Gray and Ductile irons are the only metals known to mankind that are denser in the liquid state than they are in the solid. During solidification, there is a net expansion, which is the reason why these metals are so castable. The self-feeding phenomena generated by the carbon in Gray and Ductile iron is the main reason why we can cast complex shapes with different section sizes and still produce sound castings. Metal Classifications Gray Iron     ASTM A48 Grades 20, 25, 30, 35, 40, 45, 50 & 60 A, B, & C     ASTM A126 Class A, B, & C     ASTM A278 Grades 30, 35, 40, 50, 60     ASTM A159 Grades G1800, G2500, G3000, G3500 & G4000     Special alloys are available upon customer request. Gray Iron Properties Table Class Iron 20            30            40            50            60   All Strength   Machinability   Better Machining Finish Heat Shock Resistance   Elevated Temperature Strength Dampening Capacity   Modulus of Elasticity Thinner Sections Possible   Wear Resistance Ductile Iron         ASTM A536 Grades       60-40-18 65-45-12 80-55-06 100-70-03 120-90-02         Mil Specifications MTL I-11466A & MIL I-24137            Special alloys are available upon customer request. Ductile Iron Properties Table Class Iron 60            80            100            120   Yield Strength   Machinability   Wear Resistance   Ductility   Hardenability   Impact Strength Austempered Ductile Iron ADI is an all purpose ductile iron that bridges the gap between standard ductile irons and steel castings and forgings. The ausferritic matrix of ADI is a mixture of acicular ferrite and high carbon retained austenitc. This matrix gives ADI impact resistance and toughness comparable to steel castings and forgings. Other ADI advantages are a 10% lighter casting than steel castings, and outside casting surface can stress harden to a Rockwell 52C while the balance of the casting retains its impact resistance and toughness, and ADI mantains its mechanical properties at sub zero temperatures. Abrasion Resistance Applications Acicular Iron - Medium & High Hardness West Cast - 300 BHN All stress hardened grades of ADI High Temperature Applications Gray Iron - ASTM 319 Grades I, II, & III Type A, B, C, & D Ductile - ASTM A395 60-40-18                 HS - High Silicon For more information on ADI please see our dedicated section on this website.