Driving torque: Driving torque is the main consideration in the application of screw cutting, screw rolling and self-locking parts. As a rotating part, the requirement is certain. Excessive driving torque will cause rotation failure and rotation failure All these will increase the cost of fasteners, so it is very necessary to reduce the driving torque as much as possible. This demand leads to another engineering requirement "drive-pull ratio". It is required to drive high-strength fasteners The relationship between the torque value and the required torque value of the internal thread that is resistant to falling or damage. The larger the value range, the more conducive to reducing poor assembly, repeated assembly and reducing the corresponding cost, the more suitable the fastener. For thread rolling For self-tapping screws, the required Drive to Strip Ratio (Drive to Strip Ratio) is 1: 3, that is, with one unit of drive torque, three units of tensile strength must be matched with thread strength.

Tightening torque: The tightening torque is the force to turn the fastener to the required tightness or torque-tension value. It is expressed as a large value. This means that the specified tightness should be obtained when the large torque is less than the specified The degree or clamping force is very important in any situation. Because the fasteners should be able to be properly tightened to ensure normal assembly, but this should not increase the torque excessively. Excessive torque requirements will cause the failure of the drive system , Increased labor intensity, failure of cooperation, all of which will increase the cost of fasteners.

Loosening torque: Loosening torque refers to the rotational force when the fastener is loosened from the locked state. This has practical significance when the fastener is easy to loosen. The loosening torque is generally related to self-locking fasteners (not only self-locking Fasteners and anti-loosening fasteners are included), it is expressed as a small value, that is, the fastener processing cannot be separated from the assembly with a torque less than the loosening torque.