D. Devakumar ¹, D. B. Jabaraj ², V. K. Bupesh Raja ³, J. Jayaprakash ²

Affiliations
1 Department of Mechanical Engineering, St Peters University, Avadi, Chennai - 600054, IN
2 Department of Mechanical Engineering, Dr. MGR Educational and Research Institute University, Chennai - 600095, IN
3 Department of Automobile Engineering, Sathyabama University, Chennai - 600119, IN

Abstract

Objectives: The Gas Tungsten Arc Welding (GTAW) of blanks 2 mm thick of Duplex Stainless Steel (DSS) and Hot Rolled Medium and High Tensile Structural Steel (HRS) is carried out to investigate the metallurgical, mechanical properties and the fracture. Methods: The characterization of the weldments involves tests, viz. macrostructure, microstructure, micro composition analysis through Energy Dispersive Analysis of X ray (EDAX) to find out the metallurgical properties and micro hardness test, tensile test, bend test to determine the mechanical properties of the weldments. Topography of tensile test fractured specimens was analyzed with the help of Scanning Electron Microscope (SEM) and determines the influence of the welding on the ductility of the weld material. Findings: The increase in the weld zone micro hardness and formation of dendritic delta ferrite microstructure, when compared with the DSS parent metal having elongated grained austenite with ferrite and the HRS parent metal having fine grains of ferrite, caused the joint efficiency of the DSS/HRS weldment to increase. The Energy Dispersive Analysis of X ray (EDAX) indicates the formation of dendritic delta ferrite microstructure is attributed to the presence of elements like Si and Cr. The SEM fractography analysis indicates that the weldments possess good tensile strength without decrease in ductility of the fusion zone. Applications: Experimental investigation of mechanical properties and microstructure of DSS-HRS dissimilar GTAW weld joints and fracture analysis with EDAX to identify the changes in the chemical compositions of the fractured specimen.

Keywords

Duplex Stainless Steel, GTAW, Hot Rolled Steel, Mechanical Properties, Microstructure.

Full Text

   

A. Subrammanian ¹, D. B. Jabaraj ², J. Jayaprakash ³, V. K. Bupesh Raja ⁴

Affiliations
1 Department of Mechanical Engineering, St Peters University, Avadi, Chennai - 600054, Tamil Nadu, IN
2 Dr MGR Educational and Research Institute University, Chennai - 600095, Tamil Nadu, IN
3 Department of Mechanical Engineering, Dr MGR Educational and Research Institute University, Chennai - 600095, Tamil Nadu, IN
4 Department of Automobile Engineering, Sathyabama University, Chennai - 600119, Tamil Nadu, IN

Abstract

Objectives: This study aims to investigate the mechanical properties and phase transformations in dissimilar metal joints between AISI 301 Austenitic Stainless Steel and AISI 409M Ferritic Stainless Steel, joined by resistance spot welding. Methods/Analysis: Mechanical properties such as tensile shear strength, failure energy, failure mode, nugget size and surface indentation were analysed at varying current ratings. Macrostructure was examined for size and shape. Microstructure at various locations such as, fusion zone and heat affected zones were investigated. Micro hardness measurement was done at various locations along the weld. Findings: Peak load incremented progressively with rise in welding current, till the commencement of severe expulsion. Weld zone hardness showed a higher value than that of nearby heat affected zones and parent metals. Increment in welding current resulted in enlargement of weld nugget and rise in energy absorption capacity. Electrode indentation values were seen to be correlated with welding current values positively. Fusion zone microstructure consists of marten site and ferrite. Asymmetrical nugget shape was observed. Novelty/Improvement: This study explores the properties, both mechanical and microstructure of AISI 409M-AISI 301 steel dissimilar joint, joined by resistance spot welding.

Keywords

AISI301, AISI409M, Failure mode, Microstructure, Peak load.

Full Text

   

A. Subrammanian ¹, D. B. Jabaraj ², J. Jayaprakash ³, V.K. Bupesh Raja ⁴

Affiliations
1 Department of Mechanical Engineering, St Peters University, Avadi, Chennai- 600054, Tamil Nadu, IN
2 Dr MGR Educational and Research Institute University, Chennai - 600095, Tamil Nadu, IN
3 Department of Mechanical Engineering, Dr MGR Educational and Research Institute University, Chennai - 600095, Tamil Nadu, IN
4 Department of Automobile Engineering, Sathyabama University, Chennai - 600119, Tamil Nadu, IN

Abstract

Objectives: In this study, the mechanical properties and phase transformations of resistance spot welded dissimilar joints between austenitic stainless steel AISI 301 and ferity stainless steel AISI 409M are investigated. Methods/Analysis: Mechanical properties such as tensile shear strength, failure energy, failure mode, nugget size and surface indentation were analysed at varying current ratings. Macrostructure was examined for size and shape. Microstructure at various locations such as, fusion zone and heat affected zones were investigated. Micro hardness measurement was done at various locations along the weld. Findings: Tensile shear strength increases with increase in welding current in expulsion free welds. Fusion zone hardness was found to be larger than that of both base metals and heat affected zones. Nugget size and energy absorbing capacity of the spot weld were found to be in correlation with weld current in expulsion free samples. Electrode indentation on the nugget surface increases with increase in welding current. Fusion zone microstructure consists of martensite and ferrite. Asymmetrical nugget shape was observed. Novelty/Improvement: Investigating the effects of resistance spot welding on the mechanical properties and phase transformations of ferritic-austenitic dissimilar metal weld joint.

Keywords

AISI301, AISI409M, Dissimilar Metal Welding, Resistance Spot Welding, Tensile Shear Strength.

Full Text