Abstract: An apparatus for use in a crystal manufacturing system based on a floating zone method or Czochralski method, adapted to control a quantity relating to the diameter of a crystal rod at the crystallization boundary, and designed to reduce hunting in the control of the quantity relating to the crystal diameter so as to prevent disturbance in crystallization and reduce irregularities in the surface of the crystal rod even if there is a discrepancy between a predetermined pattern and the ideal pattern with respect to the quantity to be controlled.

Abstract: A carbon steel with at least 1% by weight carbon and at least one carbide-forming alloying element such as chromium is forged into a construction machine-tool part for engagement with abrasive material, the forging provides a fiber extension direction which coincides with the principal direction of abrasive action.