Steel wire rod or bar with good cold deformability and machine parts made thereof

摘要

The present invention provides a steel wire rod or bar which exhibits good cold deformability even though it does not undergo spheroidizing annealing after hot rolling. The steel wire rod or bar with good cold deformability is characterized in that its ferrite structure contains no less than 25 nitride and carbide particles in a mixed state or composite state per 25 mum on average in a sectional area three-fourths of the diameter within the circumference of the rod or bar. Such nitride and carbide precipitates contribute to the reduction of flow stress at temperatures raised by heat generation at the time of cold deforming.