Heat-resistant manganese steel based on oxide film modification, and preparation method and application thereof

Abstract

The application discloses a heat-resistant manganese steel based on oxide film modification and a preparation method and application thereof, and the chemical components of the heat-resistant manganese steel are as follows in percentage by mass: C: 1.0-2.0%, Mn: 10.0-20.0%, Al: 4.0-12.0%, Si: 0.5-1.5%, Cr: 1.0-2.2%, RE: 0.05-0.09%, S: less than or equal to 0.04%, P: less than or equal to 0.04%, and the rest is iron. The preparation method comprises the following steps: after raw materials are smelted according to the proportion of the chemical components, deoxidation treatment and modification treatment are carried out, the castings are poured and then heat-treated. Through the regulation of the Al element, the growth mode and structural composition of high-temperature oxides of the material are changed, the growth rate of the oxides is reduced, the high-temperature oxidation resistance is significantly improved, the heat-resistant manganese steel is suitable for structural parts serving under high-temperature conditions such as automobile turbine shells and exhaust pipes, metallurgical blast furnace nozzles and high-temperature stirring furnace blades, and has a good practical prospect.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of alloy materials, in particular to a heat-resistant manganese steel based on oxide film modification and a preparation method and application thereof. BACKGROUND

[0002] Manganese steel is a common steel material, which is widely used in mining, metallurgical machinery, petrochemical industry and rail transportation fields. However, the inevitable heating phenomenon during service will easily cause oxidation of the material and further aggravate failure, thereby reducing the service life. Meanwhile, with the continuous adjustment and optimization of industrial structure in various fields for the purpose of energy saving and consumption reduction, higher challenges are put forward for the service performance of manganese steel.

[0003] Lightweight of materials is one of the effective ways to reduce energy consumption during mechanical operation. With the rapid increase of motor vehicles in China, the lightweight, fuel consumption reduction and emission reduction of automobiles are the main directions of future automobile development. Among them, manganese-containing automobile steel has become one of the preferred steel materials in the automobile field due to the following characteristics: containing less alloying elements, simple smelting and preparation process, low production cost, meeting the requirements of automobile lightweight, and ensuring safety under the premise of reducing the amount of steel. However, due to the continuous improvement of motor vehicle emission standards at home and abroad, the exhaust temperature of automobile engine is also gradually increasing. Therefore, higher use requirements are put forward for the use performance of steel materials for automobile turbine shell and exhaust pipe at high temperature.

[0004] In the prior art, patent CN111575580B discloses a high-toughness and high-strength product automobile steel and a preparation method thereof. The automobile steel has the advantages that through alloying of C, Mn and Al and rolling and annealing process in a dual-phase zone, a multi-phase and multi-layer metastable microstructure is formed, and the comprehensive mechanical properties of the material are far higher than those of medium-manganese steel. Patent CN104419876A discloses a preparation technology of an austenitic heat-resistant steel for an automobile turbine shell and an exhaust pipe. The raw material of the heat-resistant steel comprises C: 0.20-0.50%, Si: 1.0-2.0%, Mn: 15.0-18.0%, Cr: 15.0-17.0%, Ni: <1.0%, Mo <0.5%, Nb: 0.9-1.1%, W: 2.0-3.0%, V: <0.15%, N: 0.2-0.4%, S <0.03%, P <0.04%, and the balance is Fe. The heat-resistant steel has good dimensional stability, high ductility and heat resistance. Although the production cost is reduced by using Mn and N to replace Ni, the presence of refractory metals such as W, V, Nb and Mo increases the preparation difficulty to some extent. Patent CN201510952246 discloses a preparation method and application of an austenitic heat-resistant cast steel. The heat-resistant steel has good comprehensive performance, but the relatively expensive elements such as cobalt, molybdenum and nickel increase the preparation cost, and the addition of nitrogen element also increases the smelting difficulty. In addition, the austenitic heat-resistant steel is easy to crack and break the oxidation film in a high-temperature steam environment, thereby reducing the service life.

[0005] Therefore, although the prior art has certain breakthroughs in the heat resistance, toughness and material lightweight of manganese steel, the expensive production cost or the complex multi-pass processing process is not conducive to the wide promotion and application of the material. In addition, the existing manganese steel does not exhibit ideal oxidation resistance during high-temperature service, so that the service life is difficult to be effectively improved, and the real energy saving and consumption reduction is not achieved.

[0006] Therefore, the present application is proposed. SUMMARY

[0007] The present application aims to provide a heat-resistant manganese steel based on oxidation film modification and a preparation method and application thereof to improve the above technical problems.

