A low-cost high-strength and high-toughness wear-resistant steel plate

Abstract

The present invention discloses a low-cost high-strength and high-toughness wear-resistant steel plate. The chemical composition by mass percentage is as follows: C: 0.28 - 0.36%, Si: 0.75 - 0.95%, Mn: 2.55 - 2.80%, Al: 0.45 - 0.60%, Ta: 0.02 - 0.06%, B ≤ 0.0015, P ≤ 0.01%, S ≤ 0.01%, and the balance is Fe and unavoidable impurities. The production process includes smelting and refining, heating and continuous rolling, water quenching and tempering treatment. The yield strength of the wear-resistant steel plate is ≥1260 MPa, the tensile strength is ≥1570 MPa, the elongation is ≥15%, the Brinell hardness is ≥470 HB, the Charpy V-notch longitudinal impact energy at room temperature is greater than or equal to ≥80 J, and the Charpy V-notch longitudinal impact energy at -40 °C is ≥40 J. Under the sliding wear condition with a load of 200 N, the wear rate of the wear-resistant plate is ≤6.1×10<supgt;‑6< / supgt; mm<supgt;3< / supgt; / N·m. The high-strength and high-toughness wear-resistant steel plate has high strength, low cost and excellent wear resistance, and has broad application prospects.

Description

Technical Field

[0001] The present invention belongs to the field of metallurgical technology, and particularly relates to a low-cost high-strength and tough wear-resistant steel plate. Background Art

[0002] Wear-resistant steel plates are mostly applied to working conditions with harsh conditions, such as mechanical equipment in fields such as mines, ports, construction, electricity, and metallurgy. With the continuous expansion of the scale of industrial production in our country, the performance requirements for wear-resistant steel plates are also continuously improving. Wear-resistant steel plates should not only have good wear resistance, hardness, and strength, but also have good toughness and ductility.

[0003] Most of the components of existing wear-resistant steel plate manufacturers are similar. By adding relatively large amounts of precious metal components such as Cr, Mn, and Ni, the mechanical properties of the steel plate are enhanced. For example, in patent CN 106086689 B, the chemical composition mass percentage of its wear-resistant steel plate is: C: 0.09 - 0.11%, Si: 0.68 - 0.74%, Mn: 1.06 - 1.13%, P ≤ 0.016%, S ≤ 0.005%, Al: 0.022 - 0.038%, Cr: 0.50 - 0.55%, Mo: 0.85 - 0.95%, W: 0.35 - 0.44%, Nb: 0.06 - 0.07%, Ni: 0.67 - 0.77%, Ca: 0.003 - 0.004%, and the balance is Fe and unavoidable impurities. This kind of high-strength wear-resistant steel plate has high hardness, good low-temperature impact toughness, and excellent comprehensive performance, especially suitable for cold days. Due to the large number of precious elements in the composition, the cost of the wear-resistant steel plate is relatively high; patent CN107893253 A can form a uniform and dense passivation film on the surface of the wear-resistant steel plate through passivation treatment of the wear-resistant steel plate, further improving the wear resistance of the surface of the wear-resistant steel plate, but it cannot effectively solve the improvement of toughness and ductility.

[0004] By adding elements such as Mn, Si, Al, Ta, and B, the present invention improves the wear resistance, strength, toughness and other performance indicators of the wear-resistant steel plate, and can also reduce the production cost. For example, Mn element is a good deoxidizer and desulfurizer. By adding manganese element, the strength and hardness of the steel plate are effectively improved, the hardenability of the steel is improved, and the hot working performance of the steel is improved; the addition of Al element expands the temperature range of the austenite single-phase region, which is beneficial to cold rolling, thereby realizing grain refinement and further improving the yield strength and impact toughness of the material; Ta element has extremely high corrosion resistance. In addition, tantalum element helps to improve the surface hardness of the material. Summary of the Invention

[0005] Aiming at the problems in the comprehensive performance and preparation method of existing wear-resistant steel plates, the purpose of the present invention is to provide a low-cost high-strength and tough wear-resistant steel plate with excellent comprehensive mechanical properties and low processing cost.

