Structure and Lattice Strains in the Surface Сr–Mn–N Steel Layer Formed by a Combination of Friction and Electron-Beam Treatments

• Published in: Physics of metals and metallography 2019-11, Vol.120 (11), p.1071-1077
• Main Authors: Narkevich, N. A., Durakov, V. G., Surikova, N. S., Mironov, Yu. P., Mel’nikov, A. G., Perevalova, O. B., Shugurov, A. R., Shulepov, I. A., Narkevich, V. V.
• Format: Article
• Language: English
• Subjects: Chemistry and Materials Science; Diffusion; Electron beams; Friction; Friction reduction; Grain size; Grain structure; Heat treating; Heat treatment; Lattice strain; Materials Science; Mechanical properties; Metallic Materials; Nitrogen; Oxygen enrichment; Phase Transformations; Residual stress; Structure; Surface layers
• ISSN: 0031-918X; 1555-6190
• DOI: 10.1134/S0031918X19110115

— The effect of surface mechanical and heat treatment, which includes successive friction and electron-beam treatments, on the structure, mechanical properties, and the elastically deformed state of a 16.5 Cr–18.8 Mn–0.53 N–0.07 C steel has been studied in this work. The mechanical and heat treatment has been shown to refine the grain structure in the surface layer to a grain size of 2 μm, form a {100} 