Austenite heat-resistant stainless steel material as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of alloy materials, and particularly relates to an austenite heat-resistant stainless steel material and a preparation method and application thereof. The stainless steel material comprises the following components in percentage by mass: 0.40 to 0.50 percent of C, 1.80 to 2.10 percent of Si, 10.00 to 11.00 percent of Mn, less than or equal to 0.05 percent of P, less than or equal to 0.01 percent of S, 20.00 to 21.50 percent of Cr, 1.50 to 3.0 percent of Ni, 0.20 to 0.30 percent of Mo, 0.05 to 0.20 percent of Co, 0.05 to 0.20 percent of V, 0.15 to 0.30 percent of Nb, 0.17 to 0.23 percent of N, less than or equal to 1.0 percent of other trace elements and the balance of Fe. The stainless steel material can keep excellent high-temperature strength, creep resistance, oxidation resistance and thermal fatigue resistance in a high-temperature environment, the use amount of precious metal Ni can be reduced, and the production cost is reduced.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of alloy materials, and particularly relates to an austenitic heat-resistant stainless steel material and a preparation method and application thereof. BACKGROUND

[0002] The CrNi austenitic heat-resistant stainless steel material widely used in the current internal combustion engine industry refers to an austenitic structure at room temperature, no phase change at high temperature, and strong high-temperature oxidation resistance, wherein Ni is the main austenite-forming element, and Cr reacts with O to form a Cr2O3 passivation film to effectively resist high-temperature oxidation.

[0003] With the gradual approach of the "national seven" emission standard, in order to meet the new emission standard, the engine of the fuel vehicle has to be greatly adjusted or the emission system is optimized, which will lead to the increase of the production cost of the fuel vehicle, but the fuel vehicle is also subject to the fierce competition of new energy vehicles in terms of pricing, so the production cost control of the fuel vehicle becomes unprecedentedly important. At present, the turbine supercharger shell casting for passenger vehicles mainly adopts the CrNi austenitic heat-resistant stainless steel material, wherein GX40CrNiSi22-10 (suitable for 1000 DEG C extreme working condition) is widely used in the production of turbine supercharger shell and exhaust manifold of high-end hybrid fuel vehicles, and the Ni content reaches 10%, and the cost of the metal material is as high as 21.2 yuan / kg (the price of Ni is calculated as 100 yuan / kg). SUMMARY

[0004] The application aims to overcome the deficiencies in the prior art and provide an austenitic heat-resistant stainless steel material and a preparation method and application thereof. The application provides a new low-cost CrMnNi austenitic heat-resistant stainless steel material, which has high-temperature strength, creep resistance, oxidation resistance and thermal fatigue resistance comparable to GX40CrNiSi22-10, can replace GX40CrNiSi22-10 for the production of automobile turbine supercharger shell castings, can reduce the use amount of valuable metal Ni, and thus reduce the production cost of the turbine supercharger.

[0005] To achieve the above technical purposes, the technical scheme adopted by the embodiments of the application is as follows: In a first aspect, the embodiments of the present application provide an austenitic heat-resistant stainless steel material, which comprises the following components in terms of mass fraction: C 0.40%-0.50%, Si 1.80%-2.10%, Mn 10.00%-11.00%, P≤0.05%, S≤0.01%, Cr 20.00%-21.50%, Ni 1.50%-3.0%, Mo 0.20%-0.30%, Co 0.05%-0.20%, V 0.05%-0.20%, Nb 0.15%-0.30%, N 0.17%-0.23%, total amount of other trace elements≤1.0%, and the balance being Fe.

