Laser Welding Method for Alloy Chip Sintered Body

Abstract

The present invention relates to a laser welding method for an alloy particle sintered body, and relates to the technical field of welding. The laser welding method for the alloy particle sintered body of the present invention comprises the following steps: (1) providing an alloy particle sintered body with a transition layer formed on the surface; and the raw material composition of the transition layer is Fe: 45-60 wt.%, Mn: 2-5 wt.%, and the balance is copper and inevitable impurities; (2) oppositely arranging the transition layer and a steel matrix, and forming a composite body by laser welding. The laser welding method of the present invention can ensure extremely high welding strength, and the appearance of the weld seam is smooth and continuous, without welding defects such as holes and depressions; and expensive metal materials such as Co are not used, so it has good economic performance and practical prospects.

Description

Technical Field

[0001] The present invention relates to the technical field of welding, and more specifically, the present invention relates to a laser welding method for an alloy particle sintered body. Background Art

[0002] In the prior art, an alloy particle sintered body is generally welded to a substrate by processes such as brazing and laser welding. However, the brazing process requires integrally sintering and forming the alloy particle material and the metal substrate, and the forming process is complex, resulting in low efficiency; while for laser welding, expensive Co is usually required, which limits the application of the laser welding process. Summary of the Invention

[0003] In order to solve the above technical problems existing in the prior art, the purpose of the present invention is to provide a laser welding method for an alloy particle sintered body.

[0004] A laser welding method for an alloy particle sintered body, characterized by comprising the following steps:

[0005] (1) Providing an alloy particle sintered body with a transition layer formed on its surface; and the raw material composition of the transition layer is Fe: 45 - 60 wt.%, Mn: 2 - 5 wt.%, and the balance is copper and inevitable impurities;

[0006] (2) Oppositely arranging the transition layer and a steel substrate, and forming a composite body by laser welding.

[0007] Among them, the bending strength of the laser weld formed by the laser welding is greater than 2200 MPa.

[0008] Among them, the thickness of the transition layer is 1.0 - 2.0 mm.

[0009] Among them, the raw material composition of the transition layer is Fe: 45 - 55 wt.%, Mn: 2 - 4 wt.%, and the balance is copper and inevitable impurities.

[0010] Among them, the content of C in the raw material composition of the transition layer is < 0.10 wt.%.

[0011] Among them, the process parameters of the laser welding are: performing double-sided laser welding with a laser, the laser spot diameter is 0.3 mm, the laser power is 700 - 730 W, the welding speed is 10 - 16 mm / s; the shielding gas is argon, the shielding gas flow rate is 0.5 L / min, the defocus amount is 1.2 - 1.8 mm, the laser beam is biased towards the substrate side, the offset amount is 0.2 - 0.4 mm, the laser incident angle is 12 - 14°, the weld width is 1 - 1.3 mm, and the penetration depth is 2 - 2.4 mm.

[0012] Among them, the thickness of the alloy particle sintered body is greater than that of the steel matrix. For example, the thickness of the hard alloy particle cutter head is 1.2 to 2.0 times, preferably 1.3 to 1.6 times, the thickness of the steel matrix.

[0013] Among them, the steel matrix is 65Mn.

[0014] Among them, the alloy particle sintered body is formed by cold pressing hard alloy particles and metal powder into a blank, and the blank is formed by hot pressing sintering.

[0015] The second aspect of the present invention also relates to a composite body obtained by the laser welding method of the above alloy particle sintered body.

[0016] Among them, the composite body is a cutting tool.

[0017] Compared with the prior art, the laser welding method of the alloy particle sintered body of the present invention has the following beneficial effects:

[0018] The laser welding method of the present invention can ensure extremely high welding strength, and the appearance of the weld is smooth and continuous, without welding defects such as holes and depressions; and expensive metal materials such as Co are not used, which is economical and has good practical prospects. Description of the Drawings

[0019] Figure 1 It is a schematic structural diagram of the composite body formed by laser welding of the alloy particle sintered body of the present invention.

