Relation entre oxydation et frottement it chaud d'un acier 28NCDV10 préoxydé dans l'air et dans la vapeur d'eau

الملخص EN

The aim of this work is to investigate the influence of pre-existent film on friction process between the forming tool and the tube, during the piercing in hot metal forming.

It was found by several autors that steam contributes to increase plasticity of oxides.

An investigation have been carried out into to effects of steam on the oxidation and hot wear behaviour of low alloyed steel (denoted 28NCDV10).

Two different atmospheres, which are air and steam, are employed for oxidizing samples of 28NCDV10 steel in range 600 - 850°C.

The kinetics of oxidation and the scale morphologies have been studied in air and by varying the partial pressure of water vapor.

It was found that steam at a partial pressure of 19 kPa and above 750°C, accelerates the oxidation.

The oxides formed in water vapor are more adherent than those formed in air.

The adherence depends on temperature and partial pressure of water vapor.

The increase in these parameters can lead to catastrophic oxidation.

A wear behaviour of 28NCDV10 steel, was studied at 1200°C on a cylinder-ring tribometer.

The experimental results show that preoxidation of the rings, notably in the case of steam, contributes to a decrease in the wear rate.