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In this paper,the oxidation of high speed steel roll material has been investigated in the temperature range 500 - 700℃,in both dry and humid atmospheres( up to 12.5% H2O).A TEM investigation of oxide scale formed on the HSS sample indicates that it consists of two sub-layers : a fine grained ( Fe,Cr) rich oxide inner layer and a larger columnar Fe oxide outer layer.Oxidation tests under a high humidity(46.5% H2O) atmosphere were carried out on the Gleeble 3500 thermal mechanical simulator.The results show that the water content in the atmosphere not only increases the oxidation rate of high speed steel,but it also influences the microstructure and morphology of the oxide scale.Nano-indentation tests revealed the different mechanical properties of the inner and outer sub-layer.A high temperature pin-on-disc tribological test was carried out to simulate the contact and tribological behaviours of oxide scale in the roll bite.Adhesive wear is the predominant wear mechanism on the pin during this period.Wear mechanism is the balance between adhesion,abrasion,and oxidation.For the first time a mini-rolling mill was successfully incorporated into the Gleeble 3500 thermal mechanical simulator to simulate a stalled hot rolling condition.Two types of roller surfaces,e.g.a relatively virgin surface and a pre-oxidised surface were investigated.