Cast Iron Mechanical Properties
Cast iron has many good mechanical
properties. According to my personal experience in Dandong Foundry
in China, herein I listed some main chemical properties for the
reference to buyers.
1. Tensile strength
Tensile strength is the most important
physical property for iron castings. Its unit is RmN/mm2. Tensile
strength will show the strength of cast iron when it is pulled until
broken. For example, the ductile iron 60-40-18 has tensile strength
of 60000 psi, therefore, it is equal to 414 Mpa. Therefore, if your
parts need to use this material, then your supplier should keep
their iron castings with min. 414 Mpa tensile strength.
2. Yield strength
Yield strength is another definition to
define the strength of cast iron, I do not talk about its real
meaning here. It is not very necessary to check this property since
it just more deeply measure the strength of cast iron. The tensile
strength has already covered the most of requirements to the
strength. As for the ductile iron 60-40-18, its yield strength is
40000 psi, equal to about 276 Mpa.
Sometimes, elongation is very important.
High elongation means the iron casting can be pulled to longer,
which means they have better ductility or called as malleability.
Therefore, they will not be broken easily. The ductile iron has
higher elongation than gray iron. As for the ductile iron 60-40-18,
it has 18% elongation.
Hardness is also important sometimes. As
for the machined parts, the hardness should not be too high to
affect the machining process. As usual, the Brinell Hardness from
160-220 should be a good range. Too high may cause the hard spots
during machining, too low will affect the application. Some buyers
required the Rockwell hardness as the standard. As for the
comparison between these two standards, please check our blog.
Some buyers will require V Charpy Impact Test to get the impact
property of cast iron. This test needs the professional lab. to
perform. As I know, most of iron foundries in China do not have this