Journals of Mechatronics Machine Design and Manufacturing Volume 1 Issue 2 Effect of Phosphorus Addition in Steel: Processed Through Cast Route and Powder Metallurgy Route Shefali Trivedi*1, Parag Gupta2 1Assistant Professor, 2M.Tech Student, Department of Mechanical Engineering, J. C. Bose University of Science and Technology YMCA, Faridabad, Haryana, India Email: *[email protected] DOI: http://doi.org/ 10.5281/zenodo.3556177 Abstract In general alloying elements are added in Iron to enhance its mechanical, electrical, attractive and tribological properties. Phosphorus is a vital alloying component in steel, since it was discovered. The addition of phosphorus content in the low carbon steels results in viably enhancement of the strength. Phosphorus additionally enhances wear resistance, magnetic properties and corrosion resistance of steel. Fe-P steels have been processed through wrought as well as powder metallurgy route. However, production of Fe- P steels through wrought processing route is troublesome due to tendency of phosphorus to isolate along the grain boundaries during solidification. Phosphorus segregation along the grain boundaries in cast route can be avoided by alloy designing. Fe-P steels have been developed through powder metallurgy route. High density Fe-P steels have been developed through powder pre-form technique. This high strength steel is valuable in basic structural applications such as to make rebars for reinforcement, corrugated sheets for roofing, flats, angles, beams, trusses etc. Fe-P steels are less expensive to existing high strength good wear and good corrosive materials. Keywords: Fe-P steels, corrosion resistance, mechanical properties, wear resistance INTRODUCTION ferrite stabilizer, alloying element in steels. The alloying elements used in steels are of It was found that the plain carbon steels two types. One is ferrite stabilizer and which contain phosphorus more than other is austenite stabilizer. Austenite 0.05% is known as Fe-P steel. These are stabilizers are elements which make also referred as phosphoric irons by some austenite (of iron) stable at lower researchers [6, 7]. From last two decade, temperature that it would occur in the pure iron phosphorus steels (Fe-P steels) are an iron. With the enough amount of austenite interesting era for the development in the stabilizer, austenite stable at room field of mechanical metallurgy due to temperature, i.e., decreasing the attractive features of phosphorus as an austenitizing temperature of iron. alloying element. In Fe-P steels, Examples of austenite stabilizers are phosphorus helps in carrying the alloy nickel, carbon, manganese etc. Ferrite constituents in to iron matrix through P/M stabilizer makes ferrite stable at higher technique. Phosphorous causes hardening temperature. Examples of ferrite stabilizer of ferrite in solid solution with iron. It can are titanium, molybdenum, phosphorus, be explain by fact that atomic radius of chromium, silicon [1−5] etc. they also phosphorus is 1.1 A° and that of iron is known for carbide former elements. 1.24 A°, so presence of phosphorus in Theses stabilizer also decreases the solid solution in ferrite, distorts lattice eutectoid composition. Phosphorus is hence strengthen the ferrite phase. 24 Page 24-28 © MAT Journals 2019. All Rights Reserved Journals of Mechatronics Machine Design and Manufacturing Volume 1 Issue 2 LITERATURE REVIEW AND solidification in steel processed through METHODOLOGY cast route which leads the initiation of The present review predominantly deals crack along the grain boundaries [13]. It with the literature on advantages of was also found that small amount of Phosphorus as an alloying element in steel carbon addition (.02−.05%) in iron through cast route and powder phosphorus alloy can avoid the segregation metallurgical route. The addition of of phosphorus along the grain boundaries phosphorus effectively improves the wear due to the site competition of carbon and resistance, corrosion resistance, ultimate phosphorus [14]. But additions of high tensile resistance and magnetic properties amount of phosphorus (0.6 to 2%) still a of low carbon steels also [1, 3−9]. Most of big challenge in steel industries through the frictional material used in commercial cast route. Das et al. (2008) and Trivedi et cars and light duty automobiles possesses al. (2010), worked on hot powder forging by addition of a suitable amount of technique for processing of Fe-P steels with phosphorus content in the range of phosphorus in order to enhance wear 0.35% to 0.7% [15, 16]. characteristics as well as mechanical properties [10]. As we discussed above that the Phosphorus provides the additional segregation of phosphorus occurred in strength with reduction of ductility to the steel during solidification through cast alloys. In Fe-P steels, other alloying route is a big problem that can be solved elements such as aluminum, copper, with the help of powder metallurgy