoidable impurities.

[0006] The thickness of the wear-resistant steel plate of the present invention is 6 - 80 mm.

[0007] The production method of the wear-resistant steel plate of the present invention includes converter smelting, LF refining, VD refining, continuous casting, heating, rolling, quenching, and self-tempering processes.

[0008] In the quenching process of the method of the present invention, the heating temperature is 810 - 920 °C, and the final cooling temperature is 250 - 400 °C.

[0009] In the quenching process of the method of the present invention, the cooling process is as follows: the water pressure in the high-pressure section is 0.70 - 0.80 MPa, the high-pressure water volume is 2000 - 3000 m 3 / h, the water ratio in the high-pressure section is 1.1 - 2.0, the water pressure in the low-pressure section is 0.40 - 0.50 MPa, the low-pressure water volume is 800 - 1350 m 3 / h, the water ratio in the low-pressure section is 1.6 - 2.5, and the roll speed is 0.1 - 0.4 m / s.

[0010] In the self-tempering process of the method of the present invention, after the temperature of the steel plate reaches 250 - 400 °C after quenching, it is directly taken offline and stacked for cooling without interruption, generating a self-tempering effect.

[0011] The stress of the wear-resistant steel plate of the present invention after self-tempering is 20 - 60 Mpa, which is equivalent to the stress of the steel plate obtained by the traditional offline quenching + offline tempering process.

[0012] The Brinell hardness of the wear-resistant steel plate of the present invention is 650 - 700 HBW.

[0013] The standard for the stress detection method of the low-stress 650HB grade wear-resistant steel plate product of the present invention refers to GB / T 33210 - 2016.

[0014] The standard for the hardness detection method of the low-stress 650HB grade wear-resistant steel plate product of the present invention refers to GB / T 231.1.

[0015] The beneficial effects produced by adopting the above technical solutions are as follows: (1) The method of the present invention can stably produce wear-resistant steel plates with a stress of 20 - 60 Mpa and a Brinell hardness of 650 - 700 HBW. The stress is low and the hardness is high, and the stress is equivalent to that of the steel plate obtained by the traditional offline quenching + offline tempering process.

[0016] (2) The present invention adopts the quenching + self-tempering process, which shortens the production process, saves energy, improves production efficiency, and the product performance is excellent.

[0017] (3) The method of the present invention can effectively remove the stress generated during the quenching process of the steel plate and avoid the defect of steel plate explosion during cutting or welding. Specific Embodiments

[0018] The present invention will be further described in detail below with reference to specific embodiments. Example 1

[0019] The thickness of the wear-resistant steel plate in this example is 6 mm, and its chemical composition and mass percentage are shown in Table 1.

[0020] The production method of the wear-resistant steel plate in this embodiment includes converter smelting, LF refining, VD refining, continuous casting, heating, rolling, quenching and self-tempering processes; the specific process steps are as follows: (1) Quenching process: Quenching heating temperature is 810 °C; Cooling process: Water pressure in the high-pressure section is 0.70 MPa, high-pressure water volume is 2000 m 3 / h, water ratio in the high-pressure section is 1.1, water pressure in the low-pressure section is 0.40 MPa, low-pressure water volume is 800 m 3 / h, water ratio in the low-pressure section is 1.6, roll speed is 0.4 m / s; Final cooling temperature is 400 °C; (2) Self-tempering process: After the temperature of the steel plate after quenching reaches 400 °C, it is directly taken offline and stacked for cooling without interruption.

[0021] The stress of the wear-resistant steel plate obtained in this embodiment is 60 Mpa, and the average hardness is 700 HB. Example 2

[0022] The thickness of the wear-resistant steel plate in this embodiment is 30 mm, and its chemical composition and mass percentage are shown in Table 1.

[0023] The production method of the wear-resistant steel plate in this embodiment includes converter smelting, LF refining, VD refining, continuous casting, heating, rolling, quenching and self-tempering processes, and the specific process steps are as follows: (1) Quenching process: Quenching heating temperature is 850 °C; Cooling process: Water pressure in the high-pressure section is 0.74 MPa, high-pressure water volume is 2378 m 3 / h, water ratio in the high-pressure section is 1.16, water pressure in the low-pressure section is 0.43 MPa, low-pressure water volume is 1047 m 3 / h, water ratio in the low-pressure section is 1.8, roll speed is 0.27 m / s; Final cooling temperature is 355 °C; (2) Self-tempering process: After the temperature of the steel plate after quenching reaches 355 °C, it is directly taken offline and stacked for cooling without interruption.

[0024] The stress of the wear-resistant steel plate in this embodiment is 48 Mpa, and the average hardness is 687 HB. Example 3

[0025] The thickness of the wear-resistant steel plate in this embodiment is 50 mm, and its chemical composition and mass percentage are shown in Table 1.

[0026] The production method of the wear-resistant steel plate in this embodiment includes converter smelting, LF refining, VD refining, continuous casting, heating, rolling, quenching and self-tempering processes; the specific process steps are as follows: (1) Quenching process: Quenching heating temperature is 870 °C; Cooling process: Water pressure in the high-pressure section is 0.77 MPa, high-pressure water volume is 2469 m 3 / h, water ratio in the high-pressure section is 1.17, water pressure in the low-pressure section is 0.45 MPa, low-pressure water volume is 1168 m3 / h, water ratio in the low-pressure section is 2.0, roll speed is 0.23 m / s; final cooling temperature is 346 °C.

