Analysis of the whole process of stainless steel casting processing: detailed process from mold design to finished product delivery
Stainless steel casting processing is one of the key molding processes in the manufacturing industry and is widely used in machinery, medical, chemical, food and other industries. Its core is to ensure that castings have good mechanical properties and corrosion resistance through reasonable mold design, melting and pouring, post-processing and other links. This article will systematically introduce the technical points of the entire process of stainless steel casting processing to help readers gain an in-depth understanding of the key steps of this process.
1. Mold design and production
Molds are the starting point of casting processing and directly affect the dimensional accuracy and surface quality of castings. There are three types of molds commonly used for stainless steel casting: sand molds, metal molds and investment molds:
sand casting: Suitable for castings with large size and simple structure, low cost but average surface finish.
Metal mold casting: Suitable for small and medium-sized batch production, long mold life, but high initial investment.
Investment casting (lost wax method): Suitable for complex precision parts, the dimensional error can be controlled within ±0.5mm.
Mold design needs to consider the shrinkage rate (usually 1.5%-2.2% for stainless steel), draft angle and parting surface position to avoid subsequent demolding difficulties.
2. Smelting and pouring process
Stainless steel casting is usually smelted by electric arc furnace or induction furnace, and the following points are controlled:
Ingredient control: The carbon, chromium, and nickel contents of common brands such as 304 and 316 must meet standards to avoid segregation.
Deoxidation treatment:Add deoxidizers such as calcium silicate to reduce pore defects.
Pouring temperature: Generally controlled at 1500-1600 degrees Celsius. If it is too high, it will easily lead to coarse grains. If it is too low, the fluidity will be poor.
It is necessary to keep it steady during pouring to avoid turbulent flow into the gas, and at the same time, use riser feeding to reduce the problem of shrinkage cavities.
3. Cooling and cleaning
After the casting solidifies, the cooling rate needs to be reasonably controlled:
rapid cooling(Such as water spray): It can refine the grains, but may increase internal stress.
cool slowly(furnace cooling): Reduces the risk of deformation, suitable for thick-walled parts.
The cleaning process includes removing the pouring riser, polishing the flash, and using sandblasting or pickling to remove the surface oxide layer.
4. Heat treatment and machining
Stainless steel castings usually require solution treatment (such as water quenching at 1050-1100 degrees Celsius) to eliminate casting stress and improve corrosion resistance. Pay attention to the following during subsequent machining:
Use carbide cutting tools to avoid sticking.
Control cutting parameters to prevent work hardening.
5. Quality inspection and FAQ
Non-destructive testing:X-ray or ultrasonic flaw detection to check for internal defects.
Dimensional inspection:3 coordinates to measure key dimensions.
FAQ: Porosity (can be solved by optimizing smelting), cracks (adjust cooling speed), uneven composition (strengthen smelting and stirring).
Every aspect of stainless steel casting processing directly affects the quality of the finished product, and strict control is required from mold design to testing. Enterprises should select appropriate process parameters based on specific needs and continue to optimize the production process to ensure that the performance of castings meets industry standards.