[0008] The present application is implemented as follows:

[0009] In a first aspect, the present application provides a heat-resistant manganese steel based on oxidation film modification. The chemical composition of the heat-resistant manganese steel is as follows in terms of mass percentage: C: 1.0-2.0%, Mn: 10.0-20.0%, Al: 4.0-12.0%, Si: 0.5-1.5%, Cr: 1.0-2.2%, RE: 0.05-0.09%, S≤0.04%, P≤0.04%, and the balance is iron.

[0010] In a second aspect, the present application also provides a preparation method of the heat-resistant manganese steel based on oxide film modification, which comprises: according to the proportions of the chemical components, smelting and deoxidizing treatment, modification treatment, and then casting into a casting, and then heat treatment of the casting.

[0011] In a third aspect, the present application also provides the use of the heat-resistant manganese steel based on oxide film modification in the preparation of high-temperature-resistant structural parts.

[0012] Optionally, the high-temperature-resistant structural part is an automobile turbine shell, an automobile exhaust pipe, a metallurgical blast furnace fuel nozzle, or a high-temperature stirring furnace blade.

[0013] The present application has the following beneficial effects: by adding a large amount of light element Al in the chemical composition of the manganese steel, the density of the manganese steel is reduced, and the lightweight of the original manganese steel is realized. At the same time, without affecting the toughness and wear resistance of the manganese steel, the strong affinity of Al element and O element is fully utilized, and Al will form a dense Al2O3 oxide film with O during high-temperature oxidation, thereby effectively protecting the base material. The elements Fe and Mn in the manganese steel can only diffuse and pass through the dense Al2O3 layer to further oxidize. Therefore, by adding a large amount of Al element in the manganese steel, the growth mode and structural composition of the high-temperature oxide of the material are changed, the growth rate of the oxide is reduced, and the high-temperature oxidation resistance of the traditional manganese steel is significantly improved. In addition, the heat-resistant manganese steel based on oxide film modification does not contain expensive refractory metal elements such as Ni, Co, W, V, Nb, and Mo, which significantly reduces the production cost and preparation difficulty. Further, the heat-resistant manganese steel based on oxide film modification has excellent high-temperature oxidation resistance, and can be applied to automobile turbine shells and exhaust pipes, metallurgical blast furnace nozzles, high-temperature stirring furnace blades, and other structural parts serving under high-temperature conditions, which has good practical prospects. BRIEF DESCRIPTION OF DRAWINGS

[0014] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiments. It should be understood that the following drawings only show some embodiments of the present application, and therefore should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can also be obtained without creative labor.

[0015] Figure 1 The microstructure scanning electron microscope image of the heat-resistant manganese steel based on oxide film modification of the present application embodiment 1;

[0016] Figure 2 The microstructure scanning electron microscope image of the heat-resistant manganese steel based on oxide film modification of the present application embodiment 5;

[0017] Figure 3The microstructure scanning electron microscope graph of the conventional heat-resistant manganese steel of the present application comparative example 2. DETAILED DESCRIPTION

[0018] In order to make the purpose, technical solutions and advantages of the embodiments of the present application more clear, the technical solutions in the embodiments of the present application will be clearly and completely described below. If the specific conditions are not specified in the embodiments, the conventional conditions or the conditions recommended by the manufacturers are adopted. If the manufacturers of the reagents or instruments are not specified, they are all conventional products that can be purchased in the market.

[0019] The heat-resistant manganese steel based on oxidation film modification, the preparation method and application thereof proposed in the present application will be specifically described below.

[0020] Some embodiments of the present application provide a heat-resistant manganese steel based on oxidation film modification, the chemical composition of which is as follows in terms of mass percentage: C: 1.0-2.0%, Mn: 10.0-20.0%, Al: 4.0-12.0%, Si: 0.5-1.5%, Cr: 1.0-2.2%, RE: 0.05-0.09%, S≤0.04%, P≤0.04%, and the rest is iron.

[0021] The inventors found through research and practice that, by optimizing the chemical composition of the heat-resistant manganese steel based on oxidation film modification and adding a large amount of Al element, the high-temperature oxidation resistance of the heat-resistant manganese steel based on oxidation film modification is 10-20 times higher than that of the manganese steel without Al at 600-1000°C. In order to maintain the heat-resistant manganese steel based on oxidation film modification to have better strength and toughness and wear resistance, other element compositions and proportions are also selected and optimized. The chemical elements have a significant influence on the density, microstructure and high-temperature oxidation resistance of the heat-resistant manganese steel based on oxidation film modification. The theoretical basis for the design of the chemical composition of the above embodiments is as follows:

[0022] Carbon: C is one of the basic elements in steel materials, is a promoting element of austenite formation, and can stabilize the austenite phase. However, when the C content is too high, the plasticity and toughness of the material will be reduced, and even the casting will crack. Therefore, the C content in the embodiments of the present application is controlled at 1.0-2.0%.

