Heat-resistant and wear-resistant steel and production method thereof

Abstract

The invention discloses heat-resistant and wear-resistant steel which comprises the following chemical components in percentage by mass: 0.20%-0.30% of C, 0.20%-0.40% of Si, 1.00%-1.50% of Mn, less than or equal to 0.012% of P, less than or equal to 0.002% of S, 0.008%-0.025% of Ti, 0.40%-0.6% of Cr, 0.20%-0.50% of Ni, 0.80%-1.20% of Mo, 0.020%-0.050% of Al, less than or equal to 0.0045% of N and the balance of Fe and inevitable impurities. The method has the advantages that high-temperature quenching and low-temperature tempering processes are adopted, the heat resistance and wear resistance of the steel plate are improved, the surface Brinell hardness of the steel plate is improved, and the stability of the core structure of the steel plate is improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of iron and steel metallurgy, and particularly relates to a heat-resistant and wear-resistant steel and a production method thereof. Background Art

[0002] In recent years, domestic steel enterprises have paid more and more attention to the investment and production of high-value-added products, and low-alloy wear-resistant steel plates belong to this type of product. The failure forms of metal materials are mainly wear, corrosion, and fracture. According to statistics, 80% of material consumption is caused by wear, and the direct economic loss caused by the wear of mechanical parts is about 40 billion yuan per year. Wear not only consumes materials, causing huge economic losses, but also increases the equipment maintenance frequency, reduces production efficiency, and greatly restricts the development of modern industry. Therefore, in order to reduce material wear and energy consumption, it is of great significance and broad market prospects to develop low-alloy wear-resistant steel plates with higher wear resistance.

[0003] Low-alloy martensitic wear-resistant steel has the advantages of low alloy cost, good processing performance, convenient and flexible production, etc., and has gradually replaced traditional high-manganese steel wear-resistant steel grades under medium- and low-stress wear conditions. However, with the gradual increase in the application fields of low-alloy wear-resistant steel, requirements for its wear resistance under harsh working conditions such as high temperature have been put forward. Summary of the Invention

[0004] The purpose of the present invention is to solve the problem of low wear resistance of existing steel plates under high-temperature working conditions, and provide a heat-resistant and wear-resistant steel to improve the heat-resistant and wear-resistant performance of the steel plate, increase the surface Brinell hardness of the steel plate, and improve the stability of the core structure of the steel plate.

[0005] In order to achieve the above purpose, the present invention adopts the following technical solutions: A heat-resistant and wear-resistant steel, the chemical composition and mass percentage thereof are as follows: C: 0.20% - 0.30%, Si: 0.20% - 0.40%, Mn: 1.00% - 1.50%, P≤0.012%, S≤0.002%, Ti: 0.008% - 0.025%, Cr: 0.40% - 0.6%, Ni: 0.20% - 0.50%, Mo: 0.80% - 1.20%, Al: 0.020% - 0.050%, N≤0.0045%, and the balance is Fe and inevitable impurities.

[0006] Further, the chemical composition and mass percentage of the heat-resistant and wear-resistant steel are as follows: C: 0.20% - 0.280%, Si: 0.20% - 0.30%, Mn: 1.00% - 1.30%, P ≤ 0.012%, S ≤ 0.002%, Ti: 0.008% - 0.020%, Cr: 0.40% - 0.50%, Ni: 0.20% - 0.40%, Mo: 0.80% - 1.00%, Al: 0.020% - 0.040%, N ≤ 0.0045%, and the balance is Fe and unavoidable impurities.

[0007] Further, the chemical composition and mass percentage of the heat-resistant and wear-resistant steel are as follows: C: 0.22% - 0.30%, Si: 0.30% - 0.40%, Mn: 1.20% - 1.50%, P ≤ 0.012%, S ≤ 0.002%, Ti: 0.010 - 0.025%, Cr: 0.50% - 0.6%, Ni: 0.30% - 0.50%, Mo: 1.00% - 1.20%, Al: 0.030% - 0.050%, N ≤ 0.0045%, and the balance is Fe and unavoidable impurities.

[0008] To further achieve the object of the present invention, a production method of the heat-resistant and wear-resistant steel is also provided, including the following steps: (1) The smelting is carried out by converter smelting, the tapping temperature is 1610 - 1650°C, LF + RH refining treatment is adopted, the RH vacuum degree ≤ 3.0 mbar, after meeting the vacuum degree requirement, the vacuum treatment time is 15 - 25 min, and the static stirring after vacuum is 15 - 30 min. After refining, it is sent to continuous casting for casting; (2) The rolling adopts conventional rolling technology, the cooling return red temperature is 200 - 300°C, the cooled steel plate is stacked and cooled, and the stacking and cooling time is 40 - 60 h; (3) Heat treatment is carried out by quenching + tempering process. The tempering temperature is 930 - 950°C for furnace charging, the quenching temperature is 200 - 400°C, and the steel plate is marked and stored after heat treatment.

