Development of a new coated electrode with low nickel content for welding ductile iron and its response to austempering

Abstract

Coated Electrodes with small amounts of nickel were developed for welding ductile iron (DI) and conversion of the same into austempered ductile iron (ADI) after austempering. Among six electrodes, Trials 3 and 4 were selected for establishing crack-free weld deposits via preheating and post-weld heat treatment. Austenitization was performed at 900°C for 2 h and austempering at 300 or 350°C for three different holding times to observe the results of austempering with respect to the microstructure, hardness, and austempering kinetics of the samples. The microstructures of the weld deposits showed needle-like bainitic ferrite with small amounts of retained austenite when treated at 300°C and feathery bainitic ferrite with large amounts of retainedaustenite when treated at 350°C. The electrode labeled with Trial 3 revealed greater austenite contents than that labeled with Trial 4 when treated with a 2 h holding time regardless of the austempering temperature applied. The transformation rate of the bainitic ferrite of Trial 3 was relatively higher than that of Trial 4 and showed a lower rate constant, leading to a higher diffusion rate of carbon in austenite.

Keywords

electrode development / microstructure / XRD analysis / transformation kinetic / microhardness

References

[1] Voigt R.C., Loper C.R. Austempered ductile iron-process control and quality assurance. J. Heat Treat., 1984, 3(4): 291.

[2] Putatunda S.K., Singar A.V., Tackett R., Lawes G. Development of a high strength high toughness ausferritic steel. Mater. Sci. Eng. A, 2009, 513, 329.

[3] Panneerselvam S., Martis C.J., Putatunda S.K., Boileau J.M. An investigation on the stability of austenite in Austempered Ductile Cast Iron (ADI). Mater. Sci. Eng. A, 2015, 626, 237.

[4] Yang J.H., Putatunda S.K. Influence of a novel two-step austempering process on the strain-hardening behavior of austempered ductile cast iron (ADI). Mater. Sci. Eng. A, 2004, 382(1-2): 265.

[5] Shanmugam P., Rao P.P., Udupa K.R., Venkataraman N. Effect of microstructure on the fatigue strength of an austempered ductile iron. J. Mater. Sci., 1994, 29(18): 4933.

[6] Putatunda S.K., Kesani S., Tackett R., Lawes G. Development of austenite free ADI (austempered ductile cast iron). Mater. Sci. Eng. A, 2006, 435, 112.

[7] Putatunda S.K., Martis C., Boileau J. Influence of austempering temperature on the mechanical properties of a low carbon low alloy steel. Mater. Sci. Eng. A, 2011, 528(15): 5053.

[8] Ahmadabadi M.N., Khazai B.A., Bahmani M. Effect of austempering variables on the mechanical properties of Ni−Mn−Cu ADI (97-74). Trans. Am. Foundry Soc., 1997, 105, 501.

[9] Greno G.L., Otegui J.L., Boeri R.E. Mechanisms of fatigue crack growth in austempered ductile iron. Int. J. Fatigue, 1999, 21(1): 35.

[10] Krzyńska A. Searching for better properties of ADI. Arch. Foundry Eng., 2013, 13(1): 91.

[11] Tanaka Y., Kage H. Development and application of austempered spheroidal graphite cast iron. Mater. Trans. JIM, 1992, 33(6): 543.

[12] Bartosiewicz L., Krause A.R., Alberts F.A., Singh I., Putatunda S.K. Influence of microstructure on high-cycle fatigue behaviour of austempered ductile cast iron. Mater. Charact., 1993, 30(4): 221.

[13] Janowak J.F., Norton P.A. A guide to mechanical properties possible by austempering, 1.5% Ni, 0.3% Mo iron. AFS Trans., 1985, 88, 123.

[14] Kumar K.M., Hariharan P., Venkateshwaran P., Tamilarasan S. Examination of microstructure and mechanical properties of austempered ductile iron (ADI) as per austempering temperature and time. Trans. Indian Inst. Met., 2015, 68(1): 67.

[15] Stokes B., Gao N., Reed P.A.S. Effects of graphite nodules on crack growth behaviour of austempered ductile iron. Mater. Sci. Eng.A, 2007, 445, 374.

[16] Zhang J.W., Zhang N., Zhang M.T., Lu L.T., Zeng D.F., Song Q.P. Microstructure and mechanical properties of austempered ductile iron with different strength grades. Mater. Lett., 2014, 119, 47.

[17] Kim Y.J., Shin H., Park H., Lim J.D. Investigation into mechanical properties of austempered ductile cast iron (ADI) in accordance with austempering temperature. Mater. Lett., 2008, 62(3): 357.

[18] Keough J.R., Hayrynen K.L., Pioszak G.L. Designing with austempered ductile iron (ADI). AFS Proc., 2010

[19] Putatunda S.K., Singar A.V., Tackett R., Lawes G. Development of a high strength high toughness ausferritic steel. Mater. Sci. Eng. A, 2009, 513, 329.

[20] Mi Y. Effect of Cu, Mo, Si on the content of retained austenite of austempered ductile iron. Scr. Metall. Mater., 1995, 32(9): 1313.

[21] El-Banna E.M., Nageda M.S., El -Saadat M.A. Study of restoration by welding of pearlitic ductile cast iron. Mater. Lett., 2000, 42(5): 311.

