The casting process flow of stainless steel

The casting process of stainless steel is a complex but delicate process involving multiple steps designed to transform stainless steel in its liquid form into the desired shape and size. This process can be roughly divided into the following main casting methods: sand casting, precision casting (lost wax method), investment casting, centrifugal casting and high pressure casting. Here we will focus on sand casting and precision casting (lost wax method), which are the two most common methods in stainless steel casting.

 

Sand casting
1. Mold preparation: First, according to the shape of the required casting, use wood or metal to make a model. This model, called the "shape," is slightly larger than the final casting to compensate for the shrinkage of the metal during cooling.

 

2. Sand box preparation: Mix sand and adhesive to form plastic sand, and then fill this sand into the sand box, and press tightly. Next, the shape is placed in the sand box and the sand is compacted to form half of the mold.

 

3. Mold separation and pouring system: After removing the pattern, the sand will retain its shape and form the mold. Then, the upper and lower parts of the mold are separated, the residue in the mold is cleaned, and the pouring system is installed, including the pouring cup, the straight runner, the cross runner and the inner gate.

 

4. Pouring: Pour the molten stainless steel into the pouring cup and flow into the mold through the pouring system.

 

5. Cooling and demoulding: Let the casting cool to room temperature in the mold, then open the mold and remove the casting.

 

6. Cleaning and post-treatment: remove the sand and other impurities on the surface of the casting, and carry out the necessary heat treatment, such as annealing, quenching, etc., to improve its mechanical properties.

 

Precision casting (lost wax process)
1. Wax molding: First, use wax to make an accurate model, the size and shape of the model fully meet the requirements of the final casting.

 

2. Shell production: the wax mold is coated with refractory materials, such as ceramic or silicate, to form a multi-layer shell. After each layer dries, apply the next until a sufficient thickness is reached.

 

3. Wax mold melting: The whole shell is heated so that the wax mold melts and flows out, leaving a cavity, which is the shape of the final casting.

 

4. Pouring and cooling: the molten stainless steel is injected into the cavity and then allowed to cool and solidify.

 

5. Shell breaking and cleaning: After cooling, break the shell, remove the casting, and clean and polish the surface.

 

6. Post-treatment: Perform the necessary heat treatment and machining to achieve the final dimensional accuracy and surface finish.

 

The above two methods have advantages and disadvantages, sand casting cost is low, suitable for mass production; Precision casting can obtain higher dimensional accuracy and surface quality, which is more suitable for the production of high-precision castings with complex shapes. Which method is chosen depends on the specific needs of the casting and the scale of production.