High-manganese non-magnetic structural steel, preparation method thereof and mechanical structural part

Abstract

The invention relates to high-manganese non-magnetic structural steel, a preparation method thereof and a mechanical structural component, and the high-manganese non-magnetic structural steel comprises the following components in percentage by mass: 0.16%-0.19% of C, 0.18%-0.42% of Si, 22.1%-24.15% of Mn, 0.0069%-0.02% of P, 0.0007%-0.003% of S, 0.065%-0.077% of V, 0.006%-0.007% of N, 1.6%-2.06% of Al and the balance of Fe and inevitable impurity elements. The steel is high in strength and good in ductility and non-magnetic performance.

Description

Technical Field

[0001] The invention relates to the technical field of alloys, and in particular to a high-manganese non-magnetic structural steel and a preparation method thereof, and a mechanical structural part. Background Art

[0002] As a steel functional material, non-magnetic steel is a low-magnetic steel material that basically does not produce magnetic induction under the action of a magnetic field. The relative magnetic permeability μ value is slightly greater than 1, and the magnetization effect in the magnetic field is very weak, that is, the so-called "non-magnetic" phenomenon occurs, so it is figuratively called non-magnetic steel. It has the characteristics of high magnetic permeability, low resistance and good processing performance, and is widely used in the manufacture of various mechanical structural parts. The room temperature structure of non-magnetic steel is required to be stable austenite. This is because ferrite, pearlite and martensite structures are ferromagnetic at room temperature, and show strong magnetization in the magnetic field, and the magnetic permeability is very high. Austenite with a face-centered cubic structure is paramagnetic and has a very low magnetic permeability. By appropriately adding alloy elements to expand the austenite zone in the Fe-C alloy phase diagram and heat treatment methods, a stable single-phase austenite structure can be obtained at room temperature, thereby keeping the magnetic permeability of the steel material at a low level. For example, 20Mn23AlV is a high-manganese non-magnetic steel with high strength, which is mainly used to manufacture internal structural parts of large transformers.

[0003] However, high manganese non-magnetic steels such as 20Mn23AlV in traditional technology generally have greater deformation resistance, are harder than general low-alloy steels, have low elongation, are prone to cracking during the rolling process, and the slabs after rolling are prone to bending and warping. In addition, ferrite or other phase structures are prone to appear in the room temperature structure, and phase changes, namely martensite and bainite, may also occur during the rolling process. How to obtain non-magnetic structural steels with both good mechanical strength and elongation is still a difficult problem to be overcome.

[0004] Therefore, the existing technology still needs to be improved. Summary of the invention

[0005] Based on this, the present invention provides a high manganese non-magnetic structural steel with high strength and good elongation, a preparation method thereof, and a mechanical structural part.

[0006] One aspect of the present invention provides a high manganese non-magnetic structural steel, which comprises, by mass percentage, 0.16-0.19% C, 0.18-0.42% Si, 22.1%-24.15% Mn, 0.0069%-0.02% P, 0.0007%-0.003% S, 0.065%-0.077% V, 0.006%-0.007% N, 1.6%-2.06% Al, the remainder Fe and unavoidable impurity elements.