[0020] Figure 2 For Figure 1 a photo of a specific application example of the composite body. Detailed Embodiments

[0021] The principles and features of the present invention will be described below with reference to the drawings. The examples given are only for explaining the present invention and are not intended to limit the scope of the present invention. The present invention will be described more specifically by way of example in the following paragraphs with reference to the drawings. The advantages and features of the present invention will be clearer according to the following description and the claims. It should be noted that the drawings are all in a very simplified form and use non-precise scales, and are only used to facilitate and clearly assist in explaining the purpose of the embodiments of the present invention.

[0022] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field to which the present invention belongs. The terms used in the specification of the present invention herein 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 of the related listed items.

[0023] Figure 1It shows a composite body formed by laser welding of a steel matrix 10 and a sintered body of alloy chips according to the present invention. Figure 2 It shows an example of a specific forming, i.e., an alloy chip cutting tool.

[0024] The laser welding method of the sintered body of alloy chips according to the present invention is characterized by including the following steps: (1) providing a sintered body of alloy chips with a transition layer having a thickness of 1.0 - 2.0 mm formed on the surface; and the raw material composition of the transition layer is Fe: 45 - 60 wt.%, Mn: 2 - 5 wt.%, and the balance is copper and inevitable impurities. Further preferably, Fe: 45 - 55 wt.%, Mn: 2 - 4 wt.%, and the balance is copper and inevitable impurities, and the content of C in the raw material composition of the transition layer < 0.10 wt.%; (2) disposing the transition layer opposite to the steel matrix and forming a composite body by laser welding. In the present invention, the addition of manganese ensures the weld quality of laser welding. When the addition amount of manganese is less than 2 wt.%, pores are likely to be generated, resulting in insufficient compactness; while if the addition amount of manganese exceeds 5 wt.%, the generation of brittle phases may be caused, resulting in a decrease in strength; since carbon is generally contained in the raw material iron, in the raw material of the transition layer, the content of carbon should be less than 0.10 wt.%, otherwise the flexural strength will decrease significantly.

[0025] The flexural strength of the laser weld formed by using the laser welding method of the present invention is greater than 2200 MPa. The transition layer is disposed opposite to the steel matrix, the light spot of the laser welding machine is adjusted to a suitable position between the transition layer and the steel matrix, the laser welding machine is started for welding, so that the sintered body of alloy chips and the steel matrix are welded together at the moment when the laser penetrates. The process parameters of the laser welding are: double-sided laser welding is carried out by using a laser, the laser spot diameter is 0.3 mm, the laser power is 700 - 730 W, the welding speed is 10 - 16 mm / s; the shielding gas is argon, the shielding gas flow rate is 0.5 L / min, the defocus amount is 1.2 - 1.8 mm, the laser beam is biased towards the matrix side, the offset amount is 0.2 - 0.4 mm, the laser incident angle is 12 - 14°, the weld width is 1 - 1.3 mm, and the penetration depth is 2 - 2.4 mm.

[0026] In the present invention, the thickness of the sintered body of alloy chips can be greater than the thickness of the steel matrix. For example, the thickness of the hard alloy chip cutter head is 1.2 - 2.0 times, preferably 1.3 - 1.6 times, the thickness of the steel matrix. The steel matrix is 65Mn.

[0027] In the present invention, the alloy particle sintered body is formed by cold pressing cemented carbide particles and metal powder into a blank, and the blank is formed by hot press sintering. As a non-limiting application example, in the present invention, by weight percentage, the raw material composition of the alloy tool bit 2 is as follows: copper 15-35%, iron 20-45%, nickel 3-8%, tin 3-9%, zinc 2-12%, manganese 2-10%, tungsten carbide 10-20%, liquid paraffin 0.1-1%, cemented carbide particles 1-2.1%. In the copper-iron matrix, an appropriate amount of zinc, manganese and tin are configured to be sintered together to ensure densification sintering under hot press sintering conditions and to ensure the infiltration and bonding of the cemented carbide particles. When the alloy particle sintered body is used as a cutting tool, the chipping and ejection of the cemented carbide particles can be greatly reduced, ensuring the safety of personnel.

