U Bolts

Standard	DIN 3570 · SAE J429
Material	40Cr / 35CrMo / 10B21
Strength Grade	8.8 / 10.9
Size Range	M6-M20
Surface Treatment	Zinc Plated / HDG / Zinc Flake

Product Description

Product Description & Key Specifications

U bolts are bent fasteners used to clamp pipes, tubes, round bars, axle components, brackets and equipment to a support surface. This range is supplied in 40Cr, 35CrMo and 10B21 with grade 8.8 / 10.9 options to DIN 3570, SAE J429 or project drawings.

U bolt selection depends on inside width, leg length, thread length, bend radius, bar diameter, thread size, nut/washer stack and the clamped pipe or frame dimension. Round bend U bolts are common for pipe and tube clamping, while square bend forms are used for rectangular frames and brackets when specified by drawing.

Zinc plated finish is used for general indoor equipment, HDG is common for outdoor construction and pipe support corrosion protection, and zinc flake can be selected for controlled coating thickness and improved corrosion resistance. RFQs should include drawing or key dimensions, finish, grade and matching nuts/washers.

Product type	U bolts / round bend or square bend clamp bolts
Standards	DIN 3570 / SAE J429 / OEM drawing
Material	40Cr / 35CrMo / 10B21
Strength grade	8.8 / 10.9
Size range	M6-M20
Common models	M8, M10, M12, M16, M20 with drawing-based inside width and leg length
Thread type	Metric thread on both legs, thread length by drawing
Surface finish	Zinc plated / Hot-dip galvanized / Zinc flake
Matched hardware	Hex nuts, flat washers, spring washers or plate saddles as specified
Documentation	CoC, MTC, dimensional report and coating report on request

Dimensions & SpecificationsDIN 3570

Technical Drawing

Dimensional Table

Parameter	Φ30	Φ38	Φ46	Φ52	Φ64	Φ82	Φ94	Φ120	Φ148	Φ176	Φ202	Φ228	Φ282	Φ332	Φ378	Φ428	Φ530
ds	10	10	10	10	12	12	12	16	16	16	16	20	20	20	24	24	24
d1	M10	M10	M10	M10	M12	M12	M12	M16	M16	M16	M16	M20	M20	M20	M24	M24	M24
h	70	76	86	92	109	125	138	171	191	217	249	283	334	385	435	487	589
P	1.5	1.5	1.5	1.5	1.75	1.75	1.75	2	2	2	2	2.5	2.5	2.5	3	3	3
n	40	48	56	62	76	94	106	136	164	192	218	248	302	352	402	452	554

Engineering references

Technical resources

Review the applicable dimensions, drawing and standard relationship before confirming the ordered specification.

Dimensions and drawingCustom & Non-Standard DIN 3570 U-BoltsOpen drawing →Standard cross-referenceDIN 3570: equivalents and replacement guideOpen cross-reference →

Selection

Selection Advantages by Application

Pipe Supports and Clamp Assemblies

DIN 3570 U bolts are used for pipe supports, tube clamps and bracket assemblies. Confirm pipe OD, inside width, leg length and saddle plate requirement before ordering.

Construction fasteners

Trailers, Frames and Equipment Mounting

Grade 8.8 / 10.9 U bolts support trailer frames, equipment mounts, skids and rectangular brackets where bend form and thread length are drawing-defined.

Industrial equipment fasteners

Outdoor Structures and Utility Supports

HDG or zinc flake U bolts are used in exposed construction and utility supports where corrosion protection matters.

Power generation fasteners

Assembly

Recommended Matching Products

Hex NutsStandard nut pairing for U bolt legs.

Carbon Steel Flat WashersWasher pairing under U bolt nuts.

Spring WashersWasher option for general clamp assemblies where specified.

Large Plate WashersPlate washer option for larger bearing area on brackets.

Hex Head Bolts Full ThreadStraight bolt alternative for non-clamp joints.

Manufacturing

Manufacturing & Quality Control

Manufacturing CapabilityQuality Control

Rod cutting, bending and thread rolling by drawingMaterial grade, bar diameter and bend dimension verification

Round bend or square bend U bolt productionInside width, leg length, bend radius and thread length inspection

Zinc plated, HDG or zinc flake coatingCoating thickness, thread fit and appearance inspection

Supply with nuts, washers or saddle platesAssembly fit check and package count verification

Project packaging by pipe size, line item or kitCoC, MTC and dimensional report prepared on request

FAQ

Common Questions Before RFQ

What dimensions are needed for a U bolt quote?

Send thread size, inside width, leg length, thread length, bend radius or pipe OD, material, grade, finish and nut/washer requirement.

Can U bolts be hot-dip galvanized?

Yes. HDG is common for outdoor use, but thread fit after galvanizing must be controlled with compatible nuts.

What is the difference between round and square U bolts?

Round U bolts clamp pipes and tubes; square U bolts clamp rectangular frames or brackets. The drawing should define the bend form.

Can high-strength U bolts be supplied?

Yes. 8.8 / 10.9 options in 40Cr or 35CrMo can be supplied when the drawing and application require higher strength.

Can nuts and washers be included?

Yes. U bolts can be supplied as complete kits with hex nuts, washers and saddle plates when specified.

Need U bolts for pipe clamps or equipment supports?

Send your U bolt drawing, pipe OD or inside width, leg length, thread size, grade, finish and nut/washer needs. We can quote zinc plated, HDG or zinc flake U bolt kits.

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