Lee M.-k.,Iljin Light Metal Co. |
Kim D.-s.,Iljin Light Metal Co. |
Kim S.-c.,Iljin Light Metal Co. |
Han S.-w.,Iljin Light Metal Co. |
And 2 more authors.
Materials Science and Engineering A | Year: 2010
A study has been made of nitriding of interstitial-free steel sheet specimens in the sodium nitrate bath. The nitriding rate increased when the bath contained a small amount of sodium chloride and calcium chloride. Accordingly, the tensile strengths and hardness values of the steel specimens nitrided in the chloride containing bath were higher than those of the same steel specimens nitrided in the pure nitrate bath when the nitriding time and temperature were controlled so that the excessive formation of brittle compound Fe4N could be prevented. © 2009 Elsevier B.V. All rights reserved.
Lee T.-H.,Korea Institute of Materials Science |
Oh C.-S.,Korea Institute of Materials Science |
Lee M.-K.,ILJIN Light Metal Co. |
Han S.-W.,ILJIN Light Metal Co.
Materials Characterization | Year: 2010
Nitride precipitation and its effect on microstrain in salt-bath nitrided interstitial-free steel were investigated using transmission electron microscopy and neutron diffraction. As the cooling rate after nitriding decreased, two nitrides, γ′-Fe4N and α"-Fe16N 2, were identified in diffusion zone. Combined analyses using Rietveld whole-profile fitting and size-strain analysis revealed that the microstrain in the nitrided specimen increased due to nitrogen supersaturation and then decreased after nitride precipitation, whereas the effective particle size continuously decreased. It was found that microstrain is the dominant factor in peak broadening of the nitrided specimen. © 2010 Elsevier Inc.