Alloy Steel Fasteners

ASTM A194 specification covers carbon, alloy and stainless steel nuts for high pressure and/or high temperature service. American National Standard Heavy Duty Hex Series (ANSI B 18.2.2) shall be used unless otherwise specified. Nuts no more than 1 inch in nominal size shall conform to UNC Series Class 2B.

Nuts with a nominal size over 1 inch shall be a UNC Series Class 2B fit or an 8 UN Series Class 2B fit. High strength ASTM A194 grade 2H nuts are common in the market and are often replaced by ASTM A563 grade DH nuts due to the limited availability of DH nuts in certain diameters and finishes.

ASTM A194 Class 2h bolts are carbon base steel heavy duty hex nuts. Sa194-2h material is a common high strength nut. This specification ASTM A194 Class 2h washers are typically used in conjunction with the following fastener standards – A193 Class B7, A325, A490.

ASTM A194 2H Heavy Duty Hex Bolts are the core product and are in stock. HT PIPE is a leading supplier of ASTM A194 2H Heavy Duty Hex Nuts. These are heavy duty hex nut type bolts as directed by ASTM A-193 specification.

ASTM A320 L7 Stud Bolts are designed for low temperature performance. These fasteners are commonly used in valves, flanges, fittings and pressure vessels. The ASTM specification recommends a minimum impact value of 20-ft-lbf -150F for ASTM A320 L7 studs.

ASTM A193 Grade B7 specification covers the requirements for high strength alloy steel bolting materials for high temperature or high pressure service and other special purpose applications. It is a standard specification that defines typical chemical composition, mechanical properties, hardness requirements, preferential heat treatment, product marking, certification, and other requirements for bolted connections used in pressure vessel service, valves, flanges, and fittings. ASTM A193 defines SI (metric) and inch-pound units.

ASTM A320 Grade L7 is a material specification for bolts, studs, nuts, and other fasteners designed for high temperature bolting applications. ASTM A320 L7 grades are divided into 4 performance classes, A, B, C, and D, each with different tensile and stress rupture properties. Class 660 fasteners are used to bolt boilers, pressure vessels, pipe flanges and valves for high temperature service.

Grade B7 is a heat treated chromium molybdenum low alloy steel with a minimum tensile strength requirement of 125 ksi (860 Mpa), a yield strength of 105 ksi (720 Mpa) and a maximum hardness of 35HRC. Boltport produces B7 headed and headless bolts from alloy steel AISI 4140 bar stock or forgings. A193 Grade B7 is the most commonly used bolting size, plus A194 Grade 2H nuts are used for bolting carbon steel pipe. A193 B7 bolts are available in metric sizes from M6 to M180 and imperial sizes from 1/4 to 7 inches in diameter.

The A320 Gr L7 stud material will undergo the following parametric tests – Impact Test, Tensile Test and Hardness Test according to the mechanical specification of A320 Grade L7 Bolts. The specification of A320 Gr L7 Hdg covers several grades of stainless steel including austenitic and ferritic stainless steels.

ASTM A193 Grade B7 is the standard material specification for chromium-molybdenum alloy steel fasteners for high-strength, high-temperature, and special-purpose applications. Grade B7 is a heat treated chromium molybdenum alloy steel with a minimum tensile requirement of 100 ksi, a yield strength of 75 ksi and a maximum hardness of 35 HRC. The ASTM A193 specification covers requirements for chemical composition, mechanical properties, hardness, heat treatment, and recommended nut washers for Class B7 fasteners. ASTM A193 Grade B7 is the broadest specification for fasteners, commonly found in bolts or pipes, pressure vessels, valves, flanges and fittings.

ASTM A320 bolts are suitable for low temperature service down to -150¡ãF and have a minimum Charpy impact value of 20-ft-lbf at this temperature. ASTM A320 Hex Bolts must obtain the durability and service of high temperature or high pressure and corrosion resistant steel. ASTM A320 Stud Bolts are available in different sizes and patterns, our premium ASTM A320 Grade L7 AS Bolts are in high demand in the market due to their speculative properties and specifications.

ASTM A193 Grade B7 bolts and studs are made from chrome molybdenum steel and are quenched and tempered (heat treated) to achieve the desired mechanical properties (strength). Grade B7 is the most commonly used A193 bolt grade in construction.

The specification for ASTM A320 Grade L7m materials covers alloy steel and stainless steel bolting materials for low temperature applications. ASTM A320 L7 Studs can also be used in applications with ambient temperatures up to -150oF. ASTM A320 grade L7m bolts and ASTM A320 bolts have a minimum Charpy impact value of 15 foot-pounds at this temperature.

B7 threaded studs and short head bolts are readily available in the market. B7 grade bolts are often used for pipe flange connections. These bolts are usually sold in a normal bare metal finish, but are usually hot-dip galvanized, galvanized, Xylan coated, PTFE coated, or otherwise treated with a corrosion resistant coating.

ASTM A193 Grade B8 Grade 1 Bolts and Studs Made of AISI 304 Stainless Steel. Type 304 is the most commonly used stainless steel grade in the fastener industry.