The Proper Use of Stud Fasteners for Flange Bolting

05 Jan 2016

Continuous thread studs are versatile fasteners that we manufacture here at Fastening Products Company (FPC). Common applications for threaded studs include flange joint assembly in structural steel erection and piping systems. The integrity of these flange joints is critical to the strength and performance of these systems, therefore, assuring the proper use of continuous thread stud fasteners is a critical part of the construction process.

The proper use and installation of threaded stud fasteners involves the following steps:

Material Selection

Outdoor or corrosive environment applications require stud materials compatible with these conditions. At FPC, we manufacture fasteners from many common engineering materials, including: carbon steels, stainless steels, aluminum, brass and copper. We can also supply fasteners in more exotic materials such as: monel, inconel, hastelloy, titanium and nitronic.

Flange and Stud Assembly

Once the proper studs have been selected, the next step is the assembly of the flange joint. The flanges are matched up and a nut installed on one end of each stud. The nut should be installed to full thread engagement plus about three turns, meaning that three threads are visible after the nut. A stud is inserted into each flange hole and a second nut installed on the other end of each stud.

NOTE: In piping system applications, a gasket will usually be placed between the flanges. Consult construction specifications to determine the gasket type and installation sequence.

Tightening and Torquing

Once the flange joint is properly assembled, it may be tightened and torqued. This is generally done in at least two passes, tightening the nuts to about 75% of the full torque specification in the first pass and achieving 100% of full torque specification in the second pass.

Tightening and torquing should be done in a “criss-cross” pattern, starting with the bolt in the “12 o’clock” position and then the bolt in the “6 o’clock” position, then “9 o’clock”, then “3 o’clock”, etc.

At Fastening Products Company, our purpose is to fulfill all of your fastener needs. Please contact us today with your needs and specifications.