Iron Castings | Alloy Guide | Waupaca Foundry

gray, ductile, and compacted graphite iron castings

Alloy Guide


Waupaca Foundry produces various grades of gray, ductile and compacted graphite iron castings. The difference in these types of iron is the characteristics of the graphite used in the material. 

Gray Iron

Gray iron is called that because when it is fractured, its surface appears a dull gray color. In this product, the graphite is flaked. Benefits of gray iron are:

  • Excellent castability
  • Good machinability
  • Good wear resistance
  • High damping capacity which means it limits vibration in a finished casting
  • High thermal conductivity and is able to wick away heat
  • Excellent compressive strength
  • Good tensile strength

We produce several different grades of gray iron castings at our foundries:
Damped G1800…145-201 HBW, Plant 1
FC150 HC…149-229 HBW, Plant 1 and Plant 5
FC150 B…170-235 HBW, Plant 5
G3000… 187-241 HBW, Plant 1, Plant 2/3, Plant 5 and Plant 6
G3500 Base…187-255 HBW, Plant 1
G3500 Alloyed…207-255 HBW, Plant 1, Plant 2/3, Plant 5 and Plant 6
G4000 Base …197-269 HBW, Plant 1
G4000 Alloyed …217-269 HBW, Plant 1 and Plant 2/3

Ductile Iron

In Ductile iron the graphite is like a pillow and acts as "crack-arresters" to give ductility and toughness superior to all other cast irons. Benefits of ductile iron are:

  • Excellent tensile strength
  • Increased ductility which ensures finished materials will bend before breaking
  • Excellent impact properties
  • Good machinability
  • High modulus of elasticity which measures the degree of “stiffness” in the material

We produce several different grades of ductile iron castings at our foundries
60-40-18 (HT) …187 HBW max, Plant 4
65-45-12 …156-217 HBW, Plant 4, Plant 5 and Plant 6
80-55-06 …187-255 HBW, Plant 4, Plant 5 and Plant 6
100-70-03 …241-302 HBW, Plant 4, Plant 5 and Plant 6
120-90-02 (Q&T), Plant 4 and Plant 5
ADI (GRADES 1 - 5), Plant 4
Carbidic ADI, Plant 4

Compacted graphite iron

Compacted graphite iron has characteristics midway between ductile and gray iron and combines many of the properties of both. Compacted graphite iron is challenging to make with uniformity, Waupaca Foundry  closely monitors the production process. This type of iron provides many advantages:

  • The internal porosity solidifies in a manner similar to gray iron with the strength of ductile iron and allows complicated castings.
  • It has the ability to dissipate heat
  • Increased dampening properties