[0007] The above-mentioned high manganese non-magnetic structural steel contains components in a specific ratio, among which: Mn is an element that expands the austenite region and strongly stabilizes austenite. Most of Mn in the steel is dissolved in austenite to form a substitutional solid solution, which strengthens the matrix. Moreover, with the increase of Mn content, the γ→ε and γ→ε→α' martensitic transformation temperatures decrease, and at the same time, the (Fe, Mn) 3 C precipitates in the temperature range, increasing the high-temperature stability of austenite; Al is a key element for improving Fe-Mn austenitic steels. Al can increase the stacking fault energy of austenite. Al can strongly inhibit the γ→ε→α' martensitic phase transformation in Fe-Mn austenitic steels, stabilize austenite, reduce cold deformation hardening, and improve corrosion resistance. At the same time, due to the addition of a specific amount of Al, the density of the steel is reduced without much change in material strength; V is a carbide-forming element. In non-magnetic steels, part of V is dissolved in the austenite matrix, and the rest is dispersed in the non-magnetic steel in the form of fine precipitates of VC, VN and V(CN). The fine dispersed VC, VN and V(CN) precipitates can inhibit the growth of austenite grains and are beneficial to the nucleation of austenite to achieve fine grain strengthening. The precipitates can also improve the comprehensive properties of steel through coherent distortion and dispersion strengthening (VC and other second-phase particles constitute resistance to dislocation movement in non-magnetic steels, and dislocations and second-phase particles interact to form dislocation entanglements, thereby strengthening the non-magnetic steel). strength and reduce magnetic permeability; C is one of the main elements of high manganese non-magnetic structural steel, which can stabilize the austenite in the alloy and keep the austenite at room temperature during rapid cooling, and present a single-phase austenite structure. With the increase of carbon content, the solid solution strengthening effect of carbon increases, which improves the strength, hardness and wear resistance of high manganese steel; N can expand the austenite phase region of steel and is a very strong element for forming and stabilizing austenite. It can also generate extremely stable nitrides such as AlN phase with elements such as Al and V in steel to strengthen the steel matrix, and can also make the structure of some steel types dense and solid, thereby improving the strength and impact toughness of non-magnetic steel; S is an original impurity element in steel, but it will form MnS phase in non-magnetic steel with high manganese content, which can prevent the hot brittleness caused by the formation of low-melting-point FeS along the grain boundaries. By controlling the specific content to improve hot rolling shaping, MnS can effectively pin dislocations to improve the mechanical properties of non-magnetic steel, and accumulate grain boundary energy by pinning dislocations to provide driving force for secondary recrystallization. At the same time, MnS at the matrix grain boundary can prevent grain growth and refine the grains; Si is mainly introduced as a deoxidizer to strengthen the solid solution and increase the yield strength, but it closes the γ phase region and promotes graphitization. When Si>0.6%, it not only easily causes coarse grains in high manganese steel, but also reduces the solubility of carbon in austenite, promotes the precipitation of carbides along grain boundaries, reduces the toughness and wear resistance of steel, and increases the thermal cracking tendency of steel. Therefore, silicon needs to be controlled within a specific range.

[0008] Therefore, the iron element and other specific components are combined in a specific ratio to make the steel have high strength, good elongation and "non-magnetic" properties.

[0009] The room temperature microstructure of the above-mentioned high manganese non-magnetic structural steel is required to be stable austenite, that is, the relative magnetic permeability μ value is slightly greater than 1, which can produce the so-called "non-magnetic" phenomenon, the tensile strength can reach 576Mpa and above, the yield strength can reach 229Mpa and above, the elongation can reach 54% and above, and the bending angle test samples are intact without breakage.

[0010] In some embodiments, the high manganese non-magnetic structural steel includes, by mass percentage, 0.19% C, 0.18% Si, 24.15% Mn, 0.0069% P, 0.0007% S, 0.076% V, 0.006% N, 2.06% Al, and the balance Fe and unavoidable impurity elements.

[0011] In some embodiments, the high manganese non-magnetic structural steel includes, by mass percentage, 0.16% C, 0.29% Si, 22.1% Mn, 0.02% P, 0.001% S, 0.065% V, 0.007% N, 1.6% Al, and the balance Fe and unavoidable impurity elements.

[0012] In some embodiments, the high manganese non-magnetic structural steel includes, by mass percentage, 0.17% C, 0.42% Si, 22.4% Mn, 0.02% P, 0.001% S, 0.077% V, 0.006% N, 1.69% Al, and the balance Fe and unavoidable impurity elements.

[0013] In some embodiments, the high manganese non-magnetic structural steel comprises, by mass percentage, 0.18% C, 0.19% Si, 22.29% Mn, 0.018% P, 0.003% S, 0.076% V, 0.007% N, 1.61% Al, and the balance Fe and unavoidable impurity elements.

[0014] In some of the embodiments, the thickness of the high manganese non-magnetic structural steel is 10 mm to 20 mm.

[0015] Another aspect of the present invention provides a method for preparing high manganese non-magnetic structural steel, comprising the following steps:

[0016] The raw materials are provided according to the stoichiometric ratio of the components of the high manganese non-magnetic structural steel, and the raw materials are subjected to smelting, casting, heat preservation and rolling treatments in sequence to produce the high manganese non-magnetic structural steel.

