Cavitation erosion degrades the surface of engineering components when the material is exposed to turbulent fluid flows. Under conditions of local pressure fluctuations, a nucleation of gas or vapor bubbles occurs. If the pressure suddenly drops below the vapor pressure, these bubbles collapse violently when subjected to higher pressure. This collapse is accompanied by the sudden flow of the liquid, which is manifested by stress pulses capable of causing plastic deformations on solid surfaces. Repeating these stress conditions can cause material removal and ultimately failure of the component itself. The present study aims to reduce the negative impact of this phenomenon on the mechanical systems components, using the TIG local surface remelting technique. Cavitation erosion tests were performed in accordance with the ASTM G32-2016 standard on samples taken from a cast high-alloy stainless steel. The alloy response for each melting current value was investigated by measuring mass loss as a function of cavitation attack time and by analyzing the damaged surfaces using optical and scanning electron microscopes. It was highlighted that the TIG remelted layers provide an increase in cavitation erosion resistance of 5–6 times as a consequence of the fine graining and microstructure induced by the technique applied.

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X.R.F. analysis of steelmaking slags has been done routinely since the 1960s. Fused buttons or pressed powdered pellets are used.Under certain conditions steelmaking slags may contain appreciable amounts of free lime and metallic iron droplets. These can cause gross inaccuracies in the result of the X.R.F. analysis as the normal correction procedures used in X-ray fluorescence techniques can not compensate for them.A special sample preparation technique as well as appropriate analytical procedures will be discussed. Examples of slags with different levels of free lime and metallic iron will be shown.

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