Gray Iron Material Grades Choosing Guide

This guide will help gray cast iron buyers understand how to select the appropriate gray cast iron material grades for their casting products.

1. Which grey cast iron grades can you choose?

The table below shows all gray iron material grades in each country. So, if you are American, then you can choose No. 20, 30, 35 or 45, etc. If you are Australian, then you can choose T150, T220, T260 or T300, etc.

2. What is the role of material grade?

The material grade comes from its specific material standard. For example, in the United States, the general material standard for ductile iron is ASTM A48. In this standard, you can find No.25 mechanical properties with the minimum tensile strength. 172 Mpa, No. 30 tensile strength 207 Mpa.

Therefore, when you tell us what material grade you need, we will know what mechanical properties you need, and then we can produce your castings accordingly.

3. How to choose the right grade of gray iron?

Choosing a gray iron material grade is a very professional job. Usually only a professional material engineer can choose the right grade. However, if you are not a material engineer but have to make a choice, then the following methods may help you.

• A. Please check the two-dimensional drawing, as well as your technical requirements, and then you may find some clues about the “material”, the finished drawing should indicate the material grade.
• B. If you cannot find any important information in the drawings, you may need to consider it based on your experience. The following experience will help you.
• B1. If you only need gray cast iron or cast iron and have no special requirements on its mechanical properties, you can choose “No.20 or No.25” (the equivalent grades in other countries are GG15, EN-GJL) -150, T150, 150 , HT150). The material equivalent table above will help you.
• B2. If the material needs high strength, high strength, and can withstand larger load forces, you can choose “No. 30” or higher grade “No. 35” (for equivalent grades, please refer to the material grade table above)).
• B3. If you need materials with very high strength, need to withstand very high pressure loads, and need to be very strong, then you can choose “No.40” or “No.45”.

On this point, let me explain. For some products, such as stove parts, high material grades will bring some difficulties to further drilling work, so do not require high grades for these parts, higher grades will lead to higher production costs and higher defect rates. So unless you really need it, the lower grades will be better used for casting production.

4. Some important issues in choosing gray iron material grades

For most foundries in China, we can produce low and medium gray cast iron material grades, but not everyone can produce high gray cast iron grades, such as No. 50 or No. 60. They need further heat treatment, so if you need very high resistance Tensile strength, but does not require the special mechanical properties of gray cast iron, and nodular cast iron material can be considered, which is stronger and tougher than gray cast iron.

If you still cannot make a good choice, then you can seek the help of some material engineers, or tell us your requirements. You just need to tell us where your parts will be used and what your application requirements are, and then we will give you our suggestions.