Threaded Rod Basics

Threaded rod, also known as all thread rod, is threaded from end to end, along its full length. All thread rod is commonly produced in, but not limited to, 3 foot, 6 foot, 10 foot and 12 foot lengths, but can be cut to specified lengths. All thread rod can be cut to shorter lengths, after which they are commonly referred to as all thread studs or stud bolts. The length of the rod is measured overall from end to end. Joints of all thread rod can vary in length by as much as a couple inches, even though it is considered a 12 foot long joint, for instance. All thread rod is well suited for a wide range of applications. It is well suited and widely used for many industrial applications such as anchoring, automotive, and electrical. Industries utilizing threaded rod range from oil and gas, chemical and power, to the manufacturing, municipal, pipeline, and construction industries. All thread rod is available in a wide range of grades, materials, lengths, diameters, and left-hand thread pitches in some grades.

 

Threaded Rod Grades & Markings

Threaded rod is available in several different grades based on the mechanical and chemical properties of the material, and the intended application of the all thread rod. All thread rod is not stamped in the same way a stud bolt or headed fastener is stamped. Most all thread is identified by a manufacturer standard paint color on both ends of the rod. While the colors used for the specific grades may be similar from different manufacturers, in most cases there is no industry standard grade/color specifications.

ASTM A307 All Thread Rod

ASTM A307 all thread rod is a common economical low carbon material often manufactured using A36 round bar. A307 threaded rods are used for general purpose applications where a high strength connection is not necessary.

ASTM F1554 Grade 55 All Thread Rod

ASTM F1554 Grade 55 all thread rod is a designed strength, low to medium carbon content grade. It has a 55 ksi yield strength which is required by the F1554 specification for anchor bolt and fastener applications. ASTM F1554 Grade 55 threaded rod covers the mechanical and material properties of steel anchor bolts having a yield strength of 36, 55 and 105 ksi. F1554 threaded rod is designed for use as, and typically mainly used for anchor bolts. All thread anchors are cut to length from the fully threaded bar. The embedded portion of the anchor bolt creates resistance to prevent the anchor from pulling out of the concrete when a load is applied.

ASTM F1554 Grade 105 All Thread Rod

ASTM F1554 Grade 105 all thread rod is manufactured from heat treated alloy steel, quenched and tempered. Inch series fasteners meeting ASTM F1554 Grade 105 specifications are typically used for anchoring structural supports to concrete foundations. Like F1554 Grade 55, Grade 105 all thread rod is typically used exclusively for anchoring applications. F1554 Grade 105 all thread may be dual certified ASTM A193 Grade B7 (which is suited for a wide range of applications) due to their properties being similar.

A354 BD/Grade 8 All Thread Rod

ASTM A354 Grade BD all thread rod is equivalent in strength to SAE J429 Grade 8 all threaded rod. It is manufactured from alloy steel, quenched and tempered. ASTM A354 specifications covers fasteners for applications at normal temperatures, where high strength is required.

ASTM A193 Grade B7 All Thread Rod

ASTM A193 B7 all thread rod is by far the most common grade of threaded rod in ASTM A193. B7 threaded rods are high strength, manufactured from a chromium-molybdenum steel and quenched and tempered. Inch series fasteners meeting ASTM A193 Grade B7 specifications are extensively used in a wide range of flange bolting applications.

ASTM A193 Grade B16 All Thread Rod

High strength fasteners manufactured from heat treated Chromium-Molybdenum-Vanadium steel, quenched and tempered. Added Vanadium allows for operating temperatures higher than that of B7 stud bolts. Inch series fasteners meeting ASTM A193 Grade B16 threaded rod specifications are typically used in the power and petrochemical industries on boilers, turbines, and other flanges and pressurized equipment with elevated temperatures.

ASTM A320 Grade L7 All Thread Rod

Manufactured from AISI 4140/4142 alloy steel, quenched and tempered. ASTM A320 L7 threaded rod is intended for low temperature service. It has the same chemical and physical properties as ASTM A193 Grade B7, but must achieve a Charpy impact value of 20 lb-ft at -150°F to ensure satisfactory performance in low temperature services. These fasteners are commonly used for valves, flanges, fittings, and pressure vessels in low temperature applications.

