Ductile Iron Material Grades Choosing Guide

This guide will help you to choose the suitable ductile iron material grades.

You know that the foundry should use ductile iron to produce the castings for you, but actually, there are several different material grades, so you are confused what material grades you should choose.

We hope this article could help you to learn about how to choose the suitable ductile iron material grades.

1. What material grades you could choose?

The following table is showing all the ductile iron material grades for each country. So, if you are American, then you could choose 60-40-18, 65-45-12, 70-50-05 etc., if you are from Australia, then you could choose 400-12, 500-7, 600-3 etc.

2. What is the function of material grades?

The material grades are from their specific material standards, for example, in USA, the common material standard for ductile iron is ASTM A536, in this standard, you could find the mechanical properties for 60-40-18 (tensile strength min. 414 Mpa, yield strength min. 276 Mpa, elongation min. 18%).

Therefore, when you tell us what material grades you need, then we will know what mechanical properties you required, then we could produce your casting parts accordingly.

3. How to choose the suitable material grades?

Choosing the ductile iron material grades is a very professional work, normally, only the professional material engineer could choose the suitable grade, but if you are not a material engineer, but you have to make one choice, then the following methods may help you.

A. Please check the 2D drawings, and the technical requirements you have, then you may find some clue for "material", the completed drawings should denote the material grades.

B. If you can not find any material information from drawings, then you may need to consider it by your experience. The following experience will help you.

B1. If you just need it to be ductile iron, and do not have special requirement to its mechanical properties, then you could choose "60-40-18" (equal grades for other countries will be GGG40, 400-12, 400-18, AS38, QT400-18). The above material equivalent table will help you.

B2. If you need the material have high strength, tough enough, could take high load force, then you could choose "65-45-12" or higher grade "70-50-05" (for its equal grades, please refer to the above material grade table).

B3. If you need the material have very high strength, need to take very high pressure load, need it to be very strong, then you could "80-60-03". However, you need to know that its elongation rate is only 3%, so its ductility is not good, and so its impact resistance is not good either.

Let me to explain more about this point. As for the grade 60-40-18, if it got large pressure load higher than 400 Mpa, it will be bent, but not broken suddenly, as for the grade 80-60-03, it can bear high pressure load up to 600 Mpa, but if the pressure load higher than 600 Mpa, it will be broken suddenly.

4. Some important issues for choosing ductile iron material grades !!!

Please do not choose higher grades than "600-3" if you do not have sufficient reasons. The higher material grades, such as 700-2, 800-2 and 900-2, although their tensile strength is very high, but their elongation rate is very low accordingly. The higher strength means the lower elongation, so means the lower impact resistance, and their brittleness will be higher.

Moreover, these high material grades will need higher production level, and further heat treatment, so means the much higher casting prices.

If you still can not make a good choice, then you could get help from some material engineer, or just tell your requirements to our dandong foundry. You just need to tell us where your parts will be used, and what kind of properties you may need. Then, we will give you our suggestion.

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