Benchmark supplies ASTM A193 Grade B8 Class 2 strain hardened stainless steel heavy hex bolts, threaded rod and stud bolts with a typical lead time of 18–25 days. When your bolting is holding up a bridge bearing install, a shutdown or a steel erection schedule, weeks — not months — matters.
B8 Class 2 is a far less common grade than Class 1. Because the strength comes from cold working (strain hardening) rather than heat treatment, headed bolts cannot simply be hot forged, and strain hardened bar is hard to source in larger diameters. Non-standard sizes from overseas manufacturers routinely take several months to arrive. Benchmark quotes a firm 18–25 day lead time so you can plan around it.
| Nominal diameter | Min. tensile (ksi) | Min. yield (ksi) | Min. elongation | Max. hardness |
|---|---|---|---|---|
| Up to 3/4″ | 125 | 100 | 12% | 35 HRC |
| 7/8″ – 1″ | 115 | 80 | 15% | 35 HRC |
| 1-1/8″ – 1-1/4″ | 105 | 65 | 20% | 35 HRC |
| 1-3/8″ – 1-1/2″ | 100 | 50 | 28% | 35 HRC |
Per ASTM A193/A193M for Grade B8 Class 2 (Type 304, carbide solution treated and strain hardened). Class 1 B8 is 75 ksi tensile / 30 ksi yield at all diameters. Always confirm requirements with the engineer of record.
Already buying bearings from us? Benchmark also manufactures slide and expansion bearings, elastomeric bearings and Vibsorb pads — one order, one schedule.
Both are Type 304 stainless and carbide solution treated. Class 2 is additionally strain hardened, raising minimum yield from 30 ksi to as high as 100 ksi (diameter dependent). If a specification says only “A193 B8”, Class 1 is assumed.
A193 B8 Class 2 fasteners are marked B8SH with the grade symbol underlined, plus the manufacturer’s identification mark.
ASTM A193 defines Class 2 properties up to 1-1/2″. Larger diameters are rarely available because strain hardening does not penetrate the core of large bar. Talk to us about your requirement and alternatives.
A193 only calls for A194 Grade 8 nuts. If your project requires strain hardened nuts, they are ordered as A194 Grade 8 with Supplementary Requirement S1. The engineer of record makes the final call.
No — not without the engineer’s approval. Class 1 is significantly weaker. Avoiding a forced substitution is exactly why a short, reliable lead time matters.
Send your bolt list to Benchmark or call 800-580-4195.