Abstract
The objective of this study was to investigate the weldability of an iron-based powder metal alloy (Fe-P-C) using the gas tungsten arc welding process (GTAW) with two different filler metals. Optical microscopy revealed that for the Fe-P-C alloys, the fusion-welded zone was free of porosity and cracks. The thickness of the slab was 4 mm. The heat affected zone did not show excessive hardness. The SEM image of the fracture specimen showed elongated dimples. X-Ray mapping confirmed the absence of Fe3P. EPMA was used to determine the ability of carbon in preventing the segregation of P to the grain boundaries. Tensile tests showed that the failures of the specimens occurred always in the base metal with tensile strength slightly superior to the value of unwelded samples. As a result, this investigation showed the feasibility of joining ironbased powder metal alloys by the GTAW process, especially while welding the Fe-P-C alloy.
Highlights
Powder metallurgy (P/M) route offers the advantage of manufacturing near net shaped components at affordable cost
Structural parts made of iron-based alloys manufactured through the powder metallurgical route have been extensively used as mechanical components due to their good balance between ductility and tensile strength, good magnetic properties and corrosion resistance
Phosphorus is intentionally added in powder metal iron to increase the densification of the iron powder since this element allows the formation of a transient liquid phase during sintering
Summary
Powder metallurgy (P/M) route offers the advantage of manufacturing near net shaped components at affordable cost. Structural parts made of iron-based alloys manufactured through the powder metallurgical route have been extensively used as mechanical components due to their good balance between ductility and tensile strength, good magnetic properties and corrosion resistance. Such P/M components can replace wrought alloys in many applications due to their low cost and high performance [1, 2]. Keeping in view the above discussion, this work was formulated in order to investigate the use of the GTAW process with two different filler metals (AWS 5.18 ER 70S-6 & Fe-0.35P-0.15C) in the weldability of powder metal iron-based alloy (Fe-0.35P-0.15C) and its effect in the microstructural and mechanical characteristics of the welded joint. The composition Fe-0.35P0.15C was deliberately chosen to obtain benefit from the two phase gamma + alpha region
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