How does the stainless steel precision casting process work?

In daily life, many alloy materials are difficult to process, and the shape of the workpiece is also very complicated. Especially in the aerospace field, the manufacturing process is even more difficult or difficult to achieve. Precision casting stainless steel, also known as investment casting or silica sol process, is a low-cut or no-cut casting process. The casting industry’s y-show craftsmanship has a wide range of applications. Not only can it cast a variety of alloys, but the dimensional accuracy and surface quality of the produced castings are higher than other casting methods. Even if it is difficult, complex, and high-temperature resistant, it is difficult to perform precision Casting. How does the precision casting process of stainless steel work? The following is an introduction to the stainless steel precision casting process.

Stainless steel precision casting process.
Molds are made according to products of different shapes; upper and lower concave molds are used to complete the process through comprehensive processes such as turning, planing, milling, etching, and EDM. The pit shape is the same size as the half of the product. Because it is mainly used for industrial wax pressing, the wax mold is mainly made of aluminum alloy material with low melting point, low hardness, low requirement, low price and light weight;
A large number of industrial wax core molds are produced with aluminum alloy molds. In general, an industrial wax core model can only correspond to one blank product;
Refine the margin around the wax mold. After deburring, glue multiple single wax molds on a pre-fabricated die (also called group tree), which is also an industrial wax core made of wax molds. Model.
After coating multiple wax molds fixed on the die with industrial glue, evenly spray the first layer of mortar (a kind of refractory mortar, silica sand is commonly used at high temperatures). This kind of sand is very small and very fine, which ensures that the final rough surface is as smooth as possible.
The wax mold sprayed from the first layer of mortar at the set room temperature (or constant temperature) will not change the shape of the internal wax mold when it is naturally air-dried. The time of natural air-drying depends on the internal complexity of the product itself. Generally, precision casting The air-drying time of a wax model is about 5-8 hours.
After the sand is sprayed and air-dried naturally, continue to spray industrial glue (silicon solution) on the surface of the wax mold to spray out No. 2 sand. The particle size of No. 2 sand is larger than that of No. 1 sand and is coarser. After sand blasting the second layer, let the wax mold air dry naturally at the set constant temperature.
After the second sand blasting is completed, it is air-dried naturally, and the third, fourth, and fifth sand blasting processes are carried out by analogy. Requirements:-Adjust the number of sandblasting according to product surface, volume, weight and other requirements. The number of sandblasting is generally 3-7 times. -The size of the sand produced by each blasting process is different. Usually, the sand produced in the subsequent process is coarser than the sand produced in the previous process, and the air-drying time is also different. Normally, the production cycle of sanding on a complete wax model is about 3~4 days.
Before the baking process, the wax mold that has completed the sandblasting process is evenly coated with a layer of white industrial latex (silicon soluble slurry) to make the sand mold bond and solidify, and seal the wax mold for the subsequent baking Preparation for the process. Through the baking process, the brittleness of the sand mold can be improved, it is convenient to knock the broken sand layer, and the blank can be removed.
In stainless steel precision casting, the baked wax mold is fixed on the die, and after the sandblasting and air drying process is completed, it is put into a special metal sealed oven for heating (usually a kerosene steam furnace). Because the melting point of industrial wax is not high and the temperature is about 150°, the wax mold used for wax removal is just an empty sand shell. The key to the precision casting process is to use this empty sand shell. (Usually this kind of wax can be reused many times, but it must be filtered, otherwise the unclean wax will affect the surface quality of the blank, such as surface blisters, pitting, etc., and also affect the shrinkage of the precision casting).
Outer wire contact
Baking the sand shell In order to make the dewaxed sand shell stronger and firmer, the sand shell must be baked first, and then poured into stainless steel water, generally baked in a high temperature (about 1000 ゜) furnace.
Pour the stainless steel water that has been dissolved into a liquid at a high temperature into the dewaxed sand shell, and then use the liquid to fill the space formed by the wax mold until it is completely filled, including the middle part of the die.
Since stainless steel will be mixed with materials of different compositions after being dissolved, the factory must check the percentage of the material. Then adjust the interpretation according to the required proportion, such as adding those aspects to achieve the required effect.
After the liquid stainless steel is cooled and solidified, the outer sand shell is broken by mechanical tools or manpower to expose the solid stainless steel product, that is, the shape of the original wax mold, which is the final required blank. Then cut and separate them one by one, and then rough-grind them to become blanks.
Inspection of blanks: blanks with blisters and pores on the surface must be repaired with argon arc, and returned to the furnace after the waste is cleaned up.
Cleaning blanks: blanks that have passed the inspection must go through the cleaning process.
Carry out other processes until the product is completed.