U Bolts, Pipe hangars, Pipe clamps, hook bolts, j bolts, swing bolts, anchor bolts, L bolts, V bolts, these are the many names that this particular range of bolting products are referred to.
U-bolts are manufactured from Rod, with the thread rolled before shaping/forming.
When formed, the minimum bend radius is governed by the type of material, but in all cases deformation will occur at the bend radius where the outside of the material is stretched.
There will be small diameter loss due to this and is often referred to as "Necking".
The minimum radius should be no less than 1/2 the rod diameter for low tensile materials. High tensile materials should have 11/16 or more.
See how the above U-bolt is clamped with 2 nuts to help guard against vibration loosening.
This can also be achieved with a Nyloc type Lock nut, or a locking washer