Thursday, 19 September 2024 |
7 a.m. | Breakfast |
8 a.m. | Introductions and Opening Remarks
Brian Smith, ANDRITZ Metals USA Inc. |
8:05 a.m. | Material Mechanics
Mark Zipf, Steel Dynamics Inc. – Aluminum Dynamics LLC
The analytic physics of material deformation and flow in multi-axis loading are discussed. An examination of Cauchy’s deviatoric invariants develops the bi-axial yield criteria in terms of Tresca and Huber-Von Mises criteria, along with the Levy’s plastic strain conditions. Mechanisms of work hardening and loading/unloading behavior are considered. |
9 a.m. | Mechanics of the Roll Bite
Mark Zipf, Steel Dynamics Inc. – Aluminum Dynamics LLC
A review of classical definitions is followed by a step-by-step discussion on the forces, torques, friction and material flow within the roll bite. The force-loaded roll gap geometry (roll flattening) is then examined leading to the formation of the pressure distribution. |
10 a.m. | Break |
10:15 a.m. | Dissection of the Circular Arc Pressure Distribution
Mark Zipf, Steel Dynamics Inc. – Aluminum Dynamics LLC
Using elemental analysis, this session provides a complete end-to-end derivation of the horizontal/vertical equilibriums and differential equations of the historical work of Nadai, Von Karman and Orowan. Methods of calculating the circular arc pressure distribution, roll separating force and torque are presented. The classical methods of Bland and Ford, Bryant and Osborn, Roberts, and Stone are derived, along with a review of key roll bite sensitivities. |
Noon | Lunch |
1 p.m. | Non-Circular Arc Rolling Theories
Mark Zipf, Steel Dynamics Inc. – Aluminum Dynamics LLC
The reality of the actual roll bite is discussed, along with the how, why and when the classical circular arc assumption is no longer valid. Slip/stick friction models are introduced and coupled with Hertzian roll flattening. The contemporary methods of Fleck and Johnson, Jortner, Alexander, Le and Sutcliffe are presented and reviewed. |
2 p.m. | Automatic Gauge Control – Single-Stand Methods
Mark Zipf, Steel Dynamics Inc. – Aluminum Dynamics LLC
The underlying analytical framework of automatic gauge control (AGC) is introduced and used to examine the classical single-stand modes of feedback, feedforward and mass flow, using roll gap, roll force, tension and speed actuation. On-line/active material adaption is also considered, with mode selection, activation and switching/spillover. |
3 p.m. | Break |
3:15 p.m. | Automatic Gauge Control – Tandem Mill Methods
Mark Zipf, Steel Dynamics Inc. – Aluminum Dynamics LLC
The various strategies of tandem mill gauge control are discussed, in classical/typical mill arrangements. Tension-by-speed and tension-by-gap actuation are reviewed. The sequential dance steps of closed-gap threading and tail-out are detailed and examined. |
4:40 p.m. | Automatic Gauge Control – Performance Assessment
Mark Zipf, Steel Dynamics Inc. – Aluminum Dynamics LLC
This closing session provides a brief review of methods often used in the characterization of the AGC performance and thickness tolerances. |
5 p.m. | End-of-Day Wrap-Up and Adjourn |
Friday, 20 September 2024 |
7 a.m. | Breakfast |
8 a.m. | Introductions and Opening Remarks
Brian Smith, ANDRITZ Metals USA Inc. |
8:05 a.m. | Shape/Flatness – Physics of the Phenomena
Mark Zipf, Steel Dynamics Inc. – Aluminum Dynamics LLC
This session takes a deep dive into the fundamental, underlying physics of shape/flatness distortions. An illustrated analytic framework is introduced to provide a means of characterizing shape/flatness defects. Classical shape/flatness defects are reviewed and classified, along with how tension influences on-line/observed results. The analytic origin of the buckling threshold is presented and a full derivation of the “I-Unit” designation is shown. |
9 a.m. | Shape/Flatness – Measurement Techniques
Mark Zipf, Steel Dynamics Inc. – Aluminum Dynamics LLC
The physics of on-line shape measurement is presented, along with on-line/off-line flatness methods. Contemporary methods/systems are reviewed, along with a discussion on the fundamental limits of what can be understood from these measurements and how “phantom” defects are formed, along with the detrimental results. |
10 a.m. | Break |
10:15 a.m. | Shape/Flatness – Control and Targeting
Mark Zipf, Steel Dynamics Inc. – Aluminum Dynamics LLC
After a quick review of multi-variable control basics and system architectures, this session takes a deep look at the advanced analytical techniques applied to vertical stack and cluster/Sendzimir/20-high mills. A full review of orthogonal polynomials is undertaken, along with how they used to characterize both the shape error and the mill’s actuation. Various methods of control/actuation partitioning are presented, including how strip edges and partial edge zone conditions are handled. Strategies for selecting shape targets and their pass-to-pass progression are discussed, including how this works in tandem mill arrangements. |
Noon | Lunch |
12:30 p.m. | Shape/Flatness – Performance Assessment
Mark Zipf, Steel Dynamics Inc. – Aluminum Dynamics LLC
This session provides a brief review of methods often used in the characterization of the on-line shape
control performance and what the applied tolerances mean with respect to off-line conditions. |
1 p.m. | Special Topics and Open Forum Discussion
Mark Zipf, Steel Dynamics Inc. – Aluminum Dynamics LLC
This closing session provides an open opportunity to talk about anything of interest: Material, process strategies, control systems, sensing/measurement, performance improvements/trade-offs, etc. Here are some examples to consider: The mysteries of the herringbone family of shape defects. Mass-flow dynamic compensation. Eccentricity measurement and compensation. Tandem mill set-up/scheduling strategies. 20-high/cluster/Sendzimir mills. 18-high/Z-high mills. Finesse rolling techniques. Bonding/cladding/skiving and inlay.
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3 p.m. | Wrap-Up Discussion/Conference Adjourn |
