Is superior in resistance scuffing Characteristic the piston ring

摘要

PROBLEM TO BE SOLVED: To provide a piston ring excellent in scuffing resistance, having superior drawability and rollability in a wire manufacturing process, and also having extremely superior bendability at the time of ring forming even in the case where a relatively high value of hardness after heat treatment is set. ;SOLUTION: The piston ring is composed of a bent martensitic steel where a surface nitrided layer is formed. This piston ring has a composition which contains, by weight, 0.2-1.2% C and 5.0-25.0% Cr and in which the value of Cr (wt.%)/C (wt.%) is regulated to 15-45. It is preferable to regulate the contents of Si and Mn to ≤0.25% and ≤0.30%, respectively, and 0.3-2.5% of one or ≥2 elements among Mo, W, V, and Nb, or ≤4.0% Cu, 2.0% Ni, and ≤1.5% Al can be incorporated. By this method, excellent scuffing resistance can be attained even in the case of a piston ring of 5.0-12.0% Cr content.;COPYRIGHT: (C)1999,JPO