ASTM A193 Grade B8M Studs and Bolts
ASTM A193 Grade B8M studs and bolts — the standard 316 stainless grade whose composition the collected datasheet calls identical to B8M3's, and whose fully annealed Class 1 / Class 1A condition is the strict NACE MR0175-compliant variant for sour service.
Last updated: 2026-11
Specifications
B8M is the baseline ASTM A193 316 stainless fastener grade. The collected B8M3 datasheet states the chemical foundation of B8M3 is identical to standard B8M — the same 2–3% molybdenum austenitic composition — so the grades diverge on condition, not chemistry: B8M in the fully annealed Class 1 / Class 1A condition is what the datasheet specifies for strict NACE MR0175 compliance, because the sour-service standard restricts austenitic stainless hardness to 22 HRC (about 99 HRB) to prevent sulfide stress cracking in H2S environments. That is the buyer decision this page exists for: dynamic high-ductility joints go to B8M3, severe sour service goes to annealed B8M.
| Designation | ASTM A193 Grade B8M (316 stainless; Class 1 / Class 1A fully annealed for strict NACE compliance per the collected datasheet) |
|---|---|
| Chemical composition | Identical to B8M3 per the collected datasheet ("the chemical foundation of B8M3 is identical to standard B8M"): C 0.08% max, Cr 16.0–18.0%, Ni 10.0–14.0%, Mo 2.00–3.00% |
| Sour-service condition | NACE MR0175 restricts austenitic stainless hardness to 22 HRC (approx. 99 HRB) to prevent sulfide stress cracking in H2S environments; engineers must specify fully annealed B8M Class 1 or Class 1A for strict NACE compliance (collected datasheet FAQ, verbatim basis) |
| Positioning vs B8M3 | Same chemistry; B8M3 adds strain hardening for strength and ductility but exits the 22 HRC sour-service envelope (up to 35 HRC) |
| Matched nuts | ASTM A194 grade 8M (collected pairing table) |
| MOQ / lead time | Not owner-confirmed for this family — confirmed at quotation |
Materials
- ASTM A193 B8M 316 stainless steel, fully annealed (Class 1 / Class 1A) for sour service
Ordering & documentation
Documents
Shipments are backed by Mill Test Certificate (MTC), Dimensional Report, Salt Spray Test Report on request, with full batch traceability from raw material to finished product. Quality management follows the owner-confirmed compliance list: ISO 9001:2015, RoHS, REACH. Exact document sets are confirmed on the order.
Quotation
- The fastener family (ASTM A193 Grade B8M Studs and Bolts) plus the standard designation from your drawing — DIN / ISO / JIS / ASTM / ANSI, or a drawing for custom parts.
- Size (diameter and length), thread type (metric or inch), property class or grade, and coating or finish.
- Quantity per size and your target delivery date.
- Destination country, and any required documents (for example a mill test certificate) so the quote includes them.
Sample & supply
Minimum order quantities and lead times for this family are confirmed at quotation — send your sizes, grades and quantities on the RFQ and the quote will carry a firm schedule. Sample availability is confirmed with the quotation.
Storage & shipping
Parts are packed for export and shipped factory-direct to buyers in Europe, Asia, the Americas and the Middle East. Store fasteners dry and protected until installation, and keep coated parts in their packaging until use; specific packing and preservation requirements can be stated on the order and confirmed at quotation.
Frequently asked questions
When is annealed B8M the right grade instead of B8M3?
When the joint must meet NACE MR0175: the collected datasheet notes the standard restricts austenitic stainless hardness to 22 HRC to prevent sulfide stress cracking, which excludes strain-hardened B8M3 (up to 35 HRC) and makes fully annealed B8M Class 1 / Class 1A the strict-compliance choice. State the sour-service requirement explicitly on the RFQ.
What should an RFQ for B8M studs state?
State the grade and condition (ASTM A193 B8M, Class 1 / Class 1A annealed if NACE MR0175 compliance is required), stud type and diameter series, matched nut grade (A194 8M), and the service environment (H2S content if sour). Commercial terms are confirmed at quotation.
Request a Quote
Get factory-direct pricing from the manufacturer.
What to include in your inquiry
- ✓ Standard and property class (e.g. DIN 912, ISO 4762, class 8.8) — or a drawing for custom parts.
- ✓ Sizes, lengths and thread type (metric or inch).
- ✓ Quantity per size and your target delivery date.
- ✓ Destination country, plus any coating or finish requirement.
- ✓ Any documents you need with the shipment (e.g. mill test certificate) so the quote includes them.
- ✓ Your inquiry goes straight to the factory team by email and gets a reply within 24 hours.
- ✓ Factory-direct pricing
- ✓ Standard and custom specifications
- ✓ Factory-direct export to buyers in Europe, Asia, the Americas and the Middle East
- ✓ Full fastener family support