[0006] In a second aspect, the embodiments of the present application provide a preparation method of the austenitic heat-resistant stainless steel material of the first aspect, which comprises the following steps: (1) batching: the raw materials comprise the following components in terms of mass percentage: 0.15%-0.35% carbon additive, 2.50%-3.50% 75 ferrosilicon, 13.00%-15.00% low-carbon ferromanganese, 34.00%-37.00% low-carbon ferrochrome, 1.50%-3.20% electrolytic nickel, 0.30%-0.55% molybdenum iron, 0.30%-0.50% niobium iron, 2.00%-4.00% chromium nitride, 0.06%-0.21% electrolytic cobalt, 0.05%-0.23% vanadium iron, and 35.00%-50.00% scrap steel; (2) smelting: the materials are grouped and weighed, the scrap steel is added into a smelting furnace, then power is supplied to heat, after the scrap steel is melted, the raw materials prepared in step (1) are sequentially added, the adding sequence is: low-carbon ferrochrome→electrolytic nickel, molybdenum iron, niobium iron, chromium nitride, electrolytic cobalt, vanadium iron, carbon additive→low-carbon ferromanganese→ferrosilicon, after the above materials are completely melted, the temperature in the smelting furnace is continuously increased to above 1650℃, a chemical composition analysis sample is taken, the chemical composition in the molten steel is analyzed by using a direct-reading spectrometer, and if an element in the spectral analysis result is not within the specified range, chemical composition adjustment is needed after calculation; The carbon content in the low-carbon ferromanganese meets the national standard GB / T3795-2014, and the C content is 0.15%-0.7%; the carbon content in the low-carbon ferrochrome meets the national standard GB / T5683-2024, and the C content is 0.15%-0.5%.

[0007] (3) deoxidation treatment: (3.1) In-furnace deoxidation: after the chemical composition of the molten steel is adjusted to be qualified, 0.1% to 1.0% of low-carbon ferromanganese by weight of the molten steel is added into the furnace, the particle size of the low-carbon ferromanganese is 10 to 30 mm; the power of the electric furnace is adjusted to be more than 30% of the rated power of the electric furnace, and the electric furnace is heated for 1 to 5 minutes, then the power of the electric furnace is adjusted to 0 kw, and the electric furnace stops heating, and is kept for 1 to 5 minutes, and a sufficient amount of deslagging agent is scattered on the surface of the molten steel to cover the furnace opening during the keeping; the content of manganese in the molten steel is high, and it is very easy to react with oxygen in the air to generate manganese oxide (the density of manganese oxide is 5.43 to 5.46 g / cm 3 , and the melting point is 1650℃), the low-carbon ferromanganese is not only a deoxidizer but also can supplement the oxidation loss of manganese elements in the furnace, and the oxidation of manganese is serious when the molten steel is heated, and a layer of paste-like molten manganese oxide will float on the upper surface of the furnace opening when the heating is stopped; (3.2) Covering deoxidation in ladle: after the molten steel is poured into a ladle, 0.1% to 0.4% of silicon carbide by weight of the molten steel is added on the surface of the ladle, and the particle size is 0.1 to 5 mm; The silicon carbide will decompose into carbon and silicon when it contacts with the high-temperature molten steel, and both the carbon and the silicon can react with the manganese oxide on the surface of the molten steel, among which the silicon dioxide generated by the deoxidation of silicon can react with the manganese oxide to generate low-density manganese silicate to float on the surface, and the carbon can reduce the manganese oxide and generate carbon monoxide gas; the silicon carbide covering on the surface of the molten steel during the transportation of the molten steel also plays a role in preventing the oxidation of the molten steel; (3.3) Stream deoxidation: after the molten steel is deslagged, the molten steel is poured, and 0.1% to 0.4% of a composite deoxidizer is added into the stream of the molten steel during the pouring to obtain an austenitic heat-resistant stainless steel material.

[0008] As the final deoxidation, the deoxidation products of the stream deoxidation will not be discharged from the molten steel, so the size of the deoxidation products is small and round, Ca and Ba can form compounds with oxygen and sulfur in the molten steel, the deoxidation effect is good, and the size of the compounds is mostly 1 to 5 μm, and the compounds are spherical, which will not cause adverse effects on the microstructure of the cast steel matrix; Zr and Al not only react with O but also react with N, and the high-melting-point compounds formed have a size of about 3 μm, which can refine the grains and improve the performance of the cast steel.

