| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a flange and a joint made of extra-low carbon stainless steel and a sealing valve element made of extra-low carbon stainless steel dispensing with a seal member by an extra-low carbon stainless steel material having both of adhesion and peelability. <P>SOLUTION: The flange is obtained by forming a hollow made of the extra-low carbon stainless steel having carbon concentration of 0.01% or less. The flange includes a seal structure on a main surface thereof, the seal structure has a protruded shape, the protruded shape includes a flat surface almost parallel to the main surface of the flange and a curvature surface extended from an end of the flat surface to the main surface of the flange. When a seal width is W1, a flat surface width is W2, a curvature radius is R, and a flat surface height is H, the following relationships are satisfied; dimension W1>W2≥0, R>W1, and R>H. Further, smoothness Ry of the flat surface is about 0.1μm, and the concentration of nitrogen injected to the flat surface is at least 1.65×10<SP>17</SP>/cm<SP>2</SP>. <P>COPYRIGHT: (C)2010,JPO&INPIT</p> |
