Effects of heat input on the mechanical properties of butt-welded high and ultra-high strength steels

Abstract

In this study, the mechanical properties of butt-welded thin plates made of S700, S960 and S1100 steels under various heat inputs (HI) are investigated. The gas metal arc welding (GMAW) process with two different levels of HI, and laser welding (LW) are implemented for this purpose. Fully automated welding process is employed to attain high quality and homogeneous weldments. Standard tensile tests of the butt-welded joints, together with micro-hardness measurements are conducted in this study. The microstructure of the heat affected zones (HAZ) of the weldments are closely examined using scanning electron microscopy (SEM). It was observed that while the fracture was occurred at the base materials of all S700 and S1100 weldments, the S960 suffered from failure at the HAZ which resulted in reduction of the joint's strength and ductility. For all the studied steels, it was found that the joint's ductility is highly dependent on HI values over the range of 0.3-1.4 kJ/mm for each welding pass. Though, the S1100 steel showed the best performance under welding HI with a moderate change in its mechanical properties and a stable microstructure after welding compared to S700 and S960.

Fatigue strength assessment of ultra-high-strength steel fillet weld joints using 4R method

“…If no cyclic softening or hardening is assumed, the monotonic stress-strain-behavior describes the material behavior in the tests. In a recent study, Amraei et al [36] determined the material behavior of the studied S960 and S1100 grades in non-welded and butt-welded components. From these tests, the Ramberg-Osgood (R-O) material models for the base materials can be obtained.…”

“…Young's moduli for the S960 and S1100 materials were determined on the basis of the digital image correlation (DIC) system, and ES960 = 204 GPa and ES1100 = 209 GPa were derived [36]. Fig.…”

Overview on the digitized production of welded steel structures

“…Prior studies, however, have clearly indicated that welding as a joining method can severely modify the high performance of parent UHSS materials. Welding of HSS and UHSS materials may incorporate several issues, such as a reduced static strength [6,7], ductility [8][9][10], and fatigue strength [11], as well as brittle failure susceptibility [12] and structural stiffness. These aspects demand a careful consideration of optimal process parameters, together with potential pre-and post-weld treatments, as well as advanced design phase to maintain the good properties of parent material, resulting in an increased amount of information needed in the fabrication.…”

Experimental Analysis of Welded Rods with a Functionally Graded Material Approach

“…Studies on microstructures and mechanical structures obtained by combining two different materials with arc welding are also available in the literature [21]. In addition, the investigation of both microstructure and mechanical properties of structures obtained by combining different materials with friction welding is another study subject [22][23][24][25][26][27][28][29][30][31][32][33]. In [34,35], microstructure properties of materials of the same type are studied.…”