G1A Gray

Dura-Bar G1A contains Type D graphite in a predominantly ferrite matrix. This specification was originally developed for the glass mold industry where fine grain structure and superior machining finish are needed. Dimensional growth due to repeated heating and cooling cycles is minimal due to the smaller graphite flake and size and ferritic matrix structure.

CENTER AREA 100x, etched in 5% Nitol EDGE AREA 100x, etched in 5% Nitol

The microstructure will contain Type VII, size 6-8 graphite as defined in ASTM A247. The matrix is predominantly ferrite. Chill carbides will be less than 5% in any field at 100x and will be well dispersed.

G1A is not intended for hardening. The matrix structure may be softened slightly by heating to 1400° F and furnace cooling to 400° F.