... 5. Carbon steel material About us We are one of the leading manufacturers of semi-precision balls from grade 100 to grade 2000 ... than 20 years experience. We have an annual production capacity of over 5000 tons steel ball, there are all sold to ... 5. Materials: SS440, SS304, SS316, SS420 Applied for all kinds of hardwires, bearings, wheels, bicycles and toys, chemical, riding media, polish ...