1.1This specification covers continuous grain flow forged carbon and alloy steel crankshafts for medium speed diesel and natural gas engines.
1.2The steel used in the manufacture of the forgings is required to be vacuum degassed.
1.3The choice of steel composition grade for a given strength class is normally made by the forging supplier, unless otherwise specified by the purchaser.
1.4Provision is made for treatment of designated surfaces of the crankshaft to provide enhanced fatigue strength, or wear resistance, or both.
1.5Except as specifically required in this specification, all provisions of Specification A788/A788M apply.
1.6Unless the order specifies the applicable “M” specification designation, the material shall be furnished to the inch-pound units.
1.7The values stated in either inch-pound units or SI (metric) units are to be regarded separately as standard. Within the text and tables the SI units are shown in brackets. The values stated in each system are not necessarily exact equivalents; therefore, to ensure conformance with the standard, each system shall be used independently of the other, and values from the two systems shall not be combined.
1.8This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.