Scope
ASTM A193 / A193M B8 specification covers alloy and ferritic and austenitic stainless steel bolting materials and bolting components for pressure vessels, valves, flanges, and fittings for high temperature or high pressure service, or other special purpose applications. Bolting Materials such as Bars and wire rods shall be hot wrought and may be further processed by center less grinding or by cold drawing. Austenitic stainless steel may be carbide solution treated or carbide solution treated and strain-hardened. Bolting type such as Hex Bolts, Heavy Hex Bolts, Studs, Socket Head Cap Screws, Hex Cap Screws, Threaded Rods and Threaded Bars can be manufactured from ¼” to 4” in imperial and M6 to M100 in metric variants both fine threads and coarse threads. Bolting Components up to 6” can be provided at TorqBolt with the same certification. PED 2014/68/EC Certified ASTM/ASME A193/A193M Bolting is available exstock.
As a b8 bolt material, ASTM A193 Grade B8 covers 304 austenitic stainless steel (UNS S30400) bolting for high-temperature and pressure-vessel service. B8 bolts are specified across five strength classes — Class 1, 1A, 1D, 2 and 2B — distinguished by heat treatment (carbide solution treatment vs strain hardening) and the resulting tensile and hardness levels. The B8 designation under ASTM A193 / A193M sits within the same specification family as B7 (chrome-moly alloy steel) and B8M (316 stainless steel with molybdenum addition).
ASTM A193 B8 Equivalent Material
ASTM A193 Grade B8 maps to 304 / 18-8 austenitic stainless steel (UNS S30400, AISI Type 304). International cross-references: EN 1.4301 / X5CrNi18-10 (European), JIS SUS304 (Japanese), GB 0Cr19Ni10 (Chinese), GOST 08Kh18N10 (Russian). The ASME Boiler and Pressure Vessel Code Section II adopts the same chemistry under designation SA-193 B8 for pressure-vessel and pressure-piping bolting.
ASTM A193 Grade B8 Classes
