Hybrid Joining Process Research Articles

차체용 1.2GPa급 초고장력 TRIP강의 Weldbond 접합부의 기계적 거동

The effect of weldbond hybrid joining process on the mechanical behavior of single lap and L-tensile joints was investigated for the newly developed 1.2GPa grade ultra high strength TRIP(transformation induced plasticity) steel. In the case of single lap shear behavior, the weldbond joint of 1.2GPa TRIP steel showed lower maximum tensile load and elongation than that of the adhesive bonding only. It was considered to be due to the reduction of real adhesion area, which was caused by the degradation of adhesive near the spot weld, and the brittle fracture behavior of the spot weld joint. In the case of L-tensile behavior, however, the maximum tensile load of the weldbond joint of 1.2GPa TRIP steel was dramatically increased and the fracture mode was change to the base metal fracture which is desirable for the spot weld joint. These synergic effect of the weldbond hybrid joining process in 1.2GPa TRIP steel was considered to be due to the stress dissipation around the spot weld joint by the presence of adhesive which resulted in the change of crack propagation path.

Adhesive–embossing Hybrid Joining Process to Fiber-reinforced Thermosetting Plastic and Metallic Thin Sheets

Aiming at increasing weight-to-strength structural performance and reducing fabrication cost, fiber-reinforced thermosetting plastics (FRPs) should be joined to other lightweight metals. However, reducing the thicknesses of components for lightweight products makes FRP-to-metal joining a greater challenge. In this study, warm embossing process was applied to improve the single-lap adhesive bonding quality for thermosetting FRP and A2017P-T3 thin sheets. The use of a dummy sheet, the relative position of the sample and dummy sheet and the embossing parameters were investigated. The effects of the types of fiber and polymeric matrix as well as the ply laminates on the feasibility of the hybrid joining were also clarified. This study shows that adhesive–embossing hybrid joining process which exhibits remarkable superiorities in terms of tensile shear load, displacement and absorption energy is a competitive joining method for ultra lightweight thermosetting FRP-metal hybrid structures.

Applicability of adhesive–embossing hybrid joining process to glass-fiber-reinforced plastic and metallic thin sheets

Adhesive–embossing hybrid joining process was applied to A2017P and three types of glass-fiber-reinforced plastic (GFRP) thin sheets. Optical microscopy shows that a sound A2017P–thermosetting GFRP hybrid joint without crack/delamination in the composite or adhesive failure can be produced by optimizing adhesive thickness, embossing stroke and embossing temperature. The results of tensile shear test indicate that the optimally hybrid-bonded A2017P–GFRP joint exhibits improved load carrying capability, slip displacement and better energy absorbing characteristics than the adhesively bonded joint when subjected to tensile loading. This investigation shows that the adhesive–embossing hybrid joining process is a competitive alternative joining method for the fabrication of ultra lightweight thermosetting GFRP-metal hybrid structures and has great potential for wider applications, which is attributed to its benefits in terms of joining properties, operation simplicity, weight-cost effectiveness and recyclability.

Friction Self-Piercing Riveting of Aluminum Alloy AA6061-T6 to Magnesium Alloy AZ31B

Implementation of lightweight low-ductility materials such as aluminum alloys, magnesium alloys and composite materials has become urgently needed for automotive manufacturers to improve the competitiveness of their products. However, hybrid use of these materials poses big challenges to traditional joining process. Self-piercing riveting (SPR) is currently the most popular technique for joining dissimilar materials and has been widely used in joining all-aluminum and multimaterial vehicle bodies. However, in riveting magnesium alloys, cracks always occur for its low ductility. In this paper, a hybrid joining process named friction self-piercing riveting (F-SPR), which combines mechanical joining mechanism of SPR with solid-state joining mechanism of friction stir spot welding (FSSW) by making rivet rotating at high speed in riveting process, was proposed aiming at joining the low-ductility materials. The effectiveness of the F-SPR process was validated via riveting 1 mm thick AA6061-T6 and 2 mm thick AZ31B. The results showed that the F-SPR process could significantly improve the rivetability of magnesium alloys, and greatly increase the joint strength, comparing with the traditional SPR process.

