Indian Welding Journal

A. Baskaran ¹, K. Shanmugam ¹, V. Balasubramanian ¹

Affiliations
1 Department of Manufacturing Engineering, Annamalai University, Annamalainagar- 608002, Tamil Nadu, IN

Abstract

In the present work an attempt was made to develop high temperature wear resistant hardfaced tools for friction stir welding (FSW) of commercial grade copper alloys. Hardfacing was applied on mild steel rod using chromium carbide forming powder by plasma transferred arc (PTA) hardfacing process. Commercially available tool materials like high carbon steel (HCS), high speed steel (HSS) and super high speed steel (SHSS) were also used to friction stir weld copper alloy for comparison purpose. From this investigation, it is found that the PTA hardfaced tool yielded defect free joints without tool wear compared to other tools. The optimum level of heat generation, formation of finer grains and higher hardness of stir zone are main reasons for the superior tensile properties of the joints fabricated by PTA hardfaced tungsten carbide tools.

Keywords

Plasma Transferred arc Hardfacing, Friction Stir Welding, Copper Alloy, Tensile Properties, Microstructure.

Full Text

     

V. Ganesan ¹, K. Shanmugam ¹, V. Balasubramanian ¹

Affiliations
1 Centre for Materials Joining & Research (CEMAJOR), Department of Manufacturing Engineering, Annamalai University, Annamalai Nagar-608002, IN

Abstract

The Austenitic Stainless Steels (ASS) are probably the most widely used materials in stainless steels, category AISI 304L is an important grade of the ASS, which is commonly used in many of important industries such as containers of transporting chemicals, oil refinery, nuclear reactor tanks, dairy industries, and textile industries. Currently, 304L Austenitic stainless steel sheets are used as fuel tanks in Armour Fighting Vehicle (AFV). These tanks are fabricated by conventional Tungsten Inert Gas (TIG) welding process. In conventional welding, fusion zones typically exhibit coarse columnar grains because of the prevailing thermal conditions during weld metal solidification. This often results in inferior weld mechanical properties. Interpulse Tungsten Inert Gas (IPTIG) welding is a new variant of conventional Tungsten Inert Gas (TIG) welding process. This process offers many advantages over conventional TIG welding process such as narrow heat affected zone, deeper penetration compared to Constant Current TIG (CCTIG) and Pulsed Current TIG (PCTIG) welding processes. The present investigation was carried out to understand the effect of arc pulsing technique on cross sectional weld bead profile, micro hardness, microstructure and the tensile properties of welded joints. It is found that IPTIG welded joints showed superior mechanical properties compared to CCTIG and PCTIG joints, and this is mainly due to formation of finer grains in the fusion zone, caused by the combined effect of arc constriction and pulsating action.

Keywords

Tungsten Inert Gas, Austenitic Stainless Steel, Interpulse TIG Welding, Tensile Properties, Microstructure.

Full Text

     

R. Selvaraj ¹, K. Shanmugam ¹, P. Selvaraj ², Prasanna Nagasai Bellamkonda ¹, Balasubramanian Visvalingam ¹

Affiliations
1 Centre for Materials Joining and Research (CEMAJOR), Department of Manufacturing Engineering, Annamalai University, Annamalainagar, IN
2 Department of Mechanical Engineering, MAM College of Engineering and Technology, Tiruchirappalli, IN

Abstract

SA213 T12 and SA213 F12 low alloy steel (LAS) tubes have been successfully welded using the rotary friction welding (RFW) process. The effect of the rotational speed on the microstructure and the mechanical properties of the joints has been studied. With increasing rotational speed, the tensile strength first increases to a certain extent and then decreases. Weld samples with the highest tensile strength (488 MPa) and maximum elongation (40.01%) are achieved at 60 rps. Using higher rotational speed (68 rpm) increased grain size in the heat-affected zone (HAZ). The samples joined at different rotational speeds failed in the HAZ. The hardness profile showed that the interface (IF) has a higher hardness than the other zones and base metal. The highest hardness of welded joints (198 HV) was observed in the 60 rps sample. The phase transformation of bainite and acicular ferrite at the weld interface was attributed to the high strength of the weld joint. Weld joint defects are observed at 55 rpm and 65 rpm, where high heat inputs and impurities at the weld interface cause incomplete metallurgical bonding, resulting in defects in the weld seam.

Keywords

Rotary Friction Welding, Low Alloy Steel, Rotational Speed, Microstructure, Mechanical Properties.

Full Text