Development process of cast stainless steel
In the process of casting production, the role of the casting mold is very important. The surface on which the mold cavity is in direct contact with the liquid metal is called the working surface.
The quality of the mold is largely determined by the quality of the working surface, as a series of physical and chemical interactions occur at the interface between the liquid metal and the working surface during the pouring and solidification of the liquid metal.
Under unfavorable conditions, the interaction between the casting mold and the liquid metal at the interface will result in rough surface of the casting, and even produce defects such as sticky sand, sand holes and pitting.
Now for the production of casting stainless steel, general manufacturers use is quartz sodium silicate sand, quartz resin sand, of course, there are special products for the use of chromite sodium silicate sand, zirconium resin sand, etc..
Coating the surface of sand mold and sand core can improve the surface strength and anti-sand adhesion ability. It is one of the effective measures to prevent the defects of sand adhesion, sand inclusion and sand hole, obtain the surface smooth casting, reduce sand falling, and reduce the amount of labor of casting cleaning.
In particular, some large steel casting sand problem is often solved by coating. Therefore, coating is very important for the surface quality of castings.
Coating should have good anti - sticky sand, and good technology, such as stability coating, room temperature strength, high temperature strength and crack resistance. Coating should have good besmear to brush a gender, ability is even ground adhesion is mixed in the surface of arenaceous core.
It also has sufficient strength and thermal stability, i.e. high fire resistance and chemical inertness. These properties of coating are to rely on the performance of raw materials, reasonable selection of formula, and the correct preparation process and use process to ensure. Sodium silicate binder is water soluble, therefore, the sodium silicate sand mold and sand core and water-based paint does not adapt, hardening of the sodium silicate sand, sand core coating, water-based paint, paint the water will into the hardened waterglass sand type, core, after being absorbed to soften sand mold and core, thereby reducing the surface of the sand mold and core strength. Therefore, it should be said that the use of alcohol - based stainless steel sand coating.
Resin sand in the process of operation itself has a toxic problem, from the point of view of the operator's health and problems, from the point of view of reducing the cost of coating, from the point of view of burning alcohol-based coating somewhat destroy resin sand surface strength, should use water-based stainless steel coating.