Alloy Steel in Casting, Cast Steel Foundry
There are many types of carbon and alloy steels used for
castings. The choice of which will depend greatly on the
Cast steels can be broken into five ge-neric groups, (Table 1),
which depend on the carbon and alloy content.
Table 1 - General Alloying Content
Steels will also contain many different alloying elements within
their chemical composition. Table 2 shows the various alloying
elements and the effects that they have on the steel alloy. The
more common elements are carbon, silicon (0.2%-2.5%), manganese
(0.25% - 2.0%), and sulfur (max 0.05%).
Cast steels are often used when the im-pact properties or
elongation of irons are insufficient for the application. Cast
steels must also be specified if the part is to be welded. Cast
steel alloys are formulated to exhibit certain material
properties. This could range from enhancing mechanical
properties like tensile strength and elongation, to improved
machinability or hardenability.
A cast steel part is almost always heat treated after shakeout
in order to get the required material properties for the part.
Exceptions would include consumable wear castings. The
mechanical properties that are achievable are greatly dependent
on the alloy being heat treated.
The more common heat treat processes are:
Anneal – provides a soft low strength structure with maximum
Normalize – provides a medium strength and hardness with
Quench and Temper – Provides the maximum strength levels with
good ductility and wear resistance.