Yogesh Kumar Singla

On the Microstructure and Wear Behavior of Fe–xCr–4Mn–3C Hardfacing Alloys

The present paper describes an investigation aimed at evaluating the microstructural and dry sliding adhesive wear characteristics of Fe–xCr–4Mn–3C hardfacing alloys applied through shielded metal arc welding. The effect of chromium addition on the microstructure of hardfacings was carried out by using optical microscope, field emission scanning electron microscope and X-ray mapping. Dry sliding wear tests were performed on a pin-on-disc wear tribometer. From the experimental results, it was observed that the primary carbides were refined and increased with the increase of chromium content. The morphology of carbides revealed that the primary carbides were rod shaped. The increased chromium content was also found to be beneficial to enhance hardness and wear resistance of hardfacings. The correlation between hardness and wear resistance exhibited the reliability of hardness as an indicator of the wear performance of hardfacings.

Influence of single and dual particle reinforcements on the corrosion behavior of aluminum alloy based composites

This article presents the results of a study on the corrosion characteristics of the single and dual particle reinforced aluminum alloy 6063 based composites. The reinforcements of silicon carbide and zircon sand were utilized to fabricate the composites by stir casting technique. The influence of reinforcement and their weight percentage on the hardness variations was investigated. The electrochemical tests in sodium chloride solution were conducted to study the corrosion performance of reinforced composites and base alloy. From the corrosion analysis, it was observed that the single particle reinforcement offered better solution on enhancing the corrosion resistance of base aluminum alloy in comparison with dual particle reinforced composites. In the single particle reinforced composites, addition of zircon sand exhibited increased corrosion resistance, when compared to silicon carbide reinforced composites. The governing mechanism behind increased corrosion resistance was found to be the absence of galvanic coupling between the elemental compounds and the corrosive media at particle–matrix interface. The scanning electron microscopy of composites was performed to analyze corrosion mechanism and correlated well with the corrosion behavior.

Modeling the impact–sliding wear characteristics of rare earth additive iron-based hardfacing alloys

This paper presents a systematic study of the effect of the cerium oxide content on the mechanical, microstructural and tribological properties of iron-based alloys. The results indicate that the microstructure of the hardfaced alloys is mainly composed of austenite, MC and M7C3 carbides. The primary austenite grain size was refined at first and then coarsened with the increase of the rare earth oxide additions. Meanwhile, the hardness of the hardfacing alloy was also increased. The increased area fraction of carbides was found to be beneficial for enhanced wear resistance. A statistical regression model was developed and verified with a number of test cases in order to evaluate the adequacy of the model. The optimal amount of rare earth was found to be less than 6 wt.%; below this composition, the microstructural, mechanical and tribological properties were excellent.

Optimization of Process Parameters for Friction Welding of Bimetallic Welds

Bimetallic welds made between ferritic steels and austenitic stainless steels are conventionally fabricated using arc welding procedures such as Tungsten Inert Gas, Metal Inert Gas, Shielded Metal Arc Welding and Submerged Arc Welding. However friction welding provides a new and unique solid state approach for joining many similar and dissimilar materials, which may not be possible to join by other welding techniques available without adding any external filler metal. This approach is mostly used in joining of dissimilar materials. The reason for increased utility being the absence of any external filler material which may otherwise add to the heterogeneity of the weld structure. In this paper, the fabrication and effect of friction welding parameters on mechanical-micro structural changes of bimetallic weld joints has been discussed. An attempt has also been made to relate the effect of friction welding parameters on the peak temperature values taken near faying surface and micro hardness changes measured in various zones of weld.