http://doi.org/10.24867/JPE-2017-01-097 97 JPE (2017) Vol.20 (1) Original Scientific Paper Singh, B. THE CORRELATION OF WELD MICROSTRUCTURE AND PROPERTIES WITH ELEMENT TRANSFER IN SAW WELDS Received: 07 March 2017 / Accepted: 19 April 2017 Abstract: This study explores the effect of various elements transfer to the welds on its microstructure and properties. The fluxes were designed using RSM and were made by agglomeration technique. This study reveals that the pearlite or ferrite formation in the welds depends upon the flux constituents. The carbon, manganese, oxygen and nickel transfer have been correlated with the pearlite formation in the welds. The welds dilution also shows a significant effect on weld properties. Key words: SAW, dilution, weld oxygen, pearlite, ferrite Korelacija mikrostrukture šava i osobine elementa u SAW varovima. Ova studija istražuje uticaj prelaza različitih elemenata u zavaru na njihova mikro svojstava. Prelazi su dizajnirani korišćenjem RSM i rađeni su tehnikom aglomeracije. Ova studija otkriva da formacija perlita ili ferita u zavaru zavisi od fluksa sastojaka. Prelaz ugljenika, mangana, kiseonika i nikla su u korelaciji sa formiranjem perlita u zavarima. Razblaživanje zavarenih spojeva takođe pokazuje značajan efekat na svojstva zavara. Ključne reči: SAW, razređivanje, kiseonik za zavarivanje, perlit, ferit 1. INTRODUCTION Submerged arc welding is also known as hidden arc welding was developed for making high quality butt welds in thicker plates. The arc is produced from the end of a continuous electrode which is buried under the thick layer of flux. The heat of the arc causes the melting of electrode, base plate and the adjacent flux. The lower layer of the flux is melted and reacts with the impurities and forms a slag while the upper unused layer is collected by a hopper and it is again used. It gives the double protection against the atmospheric contamination [1]. In recent years fully automatic and semiautomatic SAW equipments have resulted in an increase in welding speed and their use has made possible to obtain high quality joints. The electrodes used for SAW are either bare or copper coated to prevent them from corrosion. The coating also increases the electrical conductivity of the electrode wire. For welding of various types of steels various combinations of electrodes and fluxes are in use. Fluxes are the chemical substances that are used as a cleaning agent in welding. The SAW fluxes contain lime, silica, manganese oxide, calcium fluoride and other compounds. In SAW the weld pool is protected from the atmospheric contamination by being submerged under a blanket of granular fusible flux. In the molten state, the flux becomes conductive and provides a current path between the electrode and work piece. Fluxes can be categorized depending upon the method of manufacture, the extent to which they can affect the alloy content of the weld deposit and the effect on weld deposit properties. The basic functions of the fluxes in SAW are to improve arc stability, to refine the weld metal and to add the alloying elements [2-3].The various ingredients of flux decides the weld composition and properties. The physical and chemical properties of flux and welding process parameters decide the transfer of various elements to the weld. The mechanical properties of the weldments depend upon the microstructure developed during submerged arc welding [4]. The microstructure of a weld metal in turn largely depends on the heating and cooling cycle. The microstructure is also affected by the welding process, process parameters and the material to be welded. The important factors that decide the microstructure are chemical composition of the weld, heating and cooling rate and flux composition used for welding. The weld oxygen content and the shape and size of inclusions also have a definite effect on microstructure [5]. The heat input and cooling rate both have a direct effect on the microstructure of final weld metal composition [6-7]. The austenite - ferrite transformation, cooling rate and different ferrite morphologies are important considerations for improving the mechanical properties. The various microstructures formed in low carbon steel welds are grain boundary ferrite, widmanstatten ferrite, side plate ferrite and micro phases (A small amount of martensite, retained austenite or degenerated pearlite) depending on the cooling rate and composition. Dallam et al. [8] studied the microstructure of low carbon steel weld and HAZ and observed various subzone microstructures in HAZ such as spheroidized zone, partially transformed zone, grain refined zone and grain coarsened zone. The same has been verified by the various other researchers [8-10]. The weld metal microstructure is controlled mainly by cooling cycle while the metallurgical transformations in HAZ are related to both heating and cooling cycle [11-12]. The various microstructures