High Strength Hex Nuts

High-strength nuts are high-strength bolts, which are a kind of standard parts. In general, high-strength bolts can withstand a larger load than ordinary bolts of the same specification.

The shape and connection structure of high-strength nuts are basically the same as those of ordinary bolts. The main difference between the two is that the connection of ordinary bolts relies on the pressure and shear resistance of the shaft to transmit shear force, and the pre-tension force generated by the bolts is very small when the nut is tightened. , its impact will not be considered; the working principle of high-strength nut connection is to apply a large pre-tension force to the bolt intentionally, so that the extrusion force is generated between the contact surfaces of the connected parts, so there is a large friction force perpendicular to the direction of the screw rod, relying on This friction is used to transmit the connection shear. The pre-tensioning force of high-strength nuts is achieved by tightening the nuts, and ordinary high-strength nuts generally use the torque method and the angle method. Torsional shear type high-strength nuts are used to twist off the tail of the bolt to control the pre-tension.

The bolts connected by high-strength nuts are made of 10.9S or 8.8S high-quality alloy structural steel and are heat-treated, and the holes for high-strength bolts should be drilled. The aperture diameter of high-strength bolts for friction-type connections is 1.5-2.0 mm larger than the nominal diameter d of the bolts; the aperture diameter of high-strength bolts for pressure-type connections is 1.0-1.5 mm larger than the nominal diameter d of the bolts.

The construction of high-strength nuts must be initially screwed and then finally screwed. The initial screwing of high-strength nuts requires an impact-type electric wrench or torque-adjustable electric wrench; while the final screwing of high-strength nuts has strict requirements, the final screwing of high-strength shear-type high-strength nuts A torsional shear type electric wrench must be used, and a torque type electric wrench must be used for final torque type high-strength nuts.

High strength nut difference:

In general, high-strength bolts can withstand a larger load than ordinary bolts of the same specification.

The material of ordinary bolts is made of Q235 (ie A3).

The high-strength bolts are made of 45# steel, alloy steel (such as 20MnTiB, 35VB) or other high-quality materials, which are heat-treated after they are made to improve their strength.

The difference between the two is the difference in material strength.