Inner Surface Morphology and Roughness Evolution of Pilgering Thick-Walled Tubes.

A hot-working die steel thick-walled tube Pilger rolling test was carried out using an LG40 Pilger mill, and the morphology and roughness evolution of the inner surface were examined using a white-light interferometer. The experimental results showed that micro-wrinkles formed on the basis of the original inner surface morphology, the altitude difference () between the peaks and valleys of the inner surface profile increased from 3.18 to 3.