Experimental investigations on welding characteristics of sinter-forged pre-alloy Atomet 4601 steel. Issue 1 (January 2017)

• Record Type: Journal Article
• Authors: Chandramouli, R.; Kandavel, T.; Karthikeyan, P.
• Is Part Of: International journal of advanced manufacturing technology. Volume 88:Issue 1/4(2017)
• Page Start: 1065
• Page End: 1074
• Publication Date: 2017-01
• Subjects: TIG welding -- Sintering -- Atomet 4601 -- Microstructure -- SEM; Manufacturing processes -- Periodicals; Production engineering -- Periodicals; 670.427
• DOI: 10.1007/s00170-016-8825-8
• Languages: English
• ISSNs: 0268-3768

Abstract

Abstract Welding of powder metallurgy (P/M) materials continues to be challenging due to the complexities in terms of thermal and metallurgical processes as a result of porosity. Though fusion welding may reduce or totally eliminate porosity levels in the weld zone, metallurgical changes in the heat-affected zone (HAZ) and PMZ may pose problems relating to strength of the welded joints. The present research work aims to study the mechanical and metallurgical changes in a sinter-forged pre-alloy Atomet 4601 (Fe-0.54 % molybdenum (Mo)-1.8 % nickel (Ni)+0.3 %C) low alloy steel subjected to tungsten inert gas (TIG) welding. Green cylindrical compacts were sintered in a nitrogen-purged muffle furnace at a temperature of 1120 °C for 20 min and subjected to cold upsetting to get various densities of specimens. TIG welding was performed on the forged alloy steel plates with suitable filler material. The TIG-welded alloy steel was subjected to tensile and micro hardness tests, in addition to micro-examination and SEM fractographs of the fractured surfaces. Weld metal porosity has been observed in the case of parent metals with lower density. Increasing the density of alloy steel is found to enhance the tensile strength of parent metal and welded joint of alloy steels—partly due to absence of weld metal porosity. Formation of lamellar acicular ferrite at the fusion zone makes the welded joint stronger than the parent metal. The SEM image of fractured surface reveals brittle mode of fracture of the welded joint during tensile testing.