ON THE ELASTIC PROPERTIES OF STEAM-TREATED P/M MATERIALS

The elastic and plastic properties of some ferrous base materials, before and after steam treatment, have been evaluated by means of a rather new testing method, named universal hardness testing. This test makes it possible to record continuously the instantly applied load and the indentation depth. The plotted curves enable to get indications on elastic and plastic deformation works, on sintering degree and on the Young’s modulus as well. The elastic properties have been compared with the results achieved by means of strain gages in four-point bending tests. The influence of oxide layers on the elastic behaviour of steam-treated ferrous materials has been evaluated. The observation of tested areas at optical microscope helps to understand the features of oxide layers and their adhesion to the metallic matrix. The results may be useful to refine the design choice of powder metallurgy materials to be steam treated, in order to fulfil specific requirements of demanding applications, and to rate the correctness of the oxidation process.