STUD BOLT

Stud Bolts

Used in high pressure bolting situations for pipeline, drilling, petroleum / petrochemical refining and general industry for sealing and flange connections all thread, tap end and double end stud bolts are the lion’s share of the industry. The all thread stud bolt is a threaded rod with 2 heavy hex nuts, while the tap end and double end are nut continuously thread, but have a body in the middle with one nut. In a tap end the short end of the stud bolt is designed with a UNC 3A fit to go into a tapped hole on the body of a larger machined or forged equipment.

In a flanged connection the size, length, diameter and number of bolt holes is dependent of flange type and pressure class of flange.
Stud Bolt grades and sizes are defined by industry standards in ASTM A193 and ASME B16.5 standards.

Standard U.S. bolt threads are defined in ASME / ANSI Unified Inch Screw Threads. The most commonly used Unified threads are UN, UNC, UNF in thread pitches associated to the diameter. The thread diameter/pitch combinations are measured by the number of threads per inch (TPI) accompanying each diameter.

At Sigma we manufacture studs in a wide variety of ASTM grades and exotic grade high strength alloys.

Stud Bolt Ends

At manufacturer’s option, ends or points may be rounded (oval), sheared, flat or saw cut and chamfered. When rounded, the stud shall have an oval point with a radius equal to approximately one times the basic stud diameter. When flat and chamfered, the end shall be chamfered from a diameter not exceeding the minor diameter of the thread to produce a length of chamfer or incomplete thread approximately equivalent to 2 times the thread pitch.

Length

Stud bolt length is commonly measured end to end or first to first. The length of stud bolt, measured parallel to the axis, is the distance from first thread to first thread.
First thread is defined as the intersection of the major diameter of the thread with the base of the point. Stud bolts are normally available in 1/4 in. length increments.

Stud Bolts

Stud Bolts

Stud bolts are available in ASTM Grades B7, L7, B16, B16M, L7M, B8, 660 and B8M; they are also available exotic metals such as Monel, Titanium, Inconel, Alloy 20, and Hastelloy, 17-4PH. These studs are also available with industrial coatings such as SermaGard, Xylan, PTFE, Fluoropolymers and other coatings.

Stud Bolts for Pressure-Temperature Piping

• Continuous Thread Studs (Fully Threaded Studs)

Stud bolts are threaded end to end and are often used for flange bolting with two nuts on either end.

There are two types of these studs.

• Type one – usually for general purpose; the length of stud is measured from end to end. Threads are UNRC-2A.
• Type two – studs for high temperature pressure piping. These studs are made to dimensional standard requirements of ANSI B16.5 the length of this stud is measured from first thread to first thread, exclusive of points. Threads are UNRC-2A for sizes 1 inch and under and 8 UNR-2A for sizes over 1 inch. The length of stud bolt, measured parallel to the axis, is the distance from first thread to first thread. First thread is defined as the intersection of the major diameter of the thread with the base of the point.

Stud bolt for Pressure-Temperatur Piping

Standard Bolts

Socket Head Cap Screws

Standard and custom manufactured socket head cap screws.

Standard Socket Head Cap Screws

Sigma distributes quality fasteners – socket head cap screws, metric socket screws, flat head socket screws or button head socket screws. Also known as Allen head cap screws.

Custom and Modified Socket Head Cap Screws

If you specification requires a modified or custom socket head cap screw Sigma will deliver.

ASTM Material Selection Chart B7, B7M, L7, L7M, 660, 718 Inconel, 17-4 ph, MP35N

Available coated, plated and plain.

General Purpose End-to-End Studs