[0023] Manganese: Mn is also an element that stabilizes and strengthens the austenite phase. Appropriate Mn content is conducive to the transformation of γ→ε, but too high Mn content will promote the generation of β-Mn brittle phase. Therefore, the Mn content in the embodiments of the present application is controlled at 10.0-20.0%.

[0024] Chromium: Cr element plays a crucial role in steel, which can improve the hardenability of the material and reduce the temper brittleness. At the same time, the appropriate Cr content can also significantly strengthen the wear resistance and oxidation resistance of the material. Therefore, the Cr content in the embodiments of the present application is controlled at 1.0-2.2%.

[0025] Aluminum: Al is a stable ferrite forming element, and also a preferred element in the lightweight component design process of steel materials as a lightweight element. Al can increase the stacking fault energy of austenite, inhibit the transformation of γ phase to ε phase, and the formation of dense aluminum oxide on the surface in the high temperature oxygen-containing environment can further improve the high temperature oxidation resistance of the material. Therefore, the Al content in the embodiments of the present application is controlled at 4.0-12.0%.

[0026] Silicon: Si is a ferrite forming element that promotes and strengthens, and is one of the deoxidizing elements in steel. Si can prevent the precipitation of β-Mn brittle phase, and the formation of SiO2 is beneficial to the adsorption of the oxide film such as Cr2O3 and Al2O3 on the surface layer of the material, thereby improving the oxidation resistance of the material. Therefore, the Si content of the present application is controlled at 0.5-1.5%.

[0027] Rare earth: RE as a common modifier in steel can effectively play a desulfurization and deoxidization effect, purify the molten steel, and then control the morphology and distribution of inclusions. At the same time, elements such as Y and Ce in rare earth elements can also change the growth form of oxides in steel, reduce the growth rate of oxides, and improve the high temperature oxidation resistance of steel materials. Therefore, the content of rare earth elements in the embodiments of the present application is controlled at 0.05-0.09%. It should be noted that the RE in the embodiments of the present application is the commonly sold RE modifier in the market.

[0028] In summary, on the one hand, the heat-resistant manganese steel based on the modification of the oxide film does not contain expensive refractory metal elements such as Ni, Co, W, V, Nb and Mo, thereby significantly reducing the production cost and preparation difficulty. On the other hand, the addition of light element Al can further reduce the density of manganese steel, realizing the lightweight of the original manganese steel. At the same time, without affecting the strength and toughness and wear resistance of manganese steel, Al element and O element are fully utilized due to their strong affinity. In the high temperature oxidation process, Al will form a dense Al2O3 oxide film with O, and Fe and Mn elements in manganese steel can only diffuse and pass through the dense Al2O3 layer to further oxidize. Therefore, the formation of Al2O3 oxide film effectively protects the matrix material. Due to the presence of Al element in manganese steel, the growth mode and structural composition of high temperature oxides are changed, the growth rate of oxides is reduced, and the high temperature oxidation resistance of traditional manganese steel is significantly improved.

[0029] Further, in order to further improve the comprehensive performance of the oxidation film modified heat-resistant manganese steel, the inventors optimize the chemical composition of the oxidation film modified heat-resistant manganese steel, and in some embodiments, the chemical composition of the oxidation film modified heat-resistant manganese steel is as follows in terms of mass percentage: C: 1.0-2.0%, Mn: 10.0-20.0%, Al: 5.1-12.0%, Si: 0.5-1.5%, Cr: 1.0-2.2%, RE: 0.05-0.09%, S≤0.04%, P≤0.04%, and the balance being iron.

[0030] For reference, in some embodiments, the chemical composition of the oxidation film modified heat-resistant manganese steel is as follows in terms of mass percentage: C: 1.4-2.0%, Mn: 14.5-20.0%, Al: 6-12.0%, Si: 0.5-1.5%, Cr: 1.0-2.2%, RE: 0.05-0.09%, S≤0.04%, P≤0.04%, and the balance being iron.

[0031] In some embodiments, the oxidation film modified heat-resistant manganese steel has a fine single-phase austenite structure or a fine dual-phase structure of austenite and ferrite, and the density is between 6.7 g / cm 3 -7.5 g / cm 3 .

[0032] Further, in some embodiments, the oxidation film modified heat-resistant manganese steel has an oxidation rate of less than or equal to 0.05 g / (m 2 ·h) at 600°C for 100 h of oxidation, for example, the oxidation rate is 0.02-0.05 g / (m 2 ·h) under this condition, the oxidation rate is less than or equal to 0.84 g / (m 2 ·h) at 800°C for 100 h of oxidation, for example, the oxidation rate is 0.53-0.84 g / (m 2 ·h) under this condition, the oxidation rate is less than or equal to 1.51 g / (m 2 ·h) at 1000°C for 100 h of oxidation, for example, the oxidation rate is 0.02-1.51 g / (m 2 ·h) under this condition.

