Stainless Steel Gr. 316 Heavy Hex Nuts 3/4"", 20 mm

Product Details

Heavy Hex Nuts – Stainless Steel 316 (ASTM A194 Grade B8M) – ASME Standard1. Introduction Heavy Hex Nuts are high-strength, larger-dimension nuts designed for use in heavy-duty bolting applications. Manufactured as per ASME B18.2.2 (inch series) and ASME B18.2.4.6M (metric series). Material: Stainless Steel 316, conforming to ASTM A194 Grade B8M specifications. Ideal for high-temperature, corrosive environments, and critical bolted joints. 2. Standards Covered Inch Sizes: ASME B18.2.2 – Heavy Hex Nuts (Unified Inch Screw Threads – UNC, UNF, 8UN). Metric Sizes: ASME B18.2.4.6M – Heavy Hex Nuts (Metric Coarse & Fine Pitch Threads). Material Specification: ASTM A194 – Nuts for High-Pressure/High-Temperature Service. Grade: B8M (Type 316 Stainless Steel, carbide solution treated). 3. Material – ASTM A194 Grade B8M Base Material: Austenitic Stainless Steel 316. Alloying Elements: Chromium 16–18%, Nickel 10–14%, Molybdenum 2–3%. Corrosion Resistance: Superior resistance to chlorides, acids, and marine environments. Heat Treatment: Solution annealed at 1,900°F min and water quenched. 4. Mechanical Properties (ASTM A194 Gr. B8M) Tensile Strength (min): 75 ksi (515 MPa) Yield Strength (min): 30 ksi (205 MPa) Proof Load: 70 ksi (485 MPa) Elongation: 30% min Hardness: 223 HBW max (95 HRB max) 5. Dimensional Characteristics Heavy Hex Nuts have a wider across-flats (AF) and thicker height compared to standard hex nuts for greater load-bearing capacity. Example – Inch Size (ASME B18.2.2): 1" UNC Heavy Hex Nut → Across Flats: 1.50", Thickness: 0.94". Example – Metric Size (ASME B18.2.4.6M): M24 Coarse Pitch → Across Flats: 36 mm, Thickness: 21 mm. 6. Thread Series Available Inch Series: UNC (Coarse), UNF (Fine), 8UN (for large diameters). Metric Series: Coarse Pitch, Fine Pitch. Threads per ASME B1.1 (inch) and ASME B1.13M (metric). Right-hand threads standard; left-hand threads available on request. 7. Applications High-pressure piping systems (Oil, Gas, Petrochemical). Heat exchangers and pressure vessels. Marine and offshore structures. Chemical process equipment. Power generation plants. Flange assemblies where high preload is critical. 8. Advantages of Stainless Steel 316 (B8M) Heavy Hex Nuts Excellent resistance to pitting and crevice corrosion due to Molybdenum. Retains strength at elevated temperatures. Long service life in saltwater and acidic environments. Non-magnetic in annealed condition. Compliant with NACE MR0175 for sour service (when requested).