Hot working of ductile iron alloyed with molybdenum

Sand and permanent mould ductile iron castings (SMC & PMC), containing up t o 0.5% Mo, were hot worked at 1050 degrees C with different total reduction up to 90%. Most of the castings could be rolled at high reduction per pass (average 36%) of up to 75% total reduction without serious cracking, while all of the castings could be forged without cracking. Reducing reduction p er pass down to 10%, all castings could be rolled up to 90% without serious cracking. The ductile iron (DI) rolled from PMC exhibits lower tensile str ength than that rolled from SMC. The tensile strength and hardness of as-ro lled SMC and PMC are increased with high Mo content (0.5%). Heavy rolling t o 70% without reheating between passes resulted in an increase in the hardn ess. Austenite transforms into acicular and/or bainitic ferrite structure d uring the air cooling of the thin heavily rolled sheets of DI alloyed with Mo.