1.Specialized for 10 years 2.Carbon,stainless and alloy steel 3.Certified by ISO,GL,ABS 4.Heat treatment:N or Q+T 5.MOQ for Features: 1.Name: forging bearing rings2.Stabdards: ASME,ASTM,GB,JIS,DIN3.Materials: carbon steel,stainless steel and alloy steel.4.Certificates: ISO,GL and ABS5.Min Order:for 1 pc6.Best Quality and competitive price! forging bearing rings aisi4140