Auto parts castings
Pressure stainless steel castings micropores (pores, pinholes, shrinkage and shrinkage, etc.) defects seriously affect the compactness of the casting, the casting scrap, huge economic losses, casting infiltration repair is the solution to the leakage of the most simple and effective repair methods.
Infiltration is the colloidal impregnating agent to penetrate the pores of the casting, curing and then impregnated with the inner wall of the casting porosity fused achieve plugging purposes.
First, impregnating agents
1) inorganic impregnating agent. Including sulphates, aluminosilicates, chlorides, silicates, and the molten low melting point metal as a main component of various types of infiltrant. Currently the most widely used impregnating agent is a modified silicate impregnating agent, it is non-toxic, no pollution, easy to store, acid, high temperature, interstitial ability, can be cured at room temperature, easily washed with water , wide source of raw materials, easy to manufacture, low cost advantages.
2) organic impregnating agents. Including to the Pi oil and epoxy resins, phenolic resins, alkyd resins, polyester type, anaerobic synthetic resin impregnating agent. Ordinary synthetic resin impregnation agent has good sealing effect, can fill a small aperture (minimum pore size 0.2ram), corrosion resistance, high temperature (2000c) and other advantages. But there are polluting the environment, the need to heat curing and other shortcomings, it is now rarely used. Anaerobic resin infiltrant good curability, surface tension, viscosity is less than 20mPa · s, a high infiltration efficiency, solvent-free, no swelling upon curing, does not shrink, the processing can be impregnated with pore size below 0.5mm , but also has insulation resistance and Fluoride. But the price is high, commonly used in anaerobic resin impregnating agents are mainly: AIs ~ 10A is suitable for cast iron and cast aluminum parts, AIS 10B is suitable for a bronze pieces, AIS ~ 10zY-sI mainly used for steel , iron, copper, aluminum castings micropores partial impregnation process.
Second, the infiltration process
1) local infiltration. There brushing method, an injection method, vacuum pressure impregnation method and other methods to supplement local infiltration. Suitable for small batch production, equipment is simple, convenient construction, low cost. Used mostly for anaerobic resin impregnation agents, can also be modified silicate impregnated with resin-based impregnating agent or general agent. Between cast and cover with a rubber seal, it is evacuated when the inner cover, due to a pressure difference, seepage of fluid to penetrate and fill the casting porosity, once infiltration fluid penetration to the underlying stainless steel castings, to release the vacuum. Before casting sealant be cleaned, washed after curing required.
2) vacuum pressure impregnation. When treated (decontamination, cleaning, degreasing, drying) leakage of castings, after the first sealed vacuum pump to eliminate casting defects micropores air, moisture and dust, elimination of pressurized air cushion effect of pore defects and then impregnating agent injected into the vessel, impregnating agents defect filling pores in the dynamic pressure effect, then into the container filled with compressed air, further impregnating agent to penetrate deep inside the pores of stainless steel casting defects achieve pressure infiltration. |
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