Introduction
Forgings made of nodular cast iron are common components in many engineering or industrial applications from automobile gear boxes to medium-sized municipal projects. There are several different types grades of nodular cast iron each categorized according to its mechanical and physical properties. Each of these grades, whether foreign or domestic, is identified by a specific steel number or grade code.
Types of Nodular Cast Iron
Most nodular cast iron products are offered in the following types or grades specified according to ASTM A395 and ASTP A536: Grade 60-40-18, Grade 60-42-10, Grade 65-45-12, Grade 70-50-05, Grade 80-55-06, and Grade 100-70-03.Grade 60-40-18is produced with a slightly higher manganese content and a slightly lower silicon content than Specification A6683, which is equal to Grade 65-45-12. Grade 60-42-10 is produced with the same ferrous contents as Grade 60-40-18, but is heat-treated to a higher hardness level in order to achieve a more specific hardness requirement. It is also produced with a slightly higher manganese content and a correspondingly lower silicon content than Specification A6683, which is equal to Grade 65-45-12. Grade 65-45-12 is the most widely used grade of nodular cast iron because of its excellent casting capabilities combined with considerable strength and ductility. It is a higher strength version of Grade 60-40-18 and is produced with a slightly higher manganese content and a correspondingly lower silicon content than Specification A6683. Grade 70-50-05 is a higher strength version of Grade 65-45-12, produced with a slightly higher manganese content and the same silicon content as Grade 65-45-12. Grade 80-55-06 is the highest strength version of nodular cast iron. It is produced with a slightly higher manganese and nickel content and a slightly higher silicon content than Grade 65-45-12. Grade 100-70-03 is the highest strength version of nodular cast iron and is produced with a considerably higher manganese content and slightly higher nickel and silicon content than Grade 65-45-12.
Foreign Grade Numbers and Grade Codes
In addition to the grades of nodular cast iron specified according to ASTM A395 and ASTP A536, there are several other international and foreign grade numbers that are frequently used to identify the types of nodular cast iron. These grade numbers include DIN 1693 (2.0312, 2.0414, 2.0330, 2.0432, 2.0447, 2.0537 and 2.0617), UNI EN-GJS (400-18, 400-15 and 500-7), NS 12-204-01 (250-10, 300-7, 350-12 and 400-7) and SA-A536-65-45 (65-45-12). China also produces a variety of nodular cast iron grades with distinct grade numbers such as GB/T9439-2000 (QT400-18 and QT500-7).
Conclusion
Nodular cast iron is an important and versatile material used in a variety of industries from automotive to construction. There are many different types, grades and foreign grade numbers of nodular cast iron that need to be identified and specified, each identified by a specific steel number or grade code. The knowledge of different grade numbers and grade codes is necessary in order to identify and select the appropriate grade of nodular cast iron for any particular application.
