High-manganese steel powder for preparing wear-resistant coating through laser cladding and preparation method of high-manganese steel powder

Abstract

The invention discloses high-manganese steel powder for preparing a wear-resistant coating through laser cladding and a preparation method of the high-manganese steel powder, and the high-manganese steel powder comprises the components of C, Mn, Si, Mo, S, P and the balance Fe. When the alloy powder is subjected to laser cladding, water cooling and hammering are not needed in the process, continuous and high-quality cladding can be conducted, network cementite cannot be separated out, and the machining efficiency is high; the alloy powder has good laser cladding process performance, and a prepared high manganese steel coating is not prone to cracking, uniform in structure, good in hardening performance and wear resistance and capable of well achieving continuous repairing of large parts.

Description

Technical Field

[0001] The invention relates to high manganese steel powder, in particular to high manganese steel powder for preparing wear-resistant coating by laser cladding and a preparation method thereof, belonging to the technical field of laser cladding material preparation. Background Art

[0002] As a key supporting facility for railway transportation, higher requirements are placed on large basic parts such as railway turnouts and rails. For example, the frog is a key component of the railway turnout system. It is a plane crossing device that allows the wheels to pass from one rail to another. It is the component with the worst service conditions and the highest loss in the track system. Therefore, improving the performance of the frog by preparing a wear-resistant coating is of utmost importance.

[0003] High manganese steel has good deformation hardening ability. It will harden quickly under strong impact loads, increase the surface hardness, while maintaining good toughness inside. It is widely used in mining machinery, railways, metallurgy, building materials and other fields. Traditional arc welding using high manganese steel welding wire to repair large high manganese steel parts often uses low current, low speed, and intermittent welding. Water cooling and hammering are also required in the middle to reduce carbide precipitation and residual tensile stress. The welding efficiency is low and the welding quality is poor.

[0004] Laser cladding is an advanced surface coating technology for repairing metal products. The laser beam is used to heat the metal material to above the melting point, and the cladding material is added to melt it and fuse it with the workpiece, finally forming a cladding layer with good metallurgical bonding and excellent performance. In the prior art, an alloy powder for surface repair of high manganese steel disclosed in publication number CN109351958A includes the following components in mass percentage: 0.7-1.2% C, 0.2-0.6% Si, 1.5-4.5% Mn, 2-4% Ti, 5.0-9.0% Ni, 10.0-15.0% Cr, 4.0-8.0% Mo, and Fe as the balance, and is prepared by inert gas atomization after smelting in a medium frequency induction furnace. However, the high manganese steel powder prepared by the prior art does not involve the content of P and S in the composition: the P element will form a low-melting point eutectic in the steel, resulting in a sharp decrease in the plasticity and toughness of the steel at room temperature; and the S element exists in the steel in the form of iron sulfide (FeS), forming a low-melting point eutectic with iron. When the steel is hot-processed at high temperature, these eutectics melt, causing the steel to become brittle. Therefore, how to reduce the content of S and P elements as much as possible so that the high manganese steel alloy powder can further enhance the strength of the austenite matrix is ​​a problem that people in this field need to study. Based on this, the present application proposes a high manganese steel powder for laser cladding to prepare a wear-resistant coating and a preparation method thereof. Summary of the invention

[0005] The purpose of the present invention is to provide a high manganese steel powder and a preparation method thereof for laser cladding to prepare a wear-resistant coating in order to solve at least one of the above technical problems.

[0006] The present invention achieves the above-mentioned object through the following technical scheme: a high manganese steel powder for preparing a wear-resistant coating by laser cladding, comprising high manganese steel powder, wherein the components of the high manganese steel powder include C, Mn, Si, Mo, S, P, and the balance is Fe;

[0007] The components of the high manganese steel powder are respectively C: 0.8-1.2wt%; Mn: 11.0-16.0wt%; Si: 0.3-0.8wt%; Mo: 0.3-1.5wt%; S≤0.06wt%; P≤0.06wt%; and the balance is Fe.

