1.Specialized for 10 years 2.Carbon,stainless and alloy steel 3.Certified by ISO,GL,ABS 4.Heat treatment:N+Q+T 5.MOQ for 1Pc 1.Features: open die forging hollow ring with heattreatment2.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! open die forging hollow ring c45