Effect of Microstructure and Surficial Oxidation on the Wear Behavior of an UNS S41003 Stainless Steel

The UNS S41003 ferritic stainless steel is a low-carbon alloy that has great corrosion and oxidation performances in wet and aqueous environments, as well as it has high mechanical strength and ductility when compared to the most ordinary low-carbon steels. These great characteristics, allied to its relatively low manufacturing cost, have made it a potential option to replace structural steels in many applications. Although it is a current trend, there are still few published studies that relate this steel manufacturing process with microstructural evolution and mechanical behavior, mainly regarding its wear behavior, which is a substantial and sometimes limiting characteristic for its applications. In this context, this article presents a pioneering study about the use of biphasic microstructures (ferrite–martensite) and controlled surficial oxidation to enrich the wear behavior of a UNS S41003 steel type. This study concludes that, if well planned, both the increase of martensite fraction and the controlled growth of an adherent and compact oxide layer on the steel surface significantly improve its wear performance, decreasing its wear rate up to 93%.     

Application of factorial model for an optimization of partial replacement of feldspar by talc on the sintering process

This research used a factorial model containing two levels and three variables to evaluate the partial substitution of sodium feldspar (albite) by a talc ore found in abundance in the region of Itaiacoca—Brazil. The model can also be used to verify the influence of initial talc particle size, proportion, and sintering threshold temperature on the following physical properties, such as linear shrinkage, water absorption, bulk density, total porosity, and firing color. In this study, the mechanical strength of the compositions was evaluated by the flexural strength test. The factorial model indicated the sintering temperature as the variable that most affects the samples’ densification and the proportion of talc as the variable that changes the firing color. The experiment that used a higher sintering temperature combined with a coarser talc granulometry presented the highest mechanical strength. When more refined granulometry was used, there was the beginning of an overfire process. Water absorption values in the range of .04% and modulus of rupture of 49 MPa were obtained, confirming the talc's effectiveness as a secondary flux agent suitable for the formulation of ceramic bodies.