Grade B8T
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» Materials » ASTM Specifications » ASTM A193-A193M » Grade B8T
ASTM A193 Grade B8T Specification for high tensile bolts, screws, stud bolts, anchor bolts, threaded rods and other externally threaded fasteners, made from 321 stainless steel. ASTM A193 Grade B8T is a standard material specification for corrosion resistant 321 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 B8T 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 B8T Fasteners.
| Property | Description |
|---|---|
| Class 1 | Carbide Solution Treated |
| Class 2 | Carbide Solution Treated & Strain Hardened |
| Element | Austenitic Stainless Steel |
|---|---|
| AISI 321 / 321H | |
| CompositionA, % | |
| Carbon | 0.08 max |
| Manganese | 2.00 |
| Phosphorus | 0.045 max |
| Sulfur | 0.030 max |
| Silicon | 1.00 max |
| Chromium | 17.00 - 19.00 |
| Nickel | 9.00 - 12.00 |
| Titanium | 5 x Carbon Content - 0.70 |
| Nitrogen | 0.10 max |
AThe 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 1A | All Sizes | 75 | 30 | 30 | 50 | 223 HBW or 96 HRB |
Class 2B,C |
3/4 and under | 125 | 100 | 12 | 35 | 321 HBW or 35 HRC |
| over 3/4 to 1 inclusive | 115 | 80 | 15 | 35 | ||
| over 1 to 1-1/4 inclusive | 105 | 65 | 20 | 35 | ||
| over 1-1/4 to 1-1/2 inclusive | 100 | 50 | 28 | 50 |
A: Carbide Solution Treated
B: Carbide Solution Treated and Strain Hardened
C: For diameters 11⁄2 and over, center (core) properties may be lower than indicated by test reports which are based on values determined at 1⁄2 radius.
| Nut Specification | Washer Specification |
|---|---|
| ASTM A194 Grade 8T | ASTM A240 TP321 |
| Commonly Produced B8T 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 |