ASTM A193 B5 Stainless Steel — Specs, Uses & Applications
In industries where fasteners face extreme heat and pressure for prolonged periods, material choice can make the difference between reliable operation and costly failure. The ASTM A193 specification was created to define fasteners capable of meeting those demands.
Among its grades, A193 B5 stands out as a ferritic stainless steel fastener material designed for creep resistance—the ability to withstand stress and retain shape under high temperatures. This makes it a vital specification in power generation, refineries, and petrochemical facilities where long-term durability is non-negotiable.
What Is ASTM A193 B5?
ASTM A193 B5 covers fasteners manufactured from 5% chromium ferritic stainless steel (AISI 501). Unlike carbon or alloy steels that can lose strength under prolonged high-heat exposure, B5 is engineered to resist creep and maintain mechanical performance.
Key characteristics include:
Tensile strength: Minimum of 100 ksi.
Yield strength: Minimum of 80 ksi.
Ferritic stainless properties: Naturally magnetic, moderately corrosion-resistant, and heat-treated for toughness.
Temperature service: Suitable for sustained use at elevated temperatures.
While B5 offers better corrosion resistance than many alloy steels, it does not match austenitic stainless grades like B8 (304) or B8M (316) in chloride-rich or marine environments.
Properties & Heat Treatment
Fasteners manufactured to A193 B5 are typically:
Quenched & tempered to balance strength and toughness.
Hardness range: Rockwell C22–30.
Temperature performance: Reliable up to ~1050°F, ideal for high-heat systems.
Creep resistance: Maintains joint stability during long-term service under load and heat.
These properties ensure B5 fasteners are built for longevity in punishing environments, where creep failure could compromise safety and uptime.
Compatible Nuts: ASTM A194
To ensure performance, A193 B5 fasteners are paired with ASTM A194 Grade 5 or 6 nuts. Using the correct nut pairing provides:
Strength alignment for consistent load sharing.
Reduced galling risk during tightening.
Joint stability under high temperatures and stresses.
Correct nut/fastener pairing is a critical part of maintaining compliance with the ASTM specification.
Applications of ASTM A193 B5
Because of its high-temperature resilience, A193 B5 is widely specified in industries that demand both strength and durability:
Power generation: Boilers, turbines, and reactors where creep resistance is essential.
Refineries: Piping systems, pressure vessels, and flange assemblies exposed to high heat.
Petrochemical plants: Catalytic crackers and heat exchangers in constant operation.
Industrial equipment: Applications where magnetic properties are acceptable and long-term heat resistance is needed.
Each of these environments requires fasteners that can endure constant thermal and mechanical stress without deformation.
California Fastener’s Offering
At California Fastener, we supply a wide range of ASTM A193 B5-compliant fasteners, including studs and threaded rods, with:
Multiple diameters, thread pitches, and lengths.
Full certifications and traceability for compliance.
Pre-kitted assemblies for turnaround and outage projects.
Dependable lead times to keep projects on schedule.
Our role is to provide spec-compliant fasteners, delivered ready for installation, backed by documentation, and supported by reliable supply.
FAQs About ASTM A193 B5
Q: What makes A193 B5 different from B7 or B16?
A: B5 is ferritic stainless, prioritizing creep resistance at high temps. B7 and B16 are alloy steels with greater strength but less corrosion resistance.
Q: Is B5 corrosion-resistant?
A: Yes, moderately. But for marine or chloride-rich environments, B8M (316 stainless) is the better choice.
Q: Can B5 be coated or finished?
A: Yes. Zinc flake, passivation, or other finishes can extend durability in certain environments.
Q: Where is B5 most often used?
A: In boilers, reactors, turbines, refineries, and petrochemical facilities.
Engineered for Heat and Reliability
ASTM A193 B5 fasteners are designed to thrive where sustained heat and pressure make ordinary materials fail. With proven creep resistance and strong mechanical properties, B5 remains a trusted specification for industries that cannot afford downtime.
At California Fastener, we provide A193 B5-compliant fasteners that are spec-certified, fully documented, and delivered on time.
Contact us today to source ASTM A193 B5 studs, rods, and fasteners—engineered for reliability under the most demanding conditions.
