Stud bolts and hex bolts are utilised for flange connections in the chemical and petroleum industries. The Hex Bolt has a head with one nut, however the Stud Bolt has a threaded rod with two substantial hexagon nuts. Head and nuts have six sides each.
Stud Bolts
The number of bolt holes in a flange will determine how many bolts are needed for a flange connection. The diameter and length of the bolts depend on the kind and pressure class of the flange.
The ASME B16.5 standard specifies the length of the stud bolt. The effective thread length, measured perpendicular to the axis from the first to the first thread without chamfers, is equal to the length in inches (points). The primary thread diameter's junction with the point's base is known as the first thread.
Threads of Stud Bolts
ASME B1.1 Unified Inch Screw Threads defines bolt threading (UN and UNR Thread Form). The V-profiled, symmetrical shape is the most prevalent theme. 60° is the included angle. This type is extensively used in the ISO / metric threads of the Unified thread form.
In comparison to non-symmetrical threads, symmetrical threads have the benefit of being simpler to create and check. These are frequently utilised in multipurpose fasteners.
The identification of diameter/pitch combinations by threads per inch , which are applied to a single diameter, is known as a thread series.
Standard Thread
The most common thread system is the coarse thread series, which is used in the majority of screws, bolts, and nuts. For threads in low strength materials like iron, mild steel, copper, and softer alloys, aluminium, etc., coarse threads are utilised. Additionally, the coarse thread speeds up assembly and is more resilient to bad weather.
The fine thread series is frequently employed in applications that demand a higher tensile strength than those that call for the coarse thread series.
For various ASTM standards, including A193 B7, A193 B8/B8M, and A320, the 8 - Thread series is the recommended thread manufacturing technique. The majority of the diameters in this series are one inch and larger.
Hex Nut
Hex nuts and bolt threading are both described in ASME B18.2.2 and ASME B1.1, respectively. Nuts must have washer faces on one side or both sides chamfered, depending on a client requirements.
Material for Stud Bolt
The ASME B16.5 standard defines the dimensions of stud bolts. The various ASTM standards specify the stud material properties and list them by Grade. For thread rods and nuts, the grades A193 and A194 are frequently used.
For pressure vessels, valves, flanges, and fittings used in high temperature or high pressure service, as well as other specialised applications, ASTM A193 covers alloy and stainless steel bolting material.
Numerous carbon, alloy, martensitic, and austenitic stainless steel nuts are covered by ASTM A194. These nuts are designed to withstand high temperatures, high pressures, or both.
In order to identify the manufacturer or private label distributor, as applicable, thread rods and nuts must be marked by the maker with a distinctive identity. There are several ASTM examples below.
