80-55-06 Ductile Iron

Dura-Bar 80-55-06 ductile iron will contain nodular graphite in a matrix of ferrite and pearlite. The pearlite/ferrite structure provides higher wear resistance and strength when compared to a ferrite grade of ductile iron. This material is readily machinable with good surface finishes. Tensile and yield strengths are similar to AISI1040 steel in the as-rolled condition. This specification conforms to ASTM A536 grade 80-55-06. Download the 80-55-06 Ductile Iron Product Brief.

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80-55-06 Ductile Iron


The microstructure consists of Type I & Type II nodular graphite as defined in ASTM A247. The matrix is pearlite and ferrite. The edge or rim has a higher nodule count and ferrite content. 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

80-55-06 ductile iron microstructure at center

Edge Area

100x, etched in 5% Nital

80-55-06 ductile iron microstructure at edge

Heat Treat Response

Dura-Bar 80-55-06 can be oil quench hardened from 1600° (885° C) to a minimum hardness of Rockwell C 50 on the outside of the bar. The inside diameter hardness will be less than Rockwell C 50. Lower quench hardness on the inside diameters are a result of larger graphite nodules and not a loss of matrix hardness. Get more details including typical Jominy end quench curve, methods and cycle times, and temperature effects by downloading the Dura-Bar Heat Treating Guide.


Stock Sizes: 80-55-06 and 80-55-06X

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Dura-Bar round products

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.

Grade Shape Diameter (in) Surface Wt/Bar (LBS) Length Bundle Quantity
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Dura-Bar rectangle products

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.

Grade Shape Height (in) Width (in) Surface Wt/Bar (LBS) Length Bundle Quantity

Custom Shapes

Dura-Bar custom shape products

Sizes can be designed to meet your requirements.

All custom shapes are special order and are quoted individually at minimum run quantities. Contact us to find out if a Dura-Bar custom shape will work for your part.

Technical Specifications

Chemical Composition

Carbon and silicon targets are specified for each bar size in order to maintain mechanical properties. Magnesium is added as an inoculant to produce nodular graphite. Small amounts of alloying elements are used to stabilize the pearlitic structure.

Element Percentage
Carbon 3.50–3.90%
Silicon 2.25–3.00%
Manganese 0.15–0.35%
Sulfur 0.025% Max
Phosphorus 0.05% Max

Mechanical Properties

Hardness properties for various diameters are shown in the table. Hardness properties listed are minimum and maximum across the bar. For rectangles, squares and shapes, the hardness properties will depend on minimum and maximum section thickness and will be supplied on request.

Size Range BHN
Inches mm Min Max
1.000–1.500 25–38 187 255
1.501–3.000 38–76 187 255
3.001–20.000 76–508 187 255

Tensile strength is determined from a longitudinal test specimen taken from mid-radius of the as-cast bar. In bars under 1.5" diameter, elongation will be 4% minimum.

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

Dura-Bar®: Continuous Cast Iron Bar Stock

1800 West Lake Shore Drive
Woodstock, IL 60098


800-BAR-MILL (227-6455)

Fax: 815-338-1549 Sales

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