ASTM A193 Grade B8MN Class 1B (316N Stainless)
316N stainless bolting — the chloride resistance of 316 with 80 ksi tensile and 35 ksi yield in the solution-treated condition.
What A193 B8MN Class 1B is.
ASTM A193 Grade B8MN is bolting in Type 316N, which adds 0.10 to 0.16 percent nitrogen to 316. As with B8N, the nitrogen raises the solution-treated strength to 80 ksi tensile and 35 ksi yield at any diameter, so the higher design stresses of 316N can be used on large studs.
We supply B8MN from certified 316N bar in Class 1B and Class 2 with full heat traceability.
Chemical composition.
| Element | Symbol | Min % | Max % |
|---|---|---|---|
| Carbon | C | — | 0.08 |
| Manganese | Mn | — | 2.00 |
| Phosphorus | P | — | 0.045 |
| Sulfur | S | — | 0.030 |
| Silicon | Si | — | 1.00 |
| Chromium | Cr | 16.0 | 18.0 |
| Nickel | Ni | 10.0 | 13.0 |
| Molybdenum | Mo | 2.00 | 3.00 |
| Nitrogen | N | 0.10 | 0.16 |
Values per ASTM A193/A193M-24, Tables 1 and 2 (verified against the specification). Confirm the edition called out on your purchase order with our estimating team.
Mechanical properties.
| Nominal diameter (in.) | Tensile strength, min (ksi) | Yield strength 0.2% offset, min (ksi) | Elongation in 4D, min (%) | Reduction of area, min (%) | Hardness, max |
|---|---|---|---|---|---|
| Class 1B / 1D — all diameters | 80 | 35 | 30 | 40 | 223 HBW / 96 HRB |
Values per ASTM A193/A193M-24, Tables 1 and 2 (verified against the specification). Confirm the edition called out on your purchase order with our estimating team. Class 1 sizes ¾ in. and smaller may be 241 HBW / 100 HRB. Strain-hardened Class 2 properties are on the B8MN Class 2 page.
Specifications that apply.
How A193 B8MN Class 1B ships from Houston.
- Full-thread studs and stud bolts
- Hex and heavy hex bolts
- Socket head cap screws
- Hex nuts in the same alloy
- Threaded rod
- Machined components from certified bar
A193 B8MN Class 1B fasteners we make.
Every item is manufactured to your drawing or standard in A193 B8MN Class 1B, imperial or metric, with an EN 10204 3.1 certificate.
What is ASTM A193 B8MN?
B8MN is the nitrogen-bearing form of B8M. The 0.10 to 0.16 percent nitrogen gives 316N about a third more solution-treated strength than 316 and slightly better pitting resistance, since nitrogen counts toward the pitting resistance equivalent number. A193 Class 1B rates it at 80 ksi tensile and 35 ksi yield with no diameter limit; Class 2 follows the B8M strain-hardened table.
Testing, certification and marking
- Tensile and hardness tested per lot on the finished product
- Grade or alloy marking B8MN and manufacturer's identification on every piece
- EN 10204 3.1 material test report with heat number and chemistry; 3.2 witness available
ASTM A193 Grade B8MN Class 2 (316N Strain Hardened)
Nitrogen-strengthened 316N bolting cold worked to 110 ksi tensile in ¾ in. and under — chloride resistance with Class 2 strength.
ASTM A193 / ASME SA-193ASTM A193 Grade B8M Class 1 (316 Stainless)
316 stainless bolting with molybdenum for chloride and pitting resistance — offshore, marine, chemical and coastal plant fasteners.
ASTM A193 / ASME SA-193ASTM A193 Grade B8N Class 1B (304N Stainless)
304N stainless bolting — nitrogen lifts the solution-treated yield to 35 ksi and tensile to 80 ksi without cold work, for larger diameters and higher design stresses.