Effect of Heat Treatment on the Precipitation Behavior and Hardness of the Second Phase of 0Cr21Mn17Mo3N0.8 High Nitrogen Alloys

Abstract:

The effects of different heat treatment processes on the morphology, quantity and size of the precipitated nitrides phase of 0Cr21Mn17Mo3N0.8 high nitrogen alloy were studied. The microstructure of the alloy was observed and characterized by metallographic microscope, transmission electron microscope, etc. And the hardness of high nitrogen alloy under different treatment processes were tested. The results showed that sample alloy was cooling in the furnace after heat preservation of 1140°C for 8h. Lamellar nitride is precipitated from the alloy, its composition is Cr₂N, its size is about 50-100nm, and the precipitation process mainly occurs 1-2mm below the surface layer. This can make the alloys to form surface-reinforced composites. Meanwhile, the hardness of the alloy has increased significantly from 29.3HRC to 61.3HRC, because of the precipitation of the second phase. The high nitrogen alloys after slow cooling treatment were treated with spheroidization at the temperature lower than that of the complete austenitizing, and the layered deposition began fusing at 950°C. Under the temperature of 1120°C heat preservation for 8h, then water quenching, slice layer deposition completely dissolved into granule, and the particle size is about 20nm to 50nm, the alloy of hardness after spheroidizing has decreased to 48.3HRC.

• Periodical: Materials Science Forum (Volume 944)
• Pages: 373-377
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.944.373
• Online since: January 2019
• Authors: You Yang*, Yun Xiu Xu, Zi Wei Chen, Yan Huang
• Keywords: Hardness, Heat Treatment, High Nitrogen Alloy, Nitride Precipitation

References

[1] G. Stein, I. Hucklenbroich, Manufacturing and applications of high nitrogen steels, Materials and Manufacturing Processes. 19 (2004) 7-17.

DOI: 10.1081/amp-120027494

[2] P. Behjati, A. Kerrmanpur, A. Najafizadeh, Influence of nitrogen alloying on properties of Fe-18Cr-12Mn-XN austenitic stainless steels, Materials Science and Engineering: A. 588 (2013) 43-48.

DOI: 10.1016/j.msea.2013.08.053

[3] H.B. Li, Z.H. Jiang, Z.R. Zhang, et al, Mechanical properties of nickel free high nitrogen austenitic stainless steels, Journal of Iron and Steel Research, International. 14 (2007) 330-334.

DOI: 10.1016/s1006-706x(08)60105-3

[4] Y. Katada, M. Sagara, Y. Kobayashi, et al, Fabrication of high strength high nitrogen stainless steel with excellent corrosion resistance and its mechanical properties, Materials and Manufacturing Processes. 19 (2004) 19-30.

DOI: 10.1081/amp-120027495

[5] J. Talonen, T. Taulavuori, H. Hnninen, Effect of temperature on tensile behavior and microstructure evolution of nitrogen alloyed austenitic stainless steel, Int. Conf. on High Nitrogen Steels. 8 (2006) 52-58.

[6] Z.Z. Yuan, Q.X. Dai, X.N. Cheng, et al, Microstructural thermostability of high nitrogen austenitic stainless steel, Materials Characterization. 58 (2007) 87-91.

DOI: 10.1016/j.matchar.2006.04.005

[7] M. Milititsky, D.K. Matlock, A. Regully, et al, Impact toughness properties of nickel-free austenitic stainless steels, Materials Science and Engineering: A. 496 (2008) 189-199.

DOI: 10.1016/j.msea.2008.05.022

[8] F.M. Bayoumi, W.A. Ghanem, Effect of nitrogen on the corrosion behavior of austenitic stainless steel in chloride solutions, Materials Letters. 59 (2005) 3311-3314.

DOI: 10.1016/j.matlet.2005.05.063

[9] C.M. Hong, J. Shi, L.Y. Sheng, et al, Influence of hot working on microstructure and mechanical behavior of high nitrogen stainless steel, Journal of Materials Science. 46 (2011) 5097-5103.

DOI: 10.1007/s10853-011-5439-2

[10] H. Ha, H. Kwon. Effects of Cr2N on the pitting corrosion of high nitrogen stainless steels, Electrochemica Acta. 52 (2007) 2175-2180.

DOI: 10.1016/j.electacta.2006.08.034

[11] J.W. Simmons, B.S. Covino. Effect of nitride (Cr2N) precipitation on the mechanical corrosion, and wear properties of austenitic stainless steel, ISIJ international. 36 (1996) 846-854.

DOI: 10.2355/isijinternational.36.846