| 摘要 |
PROBLEM TO BE SOLVED: To provide means capable of easily and inexpensively evaluating a fastening characteristic with high accuracy under a condition close to an actual use condition.SOLUTION: An evaluation bolt 7 is used to evaluate a fastening characteristic of a bolt for fastening fastened members 15, 17 by plastic region fastening, by using a strain gauge 1. The evaluation bolt 7 is manufactured by using a bolt according to specifications same as those of a mass-produced bolt actually used to fasten the fastened members 15, 17, as material. A strength of a hardened portion 23 including a strain gauge mounting area, of the evaluation bolt 7 is made higher than a strength of an area excluding the hardened portion 23, by hardening, and tempering thereafter. The thermally-refined portion 23 is formed on a columnar portion 13 between a seat surface of a head portion 11 and a screw portion 12 of the evaluation bolt 7. The strength of the hardened portion 23 is preferably 1.1 times or more a strength of the other region. |
