Ductile Cast Iron’s (SG Iron) material grades differ as per regional standards. In the USA, for instance, the most common material standard is ASTM A356. Mechanical properties like 60-40-18 (tensile strength 414 Mpa, yield strength 276 Mpa, elongation 18%) are common. Therefore, proper communication is necessary so that the foundry manufactures castings as per the requirements with the desired mechanical properties. Selecting the correct ductile iron grade material is a tough task. However, a professional foundry can make short work of the process. Here is how the correct grade of ductile iron can be chosen according to the application.

Check 2D engineering drawing and other technical specifications. These should   point at the appropriate materials, and the completed drawings should also cover material grade information. If your customer needs only ductile cast iron with no special requirements for its mechanical properties, go for 60-40-18 (GGG40, 400-12, 400-18, AS38, QT400-18). For higher needs: strength, toughness, and stiffness, choose 70-50-05 or 65-45-12. For materials that require very high strength, very high-pressure load capability, check 80-60-03. This said, ensure its elongation rate is only 3 per cent, such that its ductility isn’t ideal which can impact resistance. Decide what actually works considering both its pros and cons. Look out for How ductile iron can replace steel.

For 60-40-18 grade ductile cast iron, it is found that it can easily bend under the impact of higher pressure loads (over 400Mpa), but not breakable like 80-60-03 grade ductile cast iron. If for anything else, pick a level notch higher than 600-3. Superior material grades feature superior tensile strength all this at the expense of lower and lower elongation. The higher the strength of the SG cast iron type, the more brittle the chosen material, and as a result there is a reduction of impact resistance. In addition, these superior material grades will need higher production levels and additional heat treatment, which will lead to comparatively higher casting costs, in general.