What happens when head bolts are torque to yield?
Torque-to-yield (TTY) head bolts are designed to stretch when used. Once stretched, they are not as strong as before. Consequently, they cannot provide the same amount of clamping force and may break or shear off if reused.
Can a torque wrench be used to tighten head bolts?
One of the most common misconceptions about using a torque wrench to tighten head bolts is that the torque reading on the wrench indicates how much load is on each bolt. The reading on the wrench only tells you how much twisting force is being applied on each bolt.
Is there a way to check the torque of a bolt?
Bolt torque can be checked with a tool such as a torque wrench, but without a value as a guideline, a torque wrench offers no advantage. To arrive at the correct torque value, several other values must be found first. Two principles influence the correct clamping pressure for each bolt, known as clamp load.
Do you tighten the nut or the bolt head?
The answer depends upon which tightening process is being used. For torque controlled tightening whether the nut is tightened and the bolt head held, or the bolt head tightened and the nut held, can be of importance. The general objective from a tightening process is to achieve a consistent bolt preload.
What is the torque for bolts?
Different bolt sizes and grades have different torque specifications. For example, 6 mm bolts with a 10.9 grade have a maximum torque value of 10 foot-pounds, while the same-size bolts with a 12.9 grade have a maximum torque value of 12 foot-pounds. Consult your shop manual for the most precise listings.
What are torque specifications?
Torque specifications are for dry threads only. The fastener threads should be free of oil, dirt, grit, corrosion, etc. The hardware should turn freely without binding when tightened by hand. It is important NOT to lubricate hardware threads or seats. The friction at which torque is measured against should come from the hardware seats.
What is a torque screw?
Screw Conveyor Torque. Torque is defined as the twisting force exerted by the drive unit on the conveyor screw. Torque is transmitted through the drive shaft of the drive unit to the screw and converted to force to convey the bulk material.