Mechanical and hardness evaluations of Fe–18Cr–18Mn alloys

Abstract

A series of Fe-18Cr-18Mn-N-C alloys was produced and evaluated to determine their mechanical and hardness properties. In one group, different levels of nitrogen and carbon were added to a base composition of Fe-18Cr-18Mn. The base Fe-18Cr-18Mn alloy had a fcc-bcc duplex microstructure. The addition of nitrogen and carbon stabilised the fcc phase. These alloys had increasing room temperature hardness, strength, and failure energy with increasing interstitial concentrations. At cryogenic and elevated temperatures, these alloys had increasing hardness (and by implication, increased strength) with increasing interstitial concentrations. In a second group, different levels of nitrogen and carbon were added to the base Fe-18Cr-18Mn composition to which minor solid solution additions of silicon, molybdenum, and nickel had been added. Minor alloy additions made only nominal improvement to mechanical and hardness properties. Nitrogen remained interstitial. However, these minor solid solution additions reduced carbon solubility resulting in the formation of M 23 C 6 precipitates that, while increasing alloy hardness and strength, greatly reduced fracture toughness. The present study suggests that replacing nickel with manganese in stainless steels results not only in more economical alloys but also in alloys with higher strength and hardness.

Oxidation Characteristics of Fe–18Cr–18Mn-Stainless Steel Alloys

“…Previous studies have characterized microstructure [8], mechanical [6], and wear properties of the alloys in this study [7]. The base composition, Fe-18Cr-18Mn, is a duplex fcc-bcc phase alloy.…”

“…Microstructure, mechanical, and wear properties of these alloys have been published in Refs. [6][7][8].…”

Effects of Nb on Pitting Corrosion Resistance of Ni-Free FeCrMnCN-Based Stainless Steels

“…[1][2][3][4][5][6][7][8][9][10][11][12][13][14][15] The interstitial alloying elements, N and C, are economical and strong austenite formers, thus they can effectively substitute for Ni which is an expensive austenite stabilizer in Fe-based alloys. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15] In addition, N and C are beneficial to enhancing the mechanical strength by solid solution strengthening without much reduction in elongation, [1][2][3]5,[8][9][10][11]15,16 and they also promote wear resistance. 1,2,11,13,16 Moreover, it has been reported that both N and C in a solid solution state improve the pitting corrosion resistance of FeCr-based stainless steels.…”

“…[1][2][3][4][5][6][7][8][9][10][11][12][13][14][15] In addition, N and C are beneficial to enhancing the mechanical strength by solid solution strengthening without much reduction in elongation, [1][2][3]5,[8][9][10][11]15,16 and they also promote wear resistance. 1,2,11,13,16 Moreover, it has been reported that both N and C in a solid solution state improve the pitting corrosion resistance of FeCr-based stainless steels. 2,6,7,13,14,17,18 Therefore, the high interstitial alloy (HIA) has been given much attention as promising structural materials to replace the conventional FeCrNibased austenitic stainless steels.…”