[0017] In some embodiments, the conditions of the smelting and casting process include: a casting temperature of 1465±10°C, a superheat of 23°C to 49°C, and a pulling speed of 0.6m / min to 0.7m / min; and / or

[0018] The casting step of the smelting and casting process is carried out in a crystallizer, and the water volume on the wide side of the crystallizer is 3500±100L / min, and the water volume on the narrow side is 400L / min.

[0019] In some embodiments, the temperature of the heat preservation treatment is 1250° C. and the time is 3 hours; and / or

[0020] The rolling treatment steps include: performing multiple rolling passes at 1130°C to 1159°C, with a reduction of 8 mm in each pass, and a final rolling temperature of 900°C to 1032°C.

[0021] In another aspect of the present invention, a mechanical structural part is provided, which comprises the above-mentioned high manganese non-magnetic structural steel or the high manganese non-magnetic structural steel prepared by the preparation method of the above-mentioned high manganese non-magnetic structural steel. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is the metallographic structure diagram of the high manganese non-magnetic structural steel prepared in Example 1;

[0023] Figure 2 This is the metallographic structure diagram of the high manganese non-magnetic structural steel prepared in Example 2;

[0024] Figure 3 This is the metallographic structure diagram of the high manganese non-magnetic structural steel prepared in Example 3;

[0025] Figure 4 This is the metallographic structure diagram of the high manganese non-magnetic structural steel prepared in Example 4. DETAILED DESCRIPTION

[0026] In order to facilitate the understanding of the present invention, the present invention will be described more comprehensively below. Preferred embodiments of the present invention are provided in the specific embodiments. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosure of the present invention more thorough and comprehensive.

[0027] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those generally understood by those skilled in the art of the present invention. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0028] the term

[0029] Unless otherwise specified or incompatible herewith, the terms and phrases used herein shall have the following meanings:

[0030] The terms "and / or", "or / and", and "and / or" used in this article have a selection range that includes any one of two or more related listed items, and also includes any and all combinations of related listed items, and the arbitrary and all combinations include any combination of two related listed items, any more related listed items, or all related listed items. It should be noted that when at least three items are connected by at least two conjunctions selected from "and / or", "or / and", and "and / or", it should be understood that in this application, the technical solution undoubtedly includes technical solutions that are all connected by "logical and", and undoubtedly includes technical solutions that are all connected by "logical or". For example, "A and / or B" includes three parallel solutions of A, B and the combination of A and B. For example, the technical solution of "A, and / or, B, and / or, C, and / or, D" includes any one of A, B, C, and D (that is, the technical solution that is all connected by "logical OR"), and also includes any and all combinations of A, B, C, and D, that is, the combination of any two or any three of A, B, C, and D, and also includes the combination of four of A, B, C, and D (that is, the technical solution that is all connected by "logical AND").

[0031] In the present invention, "optionally", "optional", and "optional" mean optional, that is, any one of the two parallel solutions of "yes" or "no". If multiple "options" appear in a technical solution, unless otherwise specified and there is no contradiction or mutual restriction, each "optional" is independent.

[0032] In the present invention, the technical features described in an open manner include closed technical solutions composed of the listed features, and also include open technical solutions containing the listed features.

[0033] In the present invention, when it comes to a numerical interval (i.e., a numerical range), unless otherwise specified, the distribution of the optional numerical values ​​in the numerical interval is considered to be continuous, and includes the two numerical endpoints (i.e., the minimum value and the maximum value) of the numerical interval, and each numerical value between the two numerical endpoints. Unless otherwise specified, when the numerical interval only refers to the integers in the numerical interval, including the two endpoint integers of the numerical range, and each integer between the two endpoints, is equivalent to directly listing each integer. When multiple numerical ranges are provided to describe features or characteristics, these numerical ranges can be merged. In other words, unless otherwise specified, the numerical range disclosed herein should be understood to include any and all sub-ranges included therein. The "numerical value" in the numerical interval can be any quantitative value, such as a number, a percentage, a ratio, etc. "Numerical interval" allows broadly including numerical interval types such as percentage intervals, ratio intervals, and ratio intervals.

[0034] The temperature parameters in the present invention, if not specifically limited, are allowed to be either constant temperature treatment or to vary within a certain temperature range. It should be understood that the constant temperature treatment allows the temperature to fluctuate within the precision range controlled by the instrument. Fluctuations within the range of ±5°C, ±4°C, ±3°C, ±2°C, and ±1°C are allowed.