[0028] In the present invention, the composition of the cemented carbide particles in the alloy tool bit 2 is LG8, commercially available LG8 (composition: 92wt% WC + 6wt% Co + 2wt% Ni), and the particle size of the cemented carbide particles is 250-425μm.

[0029] Example 1

[0030] The laser welding method of this example is as follows:

[0031] 1. Prepare a polished 65Mn steel disc-shaped substrate;

[0032] 2. Preparation of alloy particle sintered body: Take 2.3 kg of copper powder, 3.55 kg of iron, 0.64 kg of nickel, 0.84 kg of zinc, 0.72 kg of tin, 0.6 kg of manganese, and 1.1 kg of tungsten carbide, put them into a mixing barrel and mix for 30 minutes, then add 0.1 kg of liquid paraffin and 0.15 kg of cemented carbide particles and continue to mix for 3 hours, and then pour the powder into a mold for cold pressing; the raw material of the transition layer is Fe 50wt.%, Mn 4wt.%, and the balance is Cu, the C content in the raw material is <0.10wt.%, and the raw material of the transition layer is evenly mixed and then cold pressed; a 1.5 mm thick transition layer is provided on the inner side of the cold-pressed alloy particle sintered body, and the alloy particle sintered body and the transition layer are connected together by hot press sintering, and then polished by a grinding wheel and sand belt to make an alloy particle sintered body with a transition layer, where the sintering temperature of the hot press sintering is 1000°C, the pressure is 310 kg / cm 2 , and the heat preservation time is 3 minutes;

[0033] 3. Laser welding: Place the alloy particle sintered body at the corresponding positions around the 65Mn steel disc-shaped substrate. Adjust the light spot of the laser welding machine to the appropriate position between the alloy particle sintered body and the substrate, and start the laser welding machine to weld, so that the alloy particle sintered body and the 65Mn steel disc-shaped substrate are welded together at the moment when the laser penetrates; The welding process parameters are as follows: Double-sided laser welding is carried out using a laser. The laser spot diameter is 0.3 mm, the laser power is 710 W, and the welding speed is 12 mm / s; The shielding gas is argon, the shielding gas flow rate is 0.5 L / min, the defocus amount is 1.3 mm, the laser beam is biased towards the substrate side with an offset of 0.2 mm, the laser incident angle is 12°, the weld width is 1.1 mm, and the penetration depth is 2 mm.

[0034] After testing, the flexural strength of the laser weld is 2245 MPa.

[0035] Example 2

[0036] The laser welding method of this example is as follows:

[0037] 1. Prepare a polished 65Mn steel disc-shaped substrate;

[0038] 2. Preparation of alloy particle sintered body: Take 2.21 kg of copper powder, 3.69 kg of iron, 0.59 kg of nickel, 0.86 kg of zinc, 0.7 kg of tin, 0.59 kg of manganese, and 1.11 kg of tungsten carbide, put them into a mixing barrel and mix for 30 minutes, then add 0.09 kg of liquid paraffin and 0.16 kg of cemented carbide particles and continue mixing for 3 hours, and then pour the powder into a mold for cold pressing; The raw material of the transition layer is Fe 50 wt.%, Mn 3 wt.%, and the balance is Cu. The C content in the raw material is <0.10 wt.%. After the raw materials of the transition layer are evenly mixed, they are cold pressed into shape;

[0039] Set a 1.5 mm thick transition layer on the inner side of the cold-pressed alloy particle sintered body, and connect the alloy particle sintered body and the transition layer together by hot pressing sintering. After grinding with a grinding wheel and sand belt, a alloy particle sintered body with a transition layer is made. Among them, the sintering temperature of the hot pressing sintering is 1000 °C, the pressure is 310 kg / cm2, and the heat preservation time is 3 minutes;

