| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a shot peening method giving a higher compressive residual stress compared to the conventional one to a workpiece, while inhibiting cutting erosion. <P>SOLUTION: A projection material having the hardness higher within the limits of 50 to 250 HV than that of the workpiece is projected against the workpiece whose hardness HV(m) given by the following formulas (1) to (3) is 750 HV and more to give the workpiece high compressive residual stress of 1800 MPa and more, while the cutting erosion amount of the workpiece is suppressed to 5μm and less. Formula (1): HV(m1)=äf(C)-f(T, t)}(1-γ<SB>R</SB>/100)+400×γ<SB>R</SB>/100, formula (2): f(C)=-660C<SP>2</SP>+1373C+278, and formula (3): f(T, t)=0.05T(logt+17)-318, where C is a surface layer C (carbon) concentration (mass%), T is tempering temperature (K), t is tempering hold time (hr), andγ<SB>R</SB>is remaining amount of austenite (volume%). <P>COPYRIGHT: (C)2009,JPO&INPIT</p> |