[0006] A low-cost, high-strength and high-toughness wear-resistant steel plate. The production process of the low-cost, high-toughness wear-resistant steel plate includes the following steps:

[0007] a. Smelting and refining: Add scrap steel, ferrosilicon, ferromanganese, and aluminum into an electric furnace and heat it up to 1550 - 1580 °C; then place it in an LF furnace for refining until it is completely melted, heat it up to 1660 - 1680 °C, further remove impurities and reduce the phosphorus and sulfur contents, conduct vacuum treatment on the completely melted ingredients, with a vacuum degree ≥ 70 KPa and a holding time ≥ 30 min; Pour the molten steel into a steel mold, take out the billet after the steel mold cools, and roll the billet using the casting residual heat;

[0008] b. Billet heating and rolling: The billet for rolling is heated using a regenerative heating furnace, which is divided into a preheating section, a heating section, and a soaking section; The rolling process parameters are: the furnace temperature for charging ≤ 350 °C, the heating rate of the steel ingot in the preheating section ≤ 85 °C / h until it reaches 850 °C, then heat it up to 1160 °C in the heating section and hold for 3 h, the tapping temperature of the slab ≥ 1150 °C, and the rolling is carried out in the high-temperature austenite region, with the initial rolling temperature ≥ 1090 °C and the final rolling temperature ≥ 920 °C;

[0009] c. Water quenching and tempering treatment: The quenching temperature ≥ 850 °C, take it out of the water after it cools below 100 °C, and the return red temperature < 200 °C. The tempering temperature is 180 - 220 °C and hold for 6 h;

[0010] Furthermore, in step a, the mass percentages of each chemical component are: C: 0.28 - 0.36%, Si: 0.75 - 0.95%, Mn: 2.55 - 2.80%, Al: 0.45 - 0.60%, Ta: 0.02 - 0.06%, B ≤ 0.0015%, P ≤ 0.01%, S ≤ 0.01%, and the balance is Fe and unavoidable impurities;

[0011] The low-cost, high-strength and high-toughness wear-resistant steel plate prepared according to the above process has a yield strength ≥ 1260 MPa, a tensile strength ≥ 1570 MPa, an elongation ≥ 15%, a Brinell hardness ≥ 470 HB, a room-temperature Charpy V-notch longitudinal impact energy ≥ 80 J, a -40 °C Charpy V-notch longitudinal impact energy ≥ 40 J, and under the sliding wear condition of a 200 N load, its wear rate ≤ 6.1×10 -6 mm 3 / N·m;

[0012] The advantages of the present invention are as follows:

[0013] The addition of Al and Mn elements shows a significant coupling effect, effectively improving the ductility and impact resistance of the wear-resistant steel plate, inhibiting the precipitation of carbides, refining the grains, enabling the wear-resistant steel plate involved in the present invention to have high ductility and low-temperature impact toughness on the basis of high hardness and high yield strength, and can be widely applied to various wear-resistant components under high-impact service conditions. At the same time, the material composition does not contain precious alloy elements and has the advantage of low cost. Description of the Drawings

[0014] Figure 1 It is the metallographic structure diagram of the wear-resistant steel in Example 1 at 200 times magnification. Detailed Embodiments

[0015] To better understand the present invention, the content of the present invention will be further clarified below in conjunction with embodiments, but the content of the invention is not limited to the following embodiments.

[0016] Example 1

[0017] A low-cost high-strength and high-toughness wear-resistant steel plate, the mass percentage of its chemical composition is: C: 0.29%, Si: 0.75%, Mn: 2.60%, Al: 0.45%, Ta: 0.023%, B: 0.0011%, P: 0.0095%, S: 0.008%, and the balance is Fe and inevitable impurities. Its production process is as follows:

[0018] a. Smelting and refining: Add the above components according to the ratio to an electric furnace and heat up to 1580°C; then place it in an LF furnace for refining until it is completely melted, heat up to 1680°C, further remove impurities and reduce the phosphorus and sulfur content; subject the completely melted charge to vacuum treatment, with a vacuum degree of 70 kPa and a holding time of 30 min; pour the molten steel into a steel mold, take out the billet after the steel mold cools, and roll the billet with the remaining casting temperature.

[0019] b. Billet heating and rolling: The billet is heated by a regenerative heating furnace, which is divided into a billet preheating section, a heating section and a soaking section; the rolling process parameters are a charging furnace temperature of 350°C, a heating rate of the steel ingot in the preheating section of 85°C / h to 850°C, then heating to 1160°C in the heating section and holding for 3 h, the billet tapping temperature of 1156°C, and rolling in the high-temperature austenite region, with an initial rolling temperature of 1140°C and a final rolling temperature of 950°C.