[0009] Further, in step (2), after the scrap steel is completely melted, low-carbon ferrochrome is added, and after the low-carbon ferrochrome is completely melted, electrolytic nickel, ferromolybdenum, ferro-niobium, chromium nitride, electrolytic cobalt, ferrovanadium, and a carbon additive are added, and then low-carbon ferromanganese is added, and when the low-carbon ferromanganese is completely melted, 75 ferrosilicon is added.

[0010] Further, in step (2), the time for adjusting the chemical composition of the whole molten steel is controlled to be within 20 minutes, so as to reduce the oxidation loss of Mn elements.

[0011] Further, in step (3.2), the composition of the silicon carbide meets the following conditions in terms of mass fraction: SiC≥90%, Fe2O3≤2.0%, and C≤3.5%.

[0012] Further, in step (3.3), the composite deoxidizer includes the following components in terms of mass fraction: Zr 3%~5%, Al 3%~5%, Ca 1%~5%, Ba 1%~5%, Si 50%~60%, and the balance being Fe.

[0013] Further, the austenitic heat-resistant stainless steel material has the following normal-temperature mechanical properties: tensile strength≥830MPa, yield strength≥540MPa, and elongation≥26%; 900℃ yield strength≥57MPa, and 1000℃ yield strength≥27MPa.

[0014] In a third aspect, the embodiments of the present application provide an application of the austenitic heat-resistant stainless steel material of the first aspect, and the austenitic heat-resistant stainless steel material is used to prepare a turbocharger housing casting.

[0015] In a fourth aspect, the embodiments of the present application provide an application of the austenitic heat-resistant stainless steel material of the first aspect, and the austenitic heat-resistant stainless steel material is used to prepare an intake manifold casting.

[0016] The technical scheme provided by the embodiments of the present application has the following beneficial effects: The present application uses Mn to replace Ni to promote the formation of austenite, and the increase of C content and N content helps to achieve full austenitization of the base structure under the condition of low Ni content. N element has the effect of enhancing solid solution strengthening, so as to save the cost of metal materials. At the same time, the addition of various trace elements including Mo, Nb and V forms a large amount of dispersed carbides and nitrides to be dissolved in the austenitic matrix under the promotion of Mn element, thereby reducing the formation of C6 and the problem of chromium-poor grain boundary, so as to improve the high-temperature oxidation resistance of the new material. The various carbides and nitrides dispersed and dissolved in the austenitic matrix have the effect of refining the austenite grains, improving the tensile strength, yield strength and elongation of the material, and improving the high-temperature stability of the austenitic matrix. The large amount of carbides and nitrides dissolved in the austenitic matrix reduces the content of carbides and nitrides on the grain boundary, and the material has good machining performance. 23 The dispersed and dissolved carbides and nitrides in the austenitic matrix have the effect of refining the austenite grains, improving the tensile strength, yield strength and elongation of the material, and improving the high-temperature stability of the austenitic matrix. The large amount of carbides and nitrides dissolved in the austenitic matrix reduces the content of carbides and nitrides on the grain boundary, and the material has good machining performance. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 The microstructure of the turbocharger housing casting body produced in Embodiment 1 of the present application is magnified 100 times.

[0018] Figure 2 The microstructure of the turbocharger housing casting body produced in Embodiment 1 of the present application is magnified 500 times.

[0019] Figure 3 Microscope metallography of the turbocharger housing casting body produced for Comparative Example 1, sampled at 100 times magnification.

[0020] Figure 4 Microscope metallography of the turbocharger housing casting body produced for Comparative Example 1, sampled at 500 times magnification.

[0021] Figure 5 Microscope metallography of the turbocharger housing casting body produced for Comparative Example 2, sampled at 100 times magnification.

[0022] Figure 6 Microscope metallography of the turbocharger housing casting body produced for Comparative Example 2, sampled at 500 times magnification. DETAILED DESCRIPTION

[0023] In order to make the objects, technical solutions and advantages of the present application clearer, the present application will be further described in detail below with reference to the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and should not be used to limit the present application.

