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eduction rate (normal and tangential forces aremeasured as output parameters). A methodology wasdeveloped by Deltombe & al. [1]: thanks toindustrial and experimental FEM models, the testparameters enabling the experimental reproductionof industrial contact stresses and industrial plasticstrain are computed.3.2.c Thermal conditionsA convective heating system has been recentlydesigned to control interface temperature. Thissystem is associated with a convective coolingsystem to protect sensors and thus to avoid drift ofmeasurements or even their degradation.3.2.d Lubrication conditionsA new methodology of lubrication application hasbeen designed to solution this problem andreproduce industrial lubrication regime.4. SIMULATION OF LUBRICATION4.1 Lubrication by oil-in-water emulsion in coldrolling processThe Wilson theory, called dynamic concentrationtheory [9] corresponds to the process studied herein.Because of oil high viscosity, this theory supposesthat quasi no water or a tiny amount of water entersthe roll bite [10]: water is mainly used as coolantfluid.The thickness of oil penetrating the contact isdirectly influenced by rolling speeds, oil viscosityand concentration, materials, contact pressure androll bite geometry [8]. In section 2, lubrication wasdefined as almost boundary. Generally the minimallimit of a mixed regime thickness is consideredequal to:h lim = 0,35.R a [6] (1)where R a = mean strip roughness.4.2 Methodology: computation of required oilquantity to applyNo water is considered entering the roll bite: testwill be made with neat oil. Speeds not beingreproducible, lubricant feeding cannot be simulatedon URT: the solution is to apply the good amount ofneat oil on URT specimen beforehand. The usedlubricant thickness for this study is the most criticalvalue we could meet in cold rolling, i.e. h lim , definedin 4.1. The mass corresponding to this thickness iscomputed according to the following procedure.Thanks to a 3D profilometer, the first step is tocalculate the mean roughness, R a , of strip studiedherein and to deduce (1) the corresponding thicknessto apply on it. Then, from a 5 mm² specimen surfacepreviously analysed by the profilometer, computersoftware enables to calculate which volume of oil isnecessary to fill in the valleys in order to obtain therequired lubricant thickness computed in first step.Finally, knowing oil density the mass is deduced.As a validation of these recent optimisations,experimental surface aspect shows a scaly surface asfor the industrial one after two passes (Fig. 1.b, 1.d).5. TESTS AND RESULTS5.1 Test objectives and conditionsThe aim is to analyse the influence of rollingparameters such as the pass number, the interfacetemperature and the forward slip on friction andwear (iron fines creation and surface aspects). Allthe test configurations are indicated for each pass ontable 1. The quantity of lubricant applied onspecimen strip is the mass corresponding to thethickness h lim (Eq. 1). Each configuration of test hasbeen reproduced twenty five times.Table 1. URT test configurations for each passConfiguration number 1 2 3 4Forward slip 2% 2% 7% 7%Interface temperature 40°C 120°C 40°C 120°C5.2 Results and discussions• Friction:The coefficient values corresponding to eachconfiguration are represented on Fig. 3.a:o Coulomb friction coefficient is higher in passtwo than in pass one whatever the testconfiguration. This can be explained by theincrease of the contact ratio with the passnumber. As an evidence, nearly no hole (orlubricant “traps”) remains once pass 2 has beenperformed (Fig 1.b)o Coulomb friction coefficient increases withtemperature. For a quasi-boundary lubrication