Method for increasing torsional fatigue strength in crankshafts

摘要

A method for processing a cast iron crankshaft to improve the torsional fatigue strength of the crankshaft includes forming oil holes into a portion of the crankshaft, treating the portion of the crankshaft to harden an annular area of the portion, and roller burnishing a length of the interior of the oil holes to an increased diameter. The roller burnished length of the oil holes extending from a surface of the crankshaft to at least beyond the hardened annular area.