Views: 6 Author: Site Editor Publish Time: 2018-12-11 Origin: Site
In the production of stainless steel products, some products have strange shapes and hollow or solid inner structure which can not be produced by bending tube or other process. A process of filling and molding with liquid materials is developed, that is precision casting of stainless steel.
Today we will talk about the investment casting process of stainless steel.
Make moulds according to different shapes of products. The mould is divided into upper and lower moulds, and is completed by the comprehensive procedures of turning, planning, milling, etching and electric sparks. Aluminum alloy material is used to make moulds because of its low hardness, low requirements, low price and light weight.
A large number of industrial wax solid core models are produced by aluminum alloy mould. Under normal circumstances, a solid core model of industrial wax can only correspond to a blank product.
After de-burring a number of single wax molds are adhered to the pre-prepared die head (also known as group tree). This die head is also a solid core model of industrial wax produced by wax mold. (looks like a tree)
The first layer of fine sand (a kind of fire-resistant silica sand with high temperature resistance) is sprayed evenly on several wax molds that have been fixed on the head of the mold after applying industrial glue. The sand particles are very small and fine, which ensures that the final blank surface is as smooth as possible.
At the set room temperature (or constant temperature), the wax mold sprayed with the first layer of fine sand is naturally air-dried, but it cannot affect the shape change of the internal wax mold. The natural air-drying time depends on the complexity of the product itself. Generally, the first air-drying time of the investment casting is about 5-8 hours.
After the first sand spraying and natural air drying, the industrial glue (silicon slurry) is repeated and second layer of sand is applied on the surface of the wax mold. The sand particle size of the second layer is larger and thicker than the first one. After spraying the second layer of sand, let the wax mold dry naturally under the set constant temperature.
After the second sand blasting and natural air drying, the third sand blasting, the fourth sand blasting, the fifth sand blasting and so on are carried out successively. According to the product surface requirement, the volume size and self weight the sand blasting frequency shall be adjusted accordingly. In general, sand blasting frequency is 3-7 times.
A layer of white industrial latex (silicon slurry) is uniformly applied on the finished sandblasting wax mold before the baking process to bond and solidify the sand mold and seal the wax mold, so as to prepare for the later baking process.
The wax mold fixed on the mold head after sand blasting and air drying is heated in a special oven sealed with metal. Under the temperature around 150°the wax mold is thermally melted into wax water flowing out along the gate and this is called de-waxing. An empty sand shell, the key part of investment casting is formed in this process. Normally this melted wax can be used over and over again, but it has to be re-filtered or the unsanitary wax will affect the quality of the surface, such as the surface of the sand and the reduction in the production rate.
In order to get a stronger and stable sand shell baking under a high temperature as high as1000°is necessary.
After dissolving in the boiler liquid stainless steel is poured into the empty sand shell.
After the liquid stainless steel is cooled and solidified, the most exposed sand shell is broken by means of mechanical tools or human labor, and the solid stainless steel product is exposed to the shape of the original wax mold, that is, the final required blank.
Inspection: The blank with sand holes and air holes on the surface must be repaired by argon arc welding.
Cleaning: The qualified blank must go through the cleaning procedure.
Finish part is formed by other machining process.
How to produce qualified investment casting stainless steel parts? The most important thing is to go through every step perfectly. Each single process decides the final success. Sieg-Huao, equipped with advanced machines and advanced talents can help you to make good investment casting stainless steel parts! Welcome to send your inquries!