[0008] As a further solution of the present invention: high manganese steel powder is prepared by vacuum induction melting and gas atomization.

[0009] A method for preparing high manganese steel powder for preparing wear-resistant coating by laser cladding, comprising high manganese steel powder, and the method for preparing high manganese steel powder comprises the following steps:

[0010] S1. Weigh the raw materials according to the ratio of each element and load them into the crucible of the vacuum induction melting furnace in a certain order;

[0011] S2. Before smelting, the smelting chamber and atomizing chamber of the vacuum induction melting furnace are first subjected to vacuum treatment, and then inert gas is introduced and electrically heated to a certain temperature for refining, so that all metals in the raw materials are completely melted;

[0012] S3, pouring the alloy melt in step S1 into a tundish, flowing out from a nozzle under the tundish, and atomizing the inert gas through an atomizer in an atomizing chamber to form solid particles of the alloy melt, which are then collected;

[0013] S4, the solid particles collected in step S3 are screened by a vibration sieving method to obtain a powder with a desired particle size.

[0014] As a further solution of the present invention: in step S1, after the other raw materials are melted, the materials Mn and Si are added for a second time.

[0015] As a further solution of the present invention: in step S1, the furnace capacity of the vacuum induction melting furnace is 50 kg.

[0016] As a further solution of the present invention: in step S1, the crucible is made of corundum.

[0017] As a further solution of the present invention: in step S2, the inert gas introduced is high-purity argon.

[0018] As a further solution of the present invention: in step S2, the superheat of the molten metal obtained after refining by electric heating is 150-170°C, and the refining temperature after the alloy is melted into the molten metal is maintained at 1480-1520°C; the refining time is 8±2min.

[0019] As a further solution of the present invention: in step S3, the maximum number of times of the atomizer is 18 times; the atomization pressure is 2.5-3.5 MPa; the temperature of the alloy melt is maintained at 1580-1620°C when it is taken out of the furnace.

[0020] As a further solution of the present invention: in step S4, the particle size of the powder obtained by screening is 45 to 105 microns.

[0021] The beneficial effects of the present invention are:

[0022] 1) The powder of the present invention has good laser cladding process performance. The large-area cladding layer prepared by using the powder has the advantages of high hardness, wear resistance, and not easy to crack after hardening treatment;

[0023] 2) The powder composition disclosed in the present invention contains only a very small amount of S and P. By reducing the content of S and P elements, the plasticity and toughness of the steel at room temperature can be prevented from being sharply reduced; and the steel can be prevented from becoming brittle when hot-worked at high temperatures;

[0024] 3) When the alloy powder disclosed in the present invention is subjected to laser cladding, water cooling and hammering are not required in the middle, and continuous, high-quality cladding can be performed without precipitation of network cementite, and the processing efficiency is high; it has good laser cladding process performance, and the prepared high manganese steel coating is not easy to crack, has uniform structure, has good hardening performance and wear resistance, and can well realize continuous repair of large parts. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a schematic diagram of the powder surface morphology under an electron microscope of the present invention;

[0026] Figure 2 It is a schematic diagram of the cross-sectional morphology of the cladding layer of the present invention. DETAILED DESCRIPTION

[0027] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0028] Embodiment 1, a high manganese steel powder for preparing a wear-resistant coating by laser cladding, comprising high manganese steel powder, wherein the components of the high manganese steel powder include C, Mn, Si, Mo, S, P, and the balance is Fe;

[0029] The components of the high manganese steel powder are respectively C: 0.8-1.2wt%; Mn: 11.0-16.0wt%; Si: 0.3-0.8wt%; Mo: 0.3-1.5wt%; S≤0.06wt%; P≤0.06wt%; and the balance is Fe.

[0030] The addition of C element increases the stacking fault energy of austenite and plays a significant role in solid solution strengthening to enhance the strength of austenite matrix.

