Torque Shear Bolt

By AGICO

Introduction

High Strength Torque Shear Bolts (also known as Twist-off Bolts) are commonly abbreviated as TC, which originates from the English abbreviation TCB (Tension Control Bolts) to differentiate them. The ends of these bolts have a spline end and the bolt heads are generally circular (mushroom-shaped) with a spline design. A torque shear-style high-strength bolt assembly consists of one high-strength bolt, one nut, and one washer.

Twisted shear bolts are mainly used in situations that require high-strength connections and anti-theft and anti disassembly measures. Twisted shear bolt is a type of safety bolt suitable for equipment fixation and safety protection in industries such as power, communication, petrochemicals, and roads. Its special structural design makes it impossible to directly disassemble the bolts with tools, and can only be disassembled by damaging the twist shear interface or blade, thus having high anti-theft and anti disassembly performance.

During the installation of torque shear-style high-strength bolt connections, only one washer should be added on the side of the nut. The formula for calculating the initial torque value is: Tc = 0.065 * Pc * d, where Tc is the initial torque value in N·m, Pc is the construction pretension in kN, and d is the diameter of the high-strength bolt thread in mm. The final tightening is done using a wrench until the spline end breaks. Emphasis should be placed on quality inspection during the construction process supervision. Torque shear-style high-strength bolts are an improved version of large hexagon high-strength bolts for better construction. Large hexagon high-strength bolts consist of one bolt, one nut, and two washers, while torque shear-style high-strength bolts consist of one bolt, one nut, and one washer.

Features of Structural Torque Shear Bolts:

-The bolt’s manufacturing process, including the head, tail, thread, and groove, is all carried out in the same factory using cold forging. The precision and stability of the manufacturing process are excellent.

-Continuous steel strip heat treatment furnaces are used for heat treatment. Standard temperature and carbon concentration are automatically recorded to effectively control quenching temperature and gas concentration, preventing carburization or decarburization and ensuring the required mechanical properties of the bolts.

-Process control is thoroughly implemented through the use of control charts and process capability analysis methods to track processing and quality conditions, providing comprehensive data for engineering designers’ reference.

Torsion Shear Bolt Mechanical Property

Torsion Shear Bolt Physical Tensile Load

When the bolt l/d≤3, if the wedge load test cannot be done, the core hardness test is allowed. The core hardness value should comply with the table below.

Fastening Axial Force of Torsional Shear Bolt

When l is less than the value in the table below, the fastening axial force test may not be carried out. The unit is: millimeter (mm）  

Steel Materials for Structural Bolt Nut and Washer

Torsion Shear Bolt Chemical Composition