Morfologija i raspored MnS u niskoougljičnom čeliku

Non-metallic inclusions are very important (harmful) in steelmaking practice. After oxygen, sulphur is the most important non-metallic element in field of steel metallurgy and sulphides therefore form a second important group of inclusions. Since the morphology of these sulphide inclusions has significant effects on the various properties of steel, numerous studies focusing on morphology and distribution of the MnS inclusions have been conducted over the years. This paper presents the results of the investigation of the MnS inclusion shape and distribution in low carbon steel.Nemetalni uključci su veoma važni (štetni) u metalurškoj proizvodnji. U području metalurgije čelika sumpor je drugi po važnosti nemetalni element, nakon kisika, te stoga i sulfidi, po važnosti, predstavljaju drugu grupu uključaka u čeliku. Jer je morfologija i raspored ove vrste sulfida je taj bitni faktor koji ima presudan utjecaj na razna svojstva čelika izvedena su mnoga istraživanja na tom polju tijekom zadnjih nekoliko godina. U ovom radu su predstavljeni rezultati istraživanja morfologije i rasporeda MnS uključaka u niskougljičnom čeliku

Influece of the austempering temperature on the tensile strength of the austempered ductile iron (ADI) samples

Austempered Ductile Iron (ADI) is a class of ductile iron subjected to a two-step heat treatment process – austenitization and austempering. The heat treatment gives to ADI a high value of tensile strength and an especially good strength-to-weight ratio. However, designers in most cases are unfamiliar with this material that can compete favorably with steel and aluminum castings, weldments and forgings. The high tensile strength of ADI is the result of its unique ausferrite microstructure. In this paper, an investigation of the influence of the austempering temperature on the tensile strength of the ADI samples is presented

Influence of austempering heat treatment on mechanical and corrosion properties of ductile iron samples

Mechanical properties and corrosion resistance of metals are closely related to the microstructure characteristics of the material. The paper compares the results of these two sets of properties after investigating samples of base ductile iron and heat-treated samples of the base austempered ductile iron (ADI). The basic material is perlite ferritic iron alloyed with copper and nickel. To test the corrosion rate of the base material (ductile iron) and the heattreated samples (ADI), electrochemical techniques of potentiostatic polarization were used (the technique of Tafel curves extrapolation and the potentiodynamic polarization technique)