80-55-06 Ductile Iron
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80-55-06 Ductile Iron
Overview
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.
Microstructure
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.
Center Area
100x, etched in 5% Nital
Edge Area
100x, etched in 5% Nital
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
Rounds
Size Range: 2.000" 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.
Rectangles/Squares
Size Range Rectangles: 14.000" x 25.000" to 14.600" x 24.400"
As-cast rectangles and squares are made to the actual size with no allowance for machine stock added. Rectangles and squares are cast to actual dimension, with clean up stock dependent on the height and width ratio. See Stock Allowances for details. Rectangles and squares can be milled to achieve close tolerance benefits - see Services/Milling for details.
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% |