Evaluation of electrochemical properties of steel sheets for automotive applications

Galvanizing as a process of zinc coating of base material is still the most widely used technology applied in surface treatment of materials which are supposed to meet the requirement of high corrosion resistance in various environments. This article presents the results of research aimed at determining the corrosive properties of galvanized sheets in selected environments – distilled water, NaCl and SARS solution, using electrochemical potentiodynamic test

The influence of heat treatnemnt on the abrasive wear resistnace of a construction and a tool steel

The paper deals about the influence of heat and chemical-heat treatment of construction steel 100Cr6 and alloy steel X210Cr12, which were treated according to their corresponding norms. The steel X210Cr12 was also treated in an unconventional way. The influence of the material structures and hardness on the abrasion wear resistance was studied. The influence of nitridation was considered in a way how to increase the abrasion wear resistance and how the heat treatment affects the hardness and the quality of the nitrided layer. The nitridation with diffusion annealing of the tested materials caused a decrease and also an increase of the materials wear resistances

Analiza materijala elektroda za elektrootporno točkasto zavarivanje

The contribution deals with metallographic analysis of welding tip materials and workpieces used in production. Microstructures of most used alloys Cu for welding electrodes of resistance spot welding are evaluated. Alloys of CuCr1Zr, CuCoBe and CuBe2. Analysis of influence of alloying elements and production technology of the alloys on final properties of electrode materials are presented.Ovaj rad se bavi metalografskom analizom materijala elektroda za elektrootporno točkasto zavarivanje koji se koriste u proizvodnji. Mikrostrukture najčešće korištenih legura Cu za izradu otpornih elektroda za točkasto zavarivanje su evaluirane. Analizirane su legure: CuCr1Zr, CuCoBe i CuBe2. Analiza utjecaja legirajućih elemenata i tehnologije proizvodnje legura na konačna svojstva materijala elektroda je također predstavljena u radu

DEFORMATION INFLUENCE ON A LIFETIME OF WELDING ELECTRODE TIPS

The contribution deals with the influence of welding electrode tips deformation on their lifetime. The influence of material properties, production technology and the intensity of welding electrodes load on their lifetime are presented. The electrode tips of the most used type of CuCr1Zr alloy of three basic standard shapes before and after the process of welding are evaluated. The process of welding is realized with low, middle and maximum welding parameters on programmable pneumatic spot welding machine VTS BPK 20. The influence of welding parameters on chosen material characteristics of welding tips is observed. Through the use of upsetting test, dependency of forming strength and deformation of material on used technology of welding tip production is observed

POSSIBILITIES OF RENOVATION FUNCTIONAL SURFACES OF EQUIPMENTS IN THE MECHANICAL ENGINEERING INDUSTRY

The paper analyzes the possibilities of increasing the lifespan of rollers in continuous steel casting line. There are analyzed the causes of the surface rollers damage and the impact of degrading factors in metallurgical production. Three types of welding consumable electrodes designed for restoration layers formation applied by SAW surfacing technology were analyzed. There were analyzed microstructure, microhardness and properties of weld clads in tribological conditions

Resistance of surface layers to selected tribodegradation factors

Contribution presents the results of research focused on resistance of surface layers to selected tribodegradation factors. Research is focused on the renovation of dies for hot work. Newly created renovation layers made with new types of filler materials are compared with conventionally used renovation materials. X37CrMoV5-1 was chosen as the die base material, which was hardened and tempered to a working hardness of 500 ± 15HV. The experiments are carried out practical measurements of mechanical properties of cladding. The quality of cladding was evaluated in tribological conditions of adhesion wear (ČSN EN 1071-13) and abrasive wear (STN 01 5084)