Aluminum A356 is made by gravity casting followed with T6 heat treatment. Die casting is cost efficient, yet lower in mechanical strength.
2：
Brass 57 sized 1/2" to 3" are produced by forging, bigger ones by casting process. Ribbed (2) serration is required to achieve better friction force, optionally multiple for ferrule assembly. Smooth (no serration) is standard per EN14420-7.
3：
Stainless steel AISI316 and 304 are made by investment casting. Other grades, like Hastalloy, are possible. Ribbed (2) serration is required to achieve better friction force, optionally multiple for ferrule assembly.
4：
Polypropylene and nylon are processed by material injection, PP with a recipe of ~30% glassfiber compound. Ribbed (2) serration is standard.
