Materials

Stainless Steel A193 (B8 / B8M, Types 1 & 2)

• Material: High-strength, austenitic stainless steel fasteners designed for high-temperature and corrosive service, per ASTM A193 specification for bolts, studs, and other fasteners.

• Grades:

  • B8 (Type 1 & 2) – Chromium-nickel austenitic stainless steel (typically 304/304L chemistry). Type 1 is hot-forged; Type 2 is cold-finished.

  • B8M (Type 1 & 2) – Chromium-molybdenum austenitic stainless steel (typically 316/316L chemistry). Provides improved corrosion resistance in chloride-containing environments.

• Mechanical Properties:

  • Moderate to high tensile strength (~75–95 ksi for B8; slightly higher for B8M).

  • Good ductility, toughness, and fatigue resistance.

  • Retains mechanical properties up to ~800°F (425°C).

• Corrosion Resistance:

  • B8 – Excellent general corrosion resistance in atmospheres, water, and mild chemicals.

  • B8M – Superior resistance to pitting and crevice corrosion, particularly in marine or chloride-rich environments.

  • Both grades resist oxidation and general corrosion, though B8M is preferred for aggressive or high-chloride applications.

• Manufacturing Considerations:

  • Machinability is moderate; austenitic stainless steels work-harden quickly.

  • Hot forging or cold finishing is used depending on the type.

  • Weldable with proper filler metals; heat treatment is generally not required.

  • Type 1 is typically used for forged, heavy-duty fasteners, Type 2 for cold-formed or finished fasteners.

• Applications in Fasteners & Components:

  • Pressure vessel bolts, studs, and high-pressure pipe flanges in chemical, oil & gas, and petrochemical plants.

  • Marine and offshore fasteners where chloride resistance is critical (B8M preferred).

  • High-temperature service up to ~800°F, such as steam lines, refineries, and heat exchangers.

  • General-purpose austenitic stainless fasteners in industrial applications.