Microstructural characterization and mechanical properties development with Ti, Cr, or Ni addition for low carbon steel butt joints

Abstract

Welding is one of the most important industrial process, therefore many practical techniques are developed to obtain an efficient and cost effective welding for different kind of metals. In this research, the microstructural characterization and mechanical properties of welded joints using TIG welding were studied for 1020 AISI low carbon steel. Titanium, Chromium, or Nickel powder were added to the welded joint one at a time by paste it with paraffin wax in the form of a thin layer. The welds were conducted and tested, then results were compared with and without adding Ti, Cr, or Ni metal powder. The welding process was done at a constant DC current (200 Amps. and 20 Volts) using weld filler metal type ER70S-3. Tests results showed that the tensile strength of the welded joint without adding metal powders was approximately 2% higher than the tensile strength of the base metal. Additionally, the tensile strength enhanced by approximately 27%, 21%, and 2% for Titanium, Nickel, and Chromium metal powder addition to the welded joints respectively. The bending strength values for all welded joints were also higher than the base metal. Furthermore, the hardness values were increased in the welded zone for all specimens. This can be attributed to the difference in the behavior of each metal powder at high temperature. The obtained results provide an experimental reference for the development of a new welding technique. It can be used in practical welding applications to obtain the desired properties using a suitable metal powder or a combination of them.