[0009] Further, in the step (1), the tapping temperature is 1636°C, the vacuum treatment time is 21 min after meeting the vacuum degree requirement, and the static stirring after vacuum is 18 min.

[0010] Further, in the step (1), the tapping temperature is 1640°C, the vacuum treatment time is 16 min after meeting the vacuum degree requirement, and the static stirring after vacuum is 15 - 30 min.

[0011] Further, in the step (2), the cooling return red temperature is 260°C, and the stacking and cooling time is 48 h.

[0012] Further, in the step (2), the cooling and returning red temperature is 238 °C, and the stacking cooling time is 55 h.

[0013] Further, in the step (3), the tempering temperature for furnace charging is 943 °C, and the quenching temperature is 298 °C.

[0014] Compared with the prior art, the advantages of the technical solution of the present invention are as follows: (1) Through composition design and process, the present invention realizes the refinement of the surface structure of wear-resistant steel and the transformation quantity of martensite structure, realizes the heat-resistant and wear-resistant performance of the steel plate, successfully develops a new variety, and obtains market application; (2) The present invention effectively reduces the N content. By reasonably matching the ratio of Ti content to N content and increasing the Al content, the nitrogen fixation effect of Ti / Al is promoted. The content of free carbon and nitrogen in the steel is reduced, the product quality is improved. By increasing the content of molybdenum element, the hardenability and tempering stability of the steel plate are improved, the heat-resistant and wear-resistant performance of the product is improved, and the surface Brinell hardness of the steel plate is also improved; (3) The present invention adopts vacuum treatment and continuous casting process to generate calcium aluminate inclusions, and the purity of molten steel and the refinement of inclusions have significantly improved the surface wear-resistant performance of the steel plate; (4) The present invention adopts a conventional rolling process to improve production efficiency. The returning red temperature is 200 - 300 °C and stacking cooling is carried out simultaneously. There is a self-tempering effect during the stacking cooling process of the steel plate, which is beneficial to improving the stability of the core structure of the steel plate and enhancing the performance of the steel plate in the thickness direction; (5) The present invention adopts a secondary quenching process to improve the surface quality and performance of the steel plate, and improves the heat-resistant and wear-resistant performance of the product. Description of the Drawings

[0015] Figure 1 It is the metallographic structure diagram of the heat-resistant and wear-resistant steel in the first embodiment of the present invention. Detailed Description of the Invention Example 1

[0016] To make the present invention more clearly understood, the following further describes a heat-resistant and wear-resistant steel and its production method according to the present invention with reference to the drawings. The specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0017] In this embodiment, a heat-resistant and wear-resistant steel has the following chemical composition and mass percentage: C: 0.23%, Si: 0.20% - 0.30%, Mn: 1.12%, P: 0.010%, S ≤ 0.001%, Ti: 0.015%, Cr: 0.43%, Ni: 0.28%, Mo: 0.89%, Al: 0.029%, N: 0.0031%, and the balance is Fe and unavoidable impurities.

[0018] The production method of the above heat-resistant and wear-resistant steel includes the following steps: S1: The smelting is carried out by converter smelting, the tapping temperature is 1636 °C, LF+RH refining treatment is adopted, the RH vacuum degree ≤ 3.0 mbar, after meeting the vacuum degree requirement, the vacuum treatment time is 21 min, the static stirring after vacuum is 18 min, and after refining, it is sent to continuous casting for casting; S2: The rolling adopts conventional rolling technology, the cooling return red temperature is 260 °C, the cooled steel plate is stacked and cooled, and the stacking cooling time is 48 h; S3: Heat treatment is carried out by quenching + tempering process. The tempering temperature is 943 °C when entering the furnace, the quenching temperature is 298 °C, and the steel plate is marked and stored after heat treatment. The metallographic diagram of the made heat-resistant and wear-resistant steel is as Figure 1 shown. Example 2

[0019] A heat-resistant and wear-resistant steel provided in this example, its chemical composition and mass percentage are as follows: C: 0.29%, Si: 0.38%, Mn: 1.45%, P: 0.011%, S: 0.001%, Ti: 0.023%, Cr: 0.57%, Ni: 0.46%, Mo: 1.16%, Al: 0.046%, N: 0.0041%, and the balance is Fe and unavoidable impurities. Its manufacturing method includes the following steps: S1: The smelting is carried out by converter smelting, the tapping temperature is 1640 °C, LF+RH refining treatment is adopted, the RH vacuum degree ≤ 3.0 mbar, after meeting the vacuum degree requirement, the vacuum treatment time is 16 min, the static stirring after vacuum is 15 - 30 min, and after refining, it is sent to continuous casting for casting; S2: The rolling adopts conventional rolling technology, the cooling return red temperature is 238 °C, the cooled steel plate is stacked and cooled, and the stacking cooling time is 55 h; S3: Heat treatment is carried out by quenching + tempering process. The tempering temperature is 943 °C when entering the furnace, the quenching temperature is 200 - 400 °C, and the steel plate is marked and stored after heat treatment.

