U-Bolt

  • DIN 3570 / ASME B18.31.5
  • Round Bend U-Bolt
  • Square Bend U-Bolt
  • Long Leg U-Bolt

Category

U-bolts, also known as U-bend bolts, clamp bolts, horse mounting bolts, or pipe hooks, are U-shaped fasteners with threads on both ends . The name “horse mounting bolt” originates from the way the bolt straddles or “rides” on the object being secured, resembling a person riding a horse. They are widely used to secure pipes, tubes, cables, leaf springs, and structural components to support frames or mounting surfaces.

Available Shapes

Shape Description Typical Applications
Round Bend (Semicircular) Standard U-shape with rounded bend Pipes, tubes, conduit, cylindrical objects
Square Bend 90° angled bend Square tubing, rectangular profiles, structural framing
Rectangular / Long Leg Extended leg length for thicker assemblies Thick material stacks, custom mounting configurations
Special / Custom Bend Triangular, oblique, or custom shapes per design Specialized mounting requirements

Applicable Standards

Standard Scope
DIN 3570 U-bolts for pipe and structural support – metric series
ASME B18.31.5 Bent bolts, including U-bolts, J-bolts, and hook bolts – inch series
JB/ZQ 4321-2006 Chinese standard for U-bolts (U-shaped bolts)

Materials

Material Strength Grades Common Applications
Carbon Steel (Q235, Q345B) 4.8, 6.8, 8.8, 10.9 General industrial, construction, automotive
Alloy Steel 8.8, 10.9, 12.9 High-strength, heavy-duty applications
Stainless Steel A2-70 (304), A4-80 (316) Marine, food processing, corrosive environments
ASTM A320 Grade L7 130 ksi min Low-temperature service down to -150°F

Surface Finishes

  • Zinc Plating (clear, yellow, white) – moderate corrosion protection

  • Hot-Dip Galvanizing (HDG) – heavy zinc coating for outdoor use; provides 85+ microns protection

  • Black Oxide – mild corrosion protection, matte finish

  • Dacromet / Geomet – high-performance anti-corrosion coating

Common Applications

  • Automotive & Trucking: Leaf spring suspension mounting, axle attachment, exhaust systems

  • Piping & Plumbing: Securing pipes, tubes, and conduits to walls, ceilings, or structural frames

  • Construction & Structural: Mounting beams, guardrails, signposts, cable trays

  • Marine & Offshore: Corrosion-resistant applications in shipbuilding and offshore platforms

  • HVAC: Mounting ductwork, air handling units, and ventilation components

  • Electrical Infrastructure: Suspending insulators, cables, and conduit systems

  • Agricultural Equipment: Securing components on farming machinery and implements