| 摘要 |
PROBLEM TO BE SOLVED: To provide a bolt having improved toughness as well as reinforced tapping function, and to provide its manufacturing method. SOLUTION: The bolt 100 has a protruded portion 12a as a female screw forming portion which forms a female screw on the surface of a lower hole with plastic deformation. On the surface side of the protruded portion 12a, a thin carburizing layer is provided with carburizing heat treatment to impart mechanical property similar to that of a general bolt to the inside while hardening the surface of the protruded portion 12a. COPYRIGHT: (C)2006,JPO&NCIPI
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