On occasion, people still ask for “hot bends” when they don’t really want or need their bends made using a hot bending process. This seems to be a term left over from a time when people used it to differentiate field bends from shop bends as there was a time when shop cold bending was not a readily available option. In most cases, the energy companies do not have a preferred bending method and are content as long as pipe bends meet code, usually CSA Z662, CSA Z245.17, CSA Z245.16 and CSA Z245.11 but also applicable ASME codes.
Sometimes engineers involved with certain projects will have specific reasons for requiring a specific bending method but that is not common. Apart from cold bending (usually meaning compression bending or rotary draw bending at normal ambient temperatures) and hot bending (furnace bending – sand-filled or empty) there are other methods such as induction bending which is a type of hot bend. Post-bend heat treatment is required for certain end-users for some materials but this is not required or requested for the majority of pipeline bends regardless of the bending method. All methods have pros and cons and no one method can be used for everything.
We are able to bend pipe at 20D and greater radii with coated pipe (Yellow Jacket, Ultrabond and some epoxies and FBE coatings). Hot bending precludes bending coated pipe and coatings would have to be applied after bending which means the cost and time savings of bending coated pipe are not available for projects requiring hot bending.
For the majority of bends made for pipeline work, especially for sizes 16″ø and smaller, cold bending is acceptable to the majority of end-users, pipeline engineers and field project managers. Field bends are invariably cold bends.
We make hundreds of bends each year for many different clients using cold bending methods. All of our code bends come complete with mill test reports, destructive and nondestructive testing as required by CSA code and also come with final project reports.