Production method of wear-resistant high-manganese steel medium plate

Abstract

The invention discloses a production method of a wear-resistant high manganese steel medium plate. The steel comprises the following chemical components in percentage by weight: 0.90-1.05% of C, 11.0-14.0% of Mn, 0.30-0.90% of Si, less than or equal to 0.03% of P, less than or equal to 0.005% of S, 0.01-0.5% of V and the balance of Fe and inevitable impurity elements. The production process comprises the steps of molten iron pretreatment, converter smelting, LF and RH / VD refining, continuous casting, heating in a heating furnace, descaling and rolling, Mulpic cooling, finishing, detecting and warehousing. According to the method, the continuous casting billets are hot charged into the furnace, the cracking defect caused by cooling of the continuous casting billets can be effectively avoided, the qualified rate of the continuous casting billets is increased, and the heating and heat preservation time of the continuous casting billets is shortened; by optimizing the heating and controlled rolling and controlled cooling processes, a large amount of carbides are prevented from being separated out among austenite crystals in the rolling and cooling processes, on the premise that the excellent mechanical property is guaranteed, the post-rolling water toughening treatment procedure of the wear-resistant high-manganese steel medium-thickness plate is omitted, and the production process of the wear-resistant high-manganese steel medium-thickness plate is remarkably shortened.

Description

Technical Field

[0001] The invention belongs to the technical field of steel smelting and relates to a production method of a wear-resistant high-manganese steel medium and thick plate. Background Art

[0002] There are three main forms of damage to steel materials: fracture, corrosion and wear. International data statistics show that friction consumes one-third of the world's disposable energy, about 80% of machine parts fail due to wear, and about 50% of serious accidents in machinery and equipment are caused by lubrication failure and excessive wear. In developed countries such as Germany, the United States, and the United Kingdom, the losses caused by friction and wear each year account for about 2% to 7% of their GDP. An important way to reduce wear losses is to develop and apply high-performance wear-resistant materials.

[0003] High manganese steel has good plasticity and impact toughness. Under high impact loads and high pressure, its surface will produce strong work hardening. After the hardened surface layer is worn, a new surface layer will appear and continue to be work hardened. Even if the parts are worn to a very thin layer, the inner layer will still retain the original mechanical properties. High manganese steel is an austenitic steel. The austenite in the organization and the martensite formed by strain induction are the key factors affecting its wear resistance. Hot-rolled wear-resistant high manganese steel has excellent wear resistance to strong impact wear and high stress wear. It will not break during use and has easy welding, bending, cutting and other mechanical processing properties. Therefore, hot-rolled wear-resistant high manganese steel can effectively reduce the cost of equipment use and improve product competitiveness. Summary of the invention

[0004] The invention provides a production method of wear-resistant high-manganese steel medium and thick plates, which reduces production procedures and obtains excellent mechanical properties through hot charging and optimized controlled rolling and controlled cooling processes.

[0005] To achieve the above object, the present invention adopts the following technical solution: A production method for wear-resistant high manganese steel medium and thick plates, the production process includes molten iron pretreatment - converter smelting - LF and RH / VD refining - continuous casting - heating furnace heating - descaling and rolling - Mulpic cooling - finishing - testing - storage, characterized in that: the chemical composition weight percentage of the steel is: C 0.90% ~ 1.05%, Mn 11.0% ~ 14.0%, Si 0.30% ~ 0.90%, P ≤ 0.03%, S ≤ 0.005%, V 0.01 ~ 0.5%, the balance is Fe and unavoidable impurity elements. The key process steps include: After the continuous casting billet comes off the production line, it is directly loaded into the heating furnace for heating without cooling; The holding time of continuous casting billet in preheating section is ≥50 minutes, the furnace temperature of heating section of heating furnace is controlled at 1150~1250℃, the temperature of continuous casting billet out of furnace is 1180~1240℃, and the total time in furnace is ≥180 minutes; The rolling process is a two-stage rolling process. After descaling in the descaling box, rough rolling is carried out directly without waiting for warm temperature. In the rough rolling stage, only widening rolling is carried out. After the rough rolling, the steel sheet passes through the intermediate roller quickly and is directly subjected to finishing rolling without waiting for warm temperature. The reduction ratio of the first two passes of finishing rolling is ≥10%, the final rolling temperature is ≥900℃, and the steel sheet is rapidly cooled by Mulpic after rolling.

[0006] Furthermore, the surface temperature of the continuous casting billet is measured before entering the furnace, and the billet can be directly heated in the furnace only when the temperature is ≥500°C.

[0007] Furthermore, the rough rolling start temperature is ≥1150°C.

[0008] The mechanical properties of the wear-resistant high manganese steel medium and thick steel plates produced by the above method are: yield strength ≥300MPa, tensile strength ≥600MPa, total elongation ≥15%, transverse and longitudinal impact energy at -20°C ≥30J, and surface Brinell hardness ≥180.

[0009] The present invention has the following beneficial effects: by hot charging the continuous casting billet into the furnace, cracking defects caused by cooling of the continuous casting billet can be effectively avoided, the qualified rate of the continuous casting billet can be improved, and the heating and insulation time of the continuous casting billet can be shortened; by optimizing the heating and controlled rolling and controlled cooling processes, a large amount of carbide precipitation between austenite grains during rolling and cooling can be avoided, and under the premise of ensuring excellent mechanical properties, the post-rolling water toughening treatment process of the wear-resistant high manganese steel medium and thick plates is omitted, and the production process of the wear-resistant high manganese steel medium and thick plates is significantly shortened. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 This is the microstructure diagram of the wear-resistant high manganese steel in Example 1 of the present invention.

