Study of Microstructure and Mechanical properties of Welded mild steel fabricated by FCAW and Compare with GMAW Process

Subject Areas : journal of New Materials

نوید Khodabandehloo ¹ (مرکز تحقیقات مواد پیشرفته، دانشکده مهندسی مواد، واحد نجف آباد، دانشگاه آزاد اسلامی، نجف آباد، ایران)
حامد Sabet ² (مرکز تحقیقات مواد پیشرفته، دانشکده مهندسی مواد، واحد نجف آباد، دانشگاه آزاد اسلامی، نجف آباد، ایران دانشیار گروه مهندسی مواد و متالورژی، واحد کرج، دانشگاه آزاد اسلامی، کرج، ایران)

Received: 2016-06-08 Accepted : 2018-03-01 Published : 2018-02-20

Keywords: Thickness, GMAW, FCAW, Ferrite Circulators, Steel St37,

Abstract :

In this study, samples of carbon steel St37 was junction with thickness of 4 and 8 mm by two process GMAW and FCAW welding methods. The samples was junction by using solid wires and flux cored for welding GMAW and FCAW respectively, to near the chemical composition connected. Evaluation of microstructure was performed by optical microscopy and scanning electron microscopy (SEM) with EDS analysis. The results showed that, with increasing the thickness of the Ferrite circulators content reduced in the Weld zone and the amount Weidman Ashton ferrite and grain boundary ferrite phases increased. Also in the FCAW process due to potential areas for nucleation sites and the formation of Ferrite circulators than the process GMAW, better mechanical properties was observed. The results of the tensile test showed the highest the amount of tensile properties in the sample thickness of 4 mm and obtained in welded by FCAW method. Hardness test results showed, highest the amount of hardness in welding and heat affected zone related to sample with thickness 4 mm and is welded by FCAW method. SEM images were showed, the amount of inclusions and cavities weld metal was FCAW more of GMAW method. Images SEM showed that the impact test samples with the increase in thickness in both welding methods the fracture surfaces, fracture but also show evidence of brittle behavior as well.

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