Gray Iron

Gray Iron is commonly referred to as Cast Iron. The name, Gray Iron, is derived from the characteristic gray color of the casting when fractured. Characteristic properties of Gray Iron are excellent machinability, good wear resistance, high vibration absorption, and good fluidity. Types of Gray Iron are commonly designated by a class number which indicates minimum tensile strength in thousands of pounds per square inch (KSI). Lower Classes of Gray Iron provide better machinability with higher classes offering strength and wear resistance. Castings are intended for general engineering use.


  • CL 20
  • CL 30
  • CL 35
  • CL 40

Typical Applications

  • Machine Frames and Bases
  • Spindle Housings
  • Bearing Housings
  • Pump Housings
  • Sprockets

ASTM A278 – Pressure Containing Castings for elevated temperatures

ASTM A319 – Non-pressure containing castings for elevated temperatures.
A319 may be alloyed with Chrome and Copper.

Typical Applications

  • Stoker and Fire Box Castings
  • Grate Bars
  • Ingot Molds
  • Glass Molds
Ductile Iron

Ductile Iron is commonly known as Nodular Iron. The name Nodular Iron comes from the fact that graphite in Ductile Iron forms in spheres or “nodules”. This provides the metal with considerable elasticity, impact resistance and high yield strength. Ductile Iron has steel like mechanical properties with the castability, machinability, and corrosion resistance of Gray Iron. The three numbers in the Ductile Iron designation represent the physical properties of the iron. First is the Minimum Tensile strength in thousands of pounds per square inch (KSI), second is the Minimum Yield Strength (KSI) followed by the Percent Elongation.


  • 60-40-18 – Annealed
  • 65-45-12
  • 80-55-06

Typical Applications

  • Machinery castings subject to shock and fatigue loading
  • Shanks for Asphalt Mixers and Pug Mills
  • Gears and Rollers
  • Flap Valve Housings
Abrasion Resistant Iron

Abrasion Resistant Irons are low in silicon and are generally alloyed with Nickel and Chrome.  There is an insignificant amount of graphite present in Abrasion Resistant Irons.  The majority of carbon is in the form of iron carbides making it very hard, brittle and in most cases unmachinable.  Abrasion Resistant Irons excel in applications with a high degree of wear and low impact.

Ni-Hard, ASTM A532 CL 1A – 550-600 Brinell hardness

CRC Low Alloy White Iron – 300-400 Brinell hardness

Typical Applications

  • Pipes and Elbows – Conveying highly abrasive materials
  • Pug Mill Tips
  • Asphalt Mixer – Liners and Tips
  • Clinker Grinders