[0035] In the present invention, the term "room temperature" or "normal temperature" generally refers to 4°C to 35°C, for example, 20°C ± 5°C. In some embodiments of the present invention, "room temperature" or "normal temperature" refers to 10°C to 30°C. In some embodiments of the present invention, "room temperature" or "normal temperature" refers to 20°C to 30°C.

[0036] The mass or weight of the relevant components mentioned in the description of the embodiments of the present invention may not only refer to the specific content of each component, but also indicate the proportional relationship of the mass or weight between the components. Therefore, as long as the content of the relevant components is proportionally enlarged or reduced according to the description of the embodiments of the present invention, it is within the scope disclosed in the description of the embodiments of the present invention. Specifically, the mass or weight described in the description of the embodiments of the present invention may be units known in the chemical industry such as μg, mg, g, and kg.

[0037] During long-term production and research, technicians have discovered that high manganese structural steel is very likely to fail to exhibit "non-magnetic" properties due to unreasonable regulation of alloying elements, resulting in the austenite phase region not dropping below room temperature, and the appearance of ferrite or other phase structures in the room temperature structure, making it impossible to have both good mechanical strength and elongation.

[0038] After a long period of extensive creative experiments, the technical solution of this application was obtained.

[0039] An embodiment of the present invention provides a high manganese non-magnetic structural steel, which includes, by mass percentage, 0.16-0.19% C, 0.18-0.42% Si, 22.1%-24.15% Mn, 0.0069%-0.02% P, 0.0007%-0.003% S, 0.065%-0.077% V, 0.006%-0.007% N, 1.6%-2.06% Al, the remainder Fe and unavoidable impurity elements.

[0040] The above-mentioned high manganese non-magnetic structural steel contains components in a specific ratio, among which: Mn is an element that expands the austenite region and strongly stabilizes austenite. Most of Mn in the steel is dissolved in austenite to form a substitutional solid solution, which strengthens the matrix. Moreover, with the increase of Mn content, the γ→ε and γ→ε→α' martensitic transformation temperatures decrease, and at the same time, the (Fe, Mn) 3C precipitates in the temperature range, increasing the high-temperature stability of austenite; Al is a key element for improving Fe-Mn austenitic steels. Al can increase the stacking fault energy of austenite. Al can strongly inhibit the γ→ε→α' martensitic phase transformation in Fe-Mn austenitic steels, stabilize austenite, reduce cold deformation hardening, and improve corrosion resistance. At the same time, due to the addition of a specific amount of Al, the density of the steel is reduced without much change in material strength; V is a carbide-forming element. In non-magnetic steels, part of V is dissolved in the austenite matrix, and the rest is dispersed in the non-magnetic steel in the form of fine precipitates of VC, VN and V(CN). The fine dispersed VC, VN and V(CN) precipitates can inhibit the growth of austenite grains and are beneficial to the nucleation of austenite to achieve fine grain strengthening. The precipitates can also improve the comprehensive properties of steel through coherent distortion and dispersion strengthening (VC and other second-phase particles constitute resistance to dislocation movement in non-magnetic steels, and dislocations and second-phase particles interact to form dislocation entanglements, thereby strengthening the non-magnetic steel). strength and reduce magnetic permeability; C is one of the main elements of high manganese non-magnetic structural steel, which can stabilize the austenite in the alloy and keep the austenite at room temperature during rapid cooling, and present a single-phase austenite structure. With the increase of carbon content, the solid solution strengthening effect of carbon increases, which improves the strength, hardness and wear resistance of high manganese steel; N can expand the austenite phase region of steel and is a very strong element for forming and stabilizing austenite. It can also generate extremely stable nitrides such as AlN phase with elements such as Al and V in steel to strengthen the steel matrix, and can also make the structure of some steel types dense and solid, thereby improving the strength and impact toughness of non-magnetic steel; S is an original impurity element in steel, but it will form MnS phase in non-magnetic steel with high manganese content, which can prevent the hot brittleness caused by the formation of low-melting-point FeS along the grain boundaries. By controlling the specific content to improve hot rolling shaping, MnS can effectively pin dislocations to improve the mechanical properties of non-magnetic steel, and accumulate grain boundary energy by pinning dislocations to provide driving force for secondary recrystallization. At the same time, MnS at the matrix grain boundary can prevent grain growth and refine the grains; Si is mainly introduced as a deoxidizer to strengthen the solid solution and increase the yield strength, but it closes the γ phase region and promotes graphitization. When Si>0.6%, it not only easily causes coarse grains in high manganese steel, but also reduces the solubility of carbon in austenite, promotes the precipitation of carbides along grain boundaries, reduces the toughness and wear resistance of steel, and increases the thermal cracking tendency of steel. Therefore, silicon needs to be controlled within a specific range.

