Journal of Minerals and Materials Characterization and Engineering, 2018, 6, 203-217 http://www.scirp.org/journal/jmmce ISSN Online: 2327-4085 ISSN Print: 2327-4077 DOI: 10.4236/jmmce.2018.62015 Mar. 20, 2018 203 J. Minerals and Materials Characterization and Engineering Some Features of the Influence of Titanium and Nitrogen Addition to NiCrMoV Steel Saeed Ghali * , Mamdouh Eissa, Michael Mishreky Steel Technology Department, Central Metallurgical Research & Development Institute (CMRDI), Cairo, Egypt Abstract This paper reports a study of the addition effects of either titanium or tita- nium and nitrogen of steel grade DIN 56NiCrMoV7 on mechanical proper- ties. Three steel grades were produced in 30 kg-induction furnace, one con- forms the chemical composition of conventional 56NiCrMoV7 while the oth- er two produced steels were microalloyed by either titanium or titanium and nitrogen. The produced cast steel grades were reheated to 1150˚C and hold for 2 hours, followed by forging process. The forging process was carried out in temperature range 950˚C - 1100˚C. Solution treatment of hot forged steels was conducted at 880˚C, 850˚C followed by air and oil quenching, respective- ly. Quenched steel samples of different steel grades were tempered at different temperatures in the range of 300˚C to 650˚C for 45 min. The hardness varia- tions after tempering of the two modified steels comparing with the conven- tional 56NiCrMoV7 steel were studied. Microadditions of titanium or tita- nium and nitrogen were found to produce secondary hardening at 550˚C to 575˚C (45 min) with a hardness peak higher than that attained in the conven- tional 56NiCrMoV7 steel. The effect of titanium and nitrogen additions on phases formation was investigated by Thermo-Calc. SEM was used to confirm Thermo-Calc analysis. Interpretation between hardness and formed phases has been illustrated. Keywords Thermo-Calc, Tool Steel, Vanadium, Titanium, Nitrogen, Secondary Hardening 1. Introduction In tool steels chromium will form carbides of the types Cr 23 C 6 and some Cr 7 C 3 during annealing depending on the chromium content. These carbides dissolve How to cite this paper: Ghali, S., Eissa, M. and Mishreky, M. (2018) Some Features of the Influence of Titanium and Nitrogen Ad- dition to NiCrMoV Steel. Journal of Min- erals and Materials Characterization and Engineering, 6, 203-217. https://doi.org/10.4236/jmmce.2018.62015 Received: November 11, 2017 Accepted: March 17, 2018 Published: March 20, 2018 Copyright © 2018 by authors and Scientific Research Publishing Inc. This work is licensed under the Creative Commons Attribution International License (CC BY 4.0). http://creativecommons.org/licenses/by/4.0/ Open Access