ASTM A193/A193M B7 Combination Studs Step Down Studs
Alloy steel bolting for pressure vessels, valves, flanges, and fittings for high temperature or high pressure service, or other special purpose applications.
Standard: According to drawing
Inch Size: 1/4”-4” with various lengths
Metric Size: M6-M100 with various lengths
Other Available Grade:
ASTM A193/A193M B7, B7M, B16 B8 Class 1 & 2, B8M Class 1 & 2,
ASTM A320/A320M L7, L7M, L43, B8 Class 1 & 2, B8M Class 1 & 2, and so on.
Finish: Plain, Black Oxide, Zinc Plated, Zinc Nickel Plated, Cadmium Plated, PTFE etc.
Packing: Bulk about 25 kgs each carton, 36 cartons each pallet
Advantage: High Quality and Strict Quality Control, Competitive Price,Timely Delivery; Technical Support, Supply Test Reports
Please feel free to contact us for more details.
ASTM A193
Scope
Originally approved in 1936, this specification is heavily utilized in petroleum and chemical construction applications. The ASTM standard covers alloy steel and stainless steel bolting materials for high temperature service. This specification includes fasteners intended for use in pressure vessels, valves, flanges, and fittings. Although, this material is often available in national coarse (UNC) thread pitches, if being used in traditional applications, threads are specified 8 threads per inch (tpi) for diameters above one inch.
Below is a basic summary of a few of the common grades. ASTM A193 covers a number of other standard specifications not covered in this description including B5, B6, and B16.
Grades
| B7 | Alloy steel, AISI 4140/4142 quenched and tempered |
| B8 | Class 1 Stainless steel, AISI 304, carbide solution treated. |
| B8M | Class 1 Stainless steel, AISI 316, carbide solution treated. |
| B8 | Class 2 Stainless steel, AISI 304, carbide solution treated, strain hardened |
| B8M | Class 2 Stainless steel, AISI 316, carbide solution treated, strain hardened |
Mechanical Properties
| Grade | Size | Tensile ksi, min | Yield, ksi, min | Elong, %, min | RA % min |
| B7 | Up to 2-1/2 | 125 | 105 | 16 | 50 |
| 2-5/8 - 4 | 115 | 95 | 16 | 50 | |
| 4-1/8 - 7 | 100 | 75 | 18 | 50 | |
| B8 Class 1 | All | 75 | 30 | 30 | 50 |
| B8M Class 1 | All | 75 | 30 | 30 | 50 |
| B8 Class 2 | Up to 3/4 | 125 | 100 | 12 | 35 |
| 7/8 - 1 | 115 | 80 | 15 | 35 | |
| 1-1/8 - 1-1/4 | 105 | 65 | 20 | 35 | |
| 1-3/8 - 1-1/2 | 100 | 50 | 28 | 45 | |
| B8M Class 2 | Up to 3/4 | 110 | 95 | 15 | 45 |
| 7/8 - 1 | 100 | 80 | 20 | 45 | |
| 1-1/8 - 1-1/4 | 95 | 65 | 25 | 45 | |
| 1-3/8 - 1-1/2 | 90 | 50 | 30 | 45 |
Recommended Nuts and Washers
| Bolt Grade | Nuts | Washers |
| B7 | A194 Grade 2H | F436 |
| B8 Class 1 | A194 Grade 8 | SS304 |
| B8M Class 1 | A194 Grade 8M | SS316 |
| B8 Class 2 | A194 Grade 8 | SS304 |
| B8M Class 2 | A194 Grade 8M | SS316 |
Strain hardened nuts available as a supplementary requirement
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