[0041] Therefore, the iron element and other specific components are combined in a specific ratio to make the steel have high strength, good elongation and "non-magnetic" properties.

[0042] The room temperature microstructure of the above-mentioned high manganese non-magnetic structural steel is required to be stable austenite, that is, the relative magnetic permeability μ value is slightly greater than 1, which can produce the so-called "non-magnetic" phenomenon, the tensile strength can reach 576Mpa and above, the yield strength can reach 229Mpa and above, the elongation can reach 54% and above, and the bending angle test samples are intact without breakage.

[0043] Optionally, the mass percentage of carbon includes: 0.16%, 0.17%, 0.18%, 0.19%, and each value between the minimum and maximum values, or a range consisting of any two values.

[0044] Optionally, the mass percentage of silicon includes: 0.18%, 0.19%, 0.2%, 0.25%, 0.3%, 0.35%, 0.4%, 0.43%, and each value between such minimum and maximum values, or a range consisting of any two values.

[0045] Optionally, the mass percentage of manganese includes: 22.1%, 22.5%, 23.1%, 23.6%, 23.8%, 24%, 24.15%, and each value between such minimum and maximum values, or a range consisting of any two values.

[0046] Optionally, the mass percentage of P includes: 0.0069%, 0.007%, 0.008%, 0.009%, 0.01%, 0.012%, 0.014%, 0.016%, 0.018%, 0.02%, and every value between the minimum and maximum values, or a range consisting of any two values.

[0047] Optionally, the mass percentage of S includes: 0.0007%, 0.0008%, 0.0009%, 0.001%, 0.0012%, 0.0014%, 0.0016%, 0.0018%, 0.002%, 0.0025%, 0.003%, and every value between the minimum and maximum values, or a range consisting of any two values.

[0048] In some of the embodiments, the mass percentage of S is 0.0007% to 0.001%.

[0049] Optionally, the mass percentage of V mentioned above includes: 0.065%, 0.066%, 0.067%, 0.068%, 0.069%, 0.07%, 0.075%, 0.076%, 0.076%, 0.077%, and every value between such minimum and maximum values, or a range consisting of any two values.

[0050] Optionally, the mass percentage of N mentioned above includes: 0.006%, 0.0061%, 0.0062%, 0.0063%, 0.0064%, 0.0065%, 0.0066%, 0.0067%, 0.0068%, 0.0069%, 0.007%, and every value between the minimum and maximum values, or a range consisting of any two values.

[0051] Optionally, the mass percentage of Al includes: 1.6%, 1.7%, 1.8%, 1.9%, 2.06%, and any value between the minimum and maximum values, or a range consisting of any two values.

[0052] It can be understood that unavoidable impurity elements are impurities that are inevitably introduced into the smelting process due to the limitations of raw materials or process conditions, and their content is at a level that is well known in the art and does not affect the properties of the alloy.

[0053] Calculated by mass percentage, the high manganese non-magnetic structural steel includes: 0.19% C, 0.18% Si, 24.15% Mn, 0.0069% P, 0.0007% S, 0.076% V, 0.006% N, 2.06% Al, and the balance Fe and inevitable impurity elements.

[0054] In some embodiments, the high manganese non-magnetic structural steel includes, by mass percentage, 0.16% C, 0.29% Si, 22.1% Mn, 0.02% P, 0.001% S, 0.065% V, 0.007% N, 1.6% Al, and the balance Fe and unavoidable impurity elements.

[0055] In some embodiments, the high manganese non-magnetic structural steel includes, by mass percentage, 0.17% C, 0.42% Si, 22.4% Mn, 0.02% P, 0.001% S, 0.077% V, 0.006% N, 1.69% Al, and the balance Fe and unavoidable impurity elements.

[0056] In some embodiments, the high manganese non-magnetic structural steel comprises, by mass percentage, 0.18% C, 0.19% Si, 22.29% Mn, 0.018% P, 0.003% S, 0.076% V, 0.007% N, 1.61% Al, and the balance Fe and unavoidable impurity elements.