[0040] 3. Laser welding: Place the alloy particle sintered body at the corresponding positions around the 65Mn steel disc-shaped substrate. Adjust the light spot of the laser welding machine to a suitable position between the alloy particle sintered body and the substrate, and start the laser welding machine for welding, so that the alloy particle sintered body and the 65Mn steel disc-shaped substrate are welded together at the moment when the laser penetrates; the welding process parameters are as follows: double-sided laser welding is carried out using a laser, the laser spot diameter is 0.3 mm, the laser power is 720 W, and the welding speed is 6 mm / s; the shielding gas is argon, the shielding gas flow rate is 0.5 L / min, the defocus amount is 1.8 mm, the laser beam is biased towards the substrate side with an offset of 0.4 mm, the laser incident angle is 14°, the weld width is 1 mm, and the penetration depth is 2.4 mm.

[0041] After testing, the flexural strength of the laser weld is 2240 MPa.

[0042] Comparative Example 1

[0043] The laser welding method for the alloy particle sintered body in this comparative example is as follows:

[0044] 1. Prepare a polished 65Mn steel disc-shaped substrate;

[0045] 2. Preparation of the alloy particle sintered body: Take 2.3 kg of copper powder, 3.55 kg of iron, 0.64 kg of nickel, 0.84 kg of zinc, 0.72 kg of tin, 0.6 kg of manganese, and 1.1 kg of tungsten carbide, put them into a mixing barrel and mix for 30 minutes, then add 0.1 kg of liquid paraffin and 0.15 kg of cemented carbide particles and continue mixing for 3 hours, and then pour the powder into a mold for cold pressing; the raw materials for the transition layer are Fe 50 wt.%, Mn 4 wt.%, and the balance is Cu. The raw material Fe used is low-carbon steel with a carbon content of 0.25 wt%, and the raw materials for the transition layer are evenly mixed and then cold-pressed; the raw materials for the transition layer are evenly mixed and then cold-pressed; a 1.5-mm-thick transition layer is provided on the inner side of the cold-pressed alloy particle sintered body, and the alloy particle sintered body and the transition layer are connected together by hot-pressing sintering, and then polished with a grinding wheel and abrasive belt to make an alloy particle sintered body with a transition layer, where the sintering temperature of the hot-pressing sintering is 1000 °C, the pressure is 310 kg / cm 2 , and the holding time is 3 minutes;

[0046] 3. Laser welding: Place the alloy particle sintered body at the corresponding positions around the 65Mn steel disc-shaped substrate. Adjust the light spot of the laser welding machine to the appropriate position between the alloy particle sintered body and the substrate, and start the laser welding machine for welding, so that the alloy particle sintered body and the 65Mn steel disc-shaped substrate are welded together at the moment when the laser penetrates; The welding process parameters are as follows: Double-sided laser welding is carried out with a laser, the laser spot diameter is 0.3 mm, the laser power is 710 W, and the welding speed is 12 mm / s; The shielding gas is argon, the shielding gas flow rate is 0.5 L / min, the defocus amount is 1.3 mm, the laser beam is biased towards the substrate side with an offset of 0.2 mm, the laser incident angle is 12°, the weld width is 1.1 mm, and the penetration depth is 2 mm.

[0047] After testing, the flexural strength of the laser weld is 960 MPa.

[0048] Comparative Example 2

[0049] The laser welding method of this comparative example is as follows:

[0050] 1. Prepare a polished 65Mn steel disc-shaped substrate;

[0051] 2. Preparation of alloy particle sintered body: Take 2.21 kg of copper powder, 3.69 kg of iron, 0.59 kg of nickel, 0.86 kg of zinc, 0.7 kg of tin, 0.59 kg of manganese, and 1.11 kg of tungsten carbide, put them into a mixing barrel and mix for 30 minutes, then add 0.09 kg of liquid paraffin and 0.16 kg of cemented carbide particles and continue mixing for 3 hours, and then pour the powder into a mold for cold pressing; The raw material of the transition layer is Fe 50 wt.%, and the balance is Cu, the C content in the raw material is <0.10 wt.%, and after the raw materials of the transition layer are uniformly mixed, they are cold pressed into shape; After the raw materials of the transition layer are uniformly mixed, they are cold pressed into shape;

