Materials
Alloy Steels: A193 (B7, B7M, B16)
ASTM A193 Grade B7
Manufacturing Considerations:
Produced from quenched and tempered Cr-Mo alloy steel (often 4140/4142).
Machines well and responds predictably to controlled heat treatment.
Provides high tensile strength while maintaining dimensional stability.
Performance in Fasteners:
Delivers reliable high strength for bolts and studs in pressure vessels, valves, flanges, and turbomachinery.
Good balance of strength and toughness for critical bolting applications.
Proven standard choice across oil & gas, refining, and petrochemicals.
ASTM A193 Grade B7M
Manufacturing Considerations:
Same base alloy as B7 but with modified heat treatment to reduce hardness (≤235 HB).
Requires careful process control to achieve lower strength while maintaining integrity.
Typically paired with nuts manufactured to ASTM A194 Grade 2HM.
Performance in Fasteners:
Lower hardness reduces the risk of hydrogen embrittlement, sulfide stress cracking, and stress corrosion cracking.
Designed for sour service environments (H₂S, acidic, or corrosive conditions).
Frequently specified in oilfield bolting for safety-critical systems where NACE compliance is required.
ASTM A193 Grade B16
Manufacturing Considerations:
Chromium-molybdenum-vanadium alloy steel, more specialized than B7/B7M.
Precision heat treatment is crucial to maximize creep resistance and maintain high strength at elevated temperatures.
More challenging to machine but engineered fastener manufacturers can achieve required tolerances.
Performance in Fasteners:
Excels in high-temperature service (boilers, steam turbines, and turbine casings).
Vanadium addition provides superior creep and thermal fatigue resistance.
Used in power generation and turbomachinery components where long-term stability under heat and stress is critical.
Key Takeaway for Engineered Fasteners
B7: Workhorse alloy for high-strength fasteners in pressure/high-temp service.
B7M: Modified for sour/corrosive environments, ensuring safety where embrittlement is a concern.
B16: Specialized for extreme high-temperature and creep-resistant bolting in turbines and power systems.
Materials
BRASS
BRONZE
COPPER
PH STAINLESS STEEL
DOING WHATEVER IT TAKES
Putting Manufacturing Exellence Into Practice
The manufacturing processes, testing capabilities, and quality systems featured throughout WN Global support the production of critical components and engineered fastening solutions across demanding industries. Connect with our team to learn how our manufacturing capabilities can support your project requirements.
