Yes or no: Do the fin passes on a tube mill need adjustment when changing gauge?

摘要

When you change from one tube gauge to another, whether you adjust the fin passes depends on your background. A tube mill operator probably will answer yes; an engineer probably will answer no. Whether you're a tube mill operator or an engineer, the question can be answered correctly only after you consider the relevant parameters carefully. As a typical example, consider an M2 mill that makes tube with a 1.500-inch outside diameter (OD). The wall thickness range is 0.025 to 0.094 in., and the tube is welded 0.030 in. oversize. This established reduction in the sizing mill is 2.0 percent in three passes. If divided equally, this is 0.671 percent per pass, or a multiplier per pass of 0.9934. The same reduction per pass at the neutral axis is used to design the fin passes, although some may consider this excessive.