ASTM A193 Grade B8MLNA is a standard material specification for corrosion resistant 316LN fasteners such as bolts, screws, studs, threaded rods and other externally threaded parts, for use in high tensile, high temperature and special purpose applications such as pressure piping & pressure vessels bolting. Grade B8MLNA is similar to Grade B8MLN except that the latter is carbide solution treated after head forming and the former is carbide solution treated in finished condition. Grade B8MLNA is classified under tensile class 1A with minimum tensile requirement of 75 ksi, yield 30 ksi and maximum hardness limit of 192 HBW or 90 HRB. This specification covers requirements for chemical composition, mechanical properties, hardness, heat-treatment and recommended nuts-washers for Grade B8MLNA Fasteners.
| Element | Low Carbon Nitrogen Enhanced Stainless Steel |
|---|---|
| UNS S31653 / AISI 316LN / 1.4429 | |
| CompositionA, % | |
| Carbon | 0.03 max |
| Manganese | 2.00 |
| Phosphorus | 0.045 max |
| Sulfur | 0.030 max |
| Silicon | 1.00 max |
| Chromium | 16.00 - 18.00 |
| Nickel | 10.00 - 13.00 |
| Molybdenum | 2.00 - 3.00 |
| Nitrogen | 0.10 - 0.16 |
A: The intentional addition of Bi, Se, Te, and Pb is not permitted.
| Tensile Class | Diameter, Inch | Tensile Strength, min, ksi |
Yield Strength, min, 0.2% offset, ksi |
Elongation in 4D, min, % |
Reduction of Area, min, % |
Hardness, max |
|
|---|---|---|---|---|---|---|---|
| Class 1 & 1D | All Sizes | 75 | 30 | 30 | 50 | 192 HBW or 90 HRB | |
Heat Treatment: Carbide Solution Treated.
| Nut Specification | Washer Specification |
|---|---|
| ASTM A194 Grade 8MLNA | ASTM A240 UNS S31653 |
| Commonly Produced B8MLNA Fasteners | ||||
|---|---|---|---|---|
| Hex Bolts | Heavy Hex Bolts | Stud Bolts | Threaded Rods | Anchor Bolts |
| Eye Bolts | Socket Head Cap Screws | Countersunk Screws | U Bolts | Square Head Bolts |