[0024] Example 1 An austenitic heat-resistant stainless steel material, by mass fraction, includes the following components: C 0.43%, Si 2.02%, Mn 10.40%, P 0.045%, S 0.003%, Cr 20.02%, Ni 2.00%, Mo 0.25%, Co 0.10%, V 0.11%, Nb 0.24%, N 0.20%, total amount of other trace elements ≤1.0%, and the balance is Fe.

[0025] The preparation method of the austenitic heat-resistant stainless steel material includes the following steps: (1) batching: 1 ton of raw materials is prepared, by mass percentage, the raw materials include the following components: 0.30% carbon additive, 2.8% 75 ferrosilicon, 13.50% low-carbon manganese iron (in accordance with national standard GB / T 3795-2014, C content is 0.6%), 34.06% low-carbon chromium iron (in accordance with national standard GB / T 5683-2024, C content is 0.2%), 2.03% electrolytic nickel, 0.46% molybdenum iron, 0.39% niobium iron, 2.6% chromium nitride, 0.11% electrolytic cobalt, 0.14% vanadium iron, and 43.61% scrap steel; (2) Melting: using a 1 ton capacity intermediate frequency induction furnace for melting, rated power is 700 kW, the materials are weighed according to the proportioning ratio, then 436.1 kg scrap steel (group A) is added into the intermediate frequency induction furnace, then power is turned on to heat, when the scrap steel is completely melted, low-carbon chromium iron (group B) is added, when the low-carbon chromium iron is completely melted, electrolytic nickel, molybdenum iron, niobium iron, chromium nitride, electrolytic cobalt, vanadium iron and carbon additive (group C) are added, then low-carbon ferromanganese (group D) is added, when the low-carbon ferromanganese is completely melted, 75 ferrosilicon (group E) is added; continue to raise the temperature in the intermediate frequency induction furnace to above 1650℃, take a chemical composition analysis sample, analyze the chemical composition in the molten steel using a direct-reading spectrometer, the chemical composition adjustment time of the whole furnace molten steel is 17 minutes, after the molten steel is adjusted, a sufficient amount of deslagging agent is sprinkled on the surface of the molten steel to cover it, so as to reduce the contact area between the molten steel surface and the air; (3) Deoxidation treatment: 1000 kg of molten steel with qualified composition is melted, the deslagging agent covering the surface of the molten steel is removed before the molten steel is poured out, deoxidation treatment is carried out in the furnace, 5 kg of low-carbon ferromanganese block (particle size 10~30 mm) is added into the furnace, the power of the furnace is adjusted to 600 kW, heating for 2 min, then the power of the furnace is adjusted to 0 kW, the furnace stops heating, and stands for 2 min, a sufficient amount of deslagging agent is sprinkled on the surface of the molten steel to cover the furnace opening during the standing, the pouring ladle is moved to the position of the furnace opening to receive the molten steel, the deslagging agent covering the furnace opening is removed, after the temperature is measured to reach the pouring temperature, the molten steel in the furnace is poured into the pouring ladle, 500 kg of molten steel is poured into two teapot type pouring ladles respectively, one teapot type pouring ladle uses the deoxidation process of comparative example 2, and the other teapot type pouring ladle uses the following deoxidation process: 1.5 kg of silicon carbide (by mass fraction, including the following components: SiC≥90%, Fe2O3≤2.0%, C≤3.5%) is uniformly sprinkled on the surface of the molten steel in the pouring ladle (particle size 0.2~0.8 mm), so as to cover the surface of the molten steel with silicon carbide, and the ladle cover of the pouring ladle is closed; the pouring ladle is transported to the pouring line, after the ladle cover is opened, the oxidation slag on the surface of the pouring ladle is removed using the deslagging agent, deoxidation is carried out with the flow during pouring, and 9.4 g / s of composite deoxidizer is added with the flow during pouring, by mass fraction, the composite deoxidizer includes the following components: 4.1% Zr, 4.4% Al, 1.8% Ca, 1.9% Ba, 57% Si, and the balance is Fe, the addition amount of the composite deoxidizer is 0.15% of the mass of the molten steel.

