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The paper deals with the joining of dissimilar steels by adhesive bonding. The base materials for the experimental work were deep-drawn low-carbon steel DC04, and hot-dip galvanized HSLA steel HX340LAD+Z. Adhesive bonding was performed using rubber-based and epoxy-based adhesives. The research aimed to verify the importance of surface preparation of steel substrates using a formulation with organically modified silica nanoparticles and epoxy organic functional groups, where one end of the functional group can be incorporated into the organic binder of the coating material and the other end can be firmly bonded to substances of an inorganic nature (metals). Since the binder base of adhesives is very similar to that of coatings, verifying the performance of this surface preparation when interacting with the adhesive is necessary. The load-bearing tensile shear capacity of single-lapped joints and the resistance of the joints against corrosion-induced disbanding in a climate chamber were tested. The energy dissipated by the joints up to fracture was calculated from the load-displacement curves. Bonded joints with organosilane were compared with joints without surface preparation and joints prepared by chroman-free zirconate passivation treatment. Exposure of the joints in the climatic chamber did not cause a relevant reduction in the characteristics of the joints. Organosilicate formulation was proved effective when bonding ungalvanized steels with a rubber-based structural adhesive, where it improves the bond quality between the adhesive and the substrate. [ABSTRACT FROM AUTHOR]

This paper deals with joining dissimilar materials using thermal drilling technology as well as the combination of thermal drilling and adhesive bonding. The base materials for the experimental work were deep-drawn low-carbon steel DC04, HSLA steel TL 1550-220 + Z, and structural aluminum alloy EN AW-6082 T6 (AlSi1MgMn). The geometry of the formed joints was tested metallographically as the load-bearing shear capacity under the tensile shear test of single-lapped joints and the resistance of the joints against corrosion-induced disbonding in a climate chamber. The energy dissipated by the joints up to fracture was calculated from the load–displacement curves. The hybrid joints were compared with the bonded joints with the same overlap area in terms of the load-bearing capacity and energy dissipated at joint failure. The hybrid joints formed by thermal drilling and adhesive bonding with a rubber-based adhesive confirmed the synergistic effect—the adhesive provides the high load-bearing capacity of the joint, and the bushing formed by thermal drilling increases the dissipated energy of the joint at failure. The exposure of the joints in the climatic chamber did not cause a relevant reduction in the characteristics of the joints. [ABSTRACT FROM AUTHOR]

The paper deals with the evaluation of relation between roughness parameters of Ti6Al4V alloy produced by DMLS and modified by abrasive blasting. There were two types of blasting abrasives that were used – white corundum and Zirblast at three levels of air pressure. The effect of pressure on the value of individual roughness parameters and an influence of blasting media on the parameters for samples blasted by white corundum and Zirblast were evaluated by ANOVA. Based on the measured values, the correlation matrix was set and the standard of correlation statistic importance between the monitored parameters was determined from it. The correlation coefficient was also set.

This paper deals with research into the influence of surface preparation before adhesive bonding of galvanised and non-galvanised steel substrates. The steel substrates were experimentally treated with chromate-free zirconate passivation, iron phosphate, zinc phosphate and an experimental organosilane-based preparation. The roughness of the treated substrates was evaluated by a set of selected vertical and horizontal parameters. The corrosion rate of the treated substrates was tested by electrochemical impedance spectroscopy and linear polarisation. Single-lap joints were created using one-component epoxy/PVC-polymerblend adhesive with glass beads, to ensure an evenly glued gap. The joints were tested for shear strength by tension, in accordance with STN EN 1465 in the as-bonded state, as well as after the climatic cyclic test PV1200. The results show that the adhesive used had a higher adhesion to galvanised substrates with a specific morphology. Adhesion to non-galvanised substrates has been significantly improved by using organosilane for surface preparation. The organosilane layer, containing epoxy organic functional groups, was incorporated into the organic binder of the adhesive and showed increased bond strength. [ABSTRACT FROM AUTHOR]

The paper describes mechanical joining methods used in car body production. The automotive industry is a decisive industry and a driving force for the development of the Slovak economy. Mechanical connecting is the most widely used method of connecting materials. Joints are a critical factor in the production, assembly and service of cars. The joining in car body is mainly used to join material with various thicknesses, mechanical properties, surface coatings, even ferrous or nonferrous metals. Many requirements are placed on the body of the car, the important thing is sufficient stiffness of the structure under the given stress. The paper deals mainly with welded and glued joints in the design of automotive structures and their strength analysis using the finite element method. [ABSTRACT FROM AUTHOR]

The aim of the submitted work is to study the relationship between the orientation of the grains and the Indentation Size Effect (ISE). The micro-hardness was measured by tester Hanemann with applied loads ranged between 0.09807 N to 0.9807 N. The micro-hardness was measured in the middle of in the center of each of the four grains of the sample - the copper of semiconductor quality (99.995%). The influence of the load and the orientation of the grains on the micro-hardness and the ISE was evaluated by the Analysis of Variance (ANOVA), it is statistically significant for both factors. The presence and character of ISE were evaluated using Meyer's index n, PSR method, and Hays - Kendall approach. The relationship between the crystallographic orientation of the grain and ISE was confirmed. [ABSTRACT FROM AUTHOR]

The paper presents results of the research focused on the possibility of restoration of the shape parts of molds made of X15CrNiSi20-12 heat resistant austenitic chromiumnickel-stainless steel working in high-pressure die casting of aluminum alloys by clad welding. There were tested two welding wires - Thermanit 625 and Thermanit X, deposited on X15CrNiSi20-12 tool steel using cold metal transfer (CTM) welding in protective atmosphere of Ar. Two important properties of welded clads were tested - resistance of welds against dissolution in molten aluminum alloy AlSi8Cu3 and wear resistance of welds. Resistance of welds against dissolution were assessed by exposition of welded clads in aluminum melt for 120 and 300 minutes. The EDX semiquantitative microanalyses of element distribution were performed at the welding-melt interface, also build-ups were observed on the surface of welded clads. Wear resistance of the welded clads was tested using pin-on-disk test at room temperature. Results were compared to reference material - base tool steel X15CrNiSi20-12. [ABSTRACT FROM AUTHOR]