Comparison of adhesion properties of the primers for wide consumption

This research focused on comparison of adhesion properties of three different primers for wide consumption. Tested primers differed in their price range, and the conducted experiment aimed to determine whether more expensive primers were providing better adhesion between the substrate material and the coating. The primers were applied on specimens in two layers, each being 30 μm thick (total dry film thickness was 60 μm), as well as in one layer being 45 μm thick. After drying, specimens were exposed to indoor and outdoor atmospheric conditions. Adhesion properties were tested by the cross-cut test, and analysis of obtained results proved that the primers’ price range cannot be considered as an indicator of the primers’ quality with respect to their adhesion properties

Analysis of interconnection between physical and protective properties of two-component epoxy primer

This paper presents the research into protective properties of two-component epoxy primer obtained by measurements of the notch corrosion and by testing of the gloss as a physical property. In order to obtain different values of measured response, the first experiment was done by applying the primer in various amounts of the dry film thickness, while the second experiment was based on combining various contents of anti-corrosion pigment. Analysis of the obtained research results proved the interconnection between the two observed properties. It was confirmed that the obtained results were inversely proportional for both experiments. Protective properties of coating could be assessed by measuring the gloss value, which is simpler and faster than measuring the notch corrosion

Analysis of interconnection between physical and protective properties of two-component epoxy primer

This paper presents the research into protective properties of two-component epoxy primer obtained by measurements of the notch corrosion and by testing of the gloss as a physical property. In order to obtain different values of measured response, the first experiment was done by applying the primer in various amounts of the dry film thickness, while the second experiment was based on combining various contents of anti-corrosion pigment. Analysis of the obtained research results proved the interconnection between the two observed properties. It was confirmed that the obtained results were inversely proportional for both experiments. Protective properties of coating could be assessed by measuring the gloss value, which is simpler and faster than measuring the notch corrosion

Weldability prediction of high strength steel S960QL after weld thermal cycle simulation

This paper presents weld thermal cycle simulation of high strength steel S960QL, and describes influence of cooling time t_8/5 on hardness and impact toughness of weld thermal cycle simulated specimens. Furthermore, it presents analysis of characteristic fractions done by electron scanning microscope which can contribute to determination of welding parameters for S960QL steel

Resistivity during cycle loading of fine grain heat affected zone (HAZ) of 17CrNiMo7 steel prepared into laboratory furnace

Structural components which are loaded in cyclic load mostly fail due to fatigue. The fatigue strength of metals as well as weld joint regions in metals depends on mechanical properties especially hardness, the size of defect and the size of grains. Resistivity of the fine grain HAZ prepared against fatigue crack initiation will be explained in this article. Samples of material with martensitic fine grain microstructure were prepared by laboratory furnace by proper thermal treatment. Mechanical properties of fine grain heat affected zone and its microstructure were investigated. Special attention was given to behavior of fine grain during the cycle loading under stress concentration. Stress concentration was similar to the one in real welds. The S-N curve and the fatigue limit were determined. The Paris curve and the threshold for crack propagating were also determined

Impact energy analysis of quenched and tempered fine grain structural steel specimens after weld thermal cycle simulation

The paper presents impact energy results of thermal cycle simulated specimens of quenched and tempered fine grain structural steel S960QL. These results are obtained by examining notched Charpy specimens. Upon performed metallographic analysis and measured hardness, total impact energy is separated into ductile and brittle components

Impact energy analysis of quenched and tempered fine grain structural steel specimens after weld thermal cycle simulation

The paper presents impact energy results of thermal cycle simulated specimens of quenched and tempered fine grain structural steel S960QL. These results are obtained by examining notched Charpy specimens. Upon performed metallographic analysis and measured hardness, total impact energy is separated into ductile and brittle components

Dependence of hardness and impact energy on cooling time Δt8/5and temperature for S960QL

The paper deals with research into dependence of hardness and impact energy of thermal cycle simulated specimens of fine-grained structural steel S960QL on cooling time from 800 to 500 °C and on tested temperature. Results were obtained by measuring hardness of HV 10 and by experimental testing of Charpy notched tubes on instrumented Charpy hammer. Total impact energy, initiation energy and fracture propagation energy needed for occurrence of fracture is also elaborated. Key words

Weldability of microalloyed high strength steels TStE 420 and S960QL

The paper presents research of weldability of microalloyed high strength steels TStE 420 and S960QL after weld thermal cycle simulation. Beside mechanical properties hardness and impact strength, the microstructures of characteristic weld thermal cycled structures for both steels are given. The results will contribure to determination of weakest points in Heat Affected Zone of both steels

Ponašanje grubozrne zone utjecaja topline zavara tijekom cikličkog opterećenja

This paper presents results of a study on martensitic coarse grain heat affected zone that can appear in welded joints. Mechanical properties of martensitic coarse grain heat affected zone and its microstructure were investigated. Special attention was given to its behaviour during the cycle loading under stress concentration. Stress concentration was similar to the one in real welds. The S-N curve and the fatigue limit were determined. The Paris curve and the threshold for crack propagating were also determined.U radu se istražuje martenzitna grubozrnata zona utjecaja topline koja se može pojaviti pri zavarivanju. Istražena su mehanička svojstva i mikrostruktura ove zone. Posebna je pažnja posvećena njenom ponašanju tijekom cikličkog opterećenja kada je prisutna koncentracija naprezanja. Koncentracija naprezanja je slična onoj kod realnog zavarivanja. Određena je S-N krivulja i granica umaranja. Također je određena i Parisova krivulja i prag propagacije pukotine