A kind of crack-resistant high manganese steel and preparation method thereof

Abstract

The present invention discloses a crack-resistant high manganese steel, wherein the raw materials include by weight: C 0.7-0.8%, Mn 11-12%, Cr 1.7-1.9%, Si 0.3-0.7%, Mo 0.3-0.35%, N 0.1-0.11%, Ce0.01-0.02%, P <0.01%, S <0.01% and Ti, Nb, and the remainder is Fe and unavoidable impurities; wherein the sum of the weight percentages of Ti and Nb is 0.2-0.25%. The present invention also discloses a preparation method of the above-mentioned crack-resistant high manganese steel, comprising the following steps: taking each raw material for smelting, casting to obtain a billet having a composition such as the above-mentioned crack-resistant high manganese steel; then austenitizing, quenching, aging, and obtaining the crack-resistant high manganese steel. The present invention has good toughness and hardness, and good crack resistance.

Description

Technical Field

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

[0002] As a wear-resistant steel with excellent toughness and work hardening properties, high manganese steel is widely used in parts under high stress impact load abrasive wear conditions in metallurgy, construction, coal industry, etc. So far, there is no material that can completely replace high manganese steel.

[0003] The microstructure of high manganese steel is generally composed of a matrix (austenite) and a strengthening phase (carbide) that is harder and more brittle than the matrix. Under large impact loads or contact stresses, its working surface layer can produce work hardening, thereby improving wear resistance, while the core still maintains high plasticity and toughness, making high manganese steel have good comprehensive properties, so it is widely used in the manufacture of wear-resistant workpieces. However, the cast structure of high manganese steel often has coarse grains, and carbides are mainly distributed along the austenite grain boundaries in a continuous network form, resulting in low toughness, easy to produce stress concentration, cracking and other problems. Summary of the invention

[0004] Based on the technical problems existing in the background technology, the present invention proposes a crack-resistant high manganese steel and a preparation method thereof. The present invention has good toughness and hardness and good crack resistance.

[0005] The invention provides a crack-resistant high manganese steel, wherein the raw materials thereof include, by weight percentage: C 0.7-0.8%, Mn 11-12%, Cr 1.7-1.9%, Si 0.3-0.7%, Mo 0.3-0.35%, N 0.1-0.11%, Ce 0.01-0.02%, P < 0.01%, S < 0.01% and Ti, Nb, and the balance is Fe and unavoidable impurities;

[0006] The total weight percentage of Ti and Nb is 0.2-0.25%.

[0007] Preferably, the weight ratio of Ti to Nb is 1:3-4.

[0008] Preferably, the raw materials include by weight percentage: C 0.75%, Mn 12%, Cr 1.8%, Si 0.5%, Mo0.33%, N 0.1%, Ce 0.015%, P < 0.01%, S < 0.01% and Ti, Nb, and the balance is Fe and unavoidable impurities;

[0009] The total weight percentage of Ti and Nb is 0.25%.

[0010] The present invention also proposes a preparation method of the above-mentioned crack-resistant high manganese steel, comprising the following steps: melting various raw materials, casting to obtain a billet with the composition of the above-mentioned crack-resistant high manganese steel; then austenitizing, quenching, and aging to obtain the crack-resistant high manganese steel.

[0011] Preferably, the casting temperature is 1440-1460°C.

[0012] Preferably, the austenitizing procedure is: heating to 660-680° C., keeping the temperature for 1.5-2 hours, then heating to 1200-1250° C., keeping the temperature for 1.5-2 hours.

[0013] Preferably, the aging temperature is 300-350°C and the insulation time is 12-18h.

[0014] Preferably, quenching is performed with water.

[0015] The present invention selects Ti and Nb with appropriate contents to form carbonitrides with C and N. The present invention adjusts the ratio of Ti and Nb and the austenitization procedure so that TiN precipitates in austenite crystals at high temperature, and then partially wraps Nb on the surface of TiN to form carbonitrides, and inhibits the coarsening of carbonitrides, thereby improving hardness and wear resistance; the remaining Nb forms carbonitrides and is distributed in scattered points at austenite grain boundaries, inhibiting the growth of crystals; the combination of the two can avoid the problem that all Nb is distributed at the grain boundaries to form large strips, which is prone to stress concentration, resulting in reduced toughness and cracking; and the rare earth Ce can preferentially react with O and S to form inclusions distributed around the grain boundaries to further block Nb carbonitrides, Mo carbides, and Cr carbides from forming strips and networks, further improving toughness, and the inclusions and Nb carbonitrides around the grain boundaries can prevent grain growth, and further improve toughness; and an appropriate amount of Mo combined with a suitable aging process can make the carbonitrides evenly distributed, thereby achieving simultaneous improvement of wear resistance and toughness. DETAILED DESCRIPTION

[0016] The technical solution of the present invention is described in detail below through specific embodiments.