[0031] Mo is an element that stabilizes austenite. Mo in a solid solution state tends to be concentrated at the grain boundary, reducing the grain boundary energy and improving the thermal strength of high manganese steel.

[0032] Mn element can form infinite substitution solid solution in austenite; in addition, the interaction between C and Mn elements can form C-Mn strong bond complex atomic pairs, which is beneficial to improve the work hardening ability of high manganese steel;

[0033] Si is a ferrite-forming element and can inhibit the transformation from austenite to martensite, increase the austenite transformation temperature and expand the dual-phase region; and Si has a high degree of solid solution strengthening in both ferrite and austenite;

[0034] The P element will form a low-melting eutectic in steel, resulting in a sharp decrease in the plasticity and toughness of the steel at room temperature; the S element exists in the form of iron sulfide (FeS) in steel and forms a low-melting eutectic with iron. When the steel is hot-processed at high temperature, these eutectics melt, causing the steel to become brittle, so efforts should be made to reduce the content of S and P elements; the content of P and S elements in the high manganese steel powder provided by the present invention is both below 0.06wt%.

[0035] High manganese steel powder is prepared by vacuum induction melting and gas atomization.

[0036] Embodiment 2, a method for preparing high manganese steel powder for preparing wear-resistant coating by laser cladding, comprising high manganese steel powder, the method for preparing high manganese steel powder comprising the following steps:

[0037] S1. Weigh the raw materials according to the ratio of each element and load them into the crucible of the vacuum induction melting furnace in a certain order;

[0038] S2. Before smelting, the smelting chamber and atomizing chamber of the vacuum induction melting furnace are first subjected to vacuum treatment, and then inert gas is introduced and electrically heated to a certain temperature for refining, so that all metals in the raw materials are completely melted;

[0039] S3, pouring the alloy melt in step S1 into a tundish, flowing out from a nozzle under the tundish, and atomizing the inert gas through an atomizer in an atomizing chamber to form solid particles of the alloy melt, which are then collected;

[0040] S4, the solid particles collected in step S3 are screened by a vibration sieving method to obtain a powder with a desired particle size.

[0041] In step S1, after other raw materials are melted, materials Mn and Si are added for the second time. The capacity of the vacuum induction melting furnace is 50 kg. The crucible is made of corundum.

[0042] In step S2, the inert gas introduced is high-purity argon. The superheat of the molten metal obtained after the heating by electric heating for refining is 150-170°C, and the refining temperature after the alloy is melted into the molten metal is maintained at 1480-1520°C; the refining time is 8±2min.

[0043] In step S3, the maximum number of atomizers is 18 times; the atomization pressure is 2.5-3.5 MPa; the temperature of the alloy melt is maintained at 1580-1620° C. The particle size of the powder obtained by screening is 45-105 μm.

[0044] Embodiment three, as Figure 1 and 2 As shown, a method for preparing high manganese steel powder for preparing wear-resistant coating by laser cladding, raw materials are weighed according to the following mass percentages: C ~ 1.06wt%, Mn ~ 14.34wt%, Si ~ 0.61wt%, Mo ~ 1.37wt%, Fe ~ 82.63wt%;

[0045] First, put the weighed raw materials into the crucible of the smelting chamber for smelting. Before starting, evacuate the smelting chamber and then inject argon gas to normal pressure. Then start power smelting and heat to 1520℃ to completely melt the material. Then pour the molten metal in the crucible into the tundish. The molten metal flows out from the nozzle under the tundish and is impacted into small droplets by high-speed argon gas. It is then cooled in the cooling chamber to form solid particles, which are collected in the powder collecting tank. Under the protection of high-purity argon gas, the vibrating powder screening method is used to screen out metal powder particles with a particle size of 45 to 105 microns. The fluidity of the metal powder is then measured with a Hall flowmeter, which is 16.75s / 50g. The loose density of the metal powder is tested with an intelligent powder property tester, which is 4.89g / cm 3 ; Figure 1 The surface morphology of the powder under electron microscope.