[0020] c. Water quenching and tempering treatment: The quenching temperature is 850°C, and it comes out of the water after 90°C, and the return red temperature is 196°C. The tempering temperature is 220°C and it is held for 6 h.

[0021] The low-cost, high-strength and tough wear-resistant steel plate prepared according to the above process has a yield strength of 1261 MPa, a tensile strength of 1571 MPa, an elongation of 15.2%, a Brinell hardness of 471 HB, a Charpy V-notch longitudinal impact energy at room temperature of 81 J, a Charpy V-notch longitudinal impact energy at -40 °C of 41 J, and a wear rate of 5.7×10 -6 mm 3 / N·m.

[0022] Example 2

[0023] A low-cost, high-strength and tough wear-resistant steel plate, the mass percentages of its chemical components are as follows: C: 0.31%, Si: 0.83%, Mn: 2.65%, Al: 0.50%, Ta: 0.031%, B: 0.0013%, P: 0.012%, S: 0.009%, and the balance is Fe and inevitable impurities. Its production process is as follows:

[0024] a. Smelting and refining: Add the above components according to the ratio to an electric furnace and heat up to 1570 °C; then place it in an LF furnace for refining until it is completely melted, heat up to 1670 °C, further remove impurities and reduce the phosphorus and sulfur contents; subject the completely melted charge to vacuum treatment, with a vacuum degree of 75 kPa and a holding time of 40 min; pour the molten steel into a steel mold, take out the billet after the steel mold cools, and roll the billet with the remaining heat of casting;

[0025] b. Billet heating and rolling: The billet is heated by a regenerative heating furnace, which is divided into a billet preheating section, a heating section and a soaking section; the rolling process parameters are a charging furnace temperature of 340 °C, a heating rate of the steel ingot in the preheating section of 80 °C / h to 850 °C, then heating up to 1160 °C in the heating section and holding for 3 h, the billet tapping temperature of 1155 °C, and rolling in the high-temperature austenite region, with an initial rolling temperature of 1130 °C and a final rolling temperature of 930 °C;

[0026] c. Water quenching and tempering treatment: The quenching temperature is 860 °C, and it comes out of the water after 90 °C, and the red-return temperature is 190 °C. The tempering temperature is 210 °C and it is held for 6 h;

[0027] The low-cost, high-strength and tough wear-resistant steel plate prepared according to the above process has a yield strength of 1265 MPa, a tensile strength of 1595 MPa, an elongation of 15.3%, a Brinell hardness of 479 HB, a Charpy V-notch longitudinal impact energy at room temperature of 82 J, a Charpy V-notch longitudinal impact energy at -40 °C of 41 J, and a wear rate of 6.0×10 -6 mm 3 / N·m.

[0028] Example 3

[0029] A low-cost, high-strength, tough and wear-resistant steel plate, with the weight percentages of each chemical component as follows: C: 0.33%, Si: 0.90%, Mn: 2.70%, Al: 0.55%, Ta: 0.044%, B: 0.0013%, P: 0.01%, S: 0.008%, and the balance being Fe and unavoidable impurities. Its production process is as follows:

[0030] a. Smelting and refining: Add the above components according to the ratio to an electric furnace and heat up to 1560 °C; then place it in an LF furnace for refining until it is completely melted, heat up to 1660 °C, further remove impurities and reduce the phosphorus and sulfur contents; conduct vacuum treatment on the completely melted charge, with a vacuum degree of 80 kPa and a holding time of 35 min; pour the molten steel into a steel mold, take out the billet after the steel mold cools, and roll the billet using the remaining heat of casting;

[0031] b. Billet heating and rolling: The billet is heated using a regenerative heating furnace, which is divided into a billet preheating section, a heating section, and a soaking section; the rolling process parameters are a charging furnace temperature of 320 °C, a heating rate of the steel ingot in the preheating section of 75 °C / h to 850 °C, then heating up to 1160 °C in the heating section and holding for 3 h, the billet tapping temperature of 1150 °C, and rolling in the high-temperature austenite region, with an initial rolling temperature of 1100 °C and a final rolling temperature of 925 °C;

[0032] c. Water quenching and tempering treatment: The quenching temperature is 855 °C, take out the water after 95 °C, and the return red temperature is 185 °C. The tempering temperature is 190 °C and hold for 6 h;

[0033] The low-cost, high-strength, tough and wear-resistant steel plate prepared according to the above process has a yield strength of 1276 MPa, a tensile strength of 1605 MPa, an elongation of 15.6%, a Brinell hardness of 477 HB, a room temperature Charpy V-notch longitudinal impact energy of 86 J, a -40 °C Charpy V-notch longitudinal impact energy of 42 J, and under the sliding wear condition of a 200 N load, its wear rate is 5.5×10 -6 mm 3 / N·m.

