Intercorrelation of Interpass Temperature - Base Metal Thickness - Microstructure and Cracking of Weld Metal Deposited from E8010-P1 Cellulosic Electrodes

In this study, the cracking sensitivity of deposited weld of E8010-P1 cellulosic electrodes as a function of base metal thickness and interpass temperature was analyzed. For this purpose, different welded samples (different base metal thickness and interpass temperature) were subjected to the bending test according to the SEP-1390 bohler specification. Studies illustrated an increase in the minimum interpass temperature from 80?C to 120?C is required with increasing base metal thickness from 20mm to 30mm to prevent weld cracking. Increasing of interpass temperature not only decreases the welding cooling rate but also reduces the heat sink effect of base metal and therefore decreases the cracking sensitivity. Structural studies indicated that the main cause of E8010-P1 weld metal cracking is development of undesirable phases such as grain boundary and widmanstaten ferrite in the weld metal. In addition, optimum cooling time between 800-500?C (?t8/5) for preventing E8010-P1 weld metal cracking determines to be around 18010s.