[0026] Example 2 An austenitic heat-resistant stainless steel material, by mass fraction, includes the following components: C 0.40%, Si 1.83%, Mn 10.02%, P 0.048%, S 0.003%, Cr 20.06%, Ni 1.52%, Mo 0.23%, Co 0.07%, V 0.08%, Nb 0.21%, N 0.17%, total amount of other trace elements ≤1.0%, and the balance is Fe.

[0027] The stainless steel material in this embodiment is prepared with the same parameters as in Embodiment 1 except that the component ingredients are different and the chemical element contents are different from those in Embodiment 1.

[0028] Embodiment 3 An austenitic heat-resistant stainless steel material includes the following components in mass fraction: C 0.42%, Si 1.96%, Mn 10.34%, P 0.047%, S 0.003%, Cr 20.41%, Ni 1.90%, Mo 0.24%, Co 0.12%, V 0.11%, Nb 0.23%, 0.18% N, total amount of other trace elements ≤1.0%, and the balance being Fe.

[0029] The stainless steel material in this embodiment is prepared with the same parameters as in Embodiment 1 except that the component ingredients are different and the chemical element contents are different from those in Embodiment 1.

[0030] Embodiment 4 An austenitic heat-resistant stainless steel material includes the following components in mass fraction: C 0.43%, Si 1.93%, Mn 10.50%, P 0.045%, S 0.004%, Cr 20.66%, Ni 2.13%, Mo 0.23%, Co 0.16%, V 0.12%, Nb 0.24%, N 0.21%, total amount of other trace elements ≤1.0%, and the balance being Fe.

[0031] The stainless steel material in this embodiment is prepared with the same parameters as in Embodiment 1 except that the component ingredients are different and the chemical element contents are different from those in Embodiment 1.

[0032] Embodiment 5 An austenitic heat-resistant stainless steel material includes the following components in mass fraction: C 0.46%, Si 2.09%, Mn 10.82%, P 0.043%, S 0.003%, Cr 20.61%, Ni 2.45%, Mo 0.27%, Co 0.17%, V 0.15%, Nb 0.28%, N 0.21%, total amount of other trace elements ≤1.0%, and the balance being Fe.

[0033] The stainless steel material in this embodiment is prepared with the same parameters as in Embodiment 1 except that the component ingredients are different and the chemical element contents are different from those in Embodiment 1.

[0034] Embodiment 6 An austenitic heat-resistant stainless steel material, by mass fraction, comprises the following components: C 0.49%, Si 2.04%, Mn 10.78%, P 0.043%, S 0.006%, Cr 21.37%, Ni 3.00%, Mo 0.26%, Co 0.20%, 0.19% V, Nb 0.29%, N 0.23%, total amount of other trace elements ≤1.0%, and the balance being Fe.

[0035] In the preparation of the stainless steel material in this embodiment, except that the ingredients are different, the chemical element content is different from that of Example 1, and other parameters are the same as those of Example 1.

[0036] Comparative Example 1 A GX40CrNiSi22-10 stainless steel material, by mass fraction, comprises the following components: C 0.40%, Si 1.33%, Mn 0.60%, P 0.038%, S 0.004%, Cr 21.68%, Ni 9.72%, Mo 0.23%, Nb 0.47%, total amount of other trace elements ≤1.0%, and the balance being Fe.

