Studbolts are available in many diameters and lengths, metric, and imperial, in a variety of materials from Carbon and Low Alloy to Stainless and the Nickel Alloys.
The material of the hex steel nuts shall match the material of the threaded rod (generally, stud materials ASTM A193 match with nuts materials ASTM A194).
The ASME B16.5 specification covers Studbolts and nuts for ASME flanges (number, the diameter and the length of required stud bolts, i.e. “flange bolt chart”) by flange diameter, pressure class and face finish (RF, FF, RTJ).
The most common materials for stud bolts (for flanges) are ASTM A193 (grade B7, B8, B8M, B8T), ASTM A453 (grade 660), ASTM A320 (grade L7, L7M), and ASTM A182 (duplex and super duplex bolting). For aggressive environments and fluids, stud bolts can be coated (see below ‘Coated Studbolts’)
The ASTM A193 specification covers alloy-steel and stainless steel stud bolts materials for high temperature or high-pressure service.
The most common stud bolts materials covered by ASTM A193 are:
Stud bolts can be coated to increase the resistance to corrosion. The most common types of coatings for stud bolts are listed below:
The Stud Bolt is threaded according to the specifications set by ASME B1.1.
The mechanical strength of the steel nut material shall be compatible with the strength of the mated Stud Bolts.
Hex Nuts (dimensions and weights) are defined in ASME B18.2.2.as bolts the threading in ASME B1.1. Depending on customer specification, nuts must be both sites chamfered or with on one side a washer-face.
