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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]

This work focuses on joining steel to aluminum alloy using a novel method of joining by resistance spot welding with an insert element based on anticorrosive steel in combination with adhesive bonding. The method aims to reduce the formation of brittle intermetallic compounds by using short welding times and a different chemical composition of the insert element. In the experiment, deep-drawing low-carbon steel, HSLA zinc-coated steel and precipitation-hardened aluminum alloy 6082 T6 were used. Two types of adhesives—one based on rubber and the other based on epoxy resin—were used for adhesive bonding, while the surfaces of the materials joined were treated with a unique adhesion-improving agent based on organosilanes. The surface treatment improved the chemical bonding between the substrate and adhesive. It was proved, that the use of an insert element in combination with adhesive bonding is only relevant for those adhesives that have a load capacity just below the yield strength of the substrates. For bonded joints with higher load capacities, plastic deformation of the substrates occurs, which is unacceptable, and thus, the overall contribution of the insert element to the load capacity of the joint becomes negligible. The results also show that the combination of the resistance spot welding of the insert element and adhesive bonding facilitates the joining process of galvanized and nongalvanized steels with aluminum alloys and suppresses the effect of brittle intermetallic phases by minimizing the joining area and welding time. It is possible to use the synergistic effect of insert element welding and adhesive bonding to achieve increased energy absorption of the joint under stress. [ABSTRACT FROM AUTHOR]

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 applicability of flowdrill technology to join steel and aluminum alloys is studied. When used to flowdrill two overlapped thin-walled materials, a joint is formed as a secondary effect. The quality of the resulting bushings forming the interference fit joint was investigated by metallography. The joints were formed using a combination of uncoated deep drawn steel, galvanized high-strength low alloy steel and aluminum alloy, in different positions in the joint. Subsequently, tensile shear testing of single joints was performed. The load-carrying capacity of the joints was also tested in combination with adhesive bonding. The combination of both technologies yields an increase in the dissipated energy of the joint at failure. The bonded connection provides a high maximum force at failure, the mechanical connection through bushings leads to an increase in the displacement value at failure, thereby increasing the area under the loading curve. The DC-Al joint showed the highest load-carrying capacity, up to 9 kN, as well as dissipative energy, up to 10.3 J. The joints were fractured by shearing of the inner bushing under tensile stress. The failure surfaces exhibited a typical ductile character with dimpled morphology. It was found that from the point of view of the load-carrying capacity of the joint, it is advisable to place a material with a higher melting temperature in the upper position in the joint. The combination of flowdrill technology with adhesive bonding results in a sealed joint with high load-bearing capacity, reduction in the risk of crevice and galvanic corrosion. [ABSTRACT FROM AUTHOR]

The paper deals with the application of different types of surface preparation before the formation of glued joints made of the same and different steels. Iron phosphate, chromate-free passivation and an experimental preparation based on organosilane were tested. Deep-drawn uncoated steel DC04 and HSLA galvanized steel HX340LAD+Z were joined by adhesive bonding. When applying all types of surface preparation, the joints' strength was achieved at least at the level of the yield strength of weaker material (DC04). Surface preparation with organosilane leads to a bond strength that is close to the yield strength of a stronger material (HX340LAD+Z) and, therefore, can be recommended for bonding of steels with higher strength. [ABSTRACT FROM AUTHOR]