Enhancement of weld quality of AISI 304L austenitic stainless steel using a direct current pulsed TIG arc

2nd International Conference on Engineering Sciences

Ugla, A.A.^1

Department of Mechanical Engineering, College of Engineering, University of Thi-Qar, Al-Nasiriyah

64001, Iraq^1

关键词: Metallurgical characteristics;    Micro-structural characteristics;    Pulse frequencies;    Research papers;    Tungsten inert gas welding;    Weld bead geometry;    Welded components;    Welding process;   

Others  :  https://iopscience.iop.org/article/10.1088/1757-899X/433/1/012075/pdf
DOI  :  10.1088/1757-899X/433/1/012075

来源: IOP

【 摘 要 】

In welding processes, the quality of weldment usually refers to the desired weld bead geometry and its microstructural characteristics, which affect the mechanical properties of the welded components. The present paper aims to investigate the influences of the main process input factors on weld geometry, metallurgical characteristics, and mechanical properties of weldments of 3.8-mm-thick plates of austenitic stainless steel type 304L using tungsten inert gas welding with pulsed/non-pulsed current processes. This research paper investigates the effects on the arc pressure of pulse frequencies at levels of 6 and 1,000 Hz, and thereby their effects on the aspect ratio and morphology of the weld metal. The key outcomes of this work are that the frequency of arc pulsation has a strong effect on the breaking of the dendritic arms during the welding process. The obtained microstructure results reveal that the structure of the high pulse frequency current welded specimens are thus generally finer grained, with higher levels of residual ferrite and an absence of columnar grains; such pulse frequencies thus strongly influence the tensile strength and microhardness of affected weldments as compared to those seen in continuous current welded specimens. Additionally, the most important factor affecting the bead geometry and aspect ratio is identified as the pulse frequency, with a contribution of 64%.