A Araee - Associate Professor, Department of Mechanical Engineering, University of Tehran, Tehran, Iran
A Fathi - Master's degree, Department of Mechanical Engineering, University of Tehran, Tehran, Iran
A.R Farrokhi - Master's degree, Department of Mechanical Engineering, University of Tehran, Tehran, Iran

In this article, flux cored arc welding performed on steel St-52 and studies the microstructure and mechanical properties were investigated. Welding process by changing the input parameters of welding wire feeding rate, current, voltage and speed welding on steel parts was on four different values. The objective is to evaluate the effect of these parameters on the microstructure and mechanical properties of the welded joints. As well as optimum for these parameters were determined. Health’s of weld were evaluated by radiographs examination. Microstructural analysis of welded parts was performed by Metallographic testing and optical microscopy. Grain microstructures for all samples were examined in four regions including base metal, HAZ region close to the base metal, HAZ near the weld area and weld area. The mechanical properties of welded joints were evaluated by transverse tensile test. Health of all samples was confirmed by X-ray test. Metallographic examination results showed that the behavior of microstructures in the four regions for all samples is uniform and differences in grain size. Increasing the feeding rate of welding, current and voltage, causing the grain size to be larger. It also showed that the microstructure of welded samples from approaching the area of the base metal HAZ, increased strength. This can be explained by high heat input. The tensile test samples were fractured in a place outside the weld. On the other hand, by increasing the feeding rate of welding, current and voltage, tensile strength increased. On the contrary, the tensile strength decreased with increasing welding speed.

Cored welding, welding parameters, mechanical properties, microstructural behavior