Cold Pilgering is a longitudinal cold roling process that reduces the diameter and wall thickness of metal tubes in one process step.
There are two main facts to remember about the pilgering process: Pilgering, for one, is a cold working method that vastly strengthens the material structure. Second, with a reduced rate of 50-60%, it will reduce the outer diameter, internal diameter, and thickness of the tube significantly. A saddle assembly is included in the equipment, which holds the upper and lower dies. The outer diameter of the tube is squeezed by these dies. Within the tube is a mandrel that keeps the inside diameter constant while the dies reduce the outside diameter. The mandrel is tapered and stationary, but in a cyclic operation, it rotates at particular times. The lateral dimension of the tube reduces as the dies are forced in between it, while the longitudinal dimension increases.