[0037] The preparation method of the stainless steel material in this embodiment comprises the following steps: (1) ingredient preparation: 1 ton of raw materials are configured, and the raw materials comprise the following components by mass percentage: 0.31% carbon additive, 1.75% 75 ferrosilicon, 0.89% medium-carbon ferromanganese (complying with national standard GB / T3795-2014, C content is 1.91%), 39.6% low-carbon ferrochrome (complying with national standard GB / T5683-2024, C content is 0.2%), 9.8% electrolytic nickel, 0.42% molybdenum iron, 0.73% niobium iron, and 46.5% scrap steel; (2) smelting: a medium-frequency induction furnace with a capacity of 1 ton is used for smelting, and the rated power is 700 kW; after the materials are weighed according to the ingredient proportion, 465 kg of scrap steel (group A) is added to the medium-frequency induction furnace, and then power is supplied to heat; when the scrap steel is completely melted, the low-carbon ferrochrome (group B) is added; when the ferrochrome is completely melted, the electrolytic nickel, molybdenum iron, niobium iron and carbon additive (group C) are added; then the medium-carbon ferromanganese (group D) is added; when the medium-carbon ferromanganese is completely melted, the 75 ferrosilicon (group E) is added; the temperature in the medium-frequency induction furnace is continuously increased to above 1650℃, a chemical composition analysis sample is taken, the chemical composition in the molten steel is analyzed by using a direct-reading spectrometer, the chemical composition adjustment time of the whole furnace molten steel is 15 minutes, and after the molten steel is adjusted, a sufficient amount of deslagging agent is sprinkled on the surface of the molten steel to cover it, so as to reduce the contact area between the molten steel surface and the air; (3) Deoxidation treatment: 1000 kg of molten steel with qualified composition was prepared, the slag remover covering the surface of the molten steel was removed before tapping, and in-furnace deoxidation treatment was performed, 2 kg of 75 ferrosilicon (by mass fraction, including 74.2% Si, 0.7% Ca, 0.5% Al, and the balance Fe) was added, the power of the electric furnace was adjusted to 600 kW, and after heating for 2 minutes, the power of the electric furnace was adjusted to 0 kW, and the electric furnace stopped heating for 2 minutes. A sufficient amount of slag remover was sprinkled on the surface of the molten steel to cover the furnace opening, and after standing for 2 minutes, the pouring ladle was moved to the position of the furnace opening to receive the molten steel, and the slag remover covering the furnace opening was removed. After the temperature measurement reached the tapping temperature, the molten steel was poured into the teapot type pouring ladle, and when 260 kg of molten steel was poured, 1.51 kg of aluminum block (5-8 cm) was thrown into the pouring ladle for final deoxidation.

[0038] Comparative Example 2 A GX40CrNiSi22-10 stainless steel material, by mass fraction, includes the following components: C 0.40%, Si 1.60%, Mn 0.62%, P 0.038%, S 0.004%, Cr 21.68%, Ni 9.72%, Mo 0.23%, Nb 0.47%, the total amount of other trace elements ≤1.0%, and the balance Fe. In this embodiment, the stainless steel material is prepared, the batching and melting process is the same as that of Example 1, and only the deoxidation process is different. The deoxidation treatment is as follows: 500 kg of molten steel with qualified composition prepared in Example 1 is subjected to in-furnace deoxidation treatment, 1 kg of 75 ferrosilicon (by mass fraction, including 74.2% Si, 0.7% Ca, 0.5% Al, and the balance Fe) is added in the furnace, the power of the electric furnace is adjusted to 450 kW, and after heating for 2 minutes, the power of the electric furnace is adjusted to 0 kW, and the electric furnace stops heating for 2 minutes. A sufficient amount of slag remover is sprinkled on the surface of the molten steel to cover the furnace opening, and after standing for 2 minutes, the pouring ladle is moved to the position of the furnace opening to receive the molten steel, and the slag remover covering the furnace opening is removed. After the temperature measurement reaches the tapping temperature, the molten steel is poured into the teapot type pouring ladle, and when 140 kg of molten steel is poured, 0.78 kg of aluminum block (5-8 cm) is thrown into the pouring ladle for final deoxidation.

[0039] Table 1 Austenitizing element mass content and nickel equivalent in Examples 1-6 and Comparative Examples 1-2 , In Table 1, the historical empirical formula is optimized by correlation analysis and regression analysis, and the nickel equivalent calculation formula of the austenitizing degree corresponding to the mass content of each chemical element under the condition of adding trace elements such as Mo, Nb, N, Co, and V is obtained: Ni(eq)=1×Ni%+1.2×Co%+35×C%+20×N%+0.5×Mn%。

[0040] The nickel equivalent is an important index of the austenitizing degree of the metal structure of the reaction metal, and a higher nickel equivalent shows that the austenitizing degree is higher, and the stability of the metal matrix structure of the metal material under high temperature is higher, and the high temperature creep resistance is higher. As can be seen from Table 1, the nickel equivalent calculated shows that the austenitizing degree of GX43CrMnNi20-10-2 in Examples 1-6 is higher than that of GX40CrNiSi22-10.

