PROBLEM TO BE SOLVED: To provide a link capable of reducing a step caused by the wear on a tread of the link, and its manufacturing method.;SOLUTION: The link has linkage ports 15, 16 on both ends thereof, and has a tread 13 which is arranged to connect an upper portion of one linkage port 15 to an upper portion of the other linkage port. Parts in a vicinity of both ends of the tread 13 are formed low in hardness compared with a part in the center of the tread. The parts located in a vicinity of both ends of the tread can be easily worn compared with the part located in the center. Since the easily worn parts in a vicinity of both ends are closer to the linkage ports, the wear during the use is smaller than that of the part located in the center of the tread. Thus, the step generated in the tread can be reduced from the difference in the wear during the use.;COPYRIGHT: (C)2006,JPO&NCIPI
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