[0033] Some embodiments of the present application also provide a preparation method of the oxidation film modified heat-resistant manganese steel in the above embodiments, which comprises: according to the above chemical composition ratio, smelting and deoxidizing treatment, modification treatment, and then casting the castings, and then heat treating the castings.

[0034] Specifically, the preparation method of the oxidation film modified heat-resistant manganese steel in some embodiments of the present application comprises the following steps:

[0035] S1, smelting raw materials containing carbon, manganese, silicon, and chromium, the smelting temperature is 1550-1620℃; after deoxidation treatment, the molten steel is obtained, and pure aluminum is added before tapping, and then the temperature of the melt is adjusted to 1420-1520℃.

[0036] It should be noted that the raw materials are generally smelted in a medium-frequency electric furnace. The deoxidation process is deoxidized by adding a small amount of aluminum after smelting, and pure aluminum is added before tapping to avoid loss of aluminum during smelting.

[0037] S2, the molten steel after smelting is subjected to static treatment in a ladle containing RE modifier.

[0038] In some embodiments, the static treatment is carried out in a ladle with a preheating temperature above 300℃ and a preheating time greater than 5 hours. The ladle is placed with granular RE modifier coated with iron sheet at multiple positions, which are several positions that can be in contact with the molten steel and are uniformly distributed, so as to fully modify the molten steel.

[0039] S3, the molten steel in the ladle is poured into a casting.

[0040] In some embodiments, the temperature of the molten steel during pouring is controlled to be 1350-1450℃.

[0041] S4, the casting is subjected to heat treatment to form a specific microstructure.

[0042] Specifically, the heat treatment in the embodiments of the present application is a double-flow heat treatment, which specifically includes: heating the casting from room temperature to 1000-1100℃ at a heating rate of 80-100℃ / h, and then water cooling to room temperature after holding for 2-5h; then heating the casting from room temperature to 250-350℃ at a heating rate of 80-100℃ / h, and then air cooling to room temperature after holding for 5-8h. By the above heat treatment, fine single-phase austenite microstructure or fine dual-phase austenite and ferrite microstructure can be formed.

[0043] Some embodiments of the present application also provide the use of the heat-resistant manganese steel based on oxide film modification in the above embodiments in the preparation of high-temperature-resistant structural parts. Since the heat-resistant manganese steel based on oxide film modification in the above embodiments has excellent high-temperature oxidation resistance, it is suitable for structural parts serving in high-temperature environments, such as automobile turbine shell, automobile exhaust pipe, metallurgical blast furnace fuel nozzle or high-temperature stirring furnace blade, etc.

[0044] The features and properties of the present application are further described in detail below in conjunction with the examples.

[0045] Example 1

[0046] The embodiment provides a heat-resistant manganese steel based on oxide film modification, which has the following chemical components: C: 1.0%, Mn: 12.0%, Al: 4.0%, Si: 0.5%, Cr: 1.2%, RE: 0.05%, S≤0.04%, P≤0.04%, and the rest is iron.

[0047] The preparation process is specifically as follows:

[0048] (1) first, manganese iron, silicon iron, chromium iron and other raw materials are smelted in a medium-frequency electric furnace, the smelting temperature is 1550 DEG C, after deoxidation treatment, the composition before the furnace is adjusted to obtain qualified molten steel, pure aluminum is added 5 minutes before the furnace is discharged, and then the melt temperature is adjusted to 1420 DEG C.

[0049] (2) secondly, the smelted molten steel is poured into a ladle preheated at a high temperature of more than 300 DEG C for more than 5 hours, and is placed for 3 minutes.

[0050] (3) finally, the molten steel in the ladle is poured into a casting at 1350 DEG C, and the casting is subjected to double-process heat treatment, and the aluminum-based heat-resistant manganese steel based on oxide film modification is obtained. The specific double-process heat treatment process is as follows: ① the cast steel is heated from room temperature to 1000 DEG C at a heating rate of 80 DEG C / h, and is water-cooled to room temperature after 5h of heat preservation; ② the cast steel is heated from room temperature to 250 DEG C at a heating rate of 100 DEG C / h, and is air-cooled to room temperature after 8h of heat preservation.

[0051] Embodiment 2

[0052] The embodiment provides a heat-resistant manganese steel based on oxide film modification, which has the following chemical components: C: 1.4%, Mn: 14.5%, Al: 6.0%, Si: 0.75%, Cr: 1.5%, RE: 0.08%, S≤0.04%, P≤0.04%, and the rest is iron.

[0053] The preparation process is specifically as follows:

[0054] (1) first, manganese iron, silicon iron, chromium iron and other raw materials are smelted in a medium-frequency electric furnace, the smelting temperature is 1550 DEG C, after deoxidation treatment, the composition before the furnace is adjusted to obtain qualified molten steel, pure aluminum is added 5 minutes before the furnace is discharged, and then the melt temperature is adjusted to 1420 DEG C.