[0027] (2) Self-tempering process: After the temperature of the quenched steel plate reaches 346 °C, it is directly taken offline for stacking and cooling without any interval.

[0028] The stress of the wear-resistant steel plate in this embodiment is 36 Mpa, and the average hardness is 674 HB. Example 4

[0029] The thickness of the wear-resistant steel plate in this embodiment is 60 mm, and its chemical composition and mass percentage are shown in Table 1.

[0030] The production method of the wear-resistant steel plate in this embodiment includes converter smelting, LF refining, VD refining, continuous casting, heating, rolling, quenching and self-tempering processes; the specific process steps are as follows: (1) Quenching process: Quenching heating temperature is 900 °C; cooling process: water pressure in the high-pressure section is 0.78 MPa, high-pressure water volume is 2738 m 3 / h, water ratio in the high-pressure section is 1.18, water pressure in the low-pressure section is 0.47 MPa, low-pressure water volume is 1297 m 3 / h, water ratio in the low-pressure section is 2.2, roll speed is 0.15 m / s; final cooling temperature is 278 °C.

[0031] (2) Self-tempering process: After the temperature of the quenched steel plate reaches 278 °C, it is directly taken offline for stacking and cooling without any interval.

[0032] The stress of the wear-resistant steel plate in this embodiment is 53 Mpa, and the average hardness is 688 HB. Example 5

[0033] The thickness of the wear-resistant steel plate in this embodiment is 80 mm, and its chemical composition and mass percentage are shown in Table 1.

[0034] The production method of the wear-resistant steel plate in this embodiment includes converter smelting, LF refining, VD refining, continuous casting, heating, rolling, quenching and self-tempering processes; the specific process steps are as follows: (1) Quenching process: Quenching heating temperature is 920 °C; cooling process: water pressure in the high-pressure section is 0.80 MPa, high-pressure water volume is 3000 m 3 / h, water ratio in the high-pressure section is 2.0, water pressure in the low-pressure section is 0.50 MPa, low-pressure water volume is 1350 m 3 / h, water ratio in the low-pressure section is 2.5, roll speed is 0.1 m / s; final cooling temperature is 250 °C.

[0035] (2) Self-tempering process: After the temperature of the quenched steel plate reaches 250 °C, it is directly taken offline for stacking and cooling without any interval.

[0036] The stress of the wear-resistant steel plate in this embodiment is 20 Mpa, and the average hardness is 650 HB.

[0037] Table 1 Chemical composition and content of wear-resistant steel plates in each embodiment (%)

[0038] The balance of the components in Table 1 is Fe and unavoidable impurities.

[0039] The above embodiments are only used to illustrate rather than limit the technical solutions of the present invention. Although the present invention has been described in detail with reference to the above embodiments, those of ordinary skill in the art should understand that: the present invention can still be modified or equivalently replaced, and any modification or partial replacement without departing from the spirit and scope of the present invention shall be covered by the scope of the claims of the present invention.

Claims

1. A wear-resistant steel plate with a low stress level of 650 HB, characterized in that, The chemical composition and its mass percentage are as follows: C: 0.43 - 0.45%, Si: 0.61 - 0.70%, Mn: 0.55 - 0.70%, P ≤ 0.010%, S ≤ 0.008%, Cr: 1.20 - 1.40%, Al: 0.040 - 0.055%, B: 0.0025 - 0.0035%, and the balance is Fe and inevitable impurities.

2. The wear-resistant steel plate with a low stress level of 650 HB according to claim 1, characterized in that, The thickness of the wear-resistant steel plate is 6 - 80 mm.

3. The wear-resistant steel plate with a low stress level of 650 HB according to claim 1 or 2, characterized in that, The stress of the steel plate is 20 - 60 Mpa.

4. A low-stress wear-resistant steel plate with a hardness of 650 HB according to claim 1 or 2, characterized in that, The Brinell hardness of the steel plate is 650 - 700 HBW.

5. A production method of a low-stress wear-resistant steel plate with a hardness of 650 HB according to any one of claims 1-4, characterized in that, It includes the processes of converter smelting, LF refining, VD refining, continuous casting, heating, rolling, quenching and self-tempering.

6. The production method of the low-stress wear-resistant steel plate with a hardness of 650 HB according to claim 5, characterized in that, For the quenching process, the quenching heating temperature is 810 - 920 °C, and the final cooling temperature is 250 - 400 °C.

7. The production method of the low-stress wear-resistant steel plate with a hardness of 650 HB according to claim 5, characterized in that, The cooling process of the quenching process is as follows: the water pressure in the high-pressure section is 0.70 - 0.80 MPa, the high-pressure water volume is 2000 - 3000 m 3 / h, the water ratio in the high-pressure section is 1.1 - 2.0, the water pressure in the low-pressure section is 0.40 - 0.50 MPa, and the low-pressure water volume is 800 - 1350 m 3 / h, the water ratio in the low-pressure section is 1.6 - 2.5, and the roll speed is 0.1 - 0.4 m / s.

8. The production method of the low-stress wear-resistant steel plate with a hardness of 650HB according to claim 5, characterized in that, For the self-tempering process, after the temperature of the steel plate after quenching reaches 250 - 400 °C, it is directly taken offline and stacked for cooling without interruption.

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