Effect of welding speed on microstructural and mechanical properties of friction stir welded Inconel 600

Effect of precipitation on post-heat-treated Inconel 625 alloy after friction stir welding

https://www.ipen.br/biblioteca/2010/15560.pdf

Pulsed Nd:YAG laser seam welding of AISI 316L stainless steel thin foils

This study investigates the influence of the Nd?YAG laser power wave mode on the porosity and mechanical properties of SUS 304L and inconel 690 weldments. Initially, a rectangular laser power waveform is specified. The output is then progressively changed from a pulsed wave mode to a continuous wave mode by reducing the value of ?P (?P = Pp?Pb, where Pp is the peak power and Pb is the base power) to zero. Bead-on-plate (BOP) and butt welding are performed at a constant mean output power (1.7?kW). The BOP results demonstrate that the depth/width (D/W) ratio of both materials increases with ?P and attains a maximum value when full penetration just occurs. The D/W ratio and the travel speed for full penetration are higher for SUS 304L than for inconel 690. In butt-welds of inconel 690 and SUS 304L, the porosity ratio decreases from 7.1% to 0.5% and from 2.1% to 0.5%, respectively, as ?P increases from 0 to 2780?W. Therefore, the tensile strength and percentage elongation are enhanced significantly in inconel 690. The degree of porosity reduction in inconel 690 exceeds that of SUS 304L. This suggests that the viscosity of the molten inconel 690 metal is higher than that of SUS 304L. Consequently, the effect of porosity reduction due to the increase in molten metal fluidity caused by increasing ?P is greater for inconel 690 than for SUS 304L.

https://iopscience.iop.org/article/10.1088/0022-3727/38/5/009/pdf

Porosity reduction in Nd–YAG laser welding of stainless steel and inconel alloy by using a pulsed wave

The present study was carried out to evaluate the microstructure and mechanical properties of Inconel 600 subjected to laser-assisted hybrid friction-stir welding (HFSW). In this process, friction-stir welding (FSW) was performed at a constant speed (400 rpm) while a 2-kW YAG laser preheated the material just in front of the rotating tool. We found that HFSW was 1.5 times faster than conventional FSW. In addition, analysis of the grain boundary character distribution by electron back scattered diffraction (EBSD) showed that the increased welding speed and dynamic grain recrystallization caused the average grain size to decrease from 5.5 μm (in the base material) to 3.2 μm (in the stir zone of the welded specimen). This grain refinement led to 30% and 10% improvements in microhardness and tensile strength, respectively.

/pdf/development-of-microstructure-and-mechanical-properties-in-1ezfuuo6qv.pdf

Cheol-Jung Kim

Papers

Repair welding of etched tubular components of nuclear power plant by Nd:YAG laser