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Hot Rolling and Forging of Ductile Iron.
Neumeier-LA; Betts-BA; Crosby-RL
Afs Internat Cast Metals J 1976 Mar; 1(1):17-28
The Bureau of Mines investigated hot rolling and forging of experimental ductile iron castings made with up to 70 pct of foundry pig iron and 95 pct steelmaking pig iron. Both sand and permanent mold castings were evaluated. Between 1,550 deg and 1,950 deg f, most castings could be rolled to 90 pct reduction and forged to 70 pct without serious cracking. Charge and composition have less bearing on workability than on subsequent properties. Nickel produced some adverse effect, as did poor nodularity. Permanent mold castings, which had finer nodules and primary carbides, could be worked as readily as sand castings at 1,750 deg and 1,950 deg f. Plasticity improved with temperature. Small billets were also forged cold to 50 pct reduction without cracking. With equivalent nodularity, composition affects properties of wrought materials by altering the matrix and strength. Properties vary with reduction and improve with working temperature. Rolled material has high strength and anisotropy--low ductility in the transverse direction. Annealing improves ductility, but anisotropy persists. At 70 pct reduction, impact resistance is about twice as good in the longitudinal direction than in the transverse. Annealing about doubles impact resistance. Impact properties were somewhat lower when steelmaking pig iron was used instead of foundry pig iron. Cross rolling can reduce anisotropy by equalizing directional nodule deformation. Although workability and ductility are inferior to steel, more advantage could be taken of ductile iron's plasticity to work rough shapes to fina
Issue of Publication
Afs Internat. Cast Metals J., V. 1, No. 1, March 1976, PP. 17-28