A surface repair process for magnesium alloy plates

Abstract

The present invention relates to a surface repair process for magnesium alloy plates, comprising the following steps: S1, obtaining Al-Sb alloy powder; S2, mixing the Al-Sb alloy powder with water glass, wherein the water glass accounts for 10-30% of the total volume, and stirring evenly to form a viscous suspension; S3, sequentially sandpapering, degreasing, acetone cleaning, and cold air drying the surface of the magnesium alloy substrate to be clad; S4, evenly applying the viscous suspension to the damaged part of the plate anti-corrosion layer, with a coating thickness of 0.5-1.5 mm, and then drying in the shade to evaporate its moisture; S5, coating the plate with argon arc welding equipment. The present invention designs surface cladding and gold, and utilizes surface cladding technology to prepare a surface heat-resistant cladding layer with a certain thickness on the surface of the flame-retardant magnesium alloy plate, so that the corrosion resistance of the damaged part of the plate anti-corrosion layer can be efficiently restored; after argon arc cladding, the Al-Sb alloy has a fine microstructure and a controllable coating thickness, and can be resin-coated and applied after simple polishing.

Description

Technical Field

[0001] The present invention relates to the technical field of magnesium alloy plate processing, and in particular to a surface repair process of a magnesium alloy plate. Background Art

[0002] Before use, flame-retardant magnesium alloy sheets usually need to be treated with anodizing and other processes to prevent corrosion on the surface of the parts in order to isolate the substrate from the external corrosive environment. Common methods mainly include electroplating, chemical plating, anodizing, thermal spraying, organic coating and other technologies to form one or more layers of protection. Such coatings usually need to be prepared in a specific device, and when the coating is damaged, it is usually difficult to repair. At this time, if the metal itself does not have sufficient corrosion resistance, the parts may be scrapped in a very short time. Taking rail passenger cars as an example, they may collide with small stones when running at high speeds, which will form pits, scratches and other forms of damage on the metal surface. Failure to repair them in time will bring safety hazards. At present, the surface repair technologies of metal sheets mainly include surfacing, thermal spraying, physical and chemical vapor deposition, laser cladding and argon arc cladding. Among them, surfacing welding is only applicable to plates of a certain thickness, has certain requirements for the material, and is prone to a large number of oxidation inclusion defects for magnesium alloys; thermal spraying has high requirements for equipment, is not suitable for large-scale tooling, and is relatively expensive, and is not suitable for fine repairs; physical and chemical vapor deposition are usually only applicable to small workpieces at the laboratory level, and the cost is too high; laser cladding is prone to pores and cracks, and the expensive price of laser equipment, complex processes, and high requirements for the operating environment limit the application of laser cladding technology. In comparison, argon arc cladding is a low-cost, convenient surface repair process suitable for engineering use. It melts the self-fluxing alloy powder pre-applied on the substrate surface to form a molten pool. The melted self-fluxing powder and the molten substrate metal solution undergo a chemical metallurgical reaction in the molten pool, and are rapidly solidified at room temperature to obtain a cladding layer that is metallurgically bonded to the substrate. Summary of the Invention

[0003] In response to the above problems, the purpose of the present invention is to provide a surface repair process for magnesium alloy plates, which uses surface cladding technology to prepare a surface heat-resistant cladding layer with a certain thickness on the surface of the flame-retardant magnesium alloy plate, so that the corrosion resistance of the damaged anti-corrosion layer of the plate can be efficiently restored.

[0004] The technical solution adopted in the present invention is as follows:

[0005] The present invention proposes a magnesium alloy plate surface repair process, comprising the following steps:

[0006] S1. Obtain Al-Sb alloy powder;

[0007] S2. Mixing Al-Sb alloy powder with water glass, wherein the water glass accounts for 10-30% of the total volume, and stirring evenly to form a viscous suspension;

[0008] S3. The surface of the magnesium alloy substrate to be clad is sequentially polished with sandpaper, degreased, cleaned with acetone, and dried with cold air;

[0009] S4. Apply the viscous suspension evenly on the damaged part of the anti-corrosion layer of the plate with a coating thickness of 0.5-1.5mm, and then dry it in the shade to evaporate the moisture;

[0010] S5. Use argon arc welding equipment to coat the plate.

[0011] Furthermore, in step S1, the Al-Sb alloy powder includes the following components in terms of mass percentage: Sb: 0.05-1%, and the rest is Al and unavoidable impurities.

[0012] Furthermore, the specific process of step S5 is as follows: connect the magnesium alloy plate to the "+" pole and the tungsten electrode to the "-" pole, turn on the power, set the adjustment button of the welding machine control panel to the "welding, no pulse, DC, continuous, water cooling, TIG" position, pre-adjust the output current, fix the TIG welding gun on the automatic walking mechanism or robotic arm of the submerged arc welding, pre-adjust the height of the tungsten electrode to the surface of the specimen to 2 mm, and move the walking mechanism back and forth to ensure that the end of the tungsten electrode moves in a straight line on the specimen and maintains the same height.

[0013] Furthermore, the travel speed of the tungsten electrode is 2-10 mm / s; the current is 60-160 A; and the flow rate of argon gas is 10 L / min.

