Brittle Fracture of Rotors.

Machine rotors must be made out of steels which ensure a ratio of the nominal plasticity limit to the tensile strength of less than 0. 7. For other steels the threshold and critical crack length must be calculated. By comparing them with the length of the largest fault allowed by the forging manufacturer, a rotor design with or without an axial hole may be selected. In the case of high-speed rotors the safer design is the one with an axial hole.