The Role Of Low Carbon Steel Silica Sol Investment Casting Surface Impermeability

The role of low carbon steel silica sol investment casting surface impermeability
(1) New low carbon steel silica sol welding casting Surface impermeable zirconium powder coating for alkaline phenolic resin sand production Low carbon stainless steel silica sol welding casting, with significant surface anti-carburizing effect, Of the other ingredients have no effect to meet the production quality requirements.
(2) the use of water glass sand production process of low carbon steel silica sol welding casting, silica sol welding casting surface generally does not occur carburizing phenomenon. The reason for the occurrence of carburizing defects on the surface is mainly due to the thermal decomposition of organic matter such as resin, the resulting carbon pyrolysis products through the sand (core) The silica surface is caused by the diffusion and penetration of the surface.
(3) the new low carbon steel silica sol welding casting surface impermeable zirconium British powder coating permeability, resistance to flow and crack resistance are good, high coating strength, gas volume is small; silica sol welding casting box Most of the coating can be stripped, silica sol welding casting surface smooth, basically no sticky sand and pores, a substantial increase in silica sol investment casting clean efficiency, saving energy and reducing labor intensity.
The characteristics of crack in cold solute
Cold crack A crack formed at a lower temperature after solidification. The cracks often extend through the grain to the entire section.
Hot crack A crack formed at a higher temperature after solidification or after solidification. Its cross-section serious oxidation, no metallic luster, cracks along the grain boundary generation and development, shape twists and turns and irregular.
3. Shrinkage (shrinkage crack). Due to silica sol welding casting caused by improper shrinkage, shrinkage or shrinkage caused by uneven cracks. May appear after just solidification or at a lower temperature.
4. Heat treatment cracks. silica soldering casting A penetrating or non-penetrating crack produced during a heat treatment. Its cross-section of oxidation.
5. Mesh crack (crack). Metal type and die-casting type due to alternating thermal mechanical thermal fatigue occurred in the cavity surface of the formation of fine turtle shell crack. The mold cracked on the surface of the silica sol welding casting.
6. White point (cracked). The defects in steel are mainly caused by the precipitation of hydrogen. In the longitudinal section, it is similar to the circular or oval silver white spots, it is called white point; in the cross-section macroscopic grinding, corrosion after the show as hair.
7. cold separation. Penetrated or not penetrated on silica sol welding, with rounded corners. And more appear away from the gate of the large f surface or thin wall, the metal flow confluence and cold iron, core support and other cold parts.
8. Casting and drying. A highly visible seam on the surface. Some parts of the seam are not well welded or separated. Caused by pouring interruption.
9. heavy skin. Filling process due to molten metal splash or liquid surface fluctuations, the cavity surface has been solidified metal can not be followed by metal, the fusion caused by the silica sol communication casting epidermal fold defects.
Preparation of wax-based mold material and rosin-based mold material is usually heated melting and stirring method, the silica melting investment molding material into a liquid full mixing, filter out impurities, keep warm case, let the liquid mold in the bubble escape The If the working state of the mold material is liquid, it can be sent to the press machine for pressing and pressing. If the mold material used in the state of paste (solid liquid), then the melted after the mold material to be filtered, by side cooling method of mixing paste made of pressure for the use of pressure.
In the case of wax-based mold materials, the recovered old mold material can be used to suppress the melting of silica sol investment casting. But after repeated use, the gradual deterioration of the nature of mold material. The reason for the deterioration of the mold material properties is mainly the deterioration of stearic acid in the components. Stearic acid and other substances will saponification reaction, the reaction product known as soap or saponification. The saponified material can be mixed with the mold material to make the mold material deteriorate. For this reason, it is necessary to treat the mold material and remove the saponification product for recycling. Treatment methods are: acid treatment, active clay treatment and electrolytic treatment.