Round Bend U Bolt for Pipe Clamp DIN 3570 Carbon Steel DN20-DN500

Choose round bend (semi-circular) for round pipe, round bar and spring plate, and square bend for square tube, square shaft, profiled steel and plate frames. A round bend used on square tube contacts at only four points (about 15% of nominal contact area), which concentrates the clamping force, crushes the tube corner and can crack under vibration; a square bend on round pipe makes line contact and ovalises the pipe. We produce both forms, plus semi-round (long tangent) versions for pipe laid ag

Order by the pipe outer diameter. The inner width a of the U-bolt must match the actual pipe OD, not the nominal designation: a 2 in. pipe has a 2.375 in. OD and needs a 2-1/2 in. inner width, and a DN 50 pipe has a 60.3 mm OD against a 64 mm inner width a. Please send the pipe OD (or standard and schedule) and we will confirm the matching a, e and h values before production.

No. DIN 3570 is the metric standard covering NW 20 to NW 500 with metric threads, while ASME B18.31.5 covers inch-series bent bolts with UNC threads and its own tolerance table. Dimensions, thread form and tolerances differ, so the two series cannot be substituted without checking each dimension. We supply both series; please state the standard in your enquiry and we will produce accordingly.

S235JR carbon steel to DIN EN 10025-2 is the standard material for DIN 3570 U-bolts and suits general pipe support and structural clamping. For higher strength, property classes 4.6, 4.8 or 8.8 to ISO 898-1 are available. For corrosive environments, stainless steel A2-70, A4-70 or A4-80 to ISO 3506-1 is recommended. Please note that the withdrawn DIN 17100 St 37 grade is no longer quoted - the equivalent current designation is S235JR.

Plain (oiled) finish suits dry indoor installations. Zinc plating to ISO 4042 suits general indoor and sheltered outdoor use, while hot dip galvanizing to ISO 1461 gives heavy-duty protection for coastal, chemical and long-term outdoor pipe work, with coating mass per ISO 1461 specified against the base metal thickness. Neutral salt spray testing to ISO 9227 can be arranged on request - tell us the site condition and we will recommend the finish.