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 is similar to ASTM A536 grade 80-55-06.
The microstructure consists of Type I & Type II nodular graphite as defined in ASTM A247. The matrix is pearlite and ferrite. The "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.
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. Typical Jominy end quench test data are shown in the section on Heat Treating.