NU 2016-176

Inventors

Jian Cao*

Qiang Zeng

Kornel Ehmann

Man-Kwan Ng

Short Description

A rolling mill that enables incremental reduction and shaping of a tubular or rod-shaped workpiece

Background

Similar to the concept of rolling dough, a rolling mill is used in the metal forming process to reduce the thickness of metal gradually form it into a desired uniform shape. The cross-section of the tube/rod is reduced or shaped by the squeezing motions of two or more dies. The rolling size and shape of the tube/rod depends on the profiles of the dies used and whose radial positions are constant and not adjustable. Thus, process flexibility is low requiring a die change for different tube/rod diameters. Rolling accuracy is also limited since it depends on the tolerance of the dies. All of these characteristics of the existing rolling reduction/shaping mills lead to a die-dependent, low process controllability and limited accuracy process. To overcome these drawbacks and increase rolling flexibility, a novel system is required to meet increasingly demanding industrial applications.

Abstract

In order to overcome the limitations of current rolling mills, Northwestern inventors have developed an electrically-assisted, highly flexible dieless shaping rotary tube/rod rolling mill. It facilitates incremental radial feeding motions of the driven rollers arranged under a skew angle with respect to the tube/rod (see figure). As shown in the figure, the outer diameter/shape of the tube (center) can be formed by the rotation and radial feeding motions of the three surrounding rolls in an incremental rolling process. The axial motion of the tube can be operated back and forth by multiple passes incorporated with the radial feeding motions of the rolls. This arrangement obviates a need for diameter/shape-dependent dies facilitating the generation of tubes/rods with arbitrary diameters/shapes as well as the implementation of multi-pass tube/rod rolling processes. Electrical current is applied through rolls to the tube to assist the rolling process by contributing to reduced rolling forces and torque and, hence, significantly increases process efficiency.

Applications

• Metal Forming for tubes and rods
• General rotary forming process

Advantages

• High accuracy of the reduction and elongation rolling process
• High flexibility of the forming process
• Dieless processing
• Reduction in cost and time
• Overall ability of process controllability

IP Status

US Provisional and PCT applications have been filed.