The invention provides a steel for machine structural use, which is excellent in machinability, comprising, in percent by mass, C: 0.1-0.6%, Si: 0.01-2.0%, Mn: 0.2-2.0%, S: 0.005-0.2%, Al: not more than 0.009%, Ti: not less than 0.001% but less than 0.04%, Ca: 0.0001-0.01%, O (oxygen): 0.001-0.01%, and...http://www.google.de/patents/US20030138343?utm_source=gb-gplus-sharePatent US20030138343 - Steel for machine structural use
