Alternatives for Specimen Manufacturing in Tensile Testing of Steel Plates

Abstract:In the present study, aluminum alloy T-joints were welded using the laser stake-welding process. In order to improve the welding quality of the T-joints, an external electric current was used to aid the laser stake-welding process. The effects of the process parameters on the weld morphology, mechanical properties, and microstructure of the welded joints were analyzed and discussed in detail. The results indicate that the aided electric current should be no greater than a certain maximum value. Upon increasing the aided electric current, the weld width at the skin and stringer faying surface obviously increased, but there was an insignificant change in the penetration depth. Furthermore, the electric current and pressing force should be chosen to produce an expected weld width at the faying surface, whereas the laser power and welding speed should be primarily considered to obtain an optimal penetration depth. The tensile shear specimens failed across the faying surface or failed in the weld zone of the skin. The specimens that failed in the weld of the skin could resist a higher tensile shear load compared with specimens that failed across the faying surface. The microstructural observations and microhardness results demonstrated that the tensile shear load capacity of the aluminum alloy welded T-joint was mainly determined by the weld width at the faying surface.

Section: Methodsmentioning

confidence: 99%

Experimental Investigation on Electric Current-Aided Laser Stake Welding of Aluminum Alloy T-Joints

Zhang

Chen

et al. 2017

“…The ASTM E8 standard size specimens were manufactured by wire electrodischarge machining. The effect of the coupon manufacturing methods on tensile properties were discussed elsewhere [34]. The uniaxial tensile tests were conducted for the RD, DD, and TD, as shown in Figure 2a.…”

Section: Uniaxial Tensile and Loading-unloading Testsmentioning

confidence: 99%

Anisotropic Hardening Behaviour and Springback of Advanced High-Strength Steels

Jung

Jun

Lee³

et al. 2017

Advanced high-strength steels (AHSSs) exhibit large, and sometimes anisotropic, springback recovery after forming. Accurate description of the anisotropic elasto-plastic behaviour of sheet metals is critical for predicting their anisotropic springback behaviour. For some materials, the initial anisotropy is maintained while hardening progresses. However, for other materials, anisotropy changes with hardening. In this work, to account for the evolution of anisotropy of a dual-phase steel, an elastoplastic material constitutive model is developed. In particular, the combined isotropic-kinematic hardening model was modified. Tensile loading-unloading, uniaxial and biaxial tension, and tension-compression tests were conducted along the rolling, diagonal, and transverse directions to measure the anisotropic properties, and the parameters of the proposed constitutive model were determined. For validation, the proposed model was applied to a U-bending process, and the measured springback angles were compared to the predicted ones.

“…These processes have the advantage of being extensively used in the sheet metal forming industry, whose effect on tensile strength were lower than 5% [20]. For mechanical characterization of the welded joints, dog-bone shaped specimens were prepared after WEDM (6 mm/min, 0.18 mm Mo wire, V d = 80 V, I = 3 A) with dimensions depicted in Figure 1.…”

Section: Materials and Experimentsmentioning

confidence: 99%

“…At room temperature, the average ultimate tensile strength (UTS) was 1050 MPa, the average elongation was 4.9% and the yield strength (YS) is 993 MPa. One must be aware that the tensile properties of a given sample specimen may be dependent on the methodology used to obtain it, as described in the literature [20,34,35]. However, since the same process was used for all test specimens any potential detrimental effect is diluted within the test itself.…”

Section: Mechanical Properties Of the Jointsmentioning

confidence: 99%

Laser Welding of BTi-6431S High Temperature Titanium Alloy

Zeng

Oliveira

et al. 2017

Abstract:A new type of high temperature titanium alloy, BTi-6431S, has recently become the focus of attention as a potential material for aircraft engine applications, which could be used up to 700 • C. Pulsed laser welding was used to butt join the BTi-6431S titanium alloy in order to understand the feasibility of using fusion-based welding techniques on this material. The effect of laser energy on the microstructure and mechanical properties of the joints was investigated. The microstructural features of the joints were characterized by means of microscopy and X-ray diffraction. Tensile testing was conducted at both room temperature and high temperature to simulate potential service conditions. The results show that the microstructure of the laser welded joints consists of primary α phase and needle α' phase, while the microstructure of the heat affected zone consists of α, β, and needle α' phases. The tensile strength of the welded joints at room temperature was similar to that of the base material, despite a reduction in the maximum elongation was observed. This was related to the unfavorable microstructure in the welded joints. Nonetheless, based on these results, it is suggested that laser welding is a promising joining technique for the new BTi-6431S titanium alloy for aerospace applications.