Scope
ASME SA-193 Grade B8M is the designation used in ASME BPVC Section II Part A for the same chemistry and mechanical-property envelope as ASTM A193 Grade B8M — UNS S31600 / 316 austenitic stainless steel bolting for high-temperature and corrosive service. The SA- prefix signals that the material has been adopted into the ASME boiler and pressure-vessel code, which is the normative path for vessels, valves, flanges, and fittings built under ASME Section VIII, B31.1, B31.3, and B16.5 pressure-rating rules.
For day-to-day procurement, SA-193 B8M and A193 B8M are interchangeable supply: same chemistry envelope, same Class 1 / 1A / 1D / 2 heat-treatment routes, same mechanical-property thresholds. The choice of prefix in the purchase order is driven by which document the engineer was working from when the specification was drawn: ASTM-form orders predominate in North America and India; ASME SA-form orders predominate in the Middle East (Saudi Aramco, ADNOC, SABIC, KOC), in pressure-vessel projects worldwide, and in stamped-vessel bolt-up positions where the boiler code stamp is the audit trail.
When project specs require SA-193
Owner-engineer specifications for ASME Section VIII Division 1 and 2 vessels typically call out SA-193 explicitly because the code book Section II Part A is the only normative material catalog inside the ASME framework. Saudi Aramco's standard 32-SAMSS-007 and ADNOC's E-25 piping spec are common downstream examples that require the SA- form on the MTC. Refinery turnaround orders also tend to lock SA-193 because the boiler code stamp drives ASTM/ASME equivalence in the inspector's audit packet.
Audit-trail equivalence
The Mill Test Certificate for SA-193 supply lists the ASTM A193 origin specification, identifies the heat number, and confirms the chemistry, mechanical properties, and heat-treatment class meet both document requirements. EN 10204 Type 3.1 is the default; Type 3.2 with third-party verification is required for sour-service flanges, PED Category III positions, and Aramco / ADNOC critical bolting. The SA-193 cert is also acceptable on ASTM A193 purchase orders without modification.
Class designations under SA-193
The four heat-treatment classes map one-to-one with the ASTM A193 framework: SA-193 B8M Class 1 (solution annealed, NACE MR0175 qualified), SA-193 B8M Class 1A (annealed in the finished condition, lowest hardness), SA-193 B8M Class 1D (annealed and liquid quenched, heavier sections), and SA-193 B8M Class 2 (annealed and strain hardened, 35 HRC max, higher tensile non-sour applications).
