Fabrication of Fe–Al2O3 Composite Layer on the Surface of Carbon Steel via Gas Tungsten Arc Cladding

Abstract

In this study, Fe–Al2O3 composite cladding is fabricated on the carbon steel AISI 1040 (CK40) substrates by the cost-effective process of gas tungsten arc welding. For this purpose, after milling, Fe–Al2O3 composite powders were placed on the steel surface through the sodium silicate binder. After the surface was dried, under a constant voltage and current in a range of 110 to 180 A, the melting and the fabrication of the surface composite were carried out. For non-destructive investigations, samples were analyzed by radiographic testing which showed that there are no cracks in the surface layer created and Al2O3 particles are distributed uniformly in the surface layer. Microstructural examinations by optical microscopy, scanning electron microscopy, energy-dispersive spectroscopy, and X-ray diffraction proved the presence of a pure Fe–Al2O3 phase in the surface layer. Microscopic images showed coaxial fine grains in the weld metal, which can be caused by a thermal gradient between the weld metal and substrates and rapid solidification. Increasing the current due to enhanced input heat leads to a reduction of the grain size and an increase of dramatic micro hardness that leads to agglomeration of Al2O3 particles and reduction of the quality of the cladding layer. The purpose of this research is to achieve optimal parameters of claddings to attain specific objectives of engineering by using steel via an inexpensive supplementary method.