TIG welding repair
Welding is carried out by using the arc burning between the continuously fed welding wire and the workpiece as the heat source, and the gas shielded arc ejected from the welding torch nozzle. At present, argon arc welding is a commonly used method and can be applied to most major metals, including carbon steel and alloy steel. Melted extremely inert gas shielded welding is suitable for stainless steel, aluminum, magnesium, copper, titanium, zirconium and nickel alloys. Due to its low price, it is widely used for mold repair welding. However, it has shortcomings such as large welding heat-affected area and large solder joints. Currently, it is used in Precision mold repair has been gradually replaced by laser welding.
Mold repair machine repair
The mold repair machine is a high-tech equipment for repairing mold surface wear and processing defects. The mold repair machine strengthens the mold to have long service life and good economic benefits. It can be used to strengthen and repair the surface of molds and workpieces made of various iron-based alloys (carbon steel, alloy steel, cast iron), nickel-based alloys and other metal materials, and greatly improve their service life.
1. Principle of mold repair machine
It uses the principle of high-frequency electric spark discharge to perform heatless surfacing on the workpiece to repair surface defects and wear of the metal mold. The main features are that the heat-affected area is small, the mold will not deform after repair, no annealing is required, no stress concentration, and no The occurrence of cracks ensures the integrity of the mold; its strengthening function can also be used to strengthen the surface of the mold workpiece to meet the wear resistance, heat resistance, corrosion resistance and other performance requirements of the mold.
2. Application scope
Mold repairing machines can be used in machinery, automobiles, light industry, home appliances, petroleum, chemical and electric power industries for the repair and surface strengthening of hot extrusion dies, warm extrusion film tools, hot forging dies, rolls and key parts. .
For example, the ESD-05 electric spark surfacing repair machine can be used to repair wear, bumps, and scratches on injection molds, as well as to repair corrosion, peeling, and damage to die-casting molds such as zinc-aluminum die-casting molds. The machine power is 900W, the input voltage is AC220V, the frequency is 50~500Hz, the voltage range is 20~100V, and the output percentage is 10%~100%.
Brush plating repair
Brush plating technology uses a special DC power supply equipment. The positive electrode of the power supply is connected to the plating pen and serves as the anode during brush plating. The negative electrode of the power supply is connected to the workpiece and serves as the cathode during brush plating. The plating pen usually uses high-purity fine graphite blocks as the anode. The anode material is a graphite block wrapped in cotton and a wear-resistant polyester-cotton cover.
When working, the power supply component is adjusted to the appropriate voltage, and the plating pen immersed in the plating solution is moved at a certain relative speed to the part where the surface of the workpiece to be repaired is in contact. The metal ions in the plating solution diffuse to the workpiece under the action of the electric field force. On the surface, the electrons obtained on the surface are reduced to metal atoms, so that these metal atoms deposit and crystallize to form a coating, that is, the required uniform deposition layer is obtained on the working surface of the plastic mold cavity to be repaired.
Plasma cladding machine, plasma spray welding machine, shaft cladding repair
Laser cladding repair
Laser welding is a welding process that uses a laser beam focused by high-power coherent monochromatic photon flow as a heat source. This welding method usually includes continuous power laser welding and pulse power laser welding. The advantage of laser welding is that it does not need to be carried out in a vacuum, but the disadvantage is that the penetration power is not as strong as electron beam welding. Laser welding can achieve precise energy control, thus enabling the welding of precision devices. It can be applied to many metals, especially the welding of some difficult-to-weld metals and dissimilar metals. It has been widely used in the repair of molds.
Laser cladding technology
Laser surface deposition technology is to rapidly heat and melt the alloy powder or ceramic powder and the substrate surface under the action of the laser beam. After the beam is removed, it self-cools to form a surface coating with an extremely low dilution rate and a metallurgical bond with the substrate material. , a surface strengthening method that significantly improves the wear resistance, corrosion resistance, heat resistance, oxidation resistance and electrical properties of the substrate surface.
For example, after carbon tungsten laser cladding is performed on 60# steel, the hardness reaches a maximum of more than 2200HV, and the wear resistance is about 20 times that of the base 60# steel. After laser cladding CoCrSiB alloy on the surface of Q235 steel, the wear resistance was compared with the corrosion resistance of flame spraying, and it was found that the corrosion resistance of the former was significantly higher than that of the latter.
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Laser cladding can be divided into two categories according to different powder feeding processes: powder preset method and synchronous powder feeding method. The two methods have similar effects. The synchronous powder feeding method has the advantages of easy automatic control, high laser energy absorption rate, and no internal pores. Especially the cladding of cermets can significantly improve the cracking resistance of the cladding layer, allowing the hard ceramic phase to Even distribution within the cladding layer and other advantages.
1 Characteristics of laser cladding
(1) The cooling rate is fast (up to 106K/s), which is a rapid solidification process. It is easy to obtain fine-grained structures or produce new phases that cannot be obtained in equilibrium, such as unstable phases, amorphous states, etc.;
(2) The coating dilution rate is low (generally less than 5%), and it has a strong metallurgical bond or interface diffusion bond with the substrate. By adjusting the laser process parameters, a good coating with low dilution rate can be obtained, and the coating composition is consistent with Controllable dilution;
(3) The heat input and distortion are small, especially when using high power density and rapid cladding, the deformation can be reduced to the assembly tolerance of the part;
(4) There are almost no restrictions on powder selection, especially for depositing high melting point alloys on the surface of low melting point metals;
(5) The thickness range of the cladding layer is wide, and the thickness of one coating with single-pass powder feeding is 0.2-2.0mm;
(6) It can carry out selective welding, consumes less material, and has excellent cost performance;
(7) Beam aiming can make inaccessible areas welded;
(8) The process is easy to automate and is very suitable for the wear and repair of common wearing parts.