Hybrid joining process for carbon fiber reinforced thermosetting plastic and metallic thin sheets by chemical bonding and plastic deformation

A new joining process for thin metallic and continuous carbon fiber reinforced thermosetting plastic (CFRP) sheets is proposed. This joining process is a hybrid of chemical bonding and plastic deformation, usable for ultra-lightweight structures. In contrast to conventional joining methods, such as rivet joining with an adhesive, the proposed method does not require any additional components and can eliminate holes that would cut the continuous carbon fibers and cause stress concentration. Hence, a smaller weight and a higher joining quality can be attained, especially for thin sheets. Aiming at making comparison and demonstrating the applicability of the proposed hybrid joining method, two thermosetting CFRP sheets with different laminates were used as lap adherends in the experiment. The effects of the deformation temperature, the use of a dummy sheet and the relative positions of the sample and dummy sheet on the joining quality were systematically investigated and optimized. The optimal hybrid joint shows high-quality bonding without delamination or adhesive failure. The tensile shear test of single-lap A2017P-CFRP hybrid joints manufactured under optimal experimental conditions indicates that, compared with adhesive bonding and conventional rivet joining with an adhesive, the proposed joining method has obvious superiority in terms of tensile shear load, slip displacement and absorption energy.

Inductive Preheating in Laser Beam Welding of Multimaterial Joints of 22MnB5 and AA6016

Inductive preheating is well known as possibility to heat ferromagnetic materials. In brazing preheating causes an improvement of wetting quality, e.g. smaller wetting angles and longer wetting lengths. In this paper inductive preheating is used to support a laser beam hybrid joining process. Aluminum AA6016 is molten in order to wet the surface of AlSi- coated steel 22MnB5. Investigations on the influence of preheating on wetting characteristics and intermetallic phase seam formation were carried out. Strength values up to 230 MPa have been measured in tensile shear tests. Fraction zone occurs in the aluminum base material indicating uncritical thickness of the intermetallic phase seam at the interface.

Simulation of Hybrid Joining Technologies Using the Example of Clinch-Bonding

In this paper a method for simulating hybrid joining processes will be described. The simulation of joining processes with adhesives is necessary because mechanical joining processes are mostly applied in combination with adhesives. However, the simulation of hybrid joining processes is not state of the art. The reason is the Fluid-Structure-Interaction between the adhesive and the plates, which occurs due to the highly uneven stiffness of the materials. This problem is minimized by the use of an elastic‑plastic material model and a Lagrange formulation for the adhesives. The parameters for the material formulation and the friction have been evaluated by conducting a design of experiment. The correlation between simulation and experiment is ensured by an evaluation of the geometrical distribution of the adhesives within the clinch‑bonding point and the force-displacement diagram. Considering the very low computing time of approximately thirty minutes, the obtained result is very satisfying.

Numerical and Experimental Studies on the Clinch-Bonding and Riv-Bonding Process

A basic approach for lightweight construction on the basis of material design is to join different materials in one component. In practice bonding, joining-by-forming or the combination of both operations ore often used in these cases. The combination of bonding and mechanical joining has great potential. For assemblies, in automobile production for example, special features can be carried out, such as high strength and stiffness, leak-tightness, corrosion resistance, accuracy and crashworthiness. One challenge is the uncertainty about the stability of hybrid joining processes, which relies on deficits in the understanding of the adhesive flow during the joining operation. This article outlines how process understanding can be expanded due to numerical simulation. As a result, the mutual influences of mechanical joining and adhesive bonding are worked out numerically and experimentally.

A Hybrid Joining Technology for Aluminum/Zinc Coated Steels in Vehicles

Currently, in the automotive industry, joining of the aluminum alloys with the steel is a crucial problem to be solved. Conventional joining techniques including resistance spot and gas metal arc welding are not acceptable for those applications due to a number of metallurgical problems. The investigation was carried out to develop the hybrid joining process combining the resistance spot welding and brazing. In this study, an attempt was made to apply hybrid process to the joining of dissimilar sheet metals, Al-Mg-Si (6000 series) alloy and low carbon steel sheet. Hybrid process (resistance spot weld/brazing) using filler metal was found to be effective to overcome the incompatibility between aluminum alloy and steel. Although hybrid joining process of Al alloy sheet and steel sheet did not produce acceptable bond strength, it was proved to have reasonable interfacial bond layer if the optimal process condition was applied.