[0034] Example 4

[0035] A low-cost, high-strength, tough and wear-resistant steel plate, with the weight percentages of each chemical component as follows: C: 0.35%, Si: 0.93%, Mn: 2.75%, Al: 0.60%, Ta: 0.056%, B: 0.0014%, P: 0.009%, S: 0.008%, and the balance being Fe and unavoidable impurities. Its production process is as follows:

[0036] a. Smelting and refining: Add the above components according to the ratio into an electric furnace and heat up to 1550 °C; then place it in an LF furnace for refining until it is completely melted, heat up to 1650 °C to further remove impurities and reduce the phosphorus and sulfur content; conduct vacuum treatment on the completely melted charge, with a vacuum degree of 85 kPa and a holding time of 45 min; pour the molten steel into a steel mold, take out the billet after the steel mold cools, and roll the billet using the remaining heat of casting.

[0037] b. Billet heating and rolling: The billet for rolling is heated using a regenerative heating furnace, which is divided into a billet preheating section, a heating section, and a soaking section; the rolling process parameters are a furnace charging temperature of 300 °C, a heating rate of the steel ingot in the preheating section of 85 °C / h up to 850 °C, then heating up to 1160 °C in the heating section and holding for 3 h, the billet tapping temperature of 1150 °C, and rolling in the high-temperature austenite region, with an initial rolling temperature of 1096 °C and a final rolling temperature of 920 °C.

[0038] c. Water quenching and tempering treatment: The quenching temperature is 850 °C, water outlet at 95 °C, and the red return temperature is 183 °C. The tempering temperature is 180 °C and the holding time is 6 h.

[0039] The low-cost, high-strength and tough wear-resistant steel plate prepared according to the above process has a yield strength of 1285 MPa, a tensile strength of 1640 MPa, an elongation of 16.0%, a Brinell hardness of 480 HB, a room-temperature Charpy V-notch longitudinal impact energy of 88 J, a -40 °C Charpy V-notch longitudinal impact energy of 44 J, and under the sliding wear condition of a 200 N load, its wear rate is 6.1×10 -6 mm 3 / N·m.

[0040] The following Examples 1-4 are high-yield wear-resistant steel plates, and Comparative Example 1 is a Mn13V wear-resistant steel plate, and the weight percentages of its chemical components are shown in Table 1;

[0041] Table 1 Weight percentages of chemical components of Examples and Comparative Examples (wt%)

[0042] Component C Si Mn Ta B Al P S V Example 1 0.29 0.75 2.60 0.023 0.0011 0.45 0.009 0.008 — Example 2 0.31 0.83 2.65 0.031 0.0013 0.50 0.012 0.009 — Example 3 0.33 0.90 2.70 0.044 0.0013 0.55 0.01 0.008 — Example 4 0.35 0.93 2.75 0.056 0.0014 0.60 0.009 0.008 — Comparative Example 1 1.12 0.27 12.86 — — — 0.03 0.008 0.20

[0043] Samples were taken from the wear-resistant plate of Example 1, and its microstructure was observed under a metallurgical microscope after grinding, polishing and etching (see Figure 1 ), and it was determined to be martensite, a small amount of retained austenite, and carbide distributed dispersedly. Mechanical property tests were carried out on the wear-resistant plates of the four groups of Examples and the Comparative Example. It can be seen from Table 2 that the tensile strength of the wear-resistant steel plates of the four groups of Examples is ≥1570 MPa, the yield strength is ≥1260 MPa, the elongation is ≥15%, the Brinell hardness is ≥470 HB, the room-temperature Charpy V-notch longitudinal impact energy is greater than or equal to ≥80 J, and the -40 °C Charpy V-notch longitudinal impact energy is ≥40 J.

[0044] The addition of Mn and Al elements has an obvious coupling effect, which helps to improve the elongation and yield strength of high-strength and toughness wear-resistant steel. With the increase of the Al element content, the elongation of the wear-resistant steel increases from 15.2% to 16%. Its yield strength is increased to more than 2.7 times that of Comparative Example 1, and the elongation is increased by 12.5 - 18.5%.

