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Research Interests

Flat rolling

The essential concept of the flat rolling process is simple and it has been in use for centuries to produce sheets and strips, or in other words, flat products. Leonardo da Vinci employed it to roll lead, utilizing a hand-cranked mill, depicted in Roberts’ book, “Cold Rolling of Steel”.

The basic idea for the production of flat pieces of materials by rolling has not changed since the process has been introduced. Dimensions, materials, precision, speed, the mechanical and metallurgical quality of the product and most importantly, the mathematical analysis and the control of the process have evolved, however. Advanced techniques in the mathematically modelling of metal forming for materials including aluminum and steel are available to lend insight into this historic process. As a result, the flat rolling process may truly be considered one of the most successful “high-tech” processes, since for modern, efficient and productive applications the theories and practice of metallurgy, mechanics, mechatronics, surface engineering, automatic control, continuum mechanics, mathematical modelling, heat transfer, fluid mechanics, chemical engineering and chemistry, tribology and encompassing all, computer science are absolutely necessary.

Temper rolling

Temper rolling is a particular form of flat rolling. Its primary purpose is to suppress the yield point extension which, if present, would create Lüder’s lines, a form of surface defect. The presence of this defect in subsequent sheet metal operations – such as deep drawing, stretch forming and their combinations - would have very deleterious effects on the resulting products.

The temper rolling process subjects the flat product to a very low reduction of thickness, typically 0.5 – 5%. Other possible reasons for a temper pass include

  • Production of the required metallurgical properties;
  • Production of the required surface finish;
  • Production of the required flatness;
  • Creation of magnetic properties and
  • Correct surface flaws and shape defects.

Tribology

It is appropriate here to start with a quotation from Roberts. He writes

”Of all the variables associated with rolling, none is more important than friction in the roll bite. Friction in rolling, as in many other mechanical processes can be a best friend or a mortal enemy, and its control within an optimum range for each process is essential.”
While Roberts wrote about friction, it is further appropriate and even necessary to replace that term with “tribology”.

The study of surfaces in relative motion, in contact and under pressure - that of tribology – is a very broad subject. It has been studied by scientists and applied by engineers for thousands of years. The points of view of its practitioners are equally wide, encompassing the disciplines of tribochemistry, tribophysics, chemistry, chemical engineering, nanotribology, surface analysis, surface engineering, fluid mechanics, heat transfer, mathematics and mechanical engineering and the list is far from complete. In the present context, that is, flat rolling of metals, the focus is on three interconnected phenomena: friction, lubrication and heat transfer at the contact surfaces. These, in turn, create roll wear, and in the metal rolling industry the costs associated with wear problems account for about 10% of total production costs. The cost of inappropriate understanding or application of tribological principles has been estimated to be as high as 6% of GDP in the United States.