[0046] Alloy powder with a diameter of 45 to 105 microns was selected, and a cladding layer was obtained on a 16Mn steel plate with laser parameters set to 2600 W, a scanning speed of 8 mm / s, and a defocusing amount of 13 mm. Figure 2 This is the cross-sectional morphology of the cladding layer. After ultrasonic rolling, the hardness reaches 794.24HV.

[0047] The wear resistance of the cladding layer obtained in the above experiment was measured using an MPX-3X wear tester. The friction condition was dry sliding friction, the applied load was 100N, the speed was 240r / min, and the test time was 30min. The wear scar profile was measured using an OLYMPUSDSX1000 ultra-depth digital microscope. The wear rate was calculated. The experimental results are as follows:

[0048] The wear rate of 16Mn steel plate is 4.571×10 -5 mm 3 / N·m, the wear rate of the cladding layer is 8.01×10 -4 mm 3 / N·m, the wear rate of the cladding layer after ultrasonic rolling treatment is 3.14×10 -4 mm 3 / N·m.

[0049] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations falling within the meaning and scope of the equivalent elements of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

[0050] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A high manganese steel powder for preparing a wear-resistant coating by laser cladding, comprising high manganese steel powder, characterized in that: The components of the high manganese steel powder include C, Mn, Si, Mo, S, P, and the balance is Fe; The components of the high manganese steel powder are respectively C: 0.8-1.2wt%; Mn: 11.0-16.0wt%; Si: 0.3-0.8wt%; Mo: 0.3-1.5wt%; S≤0.06wt%; P≤0.06wt%; the balance is Fe.

2. The high manganese steel powder according to claim 1, characterized in that: The high manganese steel powder is prepared by vacuum induction melting and gas atomization.

3. A method for preparing high manganese steel powder for preparing wear-resistant coating by laser cladding, comprising the high manganese steel powder according to any one of claims 1 to 2, characterized in that: The preparation method comprises the following steps: S1. Weigh the raw materials according to the ratio of each element, and load them into the crucible of the vacuum induction melting furnace in order; S2. Before smelting, the smelting chamber and atomizing chamber of the vacuum induction melting furnace are first subjected to vacuum treatment, and then inert gas is introduced and electrically heated to a certain temperature for refining, so that all metals in the raw materials are completely melted; S3, pouring the alloy melt in step S1 into a tundish, flowing out from a nozzle under the tundish, and atomizing the inert gas through an atomizer in an atomizing chamber to form solid particles of the alloy melt, which are then collected; S4, the solid particles collected in step S3 are screened by a vibration sieving method to obtain a powder with a desired particle size.

4. The preparation method according to claim 3, characterized in that: In the step S1, after the other raw materials are melted, the materials Mn and Si are added for the second time.

5. The preparation method according to claim 4, characterized in that: In the step S1, the capacity of the vacuum induction melting furnace is 50 kg.

6. The preparation method according to claim 5, characterized in that: In the step S1, the crucible is made of corundum.

7. The preparation method according to claim 6, characterized in that: In step S2, the inert gas introduced is high-purity argon.

8. The preparation method according to claim 7, characterized in that: In the step S2, the superheat of the molten metal obtained after refining by electric heating is 150-170°C, and the refining temperature after the alloy is melted into the molten metal is maintained at 1480-1520°C; the refining time is 8±2min.

9. The preparation method according to claim 8, characterized in that: In step S3, the maximum number of times of the atomizer is 18 times; the atomization pressure is 2.5-3.5 MPa; and the temperature of the alloy melt is maintained at 1580-1620° C. when it is discharged from the furnace.

10. The preparation method according to claim 9, characterized in that: In step S4, the powder particle size obtained by screening is 45 to 105 microns.

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