Round U-Bolts

Round U-Bolts — Pipe Clamping U-Bolts | M8–M36 | DIN 3570 | Round Bar U-Bolt

Round U-bolts are U-shaped fasteners with threaded legs designed for clamping and supporting round pipes, tubes, and cylindrical components. Manufactured to DIN 3570 standards, these U-bolts feature a semi-circular bend that conforms to pipe outside diameters, providing secure gripping without point loading. Available in M8 to M36 thread sizes for pipe diameters from 1/2″ to 12″.

Material & Specifications

Size Range	M8 to M36 (thread) / pipe OD: 12mm to 300mm (1/2″ to 12″)
Standard	DIN 3570, MSS SP-69, ANSI B18.5
Material	Carbon Steel (Grade 4.6/5.6), 304 SS, 316 SS, Galvanized Carbon Steel
Surface / Coating	Hot-Dip Galvanized (HDG), Electroplated Zinc, Dacromet, Passivated (SS)
Pipe OD Range	1/2″ (21mm) to 12″ (324mm) nominal pipe sizes
Configuration	2 nuts + 2 flat washers per U-bolt (standard)

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

• Semi-circular bend conforms to pipe OD for uniform load distribution
• Galvanized finish provides excellent corrosion resistance for outdoor piping
• Threaded legs allow adjustable clamping force with standard nuts
• Stainless steel option for corrosive and sanitary applications
• Supplied with matching nuts and washers as complete assembly
• Custom pipe sizes and bend configurations available upon request

Applications

• Pipe support and anchoring in industrial piping systems
• HVAC chilled/hot water piping suspension
• Plumbing and drainage system pipe clamping
• Vehicle exhaust system and trailer pipe mounting
• Marine and offshore piping support
• Structural pipe railing and guardrail 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