Experimental study of mild steel weld bead mechanical properties in rotational arc welding process Vara Prasad Vemu a,⇑ , Pramila Devi Maganti b a UCEK (A), JNTUK Kakinada, Kakinada 533003, India b AUEC (A), Andhra University, Visakhapatnam 530003, India article info Article history: Received 18 March 2019 Received in revised form 29 April 2019 Accepted 10 May 2019 Available online xxxx Keywords: Rotational arc welding Mild steel Weld bead characteristics Mechanical properties Micro structure abstract In the present study, mild steel pieces of 6 mm thickness are welded by conventional and rotational gas metal arc welding by means of the filler metal ER 70S-6 and inert gas is carbon dioxide. The welding volt- age, current and welding speed are chosen as 25 V, 150 A and 0.18 m/min respectively. The rotational arc welding is done at different rotational speeds of 150 rpm and 180 rpm respectively. The tensile strength, hardness, penetration, and microstructures are measured for each specimen after the welding process. From the experiment it is observed that increasing the rotational speed improves the mechanical properties. Ó 2019 Elsevier Ltd. All rights reserved. Selection and peer-review under responsibility of the scientific committee of the International Conference on Recent Advances in Materials, Manufacturing & Energy Systems. 1. Introduction In gas metal arc welding (GMAW) process a consumable wire, of 0.8–2.4 mm diameter and wound in spool form, is fed at a preset speed through a welding torch supplied with a shielding gas [1]. A constant length is maintained between the torch and the work- piece with the control of electrical parameters. The shielding gas like argon, helium, nitrogen, carbon dioxide, hydrogen and their mixtures are used depending on the workpiece material. These gases are used to prevent the atmosphere from contacting the mol- ten metal and heat affected zone. In addition these gases control arc characteristics, mode of metal transfer, penetration, weld bead profile, undercutting tendency, cleaning action and speed of weld- ing. GMAW can be used for welding many materials for which compatible filler wires were developed. The main advantage is that it can produce high quality welds at high speeds and there is no flux to remove. MIG welding has many applications in automobile field. Rotating arc welding process increases productivity and quality for welding methods such as gas metal arc welding or metal-cored or flux-cored gas shielded welding. Like other arc welding pro- cesses, the molten droplets experience the same electromagnetic and gravitational forces. With spin arc, however, the centrifugal force created by rotation cleanly detaches each droplet from the wire and propels at an angle into the joint [2–7]. Thus the arc is directed to the bevel sidewall, providing thorough fusion and a consistent penetration profile into the base metal. Due to this lack of fusion, undercut and porosity are reduced effectively. 2. Experimental procedure For the experimental studies, the mild steel plates having the 100 mm  100 mm  6 mm sizes are used as the base metal due to its superior weld ability and least amount of post weld require- ment. An AC MIG welding machine is used for the welding with a shielding gas of CO 2 and the electrode is ER 70S-6 having a diame- ter of 0.8 mm. The chemical composition of filler material is shown in Table1. Surfaces of the work pieces are properly cleaned to remove dirt and oil before welding. Specimens are fixed on the table with a joint space of 2 mm. The rotating arc welding machine shown in Fig. 1 is employed for welding samples in flat position. The welding parameters used in this experiment are: welding voltage 25 V, welding current 150 A, welding speed 0.18 m/min and wire feed rate 0.394 m/min. Gas supply is adjusted by regulator and gas flow rate is 15 L/min which is measured by flow meter. The first specimen is a sample with linear gas metal arc welding as shown in Fig. 2. https://doi.org/10.1016/j.matpr.2019.05.420 2214-7853/Ó 2019 Elsevier Ltd. All rights reserved. Selection and peer-review under responsibility of the scientific committee of the International Conference on Recent Advances in Materials, Manufacturing & Energy Systems. ⇑ Corresponding author. E-mail address: varaprasadv@jntucek.ac.in (V.P. Vemu). Materials Today: Proceedings xxx (xxxx) xxx Contents lists available at ScienceDirect Materials Today: Proceedings journal homepage: www.elsevier.com/locate/matpr Please cite this article as: V. P. Vemu and P. D. Maganti, Experimental study of mild steel weld bead mechanical properties in rotational arc welding pro- cess, Materials Today: Proceedings, https://doi.org/10.1016/j.matpr.2019.05.420