WALASEK Agnieszka Silesian University of Technology

Spoluautoři SZAJNAR Jan, BARON Czesław

The paper presents a method of usable properties improvement of cast steel castings, by putting directly in casting process an alloy surface layer on the basis of Fe-Cr-C alloy. Technology of alloy surface layer guarantees mainly increase in hardness and abrasive wear resistance of cast steel castings. The new author’s description of the process of the alloyed surface layer creation was presented in the article. Its idea is based on diffusion in solid state of carbon and chromium from the insert to the cast steel area inside the ferrochromium grains as well as on the diffusion inside the area of the liquid chromium cast iron created in earlier stages of layer production as a result of the solid state diffusion. The silicon addition to the insert material influences the insert melting process what was analyzed, too. The liquidus and solidus temperatures of high-carbon ferrochromium were estimated, what is very important for this process. It was stated that Si content increasing causes the FeCrC solidus temperature decreasing what results the elements diffusion rate increasing and causes faster liquid phase creation. The carbon back-diffusion from the transition zone and cast steel was observed during the experiments. It was stated that the process is caused by carbon diffusion from the places with high carbon content to the places of carbides creation, what causes local carbon content decreasing.