[0055] (2) secondly, the smelted molten steel is poured into a ladle preheated at a high temperature of more than 300 DEG C for more than 5 hours, and is placed for 3 minutes.

[0056] (3) Finally, the molten steel in the ladle is poured into a casting at 1380°C, and the casting is subjected to double-process heat treatment, thereby obtaining the aluminum-containing heat-resistant manganese steel based on oxide film modification. The specific double-process heat treatment process is as follows: ① the cast steel is heated from room temperature to 1050°C at a heating rate of 85°C / h, and then water-cooled to room temperature after 4.5h of heat preservation; ② the cast steel is heated from room temperature to 280°C at a heating rate of 80°C / h, and then air-cooled to room temperature after 7.5h of heat preservation.

[0057] Example 3

[0058] The present example provides a heat-resistant manganese steel based on oxide film modification, which has the following chemical composition: C: 1.85%, Mn: 18.0%, Al: 7.5%, Si: 1.05%, Cr: 1.75%, RE: 0.06%, S≤0.04%, P≤0.04%, and the balance being iron.

[0059] The preparation process is specifically as follows:

[0060] (1) First, manganese iron, silicon iron, chromium iron and other raw materials are smelted in a medium-frequency electric furnace, and the smelting temperature is 1600°C. After deoxidation treatment, the composition before the furnace is adjusted to obtain qualified molten steel. Pure aluminum is added 5 minutes before the furnace is discharged, and then the temperature of the melt is adjusted to 1470°C.

[0061] (2) Second, the smelted molten steel is poured into a ladle preheated at a high temperature of more than 300°C for more than 5 hours, and is subjected to static treatment for 3 minutes.

[0062] (3) Finally, the molten steel in the ladle is poured into a casting at 1400°C, and the casting is subjected to double-process heat treatment, thereby obtaining the aluminum-containing heat-resistant manganese steel based on oxide film modification. The specific double-process heat treatment process is as follows: ① the cast steel is heated from room temperature to 1075°C at a heating rate of 90°C / h, and then water-cooled to room temperature after 4.0h of heat preservation; ② the cast steel is heated from room temperature to 300°C at a heating rate of 85°C / h, and then air-cooled to room temperature after 6h of heat preservation.

[0063] Example 4

[0064] The present example provides a heat-resistant manganese steel based on oxide film modification, which has the following chemical composition: C: 2.0%, Mn: 20%, Al: 10%, Si: 1.4%, Cr: 2.2%, RE: 0.07%, S≤0.04%, P≤0.04%, and the balance being iron.

[0065] The preparation process is specifically as follows:

[0066] (1) First, the raw materials such as manganese iron, silicon iron, chromium iron, etc. are smelted in a medium frequency electric furnace, the smelting temperature used is 1620℃, after deoxidation treatment, the qualified molten steel is obtained by adjusting the composition before furnace, pure aluminum is added 5 minutes before tapping, and then the melt temperature is adjusted to 1520℃.

[0067] (2) Secondly, the smelted molten steel is poured into a pouring ladle preheated at a high temperature above 300℃ for more than 5 hours, and is treated by standing for 3 minutes.

[0068] (3) Finally, the molten steel in the pouring ladle is poured into castings at 1450℃, and the castings are heat treated by double process, so that the aluminum-containing heat-resistant manganese steel based on oxide film modification is obtained. The specific double process heat treatment process is as follows: ① the cast steel is heated from room temperature to 1030℃ at a heating rate of 90℃ / h, and then water-cooled to room temperature after holding for 4h; ② the cast steel is heated from room temperature to 290℃ at a heating rate of 85℃ / h, and then air-cooled to room temperature after holding for 6.5h.

[0069] Example 5

[0070] The embodiment provides a heat-resistant manganese steel based on oxide film modification, which has the following chemical components: C: 1.8%, Mn: 15.5%, Al: 12%, Si: 1.5%, Cr: 2.2%, RE: 0.09%, S≤0.04%, P≤0.04%, and the rest is iron.

[0071] The preparation process is specifically as follows:

[0072] (1) First, the raw materials such as manganese iron, silicon iron, chromium iron, etc. are smelted in a medium frequency electric furnace, the smelting temperature used is 1600℃, after deoxidation treatment, the qualified molten steel is obtained by adjusting the composition before furnace, pure aluminum is added 5 minutes before tapping, and then the melt temperature is adjusted to 1500℃.

[0073] (2) Secondly, the smelted molten steel is poured into a pouring ladle preheated at a high temperature above 300℃ for more than 5 hours, and is treated by standing for 3 minutes.

