Composite-Composite Joining with through the Thickness Reinforcements for Enhanced Damage Tolerance

2015 ◽  
Vol 825-826 ◽  
pp. 883-890 ◽  
Author(s):  
Steffen Stelzer ◽  
Stephan Ucsnik ◽  
Gerald Pinter
Keyword(s):  
Load Transfer ◽  
Damage Tolerance ◽  
Cold Metal Transfer ◽  
Lap Shear ◽  
Reinforced Composite ◽  
Joining Technology ◽  
Metal Sheets ◽  
Pin Geometry ◽  
Cold Metal ◽  
Pin Reinforcement

A novel composite-composite joining technology based on metal pins oriented in through thickness direction of the composites is presented. A defined pin geometry, which is capable of establishing a through-thickness form-fit connection between composites and the metal reinforcement, is created on thin metal sheets in an automated pin production process. Based on numerical simulations of the fracture of unreinforced single lap shear (SLS) composite specimens, optimum locations for the pin reinforcement were found. Tests on reinforced SLS specimens proved that an enhanced damage tolerance can be achieved by the use of cold metal transfer welded pins (CMT pins) as through-the-thickness reinforcement of the joint area. This paper investigates the mechanisms responsible for the load transfer and failure of such through-the-thickness reinforced composite-composite joints during monotonic loading.

New Possibility for the Connection of Metal Sheets and Fiber Reinforced Plastics

2011 ◽  
Vol 690 ◽  
pp. 465-468 ◽  
Author(s):  
Stephan A. Ucsnik ◽  
Georg Kirov
Keyword(s):  
Adhesive Bonding ◽  
Load Transfer ◽  
Reaction Force ◽  
Welding Process ◽  
Cold Metal Transfer ◽  
Reinforced Plastics ◽  
Lap Shear ◽  
Metal Sheets ◽  
Form Closure ◽  
Cold Metal

This research paper presents a new possibility for the connection of metal sheets and fibre reinforced plastics (FRPs) through a cold metal transfer welding process. Small metal projections (pins) are welded onto metal surfaces by introduction of additional filler wire. These provide the possibility for building up a fixation with composites through fibre-friendly form-closure and co-curing. Results of tensile loaded double-lap shear geometries are presented for three types of pin geometries. The hybrid joints will be characterized and compared in terms of maximum reaction force and failure history. Joints with cylindrical and spiky pins inside show a certain load transfer capability, where ultimate bearing load and post failure behaviour have a high dependence on the quality of the co-cured adhesive bonding and the bending characteristics of the pins. Joints with spherical ending pins show twice as high ultimate bearing loads at a much more distinctive joint expansion.

Enhanced Performance of Steel-Aluminium Cast Nodes through Cold Metal Transfer

2013 ◽  
Vol 765 ◽  
pp. 736-740
Author(s):  
Stephan Ucsnik ◽  
Rudolf Gradinger ◽  
Almedin Becirovic ◽  
Andreas Waldhör
Keyword(s):  
Load Transfer ◽  
Welding Process ◽  
Metal Transfer ◽  
Uniaxial Tensile ◽  
Cold Metal Transfer ◽  
Cast Aluminium ◽  
Pull Out ◽  
Macro Scale ◽  
Cold Metal ◽  
Scale Roughness

At present, enhancement of hybrid metal joints for tensile pull-out load through overlap surfaces with a macro-scale roughness is one scope of research. The macro-scale roughness is established through the modified arc-welding process, called “cold metal transfer pin” (CMT-pin), which enables repetitive manufacturing of arrays of metal reinforcements (pins) on parent metal surfaces.Hybrid metal joints between parent steel sleeves and cast aluminium alloy have been investigated. Joint surfaces of parent steel sleeves, which have cylindrical cross-sections, are modified by cylinder and ballhead pins. Cast metal joints were tested under uniaxial tensile loading. At the same time, their load transfer behaviour was determined. Results of tensile tests of hybrid metal joints with different kinds of pins, as well as with different amounts of pins are presented. Comparisons with reference joints without pins or with steel sleeves containing a harmonious triangular polygon cross-section ("P3G") and endings with an enlarged diameter are carried out.The results show an enhanced load transfer performance in the case of hybrid metal joints with pins, as well as enhanced performance measures compared to reference joints. It is also shown that the pin quantity has a major impact on the ultimate joint strength and the irreversible energy absorption density. The use of a certain quantity of pins leads to a change of the failure shape of the joints, which includes steel sleeve pull-out and pin shear to rupture of the cast aluminium.

