Description
Quenched-and-tempered Cr-Mo alloy steel
ASTM A193 B7 Alloy Steel Threaded Rod
High-strength continuous threaded bar for pressure equipment, refinery piping, flange joints, supports and engineered fastening assemblies.
Product overview
ASTM A193 Grade B7 threaded rod is manufactured from chromium-molybdenum alloy steel, commonly based on 4140 or 4142 chemistry, and is quenched and tempered to achieve the required mechanical properties. ASTM A193/A193M is intended for high-temperature or high-pressure bolting and other special-purpose applications.
Unlike a finished stud bolt cut to a joint-specific length, threaded rod can be supplied in standard stock lengths or cut to the approved bill of materials. The order should state the governing standard, grade, diameter, thread series, length, coating and inspection requirements.
ASTM A193 B7 threaded rod specifications
| Bolting standard | ASTM A193/A193M, ordered edition |
|---|---|
| Grade / material | Grade B7, chromium-molybdenum alloy steel; commonly 4140/4142 type |
| Heat treatment | Quenched and tempered to the ordered specification |
| Thread systems | ASME B1.1 UNC, UNF or 8UN; ASME B1.13M / ISO metric when ordered |
| Size range | 1/4–4 in and M6–M100 typical manufacturing range; project review required |
| Length | Stock or cut-to-length; custom lengths to drawing |
| Compatible nuts | ASTM A194 Grade 2H commonly specified, subject to design requirements |
| Finish options | Plain, black oxide, zinc, hot-dip galvanized or fluoropolymer coating |
Final dimensions, tolerances, heat treatment, coating, testing and acceptance criteria follow the confirmed purchase order and the applicable standard edition. Availability depends on diameter, length, thread form and production quantity.
Why specify this material?
B7 is widely selected where carbon-steel all-thread lacks the required strength or temperature capability. It offers a practical combination of availability, machinability, heat-treatment response and established use in pressure bolting.
Engineering note
Coating selection changes friction and therefore affects torque-to-tension behavior. Confirm lubricant, nut grade, coating system and installation procedure together; do not reuse generic torque values without engineering approval.
Typical applications
Quality, inspection and documentation
B7 verification should link starting material, heat treatment, mechanical testing, hardness and thread inspection to the finished lot. Coated products should retain traceable marking and include coating inspection when specified.
- EN 10204 3.1 material test certificate
- Heat-number and batch traceability
- Chemical composition and mechanical properties
- Dimensional inspection and thread gauging
- PMI for stainless and nickel alloys when ordered
- Coating thickness or surface inspection when applicable
- Third-party inspection and additional testing by agreement
- Export marking and seaworthy packing
Information required for quotation
- Material grade, governing material/bolting standard and required edition
- Diameter, thread series, pitch and thread class or tolerance
- Overall length, cut-end requirements and quantity
- Heat treatment, surface finish or coating system
- Matching nuts and washers, including anti-galling requirements
- Inspection plan, MTC, PMI, NDE and third-party witness requirements
- Delivery destination, packaging and required schedule
Frequently asked questions
What material is ASTM A193 Grade B7?
Grade B7 is a quenched-and-tempered chromium-molybdenum alloy steel commonly produced from 4140 or 4142 type material. The ASTM grade requirements, not a commercial alloy name alone, control acceptance.
Which nut is used with B7 threaded rod?
ASTM A194 Grade 2H heavy hex nuts are commonly paired with B7 bolting. The final nut grade, style, coating and thread fit must follow the project design.
Can B7 threaded rod be hot-dip galvanized?
Galvanizing can be supplied in suitable sizes when allowed by the project, but thread allowance, nut oversize, coating temperature and hydrogen-related controls require review.
Is B7 the same as B7M?
No. B7M has additional heat-treatment, hardness and testing requirements intended for controlled-hardness service. The grades should not be substituted without engineering approval.
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Request a technical quotation
Send your bill of materials, drawing or project specification. SASA FLANGE will review the grade, thread, dimensions, documentation and delivery requirements before quotation.