[0074] (3) Finally, the molten steel in the pouring ladle is poured into castings at 1420℃, and the castings are heat treated by double process, so that the aluminum-containing heat-resistant manganese steel based on oxide film modification is obtained. The specific double process heat treatment process is as follows: ① the cast steel is heated from room temperature to 1060℃ at a heating rate of 100℃ / h, and then water-cooled to room temperature after holding for 2h; ② the cast steel is heated from room temperature to 300℃ at a heating rate of 90℃ / h, and then air-cooled to room temperature after holding for 6h.

[0075] Example 6

[0076] The embodiment provides a heat-resistant manganese steel based on oxide film modification, which has the following chemical components: C: 1.8%, Mn: 10.0%, Al: 10.0%, Si: 0.8%, Cr: 2.0%, RE: 0.08%, S≤0.04%, P≤0.04%, and the rest is iron.

[0077] The preparation process is specifically as follows:

[0078] (1) First, manganese iron, silicon iron, chromium iron and other raw materials are smelted in a medium-frequency electric furnace, the smelting temperature is 1575 ℃, after deoxidation treatment, the composition before the furnace is adjusted to obtain qualified molten steel, pure aluminum is added 5 minutes before the furnace is discharged, and then the melt temperature is adjusted to 1480 ℃.

[0079] (2) Secondly, the smelted molten steel is poured into a ladle preheated at a high temperature of more than 300 ℃ for more than 5 hours, and is subjected to static treatment for 3 minutes.

[0080] (3) Finally, the molten steel in the ladle is poured into a casting at 1390 ℃, and the casting is subjected to double-process heat treatment, and the heat-resistant manganese steel based on oxide film modification containing aluminum based on oxide film modification is obtained. The specific double-process heat treatment process is as follows: ① the cast steel is heated from room temperature to 1080 ℃ at a heating rate of 95 ℃ / h, and is water-cooled to room temperature after being kept for 3h; ② the cast steel is heated from room temperature to 350 ℃ at a heating rate of 95 ℃ / h, and is air-cooled to room temperature after being discharged.

[0081] Embodiment 7

[0082] The embodiment provides a heat-resistant manganese steel based on oxide film modification, which has the following chemical components: C: 1.0%, Mn: 11.0%, Al: 9.0%, Si: 1.0%, Cr: 1.0%, RE: 0.06%, S≤0.04%, P≤0.04%, and the rest is iron.

[0083] The preparation process is specifically as follows:

[0084] (1) First, manganese iron, silicon iron, chromium iron and other raw materials are smelted in a medium-frequency electric furnace, the smelting temperature is 1575 ℃, after deoxidation treatment, the composition before the furnace is adjusted to obtain qualified molten steel, pure aluminum is added 5 minutes before the furnace is discharged, and then the melt temperature is adjusted to 1480 ℃.

[0085] (2) Secondly, the smelted molten steel is poured into a ladle preheated at a high temperature of more than 300 ℃ for more than 5 hours, and is subjected to static treatment for 3 minutes.

[0086] (3) Finally, the molten steel in the ladle is poured into a casting at 1370°C, and the casting is subjected to double-process heat treatment, thereby obtaining the oxidation film modified heat-resistant manganese steel containing aluminum based on oxidation film modification. The specific double-process heat treatment process is as follows: ① the cast steel is heated from room temperature to 1100°C at a heating rate of 100°C / h, and then water-cooled to room temperature after 2h of heat preservation; ② the cast steel is heated from room temperature to 330°C at a heating rate of 90°C / h, and then air-cooled to room temperature after 5.5h of heat preservation.

[0087] Example 8

[0088] The present embodiment provides an oxidation film modified heat-resistant manganese steel containing aluminum based on oxidation film modification, which has the following chemical composition: C: 1.8%, Mn: 15.5%, Al: 12%, Si: 1.5%, Cr: 2.2%, RE: 0.09%, S≤0.04%, P≤0.04%, and the balance being iron.

[0089] The preparation process is specifically as follows:

[0090] (1) First, manganese iron, silicon iron, chromium iron and other raw materials are smelted in a medium-frequency electric furnace, and the smelting temperature used is 1600°C. After deoxidation treatment, the composition before the furnace is adjusted to obtain qualified molten steel. Pure aluminum is added 5 minutes before the furnace is discharged, and then the temperature of the melt is adjusted to 1500°C.

[0091] (2) Then, the smelted molten steel is poured into a ladle preheated at a high temperature of more than 300°C for more than 5 hours, and is subjected to static treatment for 3 minutes.

[0092] (3) Finally, the molten steel in the ladle is poured into a casting at 1420°C, and the casting is subjected to heat treatment, thereby obtaining the oxidation film modified heat-resistant manganese steel containing aluminum based on oxidation film modification. The specific heat treatment process is as follows: the cast steel is heated from room temperature to 1060°C at a heating rate of 100°C / h, and then water-cooled to room temperature after 2h of heat preservation.