Microstructure and Mechanical Performance of Cold Metal Transfer Spot Joints of AA6061-T6 to Galvanized DP590 Using Edge Plug Welding Mode

2016 ◽  
Vol 138 (7) ◽  
Author(s):  
Haiyang Lei ◽  
Yongbing Li ◽  
Blair E. Carlson ◽  
Zhongqin Lin
Keyword(s):  
Mechanical Performance ◽  
Welding Process ◽  
Metal Transfer ◽  
Weld Nugget ◽  
Weld Strength ◽  
Welding Parameters ◽  
Feed Speed ◽  
Cold Metal Transfer ◽  
Lap Shear ◽  
Cold Metal

Dissimilar joining of aluminum to steel poses a challenge for arc welding. In this study, aluminum AA6061-T6 and hot dipped galvanized DP590 steel were joined using the Fronius cold metal transfer (CMT) welding process applying an edge plug welding mode (EPW). The correlation of the welding parameters, weld characteristics, and weld strength was systematically investigated. It was found that the EPW mode created a zinc-rich zone at the weld root along the Al–steel faying interface which transitioned to a continuous and compact intermetallic compounds (IMC) layer in the middle portion of the joint. The fracture propagation in lap-shear specimens was affected by this increase of IMC layer thickness. At a wire feed speed (wfs) of 5.6 m/min, the fracture initiated along the zinc-rich layer at the faying interface and then, upon meeting the compact IMC layer, propagated into the aluminum weld nugget. Propagation followed a path within the weld nugget along the boundary between columnar and equiaxed grains leading to weld nugget pullout upon fracture. For IMC layer peak thicknesses below 10 μm, the strength increased as a function of weld nugget diameter. However, larger heat inputs resulted in IMC layer thicknesses greater than 10 μm and interfacial fracture.

Effect of path strategy on residual stress and distortion in laser and cold metal transfer hybrid additive manufacturing

2021 ◽  
pp. 102203
Author(s):  
Runsheng Li ◽  
Guilan Wang ◽  
Xushan Zhao ◽  
Fusheng Dai ◽  
Cheng Huang ◽  
...  
Keyword(s):  
Residual Stress ◽  
Additive Manufacturing ◽  
Metal Transfer ◽  
Cold Metal Transfer ◽  
Cold Metal

scholarly journals Influence of post weld heat treatment on tensile properties of cold metal transfer (CMT) arc welded AA6061-T6 aluminium alloy joints

2019 ◽  
Vol 28 (1) ◽  
pp. 135-145 ◽  
Author(s):  
Addanki Ramaswamy ◽  
Sudersanan Malarvizhi ◽  
Visvalingam Balasubramanian
Keyword(s):  
Heat Treatment ◽  
Tensile Properties ◽  
Gas Metal Arc Welding ◽  
Weight Ratio ◽  
Welding Process ◽  
Metal Transfer ◽  
Post Weld Heat Treatment ◽  
Cold Metal Transfer ◽  
Cold Metal ◽  
Weld Heat

AbstractAluminium alloys of 6xxx series are widely used in the fabrication of light weight structures especially, where high strength to weight ratio and excellent weld-ability characteristics are desirable. Gas metal arc welding (GMAW) is the most predominantly used welding process in many industries due to the ease of automation. In this investigation, an attempt has been made to identify the best variant of GMAW process to overcome the problems like alloy segregation, precipitate dissolution and heat affected zone (HAZ) softening. Thin sheets of AA6061-T6 alloy were welded by cold metal transfer (CMT) and Pulsed CMT (PCMT). Among the two joints, the joint made by PCMT technique exhibited superior tensile properties due to the mechanical stirring action in the weld pool caused by forward and rearward movement of the wire along with the controllable diffusion rate at the interface caused by shorter solidification time. However, softening still exists in the welded joints. Further to increase the joint efficiency and to minimize HAZ softening, the joints were subjected to post weld heat treatment (PWHT). Approximately 10% improvement in the tensile properties had been observed in the PWHT joints due to the nucleation of strengthening precipitates in the weld metal and HAZ.

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