Tech A says that torque-to-yield head bolts are tightened to, or just past, their yield point. Tech B says that the yield point is the torque at which the bolt breaks. Who is correct?

Question

Quizplus · Accepted Answer

Torque-to-yield head bolts are designed to be tightened to their yield point, which is the point where they begin to stretch and provide a more uniform clamping force. The yield point is not where the bolt breaks; that would be the ultimate tensile strength.

Tech a Says That Torque-To-Yield Head Bolts Are Tightened To