[0093] Comparative Example 1

[0094] The present comparative example provides an oxidation film modified heat-resistant manganese steel, which has the following chemical composition: C: 2.0%, Mn: 20%, Si: 1.4%, Cr: 2.2%, RE: 0.07%, S≤0.04%, P≤0.04%, and the balance being iron.

[0095] The preparation process is specifically as follows:

[0096] (1) First, manganese iron, silicon iron, chromium iron and other raw materials are smelted in a medium-frequency electric furnace, and the smelting temperature used is 1620°C. After deoxidation treatment, the composition before the furnace is adjusted to obtain qualified molten steel. The temperature of the melt is adjusted to 1520°C before the furnace is discharged.

[0097] (2) Secondly, the molten steel is poured into the ladle preheated at a high temperature above 300°C for more than 5 hours, and is placed for 3 minutes;

[0098] (3) Finally, the molten steel in the ladle is poured into a casting at 1450°C, and the casting is subjected to double-process heat treatment, thereby obtaining the heat-resistant manganese steel based on oxidation film modification. The specific heat treatment process is as follows: ① the cast steel is heated from room temperature to 1030°C at a heating rate of 90°C / h, and is water-cooled to room temperature after being kept for 4h; ② the cast steel is heated from room temperature to 290°C at a heating rate of 85°C / h, and is air-cooled to room temperature after being kept for 6.5h.

[0099] Comparative Example 2

[0100] The comparative example provides a heat-resistant manganese steel based on oxidation film modification, which has the following chemical components: C: 1.8%, Mn: 15.5%, Si: 1.5%, Cr: 2.2%, RE: 0.09%, S≤0.04%, P≤0.04%, and the rest is iron.

[0101] The preparation process is specifically as follows:

[0102] (1) First, manganese iron, silicon iron, chromium iron and other raw materials are smelted in a medium-frequency electric furnace, the smelting temperature is 1600°C, and after deoxidation treatment and modification treatment, the composition before the furnace is adjusted to obtain qualified molten steel, and the temperature of the melt is adjusted to 1500°C before being discharged.

[0103] (2) Secondly, the molten steel is poured into the ladle preheated at a high temperature above 300°C for more than 5 hours, and is placed for 3 minutes.

[0104] (3) Finally, the molten steel in the ladle is poured into a casting at 1420°C, and the casting is subjected to double-process heat treatment, thereby obtaining the heat-resistant manganese steel based on oxidation film modification. The specific heat treatment process is as follows: ① the cast steel is heated from room temperature to 1060°C at a heating rate of 100°C / h, and is water-cooled to room temperature after being kept for 2h; ② the cast steel is heated from room temperature to 300°C at a heating rate of 90°C / h, and is air-cooled to room temperature after being kept for 6h.

[0105] Comparative Example 3

[0106] The comparative example provides a heat-resistant manganese steel based on oxidation film modification, which has the following chemical components: C: 1.0%, Mn: 12.0%, Si: 0.5%, Cr: 1.2%, RE: 0.05%, S≤0.04%, P≤0.04%, and the rest is iron.

[0107] The preparation process is specifically as follows:

[0108] (1) First, the raw materials of manganese iron, silicon iron, chromium iron and the like are smelted in a medium frequency electric furnace, the smelting temperature used is 1550℃, after deoxidation treatment and modification treatment, the qualified molten steel is obtained by adjusting the composition before the furnace, and the temperature of the melt is adjusted to 1420℃ before the furnace is discharged;

[0109] (2) Secondly, the smelted molten steel is poured into a pouring ladle preheated at a high temperature of more than 300℃ for more than 5 hours, and is treated for 3 minutes;

[0110] (3) Finally, the molten steel in the pouring ladle is poured into a casting at 1350℃, and the casting is subjected to a double-flow heat treatment, so that the heat-resistant manganese steel based on the oxide film modification is obtained. The specific heat treatment process is as follows: ① the cast steel is heated from room temperature to 1000℃ at a heating rate of 80℃ / h, and is water-cooled to room temperature after being kept for 5h; ② the cast steel is heated from room temperature to 250℃ at a heating rate of 100℃ / h, and is air-cooled to room temperature after being discharged.

[0111] In order to highlight the excellent high-temperature oxidation resistance of the aluminum-containing heat-resistant manganese steel based on the oxide film modification, the oxidation rates of the comparative examples and the examples after continuous oxidation at 600℃, 800℃ and 1000℃ for 100h are listed in Table 1, and the oxidation behaviors of the comparative examples and the examples at different temperatures are evaluated according to the standard of HB5258-2000 "Experimental method for determination of oxidation resistance of steel and high-temperature alloy".

