A kind of high manganese steel and preparation method thereof

Abstract

The invention discloses a high manganese steel and a preparation method thereof, and belongs to the technical field of high manganese steel metallurgy. The cerium-containing high manganese steel of the invention comprises the following chemical components by mass percentage: C 0.69-0.71%, Mn 16.37-17.81%, Cr 6.84-6.69%, N 0.16-0.18%, Ce 0.010-0.025%, and the rest is Fe and inevitable impurities. The invention greatly improves the working properties such as yield strength, tensile strength, elongation and plastic toughness by adding an appropriate amount of rare earth element Ce to its high manganese steel scheme. The production process of the invention is simple, easier to implement in actual production, and has good application value.

Description

Technical Field

[0001] The invention relates to the technical field of high manganese steel metallurgy, in particular to high manganese steel and a preparation method thereof. Background Art

[0002] At present, high manganese steel is an indispensable and hugely used traditional metal material. It is widely used in fields closely related to national economic construction and people's lives, such as automobiles and railways. Improving the strength and plasticity of high manganese steel is an eternal topic in industrial applications.

[0003] Generally speaking, the strength and plasticity of high manganese steel are contradictory, and the increase in strength is always accompanied by the loss of plasticity, and vice versa. For example, the strength and hardness of high manganese steel can be greatly improved by cold rolling deformation, but its plasticity will drop sharply. Therefore, in industrial applications, most high manganese steels need to be annealed after cold rolling to reduce a certain strength to balance the lost plasticity. For another example, the strength of high manganese steel is increased by adding certain alloying elements to form a hard precipitate phase, but this will inevitably reduce plasticity. In addition, the heat treatment process required for rolling + annealing and the introduction of precipitate phases is relatively complex and delicate, and is difficult to control in large-scale industrial production. In view of these current problems, it is urgent to develop a high manganese steel that can improve both strength and plasticity and has a simple preparation process. Summary of the invention

[0004] The object of the present invention is to provide a high manganese steel and a preparation method thereof to solve the above-mentioned problems in the background technology. The present invention improves its working properties such as yield strength, tensile strength, elongation and plastic toughness to a great extent by adding an appropriate amount of rare earth element Ce to its high manganese steel scheme. The production process of the present invention is simple, easier to implement in actual production, and has good application value.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] One of the technical solutions of the present invention is to provide a cerium-containing high-manganese steel, which comprises the following chemical components by mass percentage:

[0007] C 0.69~0.71%, Mn 16.37~17.81%, Cr 6.84~6.69%, N 0.16~0.18%, Ce0.010~0.025%, and the rest are Fe and unavoidable impurities.

[0008] Preferably, the cerium-containing high manganese steel consists of the following chemical components in percentage by mass:

[0009] C 0.71%, Mn 17.16%, Cr 6.84%, N 0.17%, Ce 0.010%, and the rest are Fe and inevitable impurities.

[0010] The second technical solution of the present invention is to provide a method for preparing the above-mentioned cerium-containing high manganese steel, comprising the following steps:

[0011] Feed materials according to the design requirements of the chemical composition of steel and melt them into steel ingots;

[0012] Forging the steel ingot to obtain a forged rod;

[0013] The forged rod is subjected to a solid solution treatment to obtain the cerium-containing high-manganese steel.

[0014] Preferably, the forging comprises the following steps: heating at 1150° C. for 4 hours, final forging at 1050-1100° C. for 0.5-1 hour, and naturally cooling to obtain the forged rod.

[0015] Preferably, the solution treatment comprises the following steps: heating the forged rod at 1000-1100°C for 1 hour and then cooling it with water to 20-30°C.

[0016] After solid solution treatment, the matrix structure of the cerium-containing high-manganese steel prepared by the invention is single-phase austenite.

[0017] The beneficial technical effects of the present invention are as follows:

[0018] The present invention adds an appropriate amount of rare earth element Ce to its high manganese steel solution, thereby greatly improving its working properties such as yield strength, tensile strength, elongation and plastic toughness. The present invention obtains a high manganese steel with improved strength and plasticity at the same time by optimizing the chemical composition of the steel, which can meet the performance requirements of high manganese steel in more usage scenarios.