[0017] High manganese steel was prepared according to the formulas of Examples 1-3 and Comparative Examples 1-4. The formulas of each group are shown in Table 1.

[0018] Table 1 Formula of Examples 1-3 and Comparative Examples 1-4

[0019] Element C Mn Cr Si Mo N Ce Ti Nb Ti / Nb Example 1 0.7 11.5 1.7 0.7 0.3 0.11 0.01 0.05 0.15 1:3 Example 2 0.8 11 1.9 0.3 0.35 0.1 0.02 0.05 0.175 1:3.5 Example 3 0.75 12 1.8 0.5 0.33 0.1 0.015 0.05 0.2 1:4 Comparative Example 1 0.75 12 1.8 0.5 0.33 0.1 0.015 0.035 0.215 1:6 Comparative Example 2 0.75 12 1.8 0.5 0.33 0.1 0.015 0.08 0.17 1:2 Comparative Example 3 0.75 12 1.8 0.5 / 0.1 0.015 0.05 0.2 1:4 Comparative Example 4 0.75 12 1.8 0.5 0.33 0.1 / 0.05 0.2 1:4

[0020] Note: The units of the ingredients in Table 1 are weight percentages. In each group of formulas, P < 0.01%, S < 0.01%, and the balance is Fe.

[0021] The preparation methods of the above-mentioned embodiments 1-3 and comparative examples 1-4 are the same, comprising the following steps: melting the raw materials, casting at 1450°C to obtain a billet having the composition as described in Table 1; then heating to 670°C, keeping warm for 1.5 hours, then heating to 1200°C and keeping warm for 1.5 hours, quenching with water, heating to 320°C and keeping warm for 18 hours to obtain crack-resistant high manganese steel.

[0022] Comparative Example 5

[0023] A crack-resistant high manganese steel, whose raw material formula is the same as that of Example 3.

[0024] The preparation method of the above-mentioned crack-resistant high manganese steel includes the following steps: taking various raw materials for melting, casting at 1450°C to obtain a billet with the composition of the above-mentioned crack-resistant high manganese steel; then heating to 1200°C and keeping it for 1.5 hours, quenching with water, heating to 320°C and keeping it for 18 hours to obtain the crack-resistant high manganese steel.

[0025] The crack-resistant high manganese steels prepared in Examples 1-3 and Comparative Examples 1-5 were tested for performance, and the results are shown in Table 2.

[0026] Table 2 Test results

[0027]

[0028]

[0029] It can be seen from Table 2 that the high manganese steel of the present invention has good hardness, wear resistance and toughness.

[0030] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A crack-resistant high manganese steel, characterized in that: The raw materials include, by weight percentage: C 0.7-0.8%, Mn 11-12%, Cr 1.7-1.9%, Si 0.3-0.7%, Mo 0.3-0.35%, N 0.1-0.11%, Ce0.01-0.02%, P < 0.01%, S < 0.01% and Ti, Nb, and the balance is Fe and unavoidable impurities; The total weight percentage of Ti and Nb is 0.2-0.25%.

2. The crack-resistant high manganese steel according to claim 1, characterized in that: The weight ratio of Ti to Nb is 1:3-4.

3. The crack-resistant high manganese steel according to claim 1 or 2, characterized in that: The raw materials include by weight percentage: C0.75%, Mn 12%, Cr 1.8%, Si 0.5%, Mo 0.33%, N 0.1%, Ce 0.015%, P < 0.01%, S < 0.01% and Ti, Nb, and the balance is Fe and unavoidable impurities; The total weight percentage of Ti and Nb is 0.25%.

4. A method for preparing the crack-resistant high manganese steel according to any one of claims 1 to 3, characterized in that: The method comprises the following steps: melting various raw materials, casting to obtain a billet of crack-resistant high manganese steel having a composition as claimed in any one of claims 1 to 3; and then austenitizing, quenching and aging to obtain the crack-resistant high manganese steel.

5. The method for preparing crack-resistant high manganese steel according to claim 4, characterized in that: The casting temperature is 1440-1460℃.

6. The method for preparing crack-resistant high manganese steel according to claim 4 or 5, characterized in that: The austenitizing procedure is: heating to 660-680°C, keeping warm for 1.5-2h, then heating to 1200-1250°C, keeping warm for 1.5-2h.

7. The method for preparing the crack-resistant high manganese steel according to any one of claims 4 to 6, characterized in that: The aging temperature is 300-350℃, and the insulation time is 12-18h.

8. The method for preparing the crack-resistant high manganese steel according to any one of claims 4 to 7, characterized in that: Quench with water.

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