Torque Values for B7 Studs
One type of specialized fastener is the B7 stud. This bolt and double hex nut combination has a specific set of uses and can take on a high force load of tension and pressure. Torque (the measure of a twisting force in a connection) is an important factor to consider during the installation of a B7 stud bolt. As you will find out in the information described below, correct torque values for B7 Studs is vital to ensure an optimum connection and performance of the stud.
What Is a B7 stud?
A B7 stud is a form of stud bolt that is equipped with two hex nuts and is defined by the ASTM standards (ASTM is an international standards organization). The material quality of the stud is denoted by the grade i.e. grade B7, but the bolts and hex nut are usually created from a form of chromium alloy steel. In most cases, the bolt is supplied with an unfinished coating. However, they can also be galvanized and zinc plated for additional protection. The threaded shaft is often cut down from standard lengths of B7 bar, and the associated hex nuts are usually A193 or A194 grade (A193 and A194 are approved specifications from ASTM).
This type of stud is incredibly strong, durable and resistant to pressure; they are also tolerant of higher temperatures and are easy to install. There is a common torque setting for the B7 stud. However, this differs depending on the bolt diameter and the length of the thread — You can find torque charts that allow the cross-referencing of a particular screw with its relative tightening torque setting.
How Is a B7 Stud Used?
B7 studs are most commonly used in piping applications for the Oil, Gas, and Petrochemical industries and flanged connections. For example, stud bolts may be used to connect two sections of pipe together in a gas circuit. As they form a more secure bond than standard hex bolts, they are perfect for use in systems that require no leakage or contamination.
Why Are the Torque Values for B7 Studs important?
Torque is the measurement of force being applied to a threaded joint as a bolt is screwed. The amount of torque present in a B7 stud/hex joint can be measured. As mentioned above there are common torque values for B7 studs that should be adhered too. For example, a B7 stud with a nominal diameter of 1/4" at 20 threads per inch should have a torque value of 6ft-lbs and a clamp load of 2506lbs.
The torque values for B7 studs are highly significant. As you can see, these items are used in high-pressure systems that require lots of material integrity and resistance. If a bolt or screw is torqued to an incorrect amount, the connection could loosen or possibly end up shearing — this could prove to be extremely dangerous to equipment or personnel.
For example, what if a B7 stud had not been torqued properly on an important gas pipe intersection? What would happen if the joint failed and the pipe burst? Workers use a torque sensor to check the value, and ensure that the B7 stud was installed correctly. Are the hex nuts screwed properly onto the thread? Are the hex nuts sitting flush to the base of the connecting pipes? Is the stud connection secure and torqued to the correct value? All these factors must be considered when B7 studs or any other type of connection that requires specific torque value configurations.