[0019] The production process of the invention is simple, easier to implement in actual production, and has good application value. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0021] Figure 1 The following are scanned photos of the high manganese steel in Examples 1-2 and Comparative Example 1. (a) is 00Ce-1000, (b) is 00Ce-1050, (c) is 00Ce-1100, (d) is 10Ce-1000, (e) is 10Ce-1050, (f) is 10Ce-1100, (g) is 25Ce-1000, (h) is 25Ce-1050, and (i) is 25Ce-1100. DETAILED DESCRIPTION

[0022] Now, various exemplary embodiments of the present invention are described in detail, and this detailed description should not be considered as a limitation of the present invention, but should be understood as a more detailed description of certain aspects, characteristics and embodiments of the present invention. It should be understood that the terms described in the present invention are only for describing specific embodiments and are not used to limit the present invention.

[0023] In addition, for the numerical range in the present invention, it is understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. The intermediate value in any stated value or stated range, and each smaller range between any other stated value or intermediate value in the range is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded in the scope.

[0024] Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which the invention pertains. Although only preferred methods and materials are described herein, any methods and materials similar or equivalent to those described herein may also be used in the practice or testing of the present invention.

[0025] The words “include,” “including,” “have,” “contain,” etc. used in the present invention are open-ended terms, meaning including but not limited to.

[0026] The "room temperature" in the present invention is 20-30°C unless otherwise specified.

[0027] All raw materials used in the following examples and comparative examples of the present invention are commercially available products.

[0028] Example 1

[0029] Ce-containing high manganese steel consists of the following chemical components in percentage by mass:

[0030] C 0.71%, Mn 17.16%, Cr 6.84%, N 0.17%, Ce 0.010%, P<0.005%, S<0.003%, and the rest are Fe and unavoidable impurities.

[0031] Preparation of cerium-containing high manganese steel:

[0032] (1) The steel is charged according to the design requirements of the chemical composition, smelted in a vacuum induction furnace and cast into a 75 kg steel ingot.

[0033] (2) The steel ingot was heated to 1150°C and kept at that temperature for 4 hours, and then final forged at 1050°C for 1 hour to finally be forged into a square bar of 50×50 mm.

[0034] (3) The square rod obtained in the previous step was placed in a heat treatment furnace at 1000° C. for solution treatment for 1 h, and then water-cooled to room temperature to obtain cerium-containing high-manganese steel (denoted as 10Ce-1000).

[0035] The above operation was repeated except that only the temperature of the solution treatment was adjusted to 1050° C. and 1100° C. to obtain cerium-containing high-manganese steels 10Ce-1050 and 10Ce-1100.

[0036] Example 2

[0037] Ce-containing high manganese steel consists of the following chemical components in percentage by mass:

[0038] C 0.69%, Mn 17.81%, Cr 6.96%, N 0.18%, Ce 0.025%, and the rest are Fe and inevitable impurities.

[0039] Preparation of cerium-containing high manganese steel:

[0040] (1) The steel is charged according to the design requirements of the chemical composition, smelted in a vacuum induction furnace and cast into a 75 kg steel ingot.

[0041] (2) The steel ingot was heated to 1150°C and kept at this temperature for 4 hours, and then final forged at 1050°C for 1 hour to finally be forged into a square bar of 50×50 mm.

[0042] (3) The square rod obtained in the previous step was placed in a heat treatment furnace at 1000° C. for solution treatment for 1 h, and then water-cooled to room temperature to obtain cerium-containing high-manganese steel (denoted as 25Ce-1000).

[0043] The above operation was repeated with only the temperature of the solution treatment being adjusted to 1050° C. and 1100° C. to obtain cerium-containing high-manganese steels 25Ce-1050 and 25Ce-1100.

[0044] Comparative Example 1

[0045] High manganese steel consists of the following chemical components in mass percentage:

[0046] C 0.70%, Mn 16.36%, Cr 6.96%, N 0.16%, and the rest are Fe and inevitable impurities.

[0047] Preparation of high manganese steel:

[0048] (1) The steel is charged according to the design requirements of the chemical composition, smelted in a vacuum induction furnace and cast into a 75 kg steel ingot.

[0049] (2) The steel ingot was heated to 1150°C and kept at this temperature for 4 hours, and then final forged at 1050°C for 1 hour to finally be forged into a square bar of 50×50 mm.

[0050] (3) The square rod obtained in the previous step was placed in a heat treatment furnace at 1000° C. for solution treatment for 1 h, and then water-cooled to room temperature to obtain high manganese steel (denoted as 00Ce-1000).

[0051] The above operation was repeated with only the temperature of the solution treatment being adjusted to 1050°C and 1100°C to obtain high manganese steels 00Ce-1050 and 00Ce-1100.

[0052] Effect verification

[0053] (1) According to the standard GB / T 228.1-2010, the room temperature tensile properties of the above high manganese steel after solution treatment were tested. The specific test data are shown in Table 1.

