Strengthening behavior analysis of weld metal of laser hybrid welding for microalloyed steel

Inhomogeneous microstructure and fatigue crack propagation of thick-section high strength steel joint welded using double-sided hybrid fiber laser-arc welding

“…Such a difference arises because the laser zone was formed mainly due to the laser energy, while the arc zone was mainly determined by the arc heat source. The cooling rate of the laser welding is higher than that of the arc welding [27,28]. Consequently, the grain growth of the laser zone is restricted, as the grain growth time for the laser zone is shorter than that for the arc zone, resulting in smaller grain size in the laser zone.…”

Challenges and developments in pipeline weldability and mechanical properties

“…1 Some experimental work has been carried out to develop a new WM for the longitudinal seam weld of X120, given in Table 7. 8,9 It is possible to obtain a WM that yields a combination of strength of roughly 1000 MPa and a high toughness by appropriate 13 Hardenability of pipeline steel X100 and X120 15 [CE IIW 5CzMn/6z(MozCrzV)/5z(CuzNi)/15] 14 Effect of carbon content on simulated HAZ toughness of X100 pipe steel 48 design of the chemistry (Mn-Ni-Mo-Cr) of WM in grade X120. X100 pipeline has been developed, and the characterisation of prototype pipes has been extensively studied by pipe manufacturers and major oil companies.…”

“…1. [5][6][7][8][9][10][11][12][13] The chemical composition and mechanical properties of pipeline steel from X70 to X120 are given in Tables 1 and 2 respectively. 8,14,15 It is seen that X80 steels instead of X60 and X65 are microalloyed with molybdenum, niobium and titanium, and the reduced carbon content has been developed and utilised for gas pipelines.…”

“…However, with an increasing demand for high strength steels for pipeline applications, some novel welding techniques have been investigated to achieve higher quality welds and more efficiency operations compared to conventional SMAW and GMAW. 28,44,58,[85][86][87][88] Electron beam welding (EBW) and laser processes have been introduced into pipeline industry recently. The advantages of both processes are an extremely high power density and thus a low heat input.…”

Welding of Thermomechanically Rolled Steel by Yb:YAG Disk Laser / Spawanie Stali Walcowanej Termomechanicznie Laserem Dyskowym Yb:YAG

“…Additionally the only criterion for welding procedure (method of welding, parameters of welding, as well as the filler metal) is ensuring the tensile strength of joint not less than the tensile strength of the base metal (BM) [1,2]. However welding of these steel grades at too high heat input, especially during submerged arc welding, and also GMA welding may lead to significant decrease of plasticity and toughness of the welded joints, increase susceptibility to brittle fracture and fatigue as a result of harmful structural changes, creation of coarse structure of the weld metal and significant grain growth in the heat affected zone (HAZ) [14,19,20].…”