Key Characteristics of Stud Bolts
Threading:
Full Threaded Stud Bolts: These bolts are fully threaded along their length, providing
flexibility in adjusting the clamping force using nuts on both ends.
Partial Threaded Stud Bolts: Only part of the bolt is threaded, typically leaving the middle
section unthreaded for specific applications where high shear strength is needed.
Thread Pitch:
Stud bolts come with coarse threads (UNC) or fine threads (UNF). Coarse threads are more
resistant to wear and easier to install, while fine threads offer higher strength and resistance
to vibration.
Diameter and Length:
Stud bolts come in a variety of diameters and lengths to fit the specific requirements of the
application. Typical diameters range from 1/4 inch to over 4 inches, with lengths varying from 2
inches to over 20 inches.
Material Composition:
Stud bolts are made from various materials depending on the application and the environment.
Common materials include:
Carbon steel: Used in general industrial applications.
Stainless steel: Provides corrosion resistance for use in marine, offshore, and chemical
environments.
Alloy steel: Used in high-temperature and high-pressure applications due to its enhanced
strength.
Nickel-based alloys: Suitable for extreme environments where corrosion and high temperatures are
a concern (e.g., oil and gas industries).
Ends:
Stud bolts have two threaded ends, which are designed to be used with nuts. Some variations may
include chamfered or beveled ends to allow for easier threading and tightening of the nuts.
Types of Stud Bolts
Fully Threaded Stud Bolts:
Description: These bolts are threaded from end to end and are typically used with nuts on both
sides.
Use Case: Ideal for flanged connections and other applications where clamping is required from
both ends.
Applications: Commonly used in the petrochemical and oil & gas industries for bolting pipes and
equipment.
Tap End Stud Bolts:
Description: These bolts are threaded on both ends but have different thread lengths on each
end. One end is designed to be screwed into a tapped hole, while the other end uses a nut.
Use Case: Typically used in applications where one side of the bolt is embedded in a surface or
structure.
Applications: Used in machinery or structural assemblies where a permanent threaded connection
is needed on one end.
Double-End Stud Bolts:
Description: These have threads on both ends with an unthreaded middle section.
Use Case: Designed for high-tension and compression applications where both ends are fastened
with nuts.
Applications: Commonly used in engine components, pumps, and other heavy machinery where high
stress and torque are applied.
Reduced Shank Stud Bolts:
Description: These bolts have a reduced diameter between the two threaded ends.
Use Case: They are used in applications requiring weight reduction or to relieve stress at the
midpoint of the bolt.
Applications: Used in specialized engineering applications, such as aerospace, where reduced
weight and stress distribution are critical.
Stud Bolt Specifications
Thread Size:
Stud bolts are available in various thread sizes, commonly ranging from M6 to M100 in metric
sizes and 1/4 inch to 4 inches in imperial sizes.
Thread size determines the bolt’s load-bearing capacity and is a crucial factor in selecting the
right stud bolt.
Length:
The length of a stud bolt is measured from end to end and includes both threaded portions.
Standard stud bolt lengths vary depending on the flange type and size but can range from 2
inches to 20 inches or more.
Tensile Strength:
The tensile strength of a stud bolt depends on the material and grade. Stud bolts made from
carbon steel or alloy steel typically have high tensile strength, often exceeding 100,000 psi.
Stainless steel stud bolts are generally used for corrosion resistance and offer tensile
strengths of 70,000 psi or higher, depending on the grade.
Standards and Grades:
Stud bolts must meet various standards for specific applications. Common standards include:
ASTM A193: Standard for alloy and stainless steel stud bolts used in high-temperature and
high-pressure environments (e.g., B7 for carbon steel, B8 for stainless steel).
ASTM A320: Used for low-temperature applications (e.g., L7 for low-temperature steel).
ASTM A307: For low-carbon steel bolts used in general-purpose construction.
ASME B16.5: Standard for pipe flange connections in industrial applications.
Finish and Coating:
Stud bolts are often coated for protection against corrosion and wear. Common finishes include:
Galvanization: Hot-dip or electro-galvanized coatings for protection against corrosion.
PTFE Coating: Applied to reduce friction and provide corrosion resistance.
Zinc Plating: Provides moderate corrosion resistance for indoor applications.
Black Oxide: Adds minimal corrosion resistance but improves appearance and reduces friction
during installation.
Applications of Stud Bolts
Flange Connections:
Stud bolts are widely used to secure flanges in pipelines, pressure vessels, and other critical
industrial equipment.
Examples: Oil and gas pipelines, refineries, chemical processing plants.
Pressure Vessels and Boilers:
Stud bolts are critical in securing pressure vessels and boilers, where the integrity of the
connection is vital for safety.
Examples: High-pressure steam systems, heat exchangers, and large industrial boilers.
Machinery and Equipment Assembly:
Stud bolts are often used in heavy machinery where precise tensioning and high strength are
required.
Examples: Compressors, turbines, pumps, and automotive engines.
Oil & Gas Industry:
The oil and gas industry uses stud bolts in pipeline connections, drilling rigs, and offshore
platforms due to their high strength and corrosion resistance.
Examples: Securing subsea pipeline flanges, wellheads, and refineries.
Construction and Structural Engineering:
Stud bolts are used in large structural connections where nuts are tightened on both sides to
ensure strong joints.
Examples: Steel frame connections, bridge supports, and tower construction.
Power Generation:
Stud bolts are utilized in power plants for securing turbines, generators, and other critical
equipment.
Examples: Wind turbines, nuclear reactors, hydroelectric dams.