Enhancement of Collapse Resistance of UOE Pipe Based on Systematic Exploitation of Thermal Cycle of Coating Process

The present paper discusses recent results of an ongoing study on the effect of thermal treatment on collapse strength of cold formed pipes, for instance those following the UOE production route. It has been recognized that thermal treatment as encountered during thermal cycle of pipe coating processes may compensate the reduction of compressive yield strength owing to cold plastic deformation induced during forming. This effect has been systematically analyzed. Enhancement of collapse resistance exploiting the thermal cycle of coating process was studied based on experimental evidence, Finite Element simulations as well as theoretical analysis. It is herein shown that appropriate thermal treatment manifests itself positively with respect to compressive yield strength, leading to significantly improved collapse pressures. As a result fabrication factors of one and even higher may be applicable.