ASME 1/4"~5" Stud Bolt Duplex S31050(1.4466) Duplex Stainless Steel
1.DIN 976-1 - 2002 Stud bolts - Part 1: Metric thread
2.Why stud is used instead of bolts?
Studs provide the ability to obtain much more accurate torque
values because the studs don't twist during tightening as do bolts. Because the studs remain stationary during nut tightening, the
studs stretch in one axis alone, providing much more even and
accurate clamping forces.
3.Bolts and Nuts for flanged connections
Types of Bolts
In Petro and chemical industry for flange connections Stud Bolts
and Hex Bolts are used. The Stud Bolt is a threaded rod with 2
heavy hexagon nuts, while the Hex Bolt has a head with one nut.
Nuts and head are both six sided.
Stud Bolts general
The quantity of bolts for a flange connection will be given by the
number of bolt holes in a flange, diameter and length of bolts is
dependent of flange type and Pressure Class of flange.
Stud Bolt length are defined in ASME B16.5 standard. The length in
inches is equal to the effective thread length measured parallel to
the axis, from the first to the first thread without the chamfers
(points). First thread is defined as the intersection of the major
diameter of the thread with the base of the point.
- The length of metric Stud Bolts measured parallel to axis, is the
distance from each Stud Bolt, including the point.
- To allow the use of hydraulic tensioning equipment, larger
dimension studs shall be often one diameter longer than "standard".
That bolts to have plastic end cap protection.
Threads of Stud Bolts
Bolts threading are defined in ASME B1.1 Unified Inch Screw
Threads, (UN and UNR Thread Form). The most common thread is a
symmetrical form with a V-profile. The included angle is 60°. This
form is widely used in the Unified thread (UN, UNC, UNF, UNRC,
UNRF) form as the ISO / metric threads.
The advantage of a symmetrical threads is that they are easier to
produce and inspect compared with non-symmetrical threads. These
are typically used in general-purpose fasteners.
Thread series cover designations of diameter/pitch combinations
that are measured by the number of threads per inch (TPI) applied
to a single diameter.
Standard Thread Pitches
- Coarse thread series (UNC/UNRC) is the most widely used thread
system and applied in most of the screws, bolts and nuts. Coarse
threads are used for threads in low strength materials such as
iron, mild steel, copper and softer alloy, aluminium, etc.. The
coarse thread is also more tolerant in adverse conditions and
facilitate quick assembly.
- Fine thread series (UNF/UNRF) is commonly used in precision
applications and in there where require a higher tensile strength
than the coarse thread series.
- 8 - Thread series (8UN) is the specified thread forming method for
several ASTM standards including A193 B7, A193 B8/B8M, and A320.
This series is mostly used for diameters one inch and above.