Abstract
The authors studied the mechanical properties of four turbine rotors of Timken 16-25-6, to compare with that of the forged bars, of which they reported already. The results were as follows:
1. The effects of heat treatment on mechanical properties in the turbine rotors are the same as the forged bars. The "hot-cold worked" rotors have higher strength than the preci-pitation-hardened rotors.
2. The "hot-cold worked" rotors have the similar or somewhat lower value of the creep rupture strength and tensile and proof strength as compared with the forged bars. The rotor which have sufficient forging effects, have great ductilities and uniformity of mechanical properties.
3. The precipitation-hardened rotors have nearly the same mechanical properties when compared with the forged bars.
4. When forging effect of the rotor are insufficient, the clear pattern of micro-segregation are recognized, so that the ductilities are low and not uniform.
5. The mechanical properties of specimens which are taken in tangential or radial directions from the boss part of the upset rotor are lower in ductility than that taken from the rim part of rotors. It is because of the metal flow of the boss part that is across with the tensile direction.
