ATTEN: Manager Liu
ADD: Longhua Development Zone, Jing County, Hengshui City, Hebei Province
The rapid development of high-tech and production processes in industrial production, as well as the increasing demand of large industrial production markets around the world, is very important in China, the equipment processing industry and the construction industry are particularly good for casting quality. It is in the process of the casting process parts of the performance of the regulations are getting higher and higher. Casting coating refers to such a covering which is coated on a metal casting die or core surface layer to improve its surface refractoriness, organic chemical reliability, metal material corrosion resistance, anti-sticking sand and the like. Cast coating process is closely related to the performance of casting, casting paints the text from the effect, characteristics and other aspects to talk about the casting process performance paint hazards castings.
a, architectural coatings efficacy
1. casting surface to reduce mechanical equipment and organic slag slag and the core metal mold casting has many porosity, in The metal material liquid containing static working pressure and dynamic working pressure in the whole process of casting and coagulation will penetrate into the porosity, and the metal material sand shell which adheres to the surface of the casting part and cannot be removed is called "mechanical equipment slag". The use of foundry coating can close the porosity between the metal mold and the surface layer of the core, block the safe passage of the metal material liquid penetration, and reduce the mechanical equipment slag of the casting. Molten steel at a casting temperature or lower, the surface layer will continue to be converted into a metal oxide material, an air film, air oxidation of such a metal material film may generate an exothermic reaction and silica sand, the casting surface may result in "Organic Chemistry slag" .
applied coating metal material can be cast with liquid metal die casting to produce a surface layer or core protection, among them suppress the exothermic reaction, to reduce or clear the casting surface of the slag organic chemistry.
2. reduce sand casting surface layer and sand washing and casting process, the high temperature of the metal material was a clear effect of radiant heat and the core metal mold casting surface, the casting metal mold and the core when exposed to heat caused by hot and humid pull the compressive strength of the working pressure will cause the resulting sand casting. Casting coatings can alleviate the heat of the metal casting or core radiation source, thereby reducing or eliminating the disadvantages of sand inclusion. The architectural coating with the ability to bond work can penetrate into the middle of the sand of the metal casting and core surface, thereby improving the surface compressive strength and erosion resistance of the metal casting or core, and reducing the sand washing defects of the casting. .
3. improved surface properties and the internal quality of casting The plus thermal insulation materials and raw materials chilled architectural coatings having improved metal die casting aluminum alloy inner wall temperature throughout the coagulation and crystallization of the whole manipulation body the efficacy of the process, thereby reducing the casting surface cracking caused by cold and hot cracking. Adding some nutrients or aluminum alloy elements to the architectural coating can have partial or surface fine-grained strengthening, which is more than improving the metallographic properties of the cast parts.
Second, the characteristics of architectural coatings
1. floats reliability architectural coatings during storage or application of the whole process, the liquid particles should form floating cases, no level, unsinkable given, not agglomerated, architectural coatings ensure uniform properties and coating quality.
2. brush of brushing excellent architectural coatings performance indicators are: smooth brush pen brush when the Baozhan architectural coatings, non-stick, do not bring sand, after brushing architectural coatings can automatic leveling, brush motor marks, the die does not produce a positive outflow perpendicular plane architectural coatings.
3. hydrophilic architectural coatings should have high quality characteristics infiltrated metal die casting and the core is a moderate depth, usually predetermined penetration depth of 1 to 2 to 3 times the diameter of the sand, architectural coatings to penetrate the sand mold porosity can increase the affinity between the sand.
4. surface compressive strength to dry after coating was scratched external force, without a trace after grinding brush effect, not powdered ability to work is called architectural coatings surface compressive strength, adequate compressive conveyance surface can be avoided, resulting in damage to the casting metal mold when the core box and bonded.
coating should have good good anti-stick properties of sand, cohesiveness, and storage stability characteristics such as a small amount of gas evolution. Lubricating oil architectural coatings for cast iron;
Third, the basic principles of a foundry casting process performance of harm
1. protective-gas and carbon   , has excellent releasability. Purity graphite casting, condensate water cooling period and is converted into light gas and carbon monoxide gas film, a metal material blocking solution with a sand mold or core surface layer interaction type, to avoid slag. In the wet die surface paint waste oil mixed with the oil mixing architectural coatings made by means of gas recovery and carbon film caused by high temperature casting, to obtain a smooth surface of the thick-walled cast iron abnormality occurs.
2. slag protective after casting, dross layer architectural coatings page layer and casting, the higher viscosity materials fireproof stone like adhesion together, blocking the infiltration of liquid metal material. The slag layer is exothermicly reacted with the metal material liquid without aluminosilicate, and the actual effect is best when the metal material liquid is not wet or the foundation is not wet. When the water is cooled, the slag shell layer and the casting metal wire gather index are very different, causing a large shear stress on the slag shell layer and the casting part page, so that the plating shell can be fully detached, and such slag layer is used. The basic theory of avoiding slag inclusion is called "slag protection theory". It is configured into a building paint with metal materials and hydroxides that are easily reflected, and is subjected to a thermal reaction to be converted into a new fireproofing material compound, which can block the penetration of the metal material liquid.
3.Chemical action The basic theory is that the casting is not a slag between the casting and the architectural coating layer is a thick layer of compound layer, the thickness is about 100μm. In order to avoid organic chemical slag, the thickness of the compound should be increased. When it exceeds the critical value, the coating or the calcined layer of the molding sand and hydroxide is easily detached from the casting. The dolomite sand mold reflects the following when pouring stainless steel castings: CaCO3=CaO CO2, which causes strong air oxidation atmosphere inside the metal casting cavity, which aggravates the surface air oxidation of stainless steel castings, so the dolomite sand has high quality anti-stick sand. effect. The use of architectural coatings in stainless steel casting sand molds is very easy to slag on cast iron sand molds, and even more severe slag inclusions, which can be easily converted from the surface layer of stainless steel castings into compound layers.
The raw iron has a high carbon content, and the carbon element is oxidized by iron air. Therefore, when the cast iron is cast, there is no way to convert the compound layer beyond the critical value, so the basic theory of "chemical action" is unsuitable for the anti-adhesive sand of the cast iron piece. Architectural Coatings.
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