[0052] Set a 1.5 mm thick transition layer on the inner side of the cold-pressed alloy particle sintered body, and connect the alloy particle sintered body and the transition layer together by hot pressing sintering. After grinding with a grinding wheel and sand belt, a alloy particle sintered body with a transition layer is made. Among them, the sintering temperature of the hot pressing sintering is 1000 °C, the pressure is 310 kg / cm2, and the heat preservation time is 3 minutes;

[0053] 3. Laser welding: Place the alloy particle sintered body at the corresponding positions around the 65Mn steel disc-shaped substrate. Adjust the light spot of the laser welding machine to a suitable position between the alloy particle sintered body and the substrate, and start the laser welding machine to weld, so that the alloy particle sintered body and the 65Mn steel disc-shaped substrate are welded together at the moment when the laser penetrates; the welding process parameters are as follows: double-sided laser welding is carried out using a laser, the laser spot diameter is 0.3 mm, the laser power is 720 W, and the welding speed is 6 mm / s; the shielding gas is argon, the shielding gas flow rate is 0.5 L / min, the defocus amount is 1.8 mm, the laser beam is biased towards the substrate side, the offset amount is 0.4 mm, the laser incident angle is 14°, the weld width is 1 mm, and the penetration depth is 2.4 mm.

[0054] After testing, the flexural strength of the laser weld is 1050 MPa.

[0055] For those of ordinary skill in the art, the specific embodiments are only exemplary descriptions of the present invention. Obviously, the specific implementation of the present invention is not limited by the above methods. As long as various non-substantive improvements are made by adopting the method concept and technical solution of the present invention, they are all within the protection scope of the present invention.

Claims

1. A laser welding method for an alloy particle sintered body, characterized in that it includes the following steps: (1) Provide an alloy particle sintered body with a transition layer formed on its surface; and the raw material composition of the transition layer is Fe: 45 - 60 wt.%, Mn: 2 - 5 wt.%, the balance being copper and inevitable impurities, and the content of C < 0.10 wt.%; the thickness of the transition layer is 1.0 - 2.0 mm; the thickness of the alloy particle sintered body is 1.2 - 2.0 times the thickness of the steel substrate; the raw material composition of the alloy particle sintered body by weight percentage is as follows: copper 15 - 35%, iron 20 - 45%, nickel 3 - 8%, tin 3 - 9%, zinc 2 - 12%, manganese 2 - 10%, tungsten carbide 10 - 20%, liquid paraffin 0.1 - 1%, hard alloy particles 1 - 2.1%; (2) Oppositely arrange the transition layer and the steel substrate, and form a composite body by laser welding; the process parameters of the laser welding are: perform double-sided laser welding with a laser, the laser spot diameter is 0.3 mm, the laser power is 700 - 730 W, the welding speed is 10 - 16 mm / s; the shielding gas is argon, the shielding gas flow rate is 0.5 L / min, the defocus amount is 1.2 - 1.8 mm, the laser beam is biased towards the substrate side, the offset amount is 0.2 - 0.4 mm, the laser incident angle is 12 - 14°, the weld width is 1 - 1.3 mm, and the penetration depth is 2 - 2.4 mm; the bending strength of the laser weld formed by the laser welding is greater than 2200 MPa.

2. The laser welding method for an alloy particle sintered body according to claim 1, characterized in that: the raw material composition of the transition layer is Fe: 45 - 55 wt.%, Mn: 2 - 4 wt.%, the balance being copper and inevitable impurities.

3. The laser welding method for an alloy particle sintered body according to claim 1, characterized in that: the thickness of the alloy particle sintered body is 1.3 - 1.6 times the thickness of the steel substrate.

4. The laser welding method for an alloy particle sintered body according to claim 1, characterized in that: the steel substrate is 65Mn.

5. A composite body, characterized in that: it is obtained by the laser welding method for an alloy particle sintered body according to any one of claims 1 to 4.

6. The composite body according to claim 5, characterized in that: the composite body is a cutting tool.

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