route. silicon, vanadium, nickel, sulphur, In powder metallurgy route, phosphorus is manganese and small amount of carbon uniformly distributed under the action of can be added to improve the mechanical capillary forces [8]. It’s also having the properties. Additions of different alloying ability to form alloys with lower eutectic elements in to the iron matrix serve the point that means Fe-C-P alloys having different purposes such as copper helps to relatively low melting points as compare reduce the porosity during alloy to Fe-C alloys [17]. Phosphorus is also fabrication in powder metallurgy route known for its good fluidity and adhesion to [11]. Sulphur is used to improve the metals [18]. machinability, addition of aluminum improves the ductility, addition of carbon It was found that high density product provides the strength, chromium improves the corrosion resistance etc [5, 12]. can be developed through powder pre form forging technique [19, 20]. Phosphorus generally treated as impurity Important applications of Fe-P steels in steels, because phosphorus segregates and amount of phosphorus in weight along the grain boundaries during percent is summarized in Table 1. Table 1: Show the different Fe-P steels which are used for various purposes. Types of Base Phosphorus Other alloying References Properties material element (Wt %) elements Improve mechanical Constructional Fe 0.3-0.8 C, Cu, Ni, Mg [7, 19, 20] properties C, Cu, Mo, S + Increase wear resistance as Anti-frictional Fe 0.5-1.0 solid lubricant well as increase overall [10, 21, 22, 23] like graphite strength C, Sn, Al, Pb, Improve wear properties, Frictional Fe 0.7-1.2 [22, 24, 25] Silicon etc. hardness Increase density, wear - resistance, improves [18, 21, 26 Soft Magnetic Fe 0.8-1.2 magnetic properties. 25 Page 24-28 © MAT Journals 2019. All Rights Reserved Journals of Mechatronics Machine Design and Manufacturing Volume 1 Issue 2 It was estimated the effect of phosphorus 32]. Addition of Phosphorus improves the in different alloys and set a basis for the alloy corrosion resistance, but the addition development of iron phosphorus alloys. It of Chromium with phosphorus increases have also estimated that phosphorus not the atmospheric corrosion resistance in all only improve the mechanical properties the cases [24]. Chromium increases the and wear characteristics but also a cost electrical resistivity of Fe-P based alloys effective medium of development of and being a ferrite stabilizer, it also alloys. It was also estimated that cost of improves magnetic properties of Fe-based parts developed from a Fe-0.3% P powder alloys. Chromium also improves is two third of part developed from Fe- formability of the iron-based alloys 0.5% Ni powder, the level of properties significantly. being the same [27]. Fe-P based sintered friction materials are In anti-frictional material like Fe-P-S best suited for brake applications where alloys, phosphorus improves the operating temperature during braking, may even go characteristics as well as help to reduce the up to 1100°C. Fe-P based sintered friction coefficient of friction [28, 29]. In anti materials are less costly as compared to frictional material, phosphorus is limited other frictional materials. Temperature rise to (0.5-1.0%) but small addition of for hybrid composite is more than that of manganese also improves the temperature rise for binary composite (Fe- machinability. P). Therefore Fe-P based friction materials are used in heavy duty brake applications It is also found that the addition of such as in commercial/fighter aircrafts [25, phosphorus in low carbon alloy can 33]. improve the wear resistance as like of nitro- carburizing improve the surface Weld ability of Fe-P cast steels is limited resistance. Phosphorus is also added to to a certain range (.04-.012) to avoid the copper and bronze base alloy to enhance cracks nearby the weld area due to its high anti frictional characteristics. It has been brittleness. It also requires some kind of proposed that phosphorus should be added preheating before undergoing for welding in the form of Ni-P or Co-P powder to to improve the weld joint strength as well improve mechanical properties of steel as to reduce the chances of cracks. It was [18, 30]. realized that phosphorus in the base steel retards alloy layer formation, thus Powder forging route offers a good scope reducing the alloying rate during for enhancing density of parts made from galvanizing. Addition of phosphorus was binary Fe-P powder alloys, as well as found to be significantly improved the ternary Fe-P-Cr and Fe-P-Si powder corrosion resistance of phosphated steel. alloys. In powder metallurgy route, addition of optimum amount of phosphorus (0.8-1.2%) increases the It was also found that addition of electrical resistivity of material as well as phosphorus in iron matrix above 2.67 % reduces the magnetic losses; due to this makes the material to brittle with high loss advantage phosphorus can be used for of ductility [32].