[0041] Test scheme: two pieces of the same model turbocharger shell castings produced by the materials of Examples 1-6 and Comparative Example 1 were taken, weighed respectively, and then put into a muffle furnace heated to 1020℃, and the castings were taken out after 1 hour of heat preservation and cooled at room temperature. After 1 hour of cooling, the castings were again put into a muffle furnace at 1020℃, and the castings were weighed, and the results are shown in Table 1.

[0042] Table 2 Comparison of high temperature oxidation resistance test results of the materials in Examples 1-6 and Comparative Example , As can be seen from Table 2, the average oxidation loss of the castings made of the stainless steel materials of Examples 1-6 is lower than that of the castings made of the GX40CrNiSi22-10 material in Comparative Example 1, showing stronger oxidation resistance.

[0043] Table 3 Mechanical properties of stainless steel materials at room temperature and high temperature in Examples 1-6 and Comparative Examples 1 and 2 , As can be seen from the test results in the above table, the tensile strength and yield strength of the stainless steel materials of Examples 1-6 at room temperature and the high temperature yield strength at 900℃ and 1000℃ are all higher than those of GX40CrNiSi22-10, and the elongation is also greatly improved. Therefore, the material of the present application can completely replace GX40CrNiSi22-10 for the production of turbocharger shell and exhaust manifold castings under 1000℃ extreme working conditions.

[0044] Table 4 Cost accounting of different stainless steel materials (Ni is calculated at 100 yuan / kg) , As can be seen from Table 4, the average cost of the GX43CrMnNi20-10-2 stainless steel material in Examples 1-6 is 53% of that of the GX40CrNiSi22-10 stainless steel material in Comparative Example 1, which shows that the cost of the stainless steel material in the examples of the present application can be greatly reduced.

[0045] By Figure 1 and Figure 2As can be seen, the carbides and nitrides in the microstructure of the turbocharger housing cast body body sample produced in Example 1 are very fine and dispersed in the austenite matrix, and there are few carbides and nitrides on the grain boundaries. Figure 3 and Figure 4 The microstructure of the turbocharger housing cast body body produced in Comparative Example 1 shows that the carbides are mostly located on the grain boundaries and have a large size, and are in a network shape. Figure 5 and Figure 6 The microstructure of the turbocharger housing cast body body produced in Comparative Example 2 shows that the carbides and nitrides are mostly located on the grain boundaries and have a large size. Figure 5 and 6 As can be seen, the size of the in-grain and grain boundary edge inclusions is large, which has an adverse effect on the tensile strength, elongation and high-temperature mechanical properties of the steel.

[0046] Finally, it should be noted that the above specific embodiments are only used to illustrate the technical solutions of the present application and not to limit it. Although the present application has been described in detail with reference to the examples, it should be understood by those skilled in the art that the technical solutions of the present application can be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present application, and they should be covered in the scope of the claims of the present application.

Claims

1. An austenitic heat-resistant stainless steel material, characterized by, By mass fraction, comprising the following components: C 0.40%~0.50%, Si 1.80%~2.10%, Mn 10.00%~11.00%, P≤0.05%, S≤0.01%, Cr 20.00%~21.50%, Ni1.50%~3.0%, Mo 0.20%~0.30%, Co 0.05%~0.20%, V 0.05%~0.20%, Nb 0.15%~0.30%, N 0.17%~0.23%, other trace elements total amount≤1.0%, the balance is Fe.

