A THEORY FOR PREDICTING THE INTERFACE PRESSURE OF ROLLED JOINTS

摘要

When pipes cannot be joined by welding, one alternative is to make a rolled joint. Basically this process consists of running rollers round the inside of a tube/hub pair on an expanding pitch circle to produce a predetermined amount of plastic deformation in the tube. Such joints must rely to some extent on the development of a solid interface pressure. This Report describes a fairly elementary theoretical approach to the problem, which yields a simple answer consistent with such observations as are so far available. The prediction is that in suitable circumstances, mainly the provision of a sufficiently strong hub, rolling develops a hoop compressive stress in the tube slightly in excess of its compressive yield stress, from which interface pressure can be readily calculated.