Dura-Bar 100-70-03 ductile iron contains nodular graphite in a matrix of pearlite with small amounts of ferrite. The pearlitic structure maximizes strength and wear characteristics in a non-alloyed as-cast ductile iron. This specification is similar to ASTM A536 100-70-03.
The microstructure consists of Type I & Type II nodular graphite as defined in ASTM A247. The matrix is highly pearlite with small amounts of ferrite. The "rim" will have a higher nodule count and contain slightly higher ferrite concentration when compared to the center. Chill carbides will be less than 5% in any field at 100x and will be well dispersed.
Heat Treat Response
Dura-Bar 100-70-03 can be oil quench hardened from 1600° F (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 for 80-55-06 ductile iron are shown in the Heat Treating section. Similar data applies to 100-70-03.