Specialty Steels and Other Iron Alloys Information

Rolls of silicon steelSpecialty steels and other iron alloys have specialized or proprietary compositions or properties that are specifically engineered for certain service conditions.  There are different variations of specialty steels and iron alloys made for different conditions and services. These can be categorized by the composition of the steel or alloy or by the design purpose.

Stainless steels are steels that contain a minimum of 10% chromium and are more resistant to corrosion than normal steels. They can vary in composition from a simple alloy of iron and chromium to complex alloys containing chromium, nickel, and various other elements in small quantities. Stainless steel’s corrosion resistance makes it ideal for a variety of applications including cookware, cutlery, hardware, surgical instruments, appliances, industrial equipment, and structural alloys for the automotive and aerospace industries. Nitronic 50 is a specialty stainless steel that offers greater corrosion resistance and higher yield strength than most other commercial stainless steels.

Alloy steels are steels alloyed with various different metals and materials to improve mechanical properties. Common alloy materials include manganese, nickel, chromium, molybdenum, silicon, and vanadium. Many of these steels find their use in exotic and highly-demanding applications such as turbine blades, electric motors, and transformers in the aerospace, nuclear, and electrical power industries. 

Electrical steel or silicon steel is specialty steel made from the alloying of silicon with iron. It is designed to exhibit certain magnetic properties that provide high permeability and low core loss for more efficient transformers and other electrical systems. The silicon alloy gives the steel its high electrical resistivity. Electric steels play a vital role in the generation, transmission, distribution, and use of electrical power. 

Tool steels are wear-resistant, ferrous alloys based on iron and carbon with high levels of alloying (hardenability and property modifying) elements such as chromium, molybdenum, tungsten, and vanadium. They are specially designed for use as machine and tool blades and components such knives, dies, rolls, stamps, drills and screws. Choice of tool steel grade depends on whether the most important property of the material is a sharp cutting edge (knives and blades), impact resistance (hammer mills), or heat resistance (high speed cutting).


Selecting metals and metal alloys requires an analysis of the desired specifications. Dimensions to consider include:

  • Outer diameter (OD)
  • Inner diameter (ID)
  • Overall length
  • Overall thickness

Other specifications of importance (based on application) include product shape, tensile strength, yield strength, melting point, conductivity, corrosion resistance, ductility, and malleability. These properties differ based on the material or alloy composition.

Image credit:

HPSC Steel Joint Stock Company