Microstructure Evolution of Cold Pilgering Stainless Steel Tubes

The 347 stainless steel tube cold rolling test was carried out by a LG60 two-roll pilger mill. The microstructure evolution was examined by microscope, SEM, and XRD tests. The finite element software DEFORM-3D has been used to simulate the pilgering process, and the obtained equivalent stress and metal flow were analyzed. The experimental results showed that the internal slip line was randomly distributed, the deformation of the inner wall was more intense than the outer wall structure, and the austenite γ phase was transformed into the α′-martensitic phase. The simulation results indicated that the direction of metal flow was constantly changing, and the equivalent stress of the inner wall of the steel tube was greater than the equivalent stress of the outer wall. In addition, the slip zone of the inner wall of the characteristic section was more severe than that near the outer wall slip zone. The simulation verified the experimental results to some extent.