Effect of Normalizing Process on Mechanical Properties of Submerged-arc Weldment


Submerged arc welding is carried out and efficient metal- joining process widelyused in great importance in many industrial applications, structures of ships, storagetanks and agriculture equipments. Low alloy steel used under welding conditionswhich are, (560 Amp) welding current, (42cm/min) welding speed, (3.25mm) wirediameter, direct current straight polarity (DCSP) with the joint geometry of single -Vbuttjoint and weld one pass are used for plate of thickness 16mm. After welding, thecomponents have be submitted to a normalization heat treatment in order to recoverthe original mechanical properties of the welds. In this work two different filer metalsboth in the as welded condition and after normalizing heat treatment have been studied.Optical microscopy was used to observe the weld microstructure. Tensile and CharpyV toughness testing and microhardness measurements were used to evaluate themechanical properties of joint. Results show that normalizing reduces the originalcolumnar structure in the as welded condition to an equiaxial structure. It was observeda high decrease in the tensile properties specially the yield strength after normalizing.In respect of toughness, the normalizing heat treatment was observed to increase theCharpy V energy.