2. The method of producing the austenitic heat-resistant stainless steel material according to claim 1, characterized by, Comprising the following steps: (1) batching: by mass percentage, the raw materials include the following components: 0.15%~0.35% carbon additive, 2.50%~3.50% 75 ferrosilicon, 13.00%~15.00% low-carbon ferromanganese, 34.00%~37.00% low-carbon ferrochrome, 1.50%~3.20% electrolytic nickel, 0.30%~0.55% ferromolybdenum, 0.30%~0.50% columbium iron, 2.00%~4.00% chromium nitride, 0.06%~0.21% electrolytic cobalt, 0.05%~0.23% vanadium iron and 35.00%~50.00% scrap steel; (2) smelting: the materials are grouped and weighed, the scrap steel is added into the smelting furnace, then the temperature is sent to rise, when the scrap steel is melted, the raw materials prepared in step (1) are sequentially added, the order of adding is: low-carbon ferrochrome→ electrolytic nickel, ferromolybdenum, columbium iron, chromium nitride, electrolytic cobalt, vanadium iron, carbon additive→ low-carbon ferromanganese→ ferrosilicon, when the above materials are completely melted, the temperature in the smelting furnace is continuously increased to above 1650℃, the chemical composition analysis sample is taken, the chemical composition in the molten steel is analyzed by using direct-reading spectrometer, if an element in the spectrum analysis result is not within the specified range, the chemical composition needs to be adjusted after calculation; (3) deoxidation treatment: (3.1) in-furnace deoxidation: after the chemical composition of the molten steel is qualified, 0.1%~1.0% low-carbon ferromanganese with a particle size of 10~30mm is added into the molten steel in the furnace, the power of the electric furnace is adjusted to more than 30% of the rated power of the electric furnace, and heated for 1~5min, then the power of the electric furnace is adjusted to 0 kW, the electric furnace stops heating, and stands for 1~5min, while standing, a sufficient amount of deslagging agent is sprinkled on the surface of the molten steel to cover the furnace opening; (3.2) covered deoxidation in ladle: after the molten steel is poured into the ladle, 0.1%~0.4% silicon carbide with a particle size of 0.1~5mm is added on the surface of the ladle; (3.3) stream deoxidation: after the molten steel is deslagged, it is poured, and 0.1~0.4% composite deoxidizing agent is added with the molten steel stream to obtain an austenitic heat-resistant stainless steel material.

3. The method of producing an austenitic heat-resistant stainless steel material according to claim 2, characterized by, In step (2), after the scrap steel is completely melted, low-carbon ferrochrome is added, after the low-carbon ferrochrome is completely melted, electrolytic nickel, ferromolybdenum, columbium iron, chromium nitride, electrolytic cobalt, vanadium iron and carbon additive are added, then low-carbon ferromanganese is added, and when the low-carbon ferromanganese is completely melted, 75 ferrosilicon is added.

4. The method of producing an austenitic heat-resistant stainless steel material according to claim 2, characterized by, In step (2), the chemical composition adjustment time of the whole molten steel is controlled within 20 minutes to reduce the oxidation loss of manganese element.

5. The method of producing an austenitic heat-resistant stainless steel material according to claim 2, characterized by, In step (3.2), the composition of the silicon carbide meets the following conditions in terms of mass fraction: SiC≥90%, Fe2O3≤2.0%, and C≤3.5%. 6.The method of claim 2, wherein the austenitic heat-resistant stainless steel material is characterized in that, In step (3.3), the composite deoxidizer includes the following components in terms of mass fraction: Zr 3%~5%, Al 3%~5%, Ca 1%~5%, Ba 1%~5%, Si 50%~60%, and the balance of Fe. 7.The method of claim 2, wherein the austenitic heat-resistant stainless steel material is characterized in that, The austenitic heat-resistant stainless steel material has the following mechanical properties at room temperature: tensile strength≥830MPa, yield strength≥540MPa, and elongation≥26%; 900℃ yield strength≥57MPa, and 1000℃ yield strength≥27MPa.

8. Use of the austenitic heat-resistant stainless steel material according to claim 1, characterized in that, The austenitic heat-resistant stainless steel material is used to prepare a turbocharger housing casting.

9. Use of the austenitic heat-resistant stainless steel material according to claim 1, characterized in that, The austenitic heat-resistant stainless steel material is used to prepare an intake manifold casting. The austenitic heat-resistant stainless steel material is used to prepare an intake manifold casting.

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