The influence of experimental parameters, such as temperature, time, alloy composition and nitriding bath composition, on nitriding case formation on three steels has been investigated. Two of the steels are of low alloy type, one with low carbon (DIN 1·6523) and the other with medium carbon (DIN 1·7225). The third alloy is a nitriding alloy (DIN 1·8550). Two cyanate baths are used, i.e. type 1 (80 wt-% potassium cyanate) and type 2 (40 wt-% potassium cyanate). Higher temperatures, times and bath compositions result in a thicker case. As it thickens, the compound layer becomes composed of ϵ type nitrides. In general, DIN 1·6523 has developed thicker cases, and DIN 1·8550 with Al and Cr has formed thinner cases. Porosity has been observed in the cases, and the roughness of the nitrided surfaces has been measured to be greater for the higher carbon content alloy (DIN 1·7225) in this study.
StephenM C, ed (ed.): in ‘ASM handbook’, Vol. 4, 1st edn, ‘Heat treatment’, 376–436; 1991, Materials Park, OH, ASM International.
2.
PyeD: ‘Steel heat treatment handbook’, (ed. , TottenG E, HowesM A H, ed), 1st edn, 721–764; 1997, New York, CRC Press.
3.
MridhaS, KhanAA: J. Mater. Process. Technol., 2008, 201, 325–330.
4.
PyeD: ‘Practical nitriding and ferritic nitrocarburizing’, 1–22, 127–128; 2003, Materials Park, OH, ASM International.
5.
ShoemakerRH, WoodWG: J. Spacecraft Rockets, 1975, 12, 51–53.
6.
YükselM, UzunF: J. Eng. Mach., 1988, 29, 12–19.
7.
CwiekJ: Adv. Mater. Sci. Eng., 2009, 9, 4–13.
8.
LeppänenR, JonssonH: ‘Properties of nitrided components – a result of the material and the nitriding process’, Technical report no. 1, Ovako Steels, Hofors, Sweden, 1999.
9.
SunY: Surf. Eng., 2010, 26, 114–122.
10.
de SousaRRM, de AraujoFO, RibeiroKJB, DumelowT, da CostaJAP, AlvesC: Surf. Eng., 2008, 24, 52–56.
11.
BloyceA: Surf. Eng., 2010, 26, 55–60.
12.
LiCX: Surf. Eng., 2010, 26, 135–141.
13.
JackDH, JackKH: Mater. Sci. Eng., 1973, 11, 1–27.
14.
SomersMAJ, KooiBJ, MaldzinskfL, MittemeijerEJ, van der HorstAA, van der KraanAM, van der PersNM: Acta Mater., 1997, 45, 2013–2025.
15.
CampbellFC: ‘Elements of metallurgy and engineering alloys’, 403–406; 2007, Materials Park, OH, ASM International.
16.
LilientalWK, MaldzinskiL, MorawskiCD, TymowskiGJ: ‘Potential-controlled gas nitriding applied to gears’, Internal publication, Nitrex Metal Inc., Saint-Laurent, Que., Canada, 2000.
SemiatinSL: ‘Ion nitriding’, Techcommentary, Vol. 2, no. 5, EPRI Center for Material Fabrication, Columbus, OH, USA, 1994.
20.
CalossoF, ErnstC, HuchelU: Proc. 7th Int. Tooling Conf. on ‘Tooling materials and their applications from research to market’, Turin, Italy, May
2006, Politecnico Di Torino, 191–198.
21.
J SomersMA, ColijnPF, SloofWG, MittemeijerEJ: Z. Metallkd, 1990, 81, 33–43.
22.
PantazopoulosG, AntoniouS: J. Fail. Anal. Prev., 2004, 4, 51–57.
TrotterD, VarcoeD, ReevesR, AndersonSH: ‘Use of HBI and DRI for nitrogen control in steel products’, The Hot Briquetted Iron Association, Matthews, NC, USA, 2002.
SpalvlnsT: ‘Frictional and structural characterization of ion-nitrided low and high chromium steels’, NASA technical memorandum no. 86991, Cleveland, OH, USA, 1985.
41.
SchneiderRSE, HieblerH: J. Mater. Sci., 1998, 33, 1737–1744.
42.
KorwinMJ, MorawskiCD, TymowskiGJ, LilientalWK:in ‘Handbook of metallurgical process design’(, TottenG E, et al..), 545–590; 2004, New York, CRC Press.
