China A193 B8M Class 2 Stud Bolt,B8M CL2 Stud bolt manufacturer
ASTM A193 Grade B8M Class 2 Stud bolt is made of stainless steel 316/316L rod,with thread rolling or machining.ASTM A193 Grade B8M Class 2 is required with carbide solution treated and strain hardened Treatment,Its tensile strength requirement of 125 ksi or 860 MPa and 100 ksi or 690 MPa and maximum hardness of 321 HBW or 35HRC
A193 B8M Class 2 Stud Bolt Specifications
Thread Diameters : Up to 2-1/2
Threads Configuration : ASME B1.1 2A/3A – 2B/3B Inch Unified Threads and B1.13M 6h-6G Metric Coarse Threads
Certification : EN 10204 3.1
Standard Specification for Alloy-Steel and Stainless Steel Bolting Materials for High-Temperature Service
ASTM A193 specification covers alloy steel and stainless steel bolting material for pressure vessels, valves, flanges, and fittings for high temperature or high pressure service, or other special purpose applications. Several grades are covered, including ferritic steels and austenitic stainless steels designated B5, B8, B8M and so forth. Selection will depend upon design, service conditions, mechanical properties, and high temperature characteristics.
Stud Bolt according to ASTM A193 B8M Class 2 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.
The difference between ASTM A193 Grade B8M Class 2 and ASTM A193 Grade B8M Class 1
. A193 and A320 grades B8 and B8M are assumed to be Class 1 unless otherwise specified. Class 1 fasteners are carbide solution treated, while class 2 fasteners are carbide solution treated and strain hardened. The work hardening that occurs in the manufacturing of Class 2 fasteners increases their strength. Class 2 fasteners are differentiated by the letters “SH” after the grade marking on the fastener and an underline for both A193 and A320 fasteners. The marking typically appears on the heads of bolts or the ends of threaded studs. For both A193 and A320, the marking requirement historically was only the underline, the “SH” lettering was added in approximately 2006.
| ASTM Specification | Stainless Grade | Application | Marking Class 1 | Marking Class 2 |
|---|---|---|---|---|
| A193 Grade B8 | Type 304 | High temperature / High pressure | B8 | B8SH |
| A320 Grade B8 | Type 304 | Low temperature | B8 | B8 |
| A193 Grade B8M | Type 316 | High temperature / High pressure | B8M | B8MSH |
| A320 Grade B8M | Type 316 | Low temperature | B8M | B8M |
1.Raw material and main application for A193 B8 and A193 B8M..
| Specification | Stainless | Application |
| Grade | ||
| A193 Grade B8 | Type 304 | High temperature / High pressure |
| A320 Grade B8 | Type 304 | Low temperature |
| A193 Grade B8M | Type 316 | High temperature / High pressure |
| A320 Grade B8M | Type 316 | Low temperature |
2.Heat treatment for A193 B8M Cl2 stud bolt
| 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 |
3.A193 B8 and A193 B8M Stud bolt mechanical property :
| Grade | Size | Tensile ksi, min | Yield, ksi, min | Elong, %, min | RA % min | HBW | HRC |
| B8 Class 1 | All | 75 | 30 | 30 | 50 | 223 max | 35 max |
| B8M Class 1 | All | 75 | 30 | 30 | 50 | 223 max | 96 max |
| B8 Class 2 | Up to 3/4″ | 125 | 100 | 12 | 35 | 321 max | 35 max |
| 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 | 321 max | 35 max |
| 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 |
4.A193 B8M stud bolt Chemical composition :
| Element | B8 (AISI 304) | B8M (AISI 316) |
| Carbon | 0.08% max | 0.08% max |
| Manganese | 2.00% max | 2.00% max |
| Phosphorus, max | 0.05% | 0.05% |
| Sulfur, max | 0.03% | 0.03% |
| Silicon | 1.00% max | 1.00% max |
| Chromium | 18.0 – 20.0% | 16.0 – 18.0% |
| Nickel | 8.0 – 11.0% | 10.0 – 14.0% |
| Molybdenum | 2.00 – 3.00% |