80-55-06X Ductile Iron

80-55-06X is a grade of ductile iron available in larger rounds and rectangles. This grade tends to contain more pearlite making the material a good fit in applications where considerations to wear resistance and surface finish are required. The additional pearlite also makes this material responsive to heat treating, like through-hardening and surface hardening. Download the 80-55-06X Product Brief, or X Products for all X grades.

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80-55-06x Ductile Iron


The microstructure consists of Types I & II nodular graphite as defined in ASTM A247. The matrix is ferrite with approximately 5–25% pearlite. The edge or rim will have a higher nodular count and will be mostly ferrite. Chill carbides will be less than 5% in any field at 100x and will be well dispersed.

Microstructure area diagram

Center Area

100x, etched in 5% Nital

65-45-12 ductile iron microstructure at center

Edge Area

100x, etched in 5% Nital

65-45-12 ductile iron microstructure at edge

Heat Treat Response

Dura-Bar 80-55-06X can be heat treated by conventional methods. Hardening can be accomplished by heating and quenching the material from 1600° F resulting in Rockwell C hardness up to 50 HRC.  Induction and flame hardening can be performed but may require an additional pre-heat treatment to accomplish the desired hardness and microstructure.

Stock Sizes


Size Range: 25.180" to 26.560"

As-cast round bars are made to clean up at the nominal size. Additional stock is added to allow for out-of-round and normal imperfections in the as-cast surface. Stock allowance is a function of the bar diameter - see Stock Allowances for details. Other finishes available are Centerless Grinding and Centerless Turning, for demanding tolerance applications.


Size Range Rectangles:14.600" x 24.400"

As-cast rectangles are made to the actual size with no allowance for machine stock added. Rectangles are cast to actual dimension, with clean up stock dependent on the height and width ratio. See Stock Allowances for details. Rectangles can be milled to achieve close tolerance benefits - see Services/Milling for details.

Technical Specifications

Chemical Composition

Magnesium is added as an inoculant to produce nodular graphite. Small amounts of alloying elements are used to stabilize the pearlitic structure.

Sulfur0.02% Max
Phosphorus0.08% Max

Mechanical Properties

Hardness properties listed are minimum and maximum across the bar. For rectangles and squares the hardness properties will depend on minimum and maximum section thickness and will be supplied on request.

Size RangeBHN

Tensile strength is determined from a longitudinal test specimen taken from mid-radius of the as-cast bar.

Mechanical Properties
Tensile strength psi (min)80,000
Yield strength psi (min)55,000
Elongation (min)6%

Typical Applications



Fluid Power:

Cylinder blocks, Gerotors, Glands, Manifolds, Pistons, Rotors, Valves


Barrell Rollers, Bushings, Chain Sheave Rollers, Chuck Bodies, Die Blocks, Flywheels, Gear Racks, Gears, Housings, Pile Drivers, Press Rams, Pulleys, Rams, Rotary Tables, Tie Rod Nuts


Core Boxes, Dies, Disamatic Pouring Rails, Grinding Rolls, Mill Liners , Pattern Plates, Plunger Pin

Power Transmission:

Gears, Pulleys

Pump and Compressor:

Gears, Housings,  Liners, Pistons, Rotary Screws, Rotors

Steel Mill:

Guide Rolls, Pinch Rolls, Runout Table Rolls


Gears, Motorcycle Disk Brake, Pulleys, Rail Spacers