STUDNICKI Andrzej Politechnika Śląska

Spoluautoři KONDRACKI Marcin, SZAJNAR Jan

In this paper the analysis of primary crystallization for corrosive and abrasive wear resistant chromium cast steel was presented. The investigations were performed with use of developed thermal and derivative analysis (TDA). During the studies chromium cast steel with 0,5% C modified with V and Ti and with chromium content of 18%, 12% and 6 % was analysed. Other elements (Ni, Mo) were introduced in a constant amount of 1,5% (Ni) and 0,75% (Mo). The Crystaldigraph-PC apparatus was applied for cooling curve registration, using three different samplers characterised by different geometrical features and thermophysical properties of the mould material used, thus enabling the crystallization analysis at different cooling rates (metastable conditions). The average cooling rate registered during the primary crystallization speeds was: 100 K/min (ATD-C sampler), 50 K/min (ATD-Is) and 10 K/min (ATD-Is100). The crystallization analysis in the first step was based on the Fe-C-Cr phase equilibrium system. Next, the numerical modelling was used to determine the phase transitions during the crystallization of alloys with given chemical composition. The last stage was the experimental studies of the primary crystallization based on TDA curves for different cooling rates and the metallographic observations. Conducted investigations confirmed the strong influence of cooling conditions on the crystallization parameters, resulting in changes of alloy structure. Presented crystallization analysis was carried out in metastable conditions, comparable with industrial conditions observed during steel castings production.