Filler metal

About: Filler metal is a research topic. Over the lifetime, 11152 publications have been published within this topic receiving 86590 citations.

Spreading behavior and microstructure characteristics of dissimilar metals TIG welding–brazing of aluminum alloy to stainless steel

Abstract: Dissimilar metals TIG welding–brazing of 5A06 aluminum alloy to SUS321 stainless steel had been conducted using 4047 Al–Si eutectic filler metal and modified non-corrosive flux. And spreading behavior of filler metal on the groove surface and microstructure characteristics of the butt joint were investigated. The spreading behavior of liquid filler metal consisted of two parts: one was to spread on the back face to pack the steel; the other was to uphill spread on the front face of the groove to form a sound brazed seam. The interfacial layer, unequal in thickness at different position, ranged from 5 μm to 35 μm. And it was made up of three different kinds of IMC layers: from the welded seam to stainless steel, the first was τ 5 -Al 7.2 Fe 2 Si and α-Al phases, the second was η-Fe 2 Al 5 phase, and the third was FeSi 2 and η-Fe 2 Al 5 phases. Average tensile strength of the butt joint reached 120.0 MPa and fracture occurred at the interfacial layer. Cracks derived from the top part of brittle η-Fe 2 Al 5 interfacial layer when its thickness exceeded 10 μm.

Elucidation of high-power fibre laser welding phenomena of stainless steel and effect of factors on weld geometry

Abstract: The fibre laser has been receiving great attention due to its advantages of high efficiency, high power and high beam quality, and is expected to be one of the most desirable heat sources for high-speed and deep-penetration welding. In this study, therefore, in bead-on-plate welding of Type 304 stainless steel plates with 6 kW fibre laser, the effects of laser power, power density and welding speed on the formation of sound welds were investigated with four laser beams of 130, 200, 360 and 560 µm in spot diameter, and their welding phenomena were clarified with high-speed video cameras and an x-ray transmission real-time imaging system. The weld beads showed a keyhole type of penetration at any diameter, and the maximum penetration of 11 mm in depth was obtained at 130 µm spot diameter and 0.6 m min−1 welding speed. It was found that the laser power density exerted a remarkable effect on the increase in weld penetration at higher welding speeds, and sound partially penetrated welds without welding defects such as porosity, underfilling or humping could be produced at wide process windows of welding speeds between 4.5 and 10 m min−1 with fibre laser beams of 360 µm or 560 µm in spot diameter. The high-speed video observation pictures and the x-ray images of the welding phenomena at 6 m min−1 welding speed and 360 µm spot diameter show that a sound weld bead was formed owing to a long molten pool suppressing and accommodating spattering and a stable keyhole generating no bubbles from the tip, respectively.