[0014] Compared with the prior art, the present invention has the following beneficial effects:

[0015] The present invention designs a surface cladding alloy and uses surface cladding technology to prepare a surface heat-resistant cladding layer with a certain thickness on the surface of a flame-retardant magnesium alloy plate, so that the corrosion resistance of the damaged anti-corrosion layer of the plate can be efficiently restored; after argon arc cladding, the Al-Sb alloy has a fine microstructure and a controllable coating thickness, and can be resin-coated and applied after simple polishing. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 Schematic diagram of the mechanism of argon arc cladding of the present invention;

[0017] Figure 2 Schematic diagram of the microstructure of the Al-Sb alloy in the present invention. DETAILED DESCRIPTION

[0018] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0019] The present invention proposes a magnesium alloy plate surface repair process, such as Figure 1 The specific implementation process is as follows:

[0020] S1. Prepare Al-Sb alloy powder by metallurgical means, using atomization spray deposition to obtain spherical powder with a particle size of 10-100 μm, wherein the Al-Sb alloy powder comprises the following components by mass percentage: Sb: 0.05-1%, and the remainder is Al and unavoidable impurities;

[0021] S2. Mixing the prepared Al-Sb alloy powder with water glass, wherein the water glass accounts for 10-30% of the total volume, and stirring for 30 minutes to mix them evenly to form a viscous suspension in which the Al-Sb alloy powder is evenly distributed;

[0022] S3. The surface of the magnesium alloy substrate to be clad is sequentially sanded, degreased, cleaned with acetone, and then dried with cold air;

[0023] S4. Apply the viscous suspension evenly on the damaged part of the anti-corrosion layer of the plate with a coating thickness of 0.5-1.5mm, and then dry it in the shade to completely evaporate the moisture;

[0024] S5. Use argon arc welding equipment to coat the plate: connect the magnesium alloy plate to the "+" pole and the tungsten pole to the "-" pole, turn on the power, set the adjustment button of the welding machine control panel to the "welding, no pulse, DC, continuous, water cooling, TIG" position, pre-adjust the output current, fix the TIG welding gun on the automatic walking mechanism or mechanical arm of the submerged arc welding, pre-adjust the height of the tungsten pole to the surface of the test piece to 2mm, move the walking mechanism back and forth to ensure that the end of the tungsten pole keeps moving in a straight line above the test piece and keeps the same height; wherein, the walking speed of the tungsten pole is 2-10mm / s; the current is 60-160A; the flow rate of argon gas is 10L / min. Figure 2 As shown in the figure, after argon arc cladding, the microstructure of Al-Sb alloy is fine and dense, the coating thickness is controllable, and resin coating and application can be carried out after simple polishing.

[0025] The present invention mixes a certain weight of Al-Sb alloy powder with water glass, adheres it to the surface of a substrate, and then conducts an argon arc cladding test after drying and cooling. The surface of the alloy powder layer absorbs the argon arc energy, causing it to heat up and melt. Simultaneously, heat from the surface is transferred inward through heat conduction, melting the Al-Sb alloy powder layer and part of the substrate. The molten alloy powder dissolves in the molten pool to form a multi-component alloy. After the argon arc heat source leaves, the molten metal rapidly solidifies with a phase transition, ultimately forming a metallurgically bonded alloy cladding layer on the substrate surface. Because the multi-component alloy has high corrosion resistance and a certain thickness, it can provide good protection for flame-retardant magnesium alloy plates.

[0026] Matters not described in detail in this invention are all known technologies.

[0027] The embodiments described above are merely descriptions of preferred implementations of the present invention and are not intended to limit the scope of the present invention. Without departing from the 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 fall within the scope of protection determined by the claims of the present invention.

Claims

1. A magnesium alloy plate surface repair process, characterized in that: The process comprises the following steps: S1. Obtain Al-Sb alloy powder; S2. Mixing Al-Sb alloy powder with water glass, wherein the water glass accounts for 10-30% of the total volume, and stirring evenly to form a viscous suspension; S3. The surface of the magnesium alloy substrate to be clad is sequentially polished with sandpaper, degreased, cleaned with acetone, and dried with cold air; S4. Apply the viscous suspension evenly on the damaged part of the anti-corrosion layer of the plate with a coating thickness of 0.5-1.5mm, and then dry it in the shade to evaporate the moisture; S5. Coating the plate using argon arc welding equipment; In the step S1, the Al-Sb alloy powder includes the following components in terms of mass percentage: Sb: 0.05-1%, and the rest is Al and unavoidable impurities.

2. The surface repair process of a magnesium alloy sheet according to claim 1, characterized in that: The specific process of step S5 is as follows: connect the magnesium alloy plate to the "+" pole and the tungsten electrode to the "-" pole, turn on the power, set the adjustment button of the welding machine control panel to the "welding, no pulse, DC, continuous, water cooling, TIG" position, pre-adjust the output current, fix the TIG welding gun to the automatic walking mechanism or robotic arm of the submerged arc welding, pre-adjust the height of the tungsten electrode to the surface of the specimen to 2 mm, and move the walking mechanism back and forth to ensure that the end of the tungsten electrode moves in a straight line on the specimen and maintains the same height.

3. The surface repair process of a magnesium alloy sheet according to claim 2, characterized in that: The traveling speed of the tungsten electrode is 2-10 mm / s; the current is 60-160 A; and the flow rate of argon gas is 10 L / min.

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