| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a piston ring which has good thermal conductivity and resistance to permanent set and can be applied, for example, as an oil ring and a second ring for internal combustion engines, and to provide a piston ring which has better resistance to permanent set and can also be applied as a top ring. <P>SOLUTION: The piston ring is made of a heat-treated steel which contains C, Si, Mn, and Cr in a prescribed range, wherein the values of parameters A and B calculated from these contents using the equations (1): A=8.8Si+1.6Mn+1.7Cr and (2): B=36C+4.2Si+3.8Mn+4.5Cr, are 9.0 or less and 10.8 or more, respectively. Particularly, the piston ring for the top ring is made of a heat-treated steel in which the lower limit of the content of C, Mn, and Cr is increased; the upper limit of the content of Si is decreased; and the value of parameter B is 14.0 or more. <P>COPYRIGHT: (C)2010,JPO&INPIT</p> |
