1.Specialized for 10 years 2.Carbon,stainless and alloy steel 3.Certified by ISO,GL,ABS 4.Heat treatment:N or Q+T 1.Features: ROLLING RING, OD MAX 5000MM, max weight is 15 ton. 2.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! hot forged steel ring sae4340