NATIONAL TRIBOLOGY CONFERENCE 24-26 September 2003 THE ANNALS OF UNIVERSITY “DUNĂREA DE JOS“ OF GALAğI FASCICLE VIII, TRIBOLOGY 2003 ISSN 1221-4590 115 THE USE AND BEHAVIOUR OF COMPOSITE MATERIALS WITH PARTICLES WHEN OBTAINING ROLLS FOR ROLLED SHEET IRON OILING PLANT Dumitru Dima, Olga Mito ş eriu University “Dunărea de Jos” of GalaĠi, România dimadumitru@yahoo.com ABSTRACT The experiment that has been done with rolls covered in composite material with polymer matrix and carbon particles has solved a certain issue in the rolling plant of cold steel bands, for the classical materials (from the commercial rubber field) have not made it through the mechanical conjugal efforts (abrasion, compression, shear, etc.) and chemical (oil and petrol products resistance). Using a personal technology, there have been moulded 21 rolls which equipped four lines of production during the oiling faze. Their behaviour, in time, was monitored and compared to the working parameters; in the end, the results led to an optimal recipe for their manufacture and a better understanding of the role, which the additive particles have inside the composite materials. KEYWORDS: composite material, polyurethane, carbon particles, oil and petrol products resistant material. 1. INTRODUCTION For manufacturing a lot containing the necessary rolls for equipping four lines of production for cold steel bands from LBR-Ispat Sidex GalaĠi (an element which made the object of a research contract [2]), during the oiling faze, there was elaborated a personal technology for obtaining the composite material with particles and for applying it on the metal support. There has been taken into consideration the large quantity of composite material (approximately 100 kg), elaborated in only one charge, the specified manufacture conditions and requests of the beneficiary. 2. THE ELABORATION TECHNOLOGY OF THE ROLLS COVERED IN COMPOSITE MATERIAL WITH CARBON PARTICLES The moulding technology of these rolls is very much like the manufacture technology for the cable tearing machines’cylinders, only that the net mass necessary for manufacturing an element increases 20-25 times. This implies moulding times equally increased, large tensions, which might appear during the manufacturing of the rolls covered in composite material and the risk of obtaining rejected products due to the working technology, which is 80% manually. Out of the possible manufacturing recipes, there has been chosen the one bearing the code R-30-2.02- 0.6-1.78/1.0, meeting the basic requirements of the beneficiary, that is 70º toughness, oil resistance and a very good mechanical resistance under the actual working conditions during the oiling faze of the cold rolled steel bands. This implies a modification of the reticulation agent’s ratio and the introduction of polyadditive inhibitors during the reticulation phase (citric acid, acetyl chloride etc.). Also, there has been taken into consideration the fact that after covering the metal rolls in composite material with polyurethane matrix and carbon particles, so that it would easily be processed through splintering and rectification. So it could be brought to the necessary dimensions and a neat surface without any holes. 3. EXPERIMENTS FOR ROLLS COVERED IN COMPOSITE MATERIAL The rolls covered in composite material with polyurethane matrix and carbon as additive particles have a large gauge, which implies an equal manual labour.