A threaded rod, also known as a stud, is a relatively long rod that is threaded on both ends; the thread may extend along the complete length of the rod.They are designed to be used in tension. Threaded rod in bar stock form is often called all-thread (ATR); other names include fully-threaded rod, redi-rod, continuously-threaded rod, and TFL rod.
Galvanized steel,mild steel, stainless steel, nylon, brass, copper, aluminum, and titanium are all commonly used to make threaded rods.
Studs may have a drive slot in one end to facilitate installing the stud.
With respect to shape, stud bolts a.k.a. studs are categorized into three basic types: "fully threaded stud bolts", "tap-end stud bolts", and "double-end stud bolts". Each of these studs have different application. As name suggests, fully threaded studs have full body coverage with threads for full engagement of the matings nuts or similar parts. Tap-end studs have threads at extreme ends of the body with unequal thread engagement length, while double-end stud bolts have equal thread length at both ends. Apart from these, there are stud bolts for flanges, which are fully threaded studs with chamfered ends, and double-end studs with reduced shank for special bolting applications.
For studs that are not completely threaded, there are two types of studs: full-bodied studs, and undercut studs. Full-bodied studs have a shank equal to the major diameter of the thread. Undercut studs have a shank equal to the pitch diameter of the screw thread. Undercut studs are designed to better distribute axial stresses. In a full-bodied stud the stresses are greater in the threads than in the shank.
Undercut studs (rolled thread) are also stronger because the metal is "rolled" up to the major diameter, not removed. This preserves the grain of the steel, and in some cases even enhances it. Full-bodied studs (cut thread) are weaker because metal is removed to create the thread, disturbing the grain of the steel.
Undercut studs are only required in applications where the stud is exposed to fatigue. Cut threads are entirely suitable for many applications, even when rolled threads might be slightly stronger. Mass-produced fasteners (standard bolts and studs) are usually rolled, but jobbed parts with custom features and small lot sizes are likely to be cut.
The allowable tensile force for a non-undercut threaded rod is defined by the American Institute of Steel Construction (AISC) as
where d is the nominal diameter, and Fu is the ultimate tensile strength of the material. For undercut threaded rods the allowable tensile stress is defined as
where ds is the diameter of the shank, and Fy is the yield strength of the material.
Both equations give units of force for the result, i.e. pounds-force or newtons.
Metric threaded rods are marked on the end with a color code to define the ISO strength class. The color codes are:
A tie rod or tie bar is a slender structural unit used as a tie and capable of carrying tensile loads only. It is any rod or bar-shaped structural member designed to prevent the separation of two parts, as in a vehicle.
A rivet is a permanent mechanical fastener. Before being installed, a rivet consists of a smooth cylindrical shaft with a head on one end. The end opposite the head is called the tail. On installation, the rivet is placed in a punched or drilled hole, and the tail is upset or bucked, so that it expands to about 1.5 times the original shaft diameter, holding the rivet in place. In other words, the pounding or pulling creates a new "head" on the tail end by smashing the "tail" material flatter, resulting in a rivet that is roughly a dumbbell shape. To distinguish between the two ends of the rivet, the original head is called the factory head and the deformed end is called the shop head or buck-tail.
A fastener or fastening is a hardware device that mechanically joins or affixes two or more objects together. In general, fasteners are used to create non-permanent joints; that is, joints that can be removed or dismantled without damaging the joining components. Steel fasteners are usually made of stainless steel, carbon steel, or alloy steel.
A bolted joint is one of the most common elements in construction and machine design. It consists of a male threaded fastener that captures and joins other parts, secured with a matching female screw thread. There are two main types of bolted joint designs: tension joints and shear joints.