[0011] Figure 2 This is the microstructure diagram of the wear-resistant high manganese steel in Example 2 of the present invention. DETAILED DESCRIPTION

[0012] The technical solution of the present invention will be further described below in conjunction with the embodiments of the present invention.

[0013] In the following Examples 1 and 2, the smelting process is as follows: pretreatment of molten iron, stirring and removing P in a converter, the P content of the steel is 100ppm and the C content is 0.08%; refining and removing S in an LF furnace and adding medium carbon ferromanganese to adjust the alloy composition, and the S content is 40ppm; vacuum treatment in a VD furnace, the vacuum degree is 0.3torr, the vacuuming and vacuum holding time are 5min and 10min respectively, 220×2070mm cross-section continuous casting is adopted, the pulling speed is 0.80m / min, and hot charging is performed directly after the steel is off the line. Example 1

[0014] The chemical composition of 20mm thick wear-resistant high manganese steel plate is: C=1.01%, Mn=11.9%, Si=0.52%, P=0.012%, S=0.003%, V=0.32%, and the balance is Fe and unavoidable impurity elements; the key process steps include: The surface temperature of the slab was measured before entering the furnace, and the temperature was 520℃. The holding time in the preheating section was 60 minutes. The furnace temperature in the heating section was 1172~1245℃. The core temperature of the slab out of the furnace was 1213℃, and the slab was in the furnace for 220 minutes. The rolling process is a two-stage rolling process. The rough rolling start temperature is 1162℃, and the rough rolling is widened for 2 passes. After widening, it passes through the intermediate roller quickly. The finishing rolling start temperature is 1051℃, and the first and second pass reduction rates are 18% and 17% respectively. The final rolling temperature is 915℃. After rolling, it is quickly cooled to below 200℃ by Mulpic. Example 2

[0015] The production of 40mm thick wear-resistant high manganese steel plate has the following chemical composition: C 0.95%, Mn 13.2%, Si 0.31%, P0.015%, S 0.004%, V 0.05%, and the balance is Fe and unavoidable impurity elements; the key process steps include: The surface temperature of the slab was measured before entering the furnace, and the temperature was 536℃. The holding time in the preheating section was 63 minutes. The furnace temperature in the heating section was 1168~1240℃. The core temperature of the slab out of the furnace was 1209℃, and the slab was in the furnace for 232 minutes. The rolling process is a two-stage rolling process. The rough rolling temperature is 1159℃, and the rough rolling is widened for 2 passes. After widening, the steel passes through the intermediate roller quickly. The finishing rolling temperature is 1060℃, and the first and second pass reduction rates are 16% and 15% respectively. The final rolling temperature is 940℃. After rolling, the steel passes through Mulpic to quickly cool to below 200℃. The microstructures of the wear-resistant high manganese steels prepared in Examples 1 and 2 are shown in FIG. Figure 1 , Figure 2 The mechanical properties test results are shown in Table 1.

[0016] Table 1 Mechanical properties test results of steel plates produced in Example .

Claims

1. A method for producing wear-resistant high manganese steel medium and thick plates, the production process includes molten iron pretreatment - converter smelting - LF and RH / VD refining - continuous casting - heating furnace heating - descaling and rolling - Mulpic cooling - finishing - testing - warehousing, characterized in that: The chemical composition of steel is C=0.90%~1.05%, Mn=11.0%~14.0%, Si=0.30%~0.90%, P≤0.03%, S≤0.005%, V=0.01~0.5%, and the balance is Fe and unavoidable impurity elements; The key process steps include: After the continuous casting billet comes off the production line, it is directly loaded into the heating furnace for heating without cooling; The holding time of continuous casting billet in preheating section is ≥50 minutes, the furnace temperature of heating section of heating furnace is controlled at 1150~1250℃, the temperature of continuous casting billet out of furnace is 1180~1240℃, and the total time in furnace is ≥180 minutes; The rolling process is a two-stage rolling process. After descaling in the descaling box, rough rolling is carried out directly without waiting for warm temperature. In the rough rolling stage, only widening rolling is carried out. After the rough rolling, the steel sheet passes through the intermediate roller quickly and is directly subjected to finishing rolling without waiting for warm temperature. The reduction ratio of the first two passes of finishing rolling is ≥10%, the final rolling temperature is ≥900℃, and the steel sheet is rapidly cooled by Mulpic after rolling.

2. The method for producing a wear-resistant high manganese steel medium and thick plate according to claim 1, characterized in that: The surface temperature of the continuous casting billet is measured before entering the furnace, and the billet can be directly heated in the furnace only when the temperature is ≥500°C.

3. The method for producing a wear-resistant high manganese steel medium and thick plate according to claim 1, characterized in that: The rough rolling start temperature is ≥1150°C.

4. A wear-resistant high manganese steel medium and thick plate prepared by the method according to any one of claims 1 to 3, characterized in that The mechanical properties of the steel plate are: yield strength ≥300MPa, tensile strength ≥600MPa, total elongation ≥15%, transverse and longitudinal impact energy at -20℃ ≥30J, and surface Brinell hardness ≥180.

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