Tenova started a research program in 2002 for strongly lowering NOx emissions. After the excellent results achieved in the reheating furnaces, the Tenova FlexyTech® burner family was enlarged with the TLX burner whose first application was in the furnace for austenitizing treatment of seamless tubes at TenarisDalmine (2006). The main goals of the revamping were strongly decreasing NOx emissions and increasing the productivity. The results after one year of operation are presented.

The cracking behaviour of the oxide layer formed during hot rolling was studied togetherwith different combinations of process parameters in order to find their single influenceon the surface quality and formation of oxide defects. Several trials were performed onthe CRM pilot line to study in detail the impact of strip reduction, strip temperature,entry scale thickness, roll degradation, lubrication, skin cooling, chemical compositionand humidity on the scale behaviour. In general, the degree of deformation, entry scalethickness and rolling temperatures are the most important parameters and the importancedecreases in that order.

A new technology for lubricating the work rolls during hot rolling has been successfullytested in the finishing mill of ArcelorMittal Dunkirk. This new technology allows sprayingvery low quantities of pure oil on the work rolls to reduce the rolling forces by up to20% and with an increased efficiency of 50% compared with emulsions. The lubricant was apure natural oil without any additives.

For every mill the ideal roll can be considered as one that can be used in a mill stand indefinitely. Unfortunately for the roll user, such ideal rolls do not exist. One major reason for work roll changes (planned or unplanned) is “wear”. In the context of cold rolling and temper rolling, “wear” primarily refers to loss of roughness and/or surface texture. Another limitation to roll performance is the fact that mill incidents – minor as well as major incidents – inflict damage on the work rolls, requiring redressing in the roll shop. If a major defect is present in a forged roll, e.g. due to a mill incident, catastrophic roll failure may occur in a violent, explosive manner. Improvement of the value-in-use of a work roll implies a superior wear resistance, a superior damage resistance, and elimination of the safety risks associated with explosive roll failures. In order to deal with this in a concerted R&D approach, a consortium of two roll users in the steel industry, a leading roll manufacturer, a high-tech supplier of roll damage detection equipment, and specialised research institutes have joined forces. Cold rolling trials have been performed, using pilot mills as well as industrial mills, with both novel forged HSS work rolls and conventional forged 3–5%Cr steel work rolls. Separate trials have been designed to focus on either the aspect of roughness evolution or damage resistance. Complementary data from various laboratory tests and industrial mill and roll shop data have been collected. Models have been developed for damage evolution in a roll, and for roughness evolution of the roll surface. In addition, novel non-destructive detection systems and sensors have been designed and tested. This paper provides a concise overview of the results achieved.