[22] Pascual M., Ferrer C., Rayón E. Weldability of spheroidal graphite ductile cast iron using Ni/Ni−Fe electrodes. Rev. Metal., 2009, 45(5): 334.

[23] Sun D.Q., Gu X.Y., Liu W.H., Xuan Z.Z. Welding consumable research for austempered ductile iron (ADI). Mater. Sci. Eng.A, 2005, 402(1-2): 9.

[24] Voight R.C., Loper C.R. Jr. Study of heat-affected zone structure in ductile cast iron. Weld. J., 1983, 62(3): 82.

[25] Pease G.R. The welding of ductile iron. Weld. J., 1960, 39(1): 15.

[26] Ishizaki K., Moram J.G., Mariflor S.L., Davila A. Simulation study on ductile cast iron welding by austenitic filler metal. Trans. Jpn. Weld. Soc., 1984, 15(2): 3.

[27] Yu S.K., Loper C.R. Jr. The effect of molybdenum, copper and nickel on the pearlitic and martensitic hardenability of ductile cast irons. Trans. Am. Foundry Soc., 1988, 96, 811.

[28] Kelly T.J., Bishel R.A., Wilson R.K. Welding of ductile iron with Ni−Fe−Mn filler metal. Weld. J., 1985, 64, 79.

[29] Pouranvari M. On the weldability of grey cast iron using nickel based filler metal. Mater. Des., 2010, 31(7): 3253.

[30] Kotecki D.J., Braton N.R., Loper C.R. Preheat effects on gas metal-arc welded ductile cast iron. Weld. J., 1969, 48(4): 161.

[31] El-Banna E.M. Effect of preheat on welding of ductile cast iron. Mater. Lett., 1999, 41(1): 20.

[32] Imasogie B.I., Wendt U. Characterization of graphite particle shape in spheroidal graphite iron using a computer-based image analyzer. J. Miner. Mater. Charact. Eng., 2004, 3(1): 1.

[33] Kumar S., Nath S.K., Kumar V. Isothermal transformation behavior of a low-carbon HY 85 steel. Metall. Microstruct. Anal., 2016, 5(3): 264.

[34] Cullity B.D. Elements of X-ray Diffraction, 1978, USA, Addison-Wesley Publishing Company 81.

[35] Bayati H., Elliott R. Austempering process in high manganese alloyed ductile cast iron. Mater. Sci. Technol., 1995, 11(2): 118.

[36] Sun D.Q., Zhou Z.F., Zhao Z.J. Development of a new electrode for arc welding of austempered ductile iron (ADI). J. Meter. Sci. Technol., 1992, 8(6): 401.

[37] Mitra U., Eagar T.W. Slag-metal reactions during welding: Part II. Theory. Metall. Trans. B, 1991, 22(1): 73.

[38] Mitra U., Eagar T.W. Slag metal reactions during submerged arc welding of alloy steels. Metall. Trans. A, 1984, 15(1): 217.

[39] Belton G.R., Moore T.J., Tankins E.S. Slag-metal reactions in submerged arc welding. Weld. J., 1963, 42(7): 289.

[40] Indacochea J.E., Blander M., Christensen N., Olson D.L. Chemical reactions during submerged arc welding with FeO−MnO−SiO₂ fluxes. Metall. Trans. B, 1985, 16(2): 237.

[41] N.D. Pandey, A. Bharti, and S.R. Gupta, Effect of submerged arc welding parameters and fluxes on element transfer behaviour and weld-metal chemistry, J. Mater. Process. Technol., 40 (1994), No. 1–2, p. 195.

[42] Mallia J., Grech M., Smallman R.E. Effect of silicon content on transformation kinetics of austempered ductile iron. Mater. Sci. Technol., 1998, 14(5): 452.

[43] Bhadeshia H.K.D.H., Edmonds D.V. The mechanism of bainite formation in steels. Acta Metall., 1980, 28(9): 1265.

[44] Putatunda S.K. Development of austempered ductile cast iron (ADI) with simultaneous high yield strength and fracture toughness by a novel two-step austempering process. Mater. Sci. Eng. A, 2001, 315(1-2): 70.

[45] Ramadan M., Nofal A.A., Elmahalawi I., Abdel-Karim R. Influence of graphite nodularity on microstructure and processing window of 1.5% Ni-0.3% Mo austempered cast iron. Mater. Sci. Eng. A, 2006, 435, 564.

[46] Batra U., Ray S., Prabhakar S.R. The influence of nickel and copper on the austempering of ductile iron. J. Mater. Eng. Perform., 2004, 13(1): 64.

[47] Rees G.I., Bhadeshia H.K.D.H. Bainite transformation kinetics part 1 modified model. Mater. Sci. Technol., 1992, 8(11): 985.

[48] Yescas M.A., Bhadeshia H.K.D.H. Model for the maximum fraction of retained austenite in austempered ductile cast iron. Mater. Sci. Eng. A, 2002, 333(1-2): 60.

[49] Putatunda S.K., Gadicherla P.K. Influence of austenitizing temperature on fracture toughness of a low manganese austempered ductile iron (ADI) with ferritic as cast structure. Mater. Sci. Eng. A, 1999, 268(1-2): 15.