[0112] Table 1 Oxidation rate and oxidation resistance level evaluation of experimental steel after continuous oxidation at different temperatures for 100h

[0113]

[0114] The microstructure of the heat-resistant manganese steel based on the oxide film modification of Example 1, Example 5 and Comparative Example 2 is observed by scanning electron microscopy, and the results are shown in Figure 1 、 Figure 2 、 Figure 3 . The initial heat-resistant steel is composed of coarse austenite grains Figure 3 , the addition of Al element can significantly refine the grains in the structure, and gradually change the single austenite structure to fine dual-phase structure of austenite + ferrite Figure 1 and Figure 2 .

[0115] In summary, the heat-resistant manganese steel based on oxide film modification in the embodiment of the present application is obtained through medium-frequency electric furnace smelting, deoxidation and RE modification treatment, and then through a double-flow heat treatment process. With the increase of Al content, the density of the heat-resistant manganese steel based on oxide film modification gradually decreases, the grain size in the structure is refined, and the single fine austenite structure is transformed into fine dual-phase structure composed of austenite and ferrite. The heat-resistant manganese steel based on oxide film modification has good high-temperature oxidation resistance at 600-1000 DEG C.

[0116] The above only describes the preferred embodiments of the present application and is not intended to limit the present application. For those skilled in the art, the present application can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method for producing a heat-resistant manganese steel based on oxide film modification, characterized by, The heat-resistant manganese steel based on oxide film modification has the following chemical composition in percentage by mass: C: 1.0-2.0%, Mn: 11.0-20.0%, Al: 5.1-12.0%, Si: 0.5-1.5%, Cr: 1.0-2.2%, RE: 0.05-0.09%, S≤0.04%, P≤0.04%, and the balance of iron; The preparation method of the heat-resistant manganese steel based on oxide film modification comprises the following steps: raw materials are smelted and deoxidized, treated by modification, and then cast into castings, and then the castings are heat treated; The modification treatment comprises the following step: the smelted molten steel is statically treated in a ladle containing RE modifier before casting; The heat treatment comprises the following steps: the castings are heated from room temperature to 1000-1100℃ at a heating rate of 80-100℃ / h, and then water cooled to room temperature after being kept for 2-5h; and then the castings are heated from room temperature to 250-350℃ at a heating rate of 80-100℃ / h, and then taken out and air cooled to room temperature after being kept for 5-8h.

2. The method for producing a heat-resistant manganese steel based on oxide film modification according to claim 1, characterized in that, The heat-resistant manganese steel based on oxide film modification has the following chemical composition in percentage by mass: C: 1.4-2.0%, Mn: 14.5-20.0%, Al: 6-12.0%, Si: 0.5-1.5%, Cr: 1.0-2.2%, RE: 0.05-0.09%, S≤0.04%, P≤0.04%, and the balance of iron.

3. The method for producing a heat-resistant manganese steel based on oxide film modification according to claim 1, characterized in that, The heat-resistant manganese steel based on oxide film modification has an oxidation rate of less than or equal to 0.05 g / (m 2 ·h) at 600°C for 100 h of oxidation, an oxidation rate of less than or equal to 0.84 g / (m 2 ·h) at 800°C for 100 h of oxidation, and an oxidation rate of less than or equal to 2.01 g / (m 2 ·h) at 1000°C for 100 h of oxidation.

4. The method for producing a heat-resistant manganese steel based on oxide film modification according to claim 1, characterized in that, The smelting and deoxidizing treatment comprises the following steps: raw materials containing carbon, manganese, silicon and chromium are smelted at a smelting temperature of 1550-1620℃, and then the molten steel is obtained after deoxidizing treatment, and then pure aluminum is added before being taken out, and then the temperature of the melt is adjusted to 1420-1520℃.

5. The method of producing the heat-resistant manganese steel based on oxide film modification according to claim 1, characterized in that, The temperature of the molten steel during casting is 1350-1450℃.

6. The method of producing a heat-resistant, oxide-film-modified manganese steel according to claim 1, characterized by, The static treatment is carried out in a ladle preheated at a temperature of more than 300℃ for more than 5h.

7. The method of producing the heat-resistant, oxide-film-modified manganese steel according to claim 1, characterized by, The ladle is provided with granular RE modifier wrapped with iron sheet at multiple positions.

8. The heat-resistant manganese steel based on oxide film modification prepared by the preparation method of the heat-resistant manganese steel based on oxide film modification according to any one of claims 1-7 is used for preparing high-temperature-resistant structural parts.

9. Use according to claim 8, characterized in that, The high-temperature-resistant structural parts are automobile turbine shell, automobile exhaust pipe, metallurgical blast furnace fuel nozzle or high-temperature stirring furnace blade.

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