[0045] Table 2 Comparison of mechanical properties between examples and comparative examples

[0046]

[0047] Friction and wear performance test

[0048] The test was carried out using an MM-2000 friction and wear testing machine. The test conditions were as follows: load 200N, rotation speed 200 revolutions per minute, wear test time 2h, experimental sample size 10×10×20mm, friction pair was a GCr15 steel ring, surface hardness ≥580HB, diameter 50mm. The wear rate was calculated using the volume wear rate, and the calculation formula was as follows:

[0049]

[0050] Where is the volume wear rate, unit mm 3 / (N·m); △m is the weight loss due to wear, unit mg; ρ is the density of the experimental material, taking 7.89g / cm 3 ; P is the loading pressure, unit N; L is the wear stroke, unit m.

[0051] The friction and wear performance test results of five groups of examples and comparative examples are shown in Table 3:

[0052] Table 3 Comparison of wear performance between examples and Comparative Example 1

[0053] Example 1 2 3 4 Comparative Example 1 <![CDATA[Wear rate × 10 -6 mm 3 / N·m]]> 5.7 6.0 5.5 6.1 17.5

[0054] As can be seen from Table 3, under a load of 200N, the wear rate of the high-yield wear-resistant steel plate of the present invention ≤6.1×10 -6 mm 3 / N·m, and its wear resistance is improved by more than 2.8 times compared with Comparative Example 1. In summary, the comprehensive performance of a low-cost high-strength and toughness wear-resistant steel plate of the present invention is excellent, and its strength, toughness and wear resistance indexes are significantly higher than those of Mn13V wear-resistant steel. It can be widely used in various wear-resistant components under high-impact service conditions. At the same time, the material composition does not contain precious alloy elements, and it has a significant low-cost advantage.

Claims

1. A low-cost, high-strength, tough and wear-resistant steel plate, characterized in that, It includes the following steps: S1. Mass percentage of chemical components: C: 0.28 - 0.36%, Si: 0.75 - 0.95%, Mn: 2.55 - 2.80%, Al: 0.45 - 0.60%, Ta: 0.02 - 0.06%, B ≤ 0.0015%, P ≤ 0.01%, S ≤ 0.01%, and the balance is Fe and inevitable impurities; S2. Smelting and refining: Scrap steel, ferrosilicon, ferromanganese, and aluminum materials are added to the electric furnace step by step, and the temperature is gradually raised to 1550 - 1580 °C; then it is transferred to the LF furnace for refining to further remove impurities and reduce the phosphorus and sulfur contents, and the temperature is raised to 1660 - 1680 °C. The completely melted charge is subjected to vacuum treatment with a vacuum degree ≥ 70 kPa and a holding time ≥ 30 min; the molten steel is cast in a steel mold, and the billet is taken out after the steel mold cools, and the billet is bloomed using the remaining heat of casting; S3. Heating and continuous rolling: The rolled billet is heated using a regenerative heating furnace, which is divided into a billet preheating section, a heating section, and a soaking section. The billet is charged into the furnace at a furnace temperature ≤ 350 °C, and the heating rate ≤ 85 °C / h. The billet is heated to 850 °C in the preheating section, then further heated to 1160 °C in the heating section and held for 3 h. The billet tapping temperature ≥ 1150 °C, and rolling is carried out in the high-temperature austenite region with an initial rolling temperature ≥ 1090 °C and a final rolling temperature ≥ 920 °C; S4. Water quenching and tempering treatment: The quenching temperature of the steel plate ≥ 850 °C, it is taken out of water after the temperature is lower than 100 °C, and the return red temperature < 200 °C. The tempering temperature is 180 - 220 °C and held for 6 h.

2. A low-cost high-strength, tough and wear-resistant steel plate according to claim 1, characterized in that, The yield strength of the wear-resistant steel plate is ≥1260 MPa, the tensile strength is ≥1570 MPa, the elongation is ≥15%, the Brinell hardness is ≥470 HB, the Charpy V-notch longitudinal impact energy at room temperature is ≥80 J, and the Charpy V-notch longitudinal impact energy at -40 °C is ≥40 J. Under the sliding wear condition with a load of 200 N, its wear rate is ≤6.1×10 -6 mm 3 / N·m.

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