Manufactures & Suppliers of Pipes, Tubes, Flanges, Pipe Fitting & Fasteners
ASTM A193 Gr. B7 Fasteners
ASTM A193 Grade B7 specification outlines the requirements for high-tensile alloy steel bolting materials designed for high-temperature or high-pressure service, as well as other specialized applications. This standard specification details typical chemical composition, mechanical properties, hardness requirements, preferred heat treatment, product marking, certification, and additional criteria suitable for bolting used in pressure vessel service, valves, flanges, and fittings. ASTM A193 includes both SI (metric) and inch-pound units.
ASTM A193 Gr. B7 Stud Bolt, ASTM A193 Gr. B7 Bolt, ASTM A193 Gr. B7 Nuts, ASTM A193 Gr. B7 Fasteners Supplier and Manufacturer in Mumbai, India
Grade B7 is a heat-treated chromium-molybdenum low-alloy steel with a minimum tensile strength of 125 ksi (860 MPa), a yield strength of 105 ksi (720 MPa), and a maximum hardness of 35 HRC. Natron utilizes Alloy Steel 4140 bar stock or forging stock to manufacture B7 headed and non-headed bolts. A193 Grade B7 is the most commonly used bolt specification, often paired with A194 Grade 2H nuts for bolting carbon steel pipelines. A193 B7 bolting is available in metric sizes ranging from M6 to M180 and imperial sizes from 1/4 to 7 inches in diameter.
ASTM A193 Gr. B7 Fasteners are formed using cold forging techniques; however, larger-sized fasteners or small quantities of 4140 bolts are produced by hot forging or directly machined from 4140 bar stock. We supply 4140 fasteners that offer a stable combination of high strength, toughness, weldability, and machinability, along with excellent fatigue strength.
ASTM A193 Gr. B7 Fasteners Chemical Composition
| Elements | Range | Product VariationB |
| Carbon | 0.37-0.49 % D | 0.02 % |
| Manganese, max | 0.65-1.10 % | 0.04 % |
| Phosphorus, max | 0.035 % | 0.005 % over |
| Sulfur, max | 0.040 % | 0.005 % over |
| Silicon | 0.15 - 0.35 % | 0.02 % |
| Chromium | 0.75-1.20 % | 0.05 % |
| Molybdenum | 0.15-0.25 % | 0.02 % |
ASTM A193 Gr. B7 Fasteners Mechanical Properties
| Diameter mm | Min Tempering Temperature, °C | Tensile Strength min, MPa | Yield strength, min, 0.2% offset, MPa | Elongation in 4D min, % | Reduction of Area, min, % | Hardness, max |
|---|---|---|---|---|---|---|
| M64 and Under | 593 | 860 | 720 | 16 | 50 | 321 HBW or 35 HRC |
| over M64 to M100 | 593 | 795 | 655 | 16 | 50 | 321 HBW or 35 HRC |
| over M100 to M180 | 593 | 690 | 515 | 18 | 50 | 321 HBW or 35 HRC |
