Static strength and design of aluminium-to-steel thin welded joints

Abstract

Welding together dissimilar materials, and, in particular, aluminium alloys to steel, has always been a challenge because of the significant difference in their mechanical, thermo-physical and metallurgical properties which causes the formations of hard and brittle intermetallic phases in the welding region. Recently, EWM® has developed a welding process known as ColdArc®, where the heat input and arc stability are precisely controlled. The present study was designed to investigate the static strength of aluminium-to-steel thin welded joints manufactured using EWM coldArc® welding technology. Butt, lap and cruciform welded connections were prepared to assess tensile strength and failure mode of these hybrid welded joints. The visual examination of the fracture surfaces revealed that, regardless of the geometry of the welded connections, the fracture of the joints always took place in the heat-affected zone (HAZ) on the aluminium side. This inspection indicated that the use of EWM coldArc® welding technology had improved the strength of the hybrid welded joint significantly and removed the problem of having a brittle phase in the welding zone. The results obtained from this investigation shows that Eurocode 9 can also be used to design aluminium-tosteel thin welded joints.

Review of Fatigue Assessment Approaches for Welded Marine Joints and Structures

“…Some of them were improved when the evaluation becomes more complex and a multiaxial stress state occurs [43,[56][57][58][59][60][61]. Recently, the abovementioned approaches were further assessed with several contributions, i.e., the cyclic structural stress was further developed by Dong [62,63] and extended in terms of structural strain of the LCF assessment [64,65], the elastic notch effect was reviewed in [66], the notch stress intensity approaches were deeply discussed in [66][67][68] and the peak-stress method was validated for many kinds of joints and was related to the SED and NSIF approaches [67,69].…”

“…Some of them were improved when the evaluation becomes more complex and a multiaxial stress state occurs [43,[56][57][58][59][60][61].…”

“…However, the joints produced by FSW [136] seem to give a nonuniform distribution of the mechanical properties, and the fatigue life of laser-welded joints still needs to be fully evaluated [137]. The evaluation of the current literature informs that the main four tasks to be handled in aluminum/steel welded joints are [57] reducing intermetallic compounds (IMC) at the interface, monitoring the thickness of IMC layers to avoid the advance of brittle phases, avoiding the formation of pores and cracks which lessen the global strength of aluminum/steel welded joints, and the employment of advanced mechanical characterization methods to assess and consider the non-uniformity of mechanical properties in the joint.…”

Experimental and Theoretical Research on Welded Aluminium X‐Joints

“…The range of HAZ is distributed 20 mm from the fusion line with a plate thickness of 5 mm. I. Al Zamzami et al (2018) investigated the static load capacity of steel-aluminium welded joints [7]. In their work, they concluded that the welding of different materials, especially aluminium alloys with steel, has always been a challenge due to the significant difference in their mechanical, thermo-physical and metallurgical properties that cause the formation of hard and brittle intermetallic phases in the welding area.…”

Numerical Simulation and Fatigue Properties of Laser Spot Weld-Bonding DP590 Dual-Phase Steel Joints

“…In the work of Liu and Ren, 11) they found that the adhesiveinduced gas would reduce the energy required to penetrate the upper sheet so that higher laser power density could interact with the lower sheet, leading to deeper penetration. Zhou et al 12,13) investigated the microstructure and mechanical properties of laser spot weld-bonding joints of DP590 dual-phase steel to aluminum alloy, the results pointed out that welding defects could be avoided, welding penetration depth and width increased compared with those of laser welding. Farabi et al 14) found that the soften zone formed in the laser welding process had a greater effect on the laser welding joints of DP980 compared with DP600.…”