Stud Bolts ASTM A193 B7

Stud Bolts ASTM A193 B7 — High Temperature Alloy Steel Stud Bolts | M12–M100

ASTM A193 B7 stud bolts are quenched and tempered alloy steel (AISI 4140/4142) fasteners designed for high-temperature and high-pressure applications in the oil & gas, petrochemical, and power generation industries. These fully threaded stud bolts feature chamfered ends and are supplied with two ASTM A194 2H heavy hex nuts as a complete bolting assembly. Compliant with ASME B16.5 flange bolting requirements.

Material & Specifications

Size Range	M12 to M100 / 1/2″ to 4″
Standard	ASTM A193 Grade B7, ASME SA193 B7, API 6A
Material	AISI 4140/4142 Alloy Steel — Quenched & Tempered
Surface / Coating	Black/Plain (standard), Hot-Dip Galvanized, Dacromet, PTFE Coated
Tensile Strength	≥ 860 MPa (125 ksi)
Yield Strength	≥ 725 MPa (105 ksi)
Max Service Temp	450°C (842°F) continuous

Surface Treatment & Zinc Coating Quality

At BoltNutsPlus, we understand that surface treatment is critical to fastener longevity and performance. Our products undergo rigorous coating processes to ensure maximum corrosion resistance and durability. We offer five premium coating options, each tested to international standards:

• Hot-Dip Galvanizing (HDG) — Thick zinc layer (50-120μm) providing superior long-term corrosion protection for outdoor, marine, and industrial environments. Compliant with ISO 1461 / ASTM A153 standards. Salt spray resistance: 500-1,000+ hours. Ideal for structural steel assemblies exposed to harsh weather.
• Electroplated Zinc Blue-White (Zn Blue/White) — Bright, clean silver-blue appearance with 5-15μm zinc layer. Cr3+ passivation technology, fully RoHS compliant. Ideal for indoor machinery, electronics, and general-purpose applications requiring aesthetic appeal and moderate corrosion resistance.
• Color Zinc / Yellow Zinc (Iridescent Passivation) — Multi-colored iridescent passivation film offering enhanced corrosion resistance (100-200 hours salt spray) with a distinctive golden finish. Widely preferred in automotive, agricultural equipment, and construction machinery sectors for its balanced protection and visual appeal.
• Dacromet Coating — Advanced water-based zinc-chromium coating technology with NO hydrogen embrittlement risk. Provides 1,000+ hours salt spray resistance, making it the preferred choice for high-strength fasteners in extreme environments. Environmentally friendly (no heavy metal discharge), RoHS/ELV compliant, ideal for automotive and wind energy applications.
• Multi-Element Alloy Co-Permeation — Zinc-aluminum-rare earth alloy layer offering 2-3x the corrosion resistance of traditional galvanizing. Features self-healing properties at scratch points, ensuring long-term protection even in damaged areas. Ideal for critical infrastructure, power transmission towers, coastal projects, and marine installations.

Key Features

• Quenched and tempered AISI 4140 alloy steel for high-temperature service
• Chamfered both ends for easy nut threading from either side
• Supplied with matching ASTM A194 2H heavy hex nuts (complete assembly)
• Full material certification with chemistry, mechanicals, and heat treatment records
• PTFE/Xylan coating option for corrosive and galling-prone environments
• ASME B16.5 compliant flange bolting lengths for standard pressure class flanges

Applications

• Oil & gas flange connections (ASME B16.5 pressure-rated flanges)
• Petrochemical refinery pressure vessel and heat exchanger bolting
• Power plant high-temperature piping and boiler assemblies
• Valve and pump body through-bolt connections
• Pressure vessel and tank nozzle bolting
• Offshore platform subsea and topside structural connections

Why Choose BoltNutsPlus?

• ISO 9001:2015 Certified Manufacturing — consistent quality you can trust on every batch
• 15+ Years of Export Experience — serving 40+ countries across 6 continents
• Full Traceability — material certificates (EN 10204 3.1) and comprehensive test reports included
• Custom Packaging & OEM/ODM — your brand identity, your specifications, our precision manufacturing
• Third-Party SGS / Bureau Veritas Inspection Available upon request
• 24-Hour Quote Response — same-day reply for urgent requirements; standard 24-hour turnaround