Shell casting is suitable for a variety of metals, such as cast iron, non-ferrous alloys, and cast steel (including stainless steel).
Details are as follows:
Cast iron: This includes gray cast iron and ductile iron, and is particularly suitable for producing precision castings such as engine parts and gears.
Cast steel: This includes carbon steel, stainless steel, and alloy steel. The pearl sand shell casting process can replace some lost wax casting processes, achieving CT7-CT6 precision.
Non-ferrous alloys: These include aluminum alloys and copper alloys, and are suitable for complex structural parts such as automotive parts and electrical hardware.
High-temperature alloys: These include nickel-based alloys (such as K417), and are used in high-temperature resistant components such as aircraft engine turbine blades.
This material compatibility is due to the neutral chemical properties and high refractoriness of pearl sand, as well as the process flexibility of resin-coated sand.
What are the precision grades available for shell casting?
Shell casting precision is primarily based on the CT tolerance grade. Typical precision ranges and characteristics are as follows:
1. Conventional Precision Grades
CT4-CT6: Suitable for small, complex parts (such as engine components and gears), with dimensional tolerances of 0.20-0.36mm (for sizes under 10mm).
CT7-CT9: Commonly used for small and medium-sized castings, such as aluminum alloy housings (tolerances of ±0.1mm, flatness of 0.05mm).
CT10-CT13: Used for general structural parts, typical tolerances for sand shell casting are 1.4-4.4mm (for sizes ranging from 63-100mm).
2. High-Precision Applications
Investment Shell Casting: Using coated sand shell technology, precision can reach CT4-CT6 (approaching investment casting levels), with a surface roughness of Ra ≤ 3.2μm.
Ball Sand Shell Casting: Due to the uniformity of the sand grains, tolerances are further improved, and in some cases, machining can be eliminated.
3. Special Restrictions
Dimensional Applicability: CT13-CT16 grades are not suitable for parts under 16mm and require separate marking.
Wall Thickness Tolerance: Typically one grade wider than standard sizes.
4. Comparison with Other Processes
Sand Casting: Accuracy is generally CT10-CT13, with higher surface finish.
Die Casting: Accuracy is CT5-CT7, but shell casting offers advantages for complex, thin-walled parts.
The accuracy of shell casting should be determined based on part size, material, and process requirements. CT4-CT6 grades are recommended for high-precision applications, while CT7-CT9 grades are recommended for more general needs.
Of course, if you require large quantities of custom shell castings, you can partner with Mulan Metal. Mulan Metal has 12 years of experience in shell casting production and processing. We have helped clients in over 30 countries complete custom shell casting projects and have received consistent recognition. We look forward to your inquiries.
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