ASTM A193 & ASTM A320 Grade B8 & 304 Stainless Steel Threaded Rod

304 stainless steel all thread rod and Grade B8 all thread rod are similar, but not interchangeable. 304 stainless steel all thread is manufactured of UNS30400 material. Whereas A193 or A320 B8 stainless steel all thread is also manufactured of UNS30400 material, but undergoes additional processing and testing to ensure conformance with the chemical and mechanical requirements as specified in ASTM A193 or A320.The A193 specification covers fasteners intended for high temperature and high pressure applications, while A320 covers low temperature applications. 304 stainless steel all thread rod is for general use in harsh atmospheric conditions and some corrosive environments. A193 & A320 grade B8 all thread rod is for use in pressure vessels, valves, flanges, and fittings or other special purpose applications.

ASTM A193 & ASTM A320 B8 Class 2 All Thread Rod

Manufactured from AISI 304 stainless steel, annealed and strain hardened to achieve increased strength characteristics per ASTM A193 & ASTM A320. The Class 2 designation denotes the material is strain hardened, which increases the tensile strength significantly when compared to that of standard B8 material. For use in pressure vessels, valves, flanges, and fittings or other special purpose applications.

ASTM A193 & ASTM A320 Grade B8M & 316 Stainless Steel All Thread Rod

316 stainless steel all thread rod and Grade B8M all thread rod are similar, but not interchangeable. 316 stainless steel all thread is manufactured of UNS31600 material. Whereas A193 or A320 B8M stainless steel all thread is also manufactured of UNS31600 material, but undergoes additional processing and testing to ensure conformance with the chemical and mechanical requirements as specified in ASTM A193 or A320.The A193 specification covers fasteners intended for high temperature and high pressure applications, while A320 covers low temperature applications. 316 stainless steel, ASTM A193 and ASTM A320 B8M threaded rod is used when a higher corrosion resistance than 304 stainless steel is required. A193 & A320 grade B8M all thread rod is for use in pressure vessels, valves, flanges, and fittings or other special purpose applications.

ASTM A193 & A320 B8M Class 2 All Thread Rod

Manufactured from AISI 316 stainless steel, annealed and strain hardened to achieve increased strength characteristics per ASTM A193 & ASTM A320. The Class 2 designation denotes the material is strain hardened, which increases the tensile strength significantly when compared to that of standard B8M material. For use in pressure vessels, valves, flanges, and fittings or other special purpose applications.

Brass All Thread Rod

Brass all thread rod is manufactured from an alloy of copper and zinc. Brass fasteners are commonly used by electrical and communications industries, builders hardware and some marine applications. Brass all thread rod is electrically conductive, non-magnetic, and has good corrosion resistance.

 

Common Finishes of All Thread Rod

Threaded rod is available in a variety of finishes and coatings, which play a role in the suitability of the fasteners in different applications, such as enhancing resistance to corrosion from environmental elements or chemicals. Coatings also greatly effect consistency of torque values for installation, and ease of disassembly at the end of service.

Black or Plain Finish All Thread Rod

Threaded rod is unfinished or will have a minimally protective finish. Black all thread rod offers near zero corrosion resistance, though black oxide coatings or oiled coatings do offer increased corrosion resistance over unfinished plain black threaded rod.

• Black all thread rod is commonly referred to as plain finish, black, black oxide, black phosphate, bare or light oil coated.

Galvanized All Thread Rod

Threaded rod is coated with a sacrificial zinc coating that acts as an anode to prevent the fastener underneath from corroding.

• Hot Dipped Galvanized: Fasteners are dipped in a bath of molten zinc.

Plated All Thread Rod

Threaded rod is coated with a thin layer of zinc, typically via electroplating.

• Plated all thread rod will not corrode as quickly when covered with this protective coating, even when a scratch or cut exposes the steel to air or moisture. The zinc or cadmium plating will always tarnish and corrode first.

Teflon or PTFE Coated All Thread Rod

Threaded rod has a PTFE coating (commonly referred to as the Dupont tradename “Teflon”) and are formulated with superior characteristics for maximum fastener life.

• Technical components include a tensile strength of up to 4,000 psi and an operating pressure up to 100,000 psi. The absence of thread locking oxides enable easy and safe fastener removal. PTFE coatings have extreme chemical resistance and are ideal for applications including insulating piping, boiler rooms, water filled piping, water lines and more.