Alloy steel casting is a steel casting process that is alloyed with various elements, in totals ranging from 1.0% to 50%, to enhance its mechanical properties. Alloy steels are divided into two groups: low alloy steels and high alloy steels. Most commonly, the alloy steels used in investment casting are low alloy steels.
Strictly speaking, every steel is an alloy, but not all steels are called "alloy steels". The simplest steel is an alloy of iron (Fe) and carbon (C) (about 0.1% to 1%, depending on the type). However, the term "alloyed steel" is a standard term referring to steels that have deliberately added other alloying elements in addition to carbon. Common alloying agents include manganese (the most common one), nickel, chromium, molybdenum, vanadium, silicon, and boron. Less common alloying agents include aluminum, cobalt, copper, cerium, niobium, titanium, tungsten, tin, zinc, lead, and zirconium.

Alloy Steel Castings
With investment castings made of alloy steel, we can achieve many properties including (compared to carbon steel): strength, hardness, toughness, wear resistance, corrosion resistance and hardenability. Of course, heat treatment will help to improve some of these improved properties if investment casting is not straightforward.