[0020] The present invention adopts a reasonable composition design concept, adopts high-temperature quenching and low-temperature tempering processes, realizes the formation of surface hardness and core martensite structure, and meets the stability of the product manufacturing process.

[0021] In addition to the above embodiments, the present invention can also have other implementation manners. All technical solutions formed by equivalent replacement or equivalent transformation fall within the protection scope required by the present invention.

Claims

1. A heat-resistant and wear-resistant steel, characterized in that: Its chemical composition and mass percentages are as follows: C: 0.20% - 0.30%, Si: 0.20% - 0.40%, Mn: 1.00% - 1.50%, P ≤ 0.012%, S ≤ 0.002%, Ti: 0.008% - 0.025%, Cr: 0.40% - 0.6%, Ni: 0.20% - 0.50%, Mo: 0.80% - 1.20%, Al: 0.020% - 0.050%, N ≤ 0.0045%, and the balance is Fe and unavoidable impurities.

2. The heat-resistant and wear-resistant steel according to claim 1, characterized in that: The chemical composition and mass percentages of the heat-resistant and wear-resistant steel are as follows: C: 0.20% - 0.280%, Si: 0.20% - 0.30%, Mn: 1.00% - 1.30%, P ≤ 0.012%, S ≤ 0.002%, Ti: 0.008% - 0.020%, Cr: 0.40% - 0.50%, Ni: 0.20% - 0.40%, Mo: 0.80% - 1.00%, Al: 0.020% - 0.040%, N ≤ 0.0045%, and the balance is Fe and unavoidable impurities.

3. The heat-resistant and wear-resistant steel according to claim 1, characterized in that: The chemical composition and mass percentages of the heat-resistant and wear-resistant steel are as follows: C: 0.22% - 0.30%, Si: 0.30% - 0.40%, Mn: 1.20% - 1.50%, P ≤ 0.012%, S ≤ 0.002%, Ti: 0.010 - 0.025%, Cr: 0.50% - 0.6%, Ni: 0.30% - 0.50%, Mo: 1.00% - 1.20%, Al: 0.030% - 0.050%, N ≤ 0.0045%, and the balance is Fe and unavoidable impurities.

4. A production method of the heat-resistant and wear-resistant steel as described in claim 1, characterized in that, It includes the following steps: (1) For smelting, converter smelting is adopted, the tapping temperature is 1610 - 1650 °C, LF + RH refining treatment is used, the RH vacuum degree ≤ 3.0 mbar, after meeting the vacuum degree requirement, the vacuum treatment time is 15 - 25 min, and the static stirring after vacuum is 15 - 30 min. After refining, it is sent to continuous casting for casting; (2) For rolling, conventional rolling technology is adopted, the cooling return red temperature is 200 - 300 °C, the cooled steel plate is stacked for cooling, and the stacking cooling time is 40 - 60 h; (3) Heat treatment is carried out by quenching + tempering process. The tempering temperature is 930 - 950 °C for furnace charging, the quenching temperature is 200 - 400 °C, and after heat treatment, the steel plate is marked and put into storage.

5. The production method of the heat-resistant and wear-resistant steel according to claim 4, characterized in that: In the step (1), the tapping temperature is 1636 °C, after meeting the vacuum degree requirement, the vacuum treatment time is 21 min, and the static stirring after vacuum is 18 min.

6. The production method of the heat-resistant and wear-resistant steel according to claim 4, characterized in that: In the step (1), the tapping temperature is 1640 °C, after meeting the vacuum degree requirement, the vacuum treatment time is 16 min, and the static stirring after vacuum is 15 - 30 min.

7. The production method of the heat-resistant and wear-resistant steel according to claim 4, characterized in that: In the step (2), the cooling return red temperature is 260 °C and the stacking cooling time is 48 h.

8. The production method of the heat-resistant and wear-resistant steel according to claim 4, characterized in that: In the step (2), the cooling return red temperature is 238 °C and the stacking cooling time is 55 h.

9. The production method of the heat-resistant and wear-resistant steel according to claim 4, characterized in that: In the step (3), the tempering temperature is 943 °C for furnace charging and the quenching temperature is 298 °C.

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