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High Pressure Bolting

Heavy Hex Bolts

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Heavy Hex Bolts 

Heavy Hex Head Bolt
Heavy Hex Head Bolt

There are several ASTM bolting specifications that require a heavy hex head – larger than a standard or finished hex head. These specifications include: A193, A320 and A307B. Although A325 and A490 bolts also require a heavy hex head, they refer to Structural Bolts for dimensional specifications, since structural bolts have shorter thread lengths than standard heavy hex bolts. 

Heavy Hex Bolts are used in a varity of OEM equipment and can be manufactured in multiple ASTM grades. 

ASTM Material Selection Chart  

Check Out Heavy Hex Bolts our Bolt Catalog for Sizes and Dimensions.

Stud Bolts

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Stud Bolts

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.

Double End Stud Bolts

Tap End Stud Bolts

ASTM Material Selection Chart

Stud Bolts

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Stud bolts for Pressure-Temperature Piping
Stud Bolts are used in High Pressure & Temperature flanged fittings

REFERENCE
Stud bolts for high pressure & high temperature applications conform to the requirements of ANSI/ASME B16.5, Steel Pipe Flanges and Flanged Fittings.

LENGTH-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. Please see the drawing above-this is confusing to most users!! Stud bolts are normally available from stock in 1/4 inch length increments. Length tolerances, all stud bolt sizes, shall be as tabulated below:

Length, in. Length Tolerance, in.
to 12                           +/-0.062

over 12 to 18          +/-0.125

over 18                      +/-0.250

POINTS
Points shall be flat and chamfered, or sheared at option of the manufacturer. When points are flat and chamfered, the diameter of the flat shall not exceed the minor diameter of the thread, and shall be not less than one or more than two complete threads as measured from the extreme end parallel to the axis.

THREADS
Threads shall be Unified inch coarse thread series (UNC), Class 2A, for all stud bolt sizes 1 in. and smaller, and Unified inch 8 thread series (8 UN), Class 2A, for all stud bolts larger than 1 in., in accordance with ANSI/ASME B1.1. Acceptability of screw threads shall be determined based on ANSI/ASME B1.3.

MATERIAL
Chemical and mechanical requirements shall be specified by the purchaser and shall be in accordance with applicable ASME, ASTM, and ANSI codes and specifications current at the time of ordering.

ASTM Material Selection Chart – Stud bolas are available in ASTM A193 Grade B7, B7M, L7, L7M. As well as 660, 718 Inconel, Mp35N and other high nickel alloys and stainless steels.

DESIGNATION
It is recommended that stud bolts be designated in the following sequence: product name, nominal size, threads per inch, length, material, and protective finish, if required.

Example: ANSI/ASME B16.5 stud bolt,
5/8-11 x 3-1/2, ASTM A193, Grade B7, Zinc & Clear Chromate Plated