... 2008/SGS test report/ROHS report Stainless steel ball Name: Stainless steel ballsMaterial: AISI304,316,420C,440CSize: ... type of modern steel and famous for its high corrosion resistant, wear resistance, strength and hardness ... Rockwell or higher. Martensitic Grades are known for high hardness and allowances must be made for poor ... further Information,Plz contact us! 8mm High Quality Stainless steel ball