Grade B8C
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» Materials » ASTM Specifications » ASTM A193-A193M » Grade B8C
ASTM A193 Grade B8C Specification for high tensile bolts, screws, stud bolts, anchor bolts, threaded rods and other externally threaded fasteners, made from 347 stainless steel. ASTM A193 Grade B8C is a standard material specification for corrosion resistant grade 347 stainless steel fasteners, for use in high tensile, high temperature and special purpose applications such as pressure piping & pressure vessels bolting. Grade B8C 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 B8C Fasteners.
| Property | Description |
|---|---|
| Class 1 | Carbide Solution Treated |
| Class 2 | Carbide Solution Treated & Strain Hardened |
| Element | Austenitic Stainless Steel |
|---|---|
| AISI 347 | |
| 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 |
| Columbium + tantalum | 10 x Carbon Content - 1.10 |
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 HRBC |
Class 2B |
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 11⁄2, inclusive | 100 | 50 | 28 | 45 |
A: Carbide Solution Treated
B: Carbide Solution Treated and Strain Hardened
C: For sizes 3⁄4 in. in diameter and smaller, a maximum hardness of 241 HBW (100 HRB) is permitted.
| Nut Specification | Washer Specification |
|---|---|
| ASTM A194 Grade 8C | ASTM A240 TP347 |
| Commonly Produced B8C 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 |