[0054] Table 1 Room temperature tensile properties of experimental steel after solution treatment at different temperatures

[0055] serial number Solution temperature / ℃ Yield strength / MPa Tensile strength / MPa Elongation / % 00Ce-1000 1000 478 1061 46 00Ce-1050 1050 469 1050 58 00Ce-1100 1100 451 1046 65 10Ce-1000 1000 545 1118 63 10Ce-1050 1050 527 1045 71 10Ce-1100 1100 524 1029 72 25Ce-1000 1000 545 1066 52 25Ce-1050 1050 491 1026 67 25Ce-1100 1100 468 1017 68

[0056] As shown in Table 1, after being treated in a wide solution temperature range (1000-1100°C), the yield strength of the high manganese steel containing 0.010% Ce prepared by the present invention is 524-545MPa, the tensile strength is 1029-1118MPa, and the elongation is 63-72%, and its performance is better than that of the high manganese steel without Ce and the high manganese steel containing 0.025% Ce. It can be seen that the addition of 0.010% Ce to the high manganese steel by the present invention simultaneously improves its yield strength, tensile strength and elongation, and its heat treatment process parameter range is wide, which is convenient for large-scale industrial production.

[0057] (2) The microstructure of the high manganese steel was observed. The results are as follows Figure 1 shown.

[0058] Figure 1 The following are scanned photos of the high manganese steel in Examples 1-2 and Comparative Example 1. (a) is 00Ce-1000, (b) is 00Ce-1050, (c) is 00Ce-1100, (d) is 10Ce-1000, (e) is 10Ce-1050, (f) is 10Ce-1100, (g) is 25Ce-1000, (h) is 25Ce-1050, and (i) is 25Ce-1100.

[0059] By observation Figure 1In the high manganese steel of Example 1, it can be observed that after solution treatment at 1000°C, there are more precipitates on its grain boundaries; after solution treatment at 1050°C, precipitates can still be observed, but there is a significant reduction; after solution treatment at 1100°C, almost no precipitates are observed, that is, the precipitates are basically eliminated. By observing the high manganese steel of Example 2, it can be observed that after solution treatment at 1000°C, there are more precipitates on its grain boundaries, and the grain boundaries are more obvious; after solution treatment at 1050°C, there are still precipitates on its surface, but the number is significantly reduced; the morphologies after solution treatment at 1100°C and 1050°C are similar, and there are fewer precipitates.

[0060] (3) The above high manganese steel was subjected to room temperature impact test. The results are shown in Table 2.

[0061] Table 2 Impact toughness of the test steel after solution treatment (J / cm 2 )

[0062] 00Ce-1100 10Ce-1100 25Ce-1100 1000℃ 96 117 65 1050℃ 179 183 170 1100℃ 247 258 237

[0063] As shown in Table 2, after solution treatment in a wide temperature range (1000-1100°C), the impact toughness of the high manganese steel containing 0.010% Ce prepared by the present invention is 117-258 J / cm 2 Its plasticity and toughness are better than high manganese steel without Ce and high manganese steel containing 0.025% Ce. It has higher toughness and resistance to crack propagation, which improves the safety and reliability of high manganese steel materials.

[0064] The embodiments described above are only descriptions of the preferred modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. A cerium-containing high manganese steel, characterized in that: It is composed of the following chemical components in mass percentage: C 0.71%, Mn 17.16%, Cr 6.84%, N 0.17%, Ce 0.010%, the rest is Fe and unavoidable impurities; The method for preparing the cerium-containing high-manganese steel comprises the following steps: Feed materials according to the design requirements of the chemical composition of steel and melt them into steel ingots; Forging the steel ingot to obtain a forged rod; Performing a solution treatment on the forged rod to obtain the cerium-containing high-manganese steel; The cerium-containing high-manganese steel has a yield strength of 524-545 MPa, a tensile strength of 1029-1118 MPa, an elongation of 63-72%, and an impact toughness of 117-258 J / cm 2 .

2. The cerium-containing high manganese steel according to claim 1, characterized in that: The forging comprises the following steps: heating at 1150° C. for 4 hours, final forging at 1050-1100° C. for 0.5-1 hour, and naturally cooling to obtain the forged rod.

3. The cerium-containing high manganese steel according to claim 1, characterized in that: The solution treatment comprises the following steps: heating the forged rod at 1000-1100° C. for 1 hour and then cooling the rod to 20-30° C. with water.

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