Stud welding is a technique similar to flash welding where a fastener or specially formed nut is welded onto another metal part, typically a base metal or substrate. The fastener can take different forms, but typically fall under threaded, unthreaded, or tapped. The bolts may be automatically fed into the stud welder. Weld nuts generally have a flange with small nubs that melt to form the weld. Weld studs are used in stud welding systems. Manufacturers create weld studs for the two main forms of stud welding: capacitor discharge stud welding and drawn arc stud welding
A screw thread, often shortened to thread, is a helical structure used to convert between rotational and linear movement or force. A screw thread is a ridge wrapped around a cylinder or cone in the form of a helix, with the former being called a straight thread and the latter called a tapered thread. A screw thread is the essential feature of the screw as a simple machine and also as a threaded fastener.
Anchor bolts are used to connect structural and non-structural elements to concrete. The connection can be made by a variety of different components: anchor bolts, steel plates, or stiffeners. Anchor bolts transfer different types of load: tension forces and shear forces.
In solid mechanics, shearing forces are unaligned forces acting on one part of a body in a specific direction, and another part of the body in the opposite direction. When the forces are collinear, they are called tension forces or compression forces. Shear force can also be defined in terms of planes: "If a plane is passed through a body, a force acting along this plane is called a shear force or shearing force."
Multi-jackbolt tensioners (MJT) are an alternative to traditional bolted joints. Rather than needing to tighten one large bolt, MJTs use several smaller jackbolts to significantly reduce the torque required to attain a certain preload. MJTs range in thread sizes from 3⁄4 in (19 mm) to 32 in (810 mm) and can achieve 20 million pounds-force or more. MJTs only require hand-held tools, such as torque wrenches or air/electric impacts, for loading and unloading bolted joints.
A swage nut or self-clinching nut is a type of nut or threaded insert that is used on sheet metal.
A screw and a bolt are similar types of fastener typically made of metal and characterized by a helical ridge, called a male thread.
In manufacturing, threading is the process of creating a screw thread. More screw threads are produced each year than any other machine element. There are many methods of generating threads, including subtractive methods ; deformative or transformative methods ; additive methods ; or combinations thereof.
ISO 898 is an international standard that defines mechanical and physical properties for metric fasteners. This standard is the origin for other standards that define properties for similar metric fasteners, such as SAE J1199 and ASTM F568M. It is divided into five (nonconsecutive) parts:
ASTM A325 is an ASTM International standard for heavy hex structural bolts, titled Standard Specification for Structural Bolts, Steel, Heat Treated, 120/105 ksi Minimum Tensile Strength. It defines mechanical properties for bolts that range from 1⁄2 to 1+1⁄2 inches in diameter.
ASTM F568M is an ASTM International standard for metric bolts, screws and studs that are used in general engineering applications. It is titled: Standard Specification for Carbon and Alloy Steel Externally Threaded Metric Fasteners. It defines mechanical properties for fasteners that range from M1.6 to 100 in diameter. The standard was withdrawn in 2012. and has been replaced by ISO 898-1
ASTM A354 is an ASTM International standard that defines chemical and mechanical properties for alloy steel bolts, screws, studs, and other externally threaded fasteners. It is officially titled: Standard Specification for Quenched and Tempered Alloy Steel Bolts, Studs, and Other Externally Threaded Fasteners.
ASTM A490 and ASTM A490M are ASTM International standards for heavy hex structural bolts made from alloy steel. The imperial standard is officially titled Standard Specification for Structural Bolts, Alloy Steel, Heat Treated, 150 ksi Minimum Tensile Strength, while the metric standard (M) is titled Standard Specification for High-Strength Steel Bolts, Classes 10.9 and 10.9.3, for Structural Steel Joints.
A bolt is a form of threaded fastener with an external male thread requiring a matching pre-formed female thread such as a nut. Bolts are very closely related to screws.
A mechanical joint is a section of a machine which is used to connect one or more mechanical part to another. Mechanical joints may be temporary or permanent; most types are designed to be disassembled. Most mechanical joints are designed to allow relative movement of these mechanical parts of the machine in one degree of freedom, and restrict movement in one or more others.
Zinc flake coatings are non-electrolytically applied coatings, which provide good protection against corrosion. These coatings consist of a mixture of zinc and aluminium flakes, which are bonded together by an inorganic matrix.