[0057] Another aspect of the present invention provides a method for preparing high manganese non-magnetic structural steel, comprising the following step S10.

[0058] S10, providing raw materials for preparation according to the stoichiometric ratio of the components of the high manganese non-magnetic structural steel, and subjecting the raw materials for preparation to smelting, casting, heat preservation and rolling treatments in sequence to make high manganese non-magnetic structural steel.

[0059] It should be noted that the raw materials can be adjusted according to the composition of high manganese non-magnetic structural steel. The ratio of each element in the raw materials can meet the composition of high manganese non-magnetic structural steel. There is no special requirement for the specific type. It can be a metal element or an alloy.

[0060] In some of the embodiments, the conditions of the smelting and casting process include: a casting temperature of 1465±10°C, a superheat of 23°C to 49°C, and a pulling speed of 0.6m / min to 0.7m / min.

[0061] In some of the embodiments, the continuous casting process adopts continuous casting, the casting speed is controlled at 0.9-1.1 m / min, and the casting billet adopts a light pressure reduction mode.

[0062] In some of the embodiments, the casting step of the smelting and casting process is carried out in a crystallizer, and the water volume on the wide side of the crystallizer is 3500±100 L / min and the water volume on the narrow side is 400 L / min.

[0063] In some embodiments, the temperature of the heat preservation treatment is 1250° C. and the time is 3 hours. Specifically, the ingot obtained by the smelting and casting treatment is heated to 1250° C. and kept at this temperature for 3 hours.

[0064] In some of the embodiments, the rolling treatment step includes: performing multiple rolling passes at 1130° C. to 1159° C., with a reduction of 8 mm in each pass, and a final rolling temperature of 900° C. to 1032° C.

[0065] In some of the embodiments, after the rolling step, the step of air cooling the rolled steel material to room temperature is also included.

[0066] Another embodiment of the present invention further provides a mechanical structural part, which includes the above-mentioned high manganese non-magnetic structural steel or the high manganese non-magnetic structural steel prepared by the preparation method of the above-mentioned high manganese non-magnetic structural steel.

[0067] The above steel has high strength, good elongation and "non-magnetic" properties. Mechanical structural parts include but are not limited to: internal structural parts of large transformers and structural parts in electrical components.

[0068] The present invention will be described below in conjunction with specific embodiments, but the present invention is not limited to the following embodiments. It should be understood that the attached claims summarize the scope of the present invention. Under the guidance of the concept of the present invention, those skilled in the art should realize that certain changes made to the various embodiments of the present invention will be covered by the spirit and scope of the claims of the present invention.

[0069] Specific embodiments The following are specific embodiments.

[0070] Example 1

[0071] (1) The mass percentage of each element in high manganese non-magnetic structural steel is: C 0.19%, Si 0.18%, Mn24.15%, P0.0069%, S 0.0007%, V 0.076%, N 0.006%, Al 2.06%, and the rest is iron. The corresponding preparation raw materials are provided according to the chemical composition.

[0072] (2) The prepared raw materials are melted into molten iron, and the molten iron is cast into continuous casting billets in a crystallizer: the casting temperature is 1457°C, the superheat is 28°C, the pulling speed is 0.6 m / min, the water volume on the wide side of the crystallizer is 3500 L / min, and the water volume on the narrow side of the crystallizer is 400 L / min.

[0073] (3) The ingot was heated to 1250°C and kept at this temperature for 3 h. After the end of the keeping temperature, the ingot was cooled to 1130°C for multiple rolling passes. The reduction in each pass was 8 mm. The final rolling temperature was 900°C. The final hot-rolled plate thickness was 10 mm. The ingot was air-cooled to room temperature to obtain high manganese non-magnetic steel.

[0074] (4) At room temperature, the high manganese non-magnetic steel obtained in the above steps is sampled and placed under an electron microscope to observe the metallographic structure. Figure 1 As shown in the figure, it can be seen that the structure of the steel is uniform everywhere, which is stable austenite and has "non-magnetic" characteristics.

[0075] (5) The high manganese non-magnetic structural steel coil obtained in the above steps was tested for mechanical properties using industry standards. The tensile strength was 664 MPa, the yield strength was 398 MPa, the elongation was 54%, and the bending angle test sample was intact without any breakage.

