ASTM A193 Grade B8MA Specification
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ASTM A193 Grade B8MA Specification for high tensile bolts, screws, stud bolts, anchor bolts, threaded rods and other externally threaded fasteners, made from 316 stainless steel.
ASTM A193 Grade B8MA is a standard material specification for corrosion resistant 316 stainless steel 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 B8MA is a heat-treated, work-hardened (or both) austenitic stainless steel further divided into class 1 and class 2, each having a distinguished tensile strength. This specification covers requirements for chemical composition, mechanical properties, hardness, heat-treatment and recommended nuts-washers for Grade B8MA Fasteners.
Chemical Composition
| Element | Austenitic Stainless Steel |
|---|---|
| AISI 316 / 316L | |
| CompositionA, % | |
| Carbon | 0.08 max |
| Manganese | 2.00 |
| Phosphorus | 0.045 max |
| Sulfur | 0.030 max |
| Silicon | 1.00 max |
| Chromium | 16.00 - 18.00 |
| Nickel | 10.00 - 14.00 |
| Molybdenum | 2.00 - 3.00 |
AThe intentional addition of Bi, Se, Te, and Pb is not permitted.
Mechanical Properties
| 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 1A | All Sizes | 75 | 30 | 30 | 50 | 192 HBW or 90 HRB | |
Heat Treatment: Carbide Solution Treated in finished condition.
Recommended Nuts & Washers
| Nut Specification | Washer Specification |
|---|---|
| ASTM A194 Grade 8M | ASTM A240 TP316 |
Fasteners
| Commonly Produced B8MA 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 |