000001588 001__ 1588
000001588 035__ $$a34805 
000001588 037__ $$aROMDOC-THESIS-2017-1069
000001588 041__ $$arum
000001588 100__ $$aCalcan, Cătălin Jirlău
000001588 245__ $$aCercetări privind alierea superficială a pieselor turnate
000001588 260__ $$c2012-06-17
000001588 520__ $$aThe present paper is structured and organized on two main research directions: the mathematical simulation and the laboratory experimentation and conception of a technology for the surface alloying of castings. Its purpose is to come up with a way of increasing resistance to abrasive wear of castings made by surface alloying. We proceeded to a theoretical study, by mathematical simulation, of the physical and chemical processes of diffusion that occur at the interface paste – liquid alloy or powders coating – liquid alloy, during the surface alloying casting. The physical and chemical processes that occur during alloying are based on a mass transfer process called “thermofiltration”, which means the diffusion of alloying elements of paste (layer of powder) in the liquid alloy on a certain distance. The alloying elements used for the simulation of the diffusion process were Cr and Mn, strongly carburigene elements with high diffusion quotients, which ensure an increase in the concentration of the alloying element in the layer’s depth. We also present in our paper the experimental laboratory results on obtaining a sodium-silicate-based foundry binder which is part of the composition of pastes used, in the laboratory phase, to the surface alloying of samples, as well as in the semi-industrial phase, to obtain tamping picks’ pegs through surface alloying. Experimental laboratory results concerning the surface alloying of samples FeCr, FeMn, FeV, and FeMo are also presented in the paper. The main purpose of the laboratory research is to find out - based on the available data and laboratory experiments of surface alloying of steel castings using paint or paste - the alloy surface layer depth, the hardness of the alloyed and unalloyed layers, to analyze cast alloy samples microstructure in three points, namely the unalloyed area inside the casting, the transition area from alloyed to unalloyed and the alloyed area and to determine the relation between the depth of the alloyed layer the thickness of the casting, the thickness of the paint layer and the temperature of the steel casting. We finally present the results of producing tamping picks using the surface alloying method. Specifically, the active part of the tamping machine, the peg, was made by casting and surface alloying with tungsten carbide (WC). During the use of the tamping tools the peg is the active part the most subjected to physical strain such as: abrasive wear, impacts, vibrations, etc. Tamping is the process of compacting the ballast on the railway bed, which is an important part of building and maintaining railways.
000001588 6531_ $$aPiese turnate -- Teză de doctorat
000001588 6531_ $$aAliere superficială -- Teză de doctorat
000001588 6531_ $$aTurnare -- Tehnologie mecanică -- Teză de doctorat 
000001588 8560_ $$ff_costache@library.pub.ro
000001588 8564_ $$uhttp://romdoc.upb.ro/record/1588/files/$$zAccess to Fulltext
000001588 980__ $$aTHESIS