[0076] Example 2

[0077] (1) The mass percentage of each element in high manganese non-magnetic structural steel is: C 0.16%, Si 0.29%, Mn22.1%, P0.02%, S 0.001%, V 0.065%, N 0.007%, Al 1.6%, and the rest is iron. The corresponding preparation raw materials are provided according to the chemical composition.

[0078] (2) The prepared raw materials are melted into molten iron, and the molten iron is cast into continuous casting billets in a crystallizer: the casting temperature is 1464°C, the superheat is 38°C, the pulling speed is 0.6 m / min, the water volume on the wide side of the crystallizer is 3500 L / min, and the water volume on the narrow side of the crystallizer is 400 L / min.

[0079] (3) The ingot was heated to 1250°C and kept at this temperature for 3 h. After the end of the holding period, the temperature was lowered to 1130°C for multiple rolling passes. The reduction in each pass was 8 mm. The final rolling temperature was 915°C. The final hot-rolled plate thickness was 10 mm. The ingot was air-cooled to room temperature to obtain high manganese non-magnetic steel.

[0080] (4) At room temperature, the high manganese non-magnetic steel obtained in the above steps is sampled and placed under an electron microscope to observe the metallographic structure. Figure 2 As shown in the figure, it can be seen that the structure of the steel is uniform everywhere, which is stable austenite and has "non-magnetic" characteristics.

[0081] (5) The mechanical properties of the high manganese non-magnetic structural steel coil prepared in the above steps were tested using industry standards. The tensile strength was 643 MPa, the yield strength was 354 MPa, the elongation was 58.5%, and the bending angle test sample was intact without any breakage.

[0082] Example 3

[0083] (1) The mass percentage of each element in high manganese non-magnetic structural steel is: C 0.17%, Si 0.42%, Mn22.4%, P0.02%, S 0.001%, V 0.077%, N 0.006%, Al 1.69%, and the rest is iron. The corresponding preparation raw materials are provided according to the chemical composition.

[0084] (2) The prepared raw materials are melted into molten iron, and the molten iron is cast into continuous casting billets in a crystallizer: the casting temperature is 1465°C, the superheat is 23°C, the pulling speed is 0.7m / min, the water volume on the wide side of the crystallizer is 3500L / min, and the water volume on the narrow side of the crystallizer is 400L / min.

[0085] (3) The ingot was heated to 1250°C and kept at this temperature for 3 h. After the end of the holding period, the temperature was lowered to 1130°C for multiple rolling passes. The reduction in each pass was 8 mm. The final rolling temperature was 1032°C. The final hot-rolled plate thickness was 10 mm. The ingot was air-cooled to room temperature to obtain high manganese non-magnetic steel.

[0086] (4) At room temperature, the high manganese non-magnetic steel obtained in the above steps is sampled and placed under an electron microscope to observe the metallographic structure. Figure 3 As shown in the figure, it can be seen that the structure of the steel is uniform everywhere, which is stable austenite and has "non-magnetic" characteristics.

[0087] (5) The high manganese non-magnetic structural steel coil obtained in the above steps was tested for mechanical properties using industry standards. The tensile strength was 654 MPa, the yield strength was 387 MPa, the elongation was 56%, and the bending angle test sample was intact without any breakage.

[0088] Example 4

[0089] (1) The mass percentage of each element in high manganese non-magnetic structural steel is: C 0.18%, Si 0.19%, Mn22.29%, P0.018%, S 0.003%, V 0.076%, N 0.007%, Al 1.61%, and the rest is iron. The corresponding preparation raw materials are provided according to the chemical composition.

[0090] (2) The prepared raw materials are melted into molten iron, and the molten iron is cast into continuous casting billets in a crystallizer: the casting temperature is 1473°C, the superheat is 49°C, the pulling speed is 0.65m / min, the water volume on the wide side of the crystallizer is 3500L / min, and the water volume on the narrow side of the crystallizer is 400L / min.

[0091] (3) The ingot was heated to 1250°C and kept at this temperature for 3 h. After the end of the holding period, the temperature was lowered to 1130°C for multiple rolling passes. The reduction in each pass was 8 mm. The final rolling temperature was 980°C. The final hot-rolled plate thickness was 10 mm. The ingot was air-cooled to room temperature to obtain high manganese non-magnetic steel.

