| 摘要 |
PURPOSE:To decrease cutting work so as to prevent loss of raw material and to increase toughness of the smaller diameter part of a shaft, by cutting the shaft from carbon steel of pearlitic structure having been subjected to spheroidization and cold working with the working direction as shaft direction. CONSTITUTION:Carbon steel for machine structure use of pearlitic structure, which has been made by melting S53C steel etc., is spheroidized to 70% or under and is subjected to cold plastic working at a reduction of area of 10% or above, pref. 30- 60% at ordinary temp. A shaft is cut so that the working direction may coincides with the shaft direction. Hence, the shaft has flattened ellipsoidal pearlitic structure which is lengthened in the axial direction, consequently, tough characteristic is given simply by utilization of work strengthening due to cold working. |
