Patent attributes
After it is tightened with a snug torque TA, a bolt is tuned by a total turning angle θS equivalent to the sum of an initial-set turning angle θA and a corrective additional-turning angle (θB+θC). The corrective additional-turning angle (θB+θC) is the sum of a first corrective additional-turning angle θB and a second corrective additional-turning angle θC, the first corrective additional-turning angle θB being to compensate for a situation where a bolt turning angle θ22 corresponding to the snug torque θA on an extension line of the bolt tightening torque properties C2 in a late tightening stage II is different from a bolt turning angle θ11 corresponding to the actual snug torque TA, the second corrective additional-turning angle θC being to compensate for a decrease of an effective bolt axial force that is caused by an existence of the initial tightening stage I.