[0092] (4) At room temperature, the high manganese non-magnetic steel obtained in the above steps is sampled and placed under an electron microscope to observe the metallographic structure. Figure 4 As shown in the figure, it can be seen that the structure of the steel is uniform everywhere, which is stable austenite and has "non-magnetic" characteristics.

[0093] (5) The high manganese non-magnetic structural steel coil obtained in the above steps was tested for mechanical properties using industry standards. The tensile strength was 576 MPa, the yield strength was 229 MPa, the elongation was 67%, and the bending angle test sample was intact without any breakage.

[0094] It can be seen from the test data of the above embodiments 1 to 4 that the high manganese non-magnetic structural steel material of the present application has high strength, good elongation and "non-magnetic" characteristics.

[0095] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0096] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A high manganese non-magnetic structural steel, characterized in that: Calculated by mass percentage, the high manganese non-magnetic structural steel includes: 0.16% to 0.19% C, 0.18% to 0.42% Si, 22.1% to 24.15% Mn, 0.0069% to 0.02% P, 0.0007% to 0.003% S, 0.065% to 0.077% V, 0.006% to 0.007% N, 1.6% to 2.06% Al, the remainder Fe and unavoidable impurity elements.

2. The high manganese non-magnetic structural steel according to claim 1, characterized in that: Calculated by mass percentage, the high manganese non-magnetic structural steel includes: 0.19% C, 0.18% Si, 24.15% Mn, 0.0069% P, 0.0007% S, 0.076% V, 0.006% N, 2.06% Al, the remainder Fe and inevitable impurity elements.

3. The high manganese non-magnetic structural steel according to any one of claims 1 to 2, characterized in that: Calculated by mass percentage, the high manganese non-magnetic structural steel comprises: 0.16% C, 0.29% Si, 22.1% Mn, 0.02% P, 0.001% S, 0.065% V, 0.007% N, 1.6% Al, the remainder Fe and inevitable impurity elements.

4. The high manganese non-magnetic structural steel according to any one of claims 1 to 2, characterized in that: Calculated by mass percentage, the high manganese non-magnetic structural steel includes: 0.17% C, 0.42% Si, 22.4% Mn, 0.02% P, 0.001% S, 0.077% V, 0.006% N, 1.69% Al, and the balance Fe and unavoidable impurity elements.

5. The high manganese non-magnetic structural steel according to any one of claims 1 to 2, characterized in that: Calculated by mass percentage, the high manganese non-magnetic structural steel includes: 0.18% C, 0.19% Si, 22.29% Mn, 0.018% P, 0.003% S, 0.076% V, 0.007% N, 1.61% Al, and the balance Fe and unavoidable impurity elements.

6. The method for preparing high manganese non-magnetic structural steel according to any one of claims 1 to 2, characterized in that: The thickness of the high manganese non-magnetic structural steel is 10 mm to 20 mm.

7. A method for preparing high manganese non-magnetic structural steel, characterized in that: The steps include: The raw materials are provided according to the stoichiometric ratio of the components of the high manganese non-magnetic structural steel according to any one of claims 1 to 6, and the raw materials are subjected to smelting, casting, heat preservation and rolling treatments in sequence to prepare the high manganese non-magnetic structural steel.

8. The method for preparing high manganese non-magnetic structural steel according to claim 7, characterized in that: The conditions of the smelting and casting treatment include: a casting temperature of 1465±10°C, a superheat of 23°C to 49°C, and a pulling speed of 0.6m / min to 0.7m / min; and / or The casting step of the smelting and casting process is carried out in a crystallizer, and the water volume on the wide side of the crystallizer is 3500±100L / min, and the water volume on the narrow side is 400L / min.

9. The method for preparing high manganese non-magnetic structural steel according to any one of claims 7 to 8, characterized in that: The temperature of the heat preservation treatment is 1250° C. and the time is 3 hours; and / or The rolling treatment steps include: performing multiple rolling passes at 1130°C to 1159°C, with a reduction of 8 mm in each pass, and a final rolling temperature of 900°C to 1032°C.

10. A mechanical structural part, characterized in that: The mechanical structural part comprises the high manganese non-magnetic structural steel as claimed in any one of claims 1 to 6 or the high manganese non-magnetic structural steel prepared by the preparation method of the high manganese non-magnetic structural steel as claimed in any one of claims 7 to 9.

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