Ultra-Narrow Gap Fiber Laser Conduction Welding Technology for 304 Stainless Steel Thick Plates and the Mechanical Properties of Welding Joints

Abstract

The application of thick metal plates is increasing, and the welding problem is becoming more and more prominent. Narrow gap laser welding is one of the important methods, and it is also a research hotspot. The stainless steel thick plates were welded using the ultra-narrow gap fiber laser conduction welding with filler wire. Results show that the ranges of technological parameters for the achievement of the weld seam with no defects are smaller when the gap width is comparatively larger. Using the optimized technological parameters, the butt welding with no defects on the 3 mm gap between two 304 stainless steel plates with 60 mm thickness was achieved through the filling 20 times. This welding method of 304 metal with large thickness is rare in the literature. The tensile strength of the welding joint can be up to 87% of that of the base metal, and the micro-hardness and yield strength of the joint are comparable with those of the base metal.

Research on the Low-Temperature Impact Toughness of a New 100-mm Ultra-Thick Offshore Steel Fabricated Using the Narrow-Gap Laser Wire Filling Welding Process

“…Elmesalamy [ 21 ] and colleagues discovered that narrow-gap laser welding can join materials much thicker than what single-pass autogenous laser welding can handle. Zhang [ 22 ] and scholars successfully welded 60-mm-thick 304 stainless steel plates using narrow-gap laser wire filling welding. Keßler [ 20 ] and others used narrow-gap laser multi-pass welding for a 72.5-mm-thick nickel-based superalloy.…”

“…Pu [ 24 ] examined the effect of wire feed speed on narrow-gap laser wire filling welding, concluding that excessively high speeds adversely affect weld quality. Zhang [ 22 ] studied narrow-gap laser wire filling welding of thick stainless-steel plates, finding that a wider gap size reduces the range of process parameters for defect-free welds. Therefore, many scholars have conducted research on how to minimize the impact of these adverse factors on welding quality.…”

Development of Laser Welding and Surface Treatment of Metals

“…In the area of joining materials, laser welding shows several advantages because it provides high-power densities and low diameter of the laser beam spot, and thus high penetration depth, high welding speed, and low, precise, and controllable heat input. The above features are particularly important for the joining of modern and advanced alloys such as ultra-high-strength steels (UHSS), advanced high-strength steels (AHSS), modern stainless duplex and super duplex steel, nonferrous metals, and light metals, e.g., titanium and aluminum alloys [ 6 , 11 , 13 , 14 , 15 , 16 , 17 ].…”

“…Continuous development of laser generators and related improvement of laser radiation and laser beam characteristics enable further development in the field of laser material processing, including laser welding and laser surface treatment. In addition to the gaseous CO 2 and solid-state rod type Nd:YAG laser generators used for the last few decades, new generations of solid-state lasers are currently available such as high-power diode lasers (HPDL), disk lasers, and fiber lasers [ 1 , 14 , 15 , 16 , 17 ]. Modern generations of laser devices offer new or expanded technological possibilities.…”

“…The design of diode lasers has been developed to the extent that today there are direct diode lasers (DDL) which emit single-mode radiation with power up to 8 kW, suitable for cutting applications. Moreover, the single-mode DDL lasers are even competitive with CO 2 gas lasers and disk lasers, as well as fiber lasers [ 1 , 14 , 17 , 18 ].…”