What is tension torque?
What is tension torque?
“Torque” is simply a measurement of the twisting force required to spin the nut up along the threads of a bolt, whereas “Tension” is the stretch or elongation of a bolt that provides the clamping force of a joint. This is the most common form of providing load to a bolt.
What method used has a better axial load accuracy torque or tension?
Whether the bolt torque is achieved through the use of a manual “clicker” torque wrench, pistol grip torque wrench, or a hydraulic torque wrench, it is the most simple method of achieving axial load. The big advantage to torquing is that is typically more cost-effective than tensioning.
How much torque do you need to tighten a bolt?
Example – Required torque for tightening a Imperial bolt. The required bolt clamping force for a joint is 20000 lbs. The torque required for a 3/4″ dry steel bolt to achieve this tension can be calculated as.
How to calculate the torque of a M30 metric bolt?
The proof load for a M30 metric bolt grad 8.8 is 373000 N. The torque required to achieve this tension with a dry bolt can be calculated as Lubricating the bolt with SAE 30 oil reduces the torque required to achieve the same tension with approximately 40%. The reduced torque can be calculated
How is the torque of a bolt calculated?
The calculator is generic an can used for imperial and metric units as long as the use of units are consistent. Note that standard dry torques are normally calculated to produce a tensile stress – or axial force or clamp load – in the bolt that equals to 70% of minimum tensile strength or 75% of proof strength.
What is the nominal value of torque tension?
Accepted nominal values for many industrial applications are: K = 0.20 for as-received steel bolts into steel holes K = 0.15 steel bolts with cadmium plating, which acts like a lubricant, K = 0.28 steel bolts with zinc plating. The K-value is not the coefficient of the friction (µ); it is an empirically derived correlation factor.
How is torque measured on a head bolt?
Traditional head bolts are tensioned to a predetermined torque measured by a torque wrench. This torque reading is not an accurate measurement of the downward clamping load but rather an accumulated measurement of friction resistance between the two threads and the spot face and bolt head and the clamping pressure.
Example – Required torque for tightening a Imperial bolt. The required bolt clamping force for a joint is 20000 lbs. The torque required for a 3/4″ dry steel bolt to achieve this tension can be calculated as.
The proof load for a M30 metric bolt grad 8.8 is 373000 N. The torque required to achieve this tension with a dry bolt can be calculated as Lubricating the bolt with SAE 30 oil reduces the torque required to achieve the same tension with approximately 40%. The reduced torque can be calculated
How does torque affect the tension of a fastener?
Tension is the force that actually holds an assembly together. Put another way: A bolt can stretch similar to a spring, as it becomes tightened once all the parts of the assembly are brought together. The higher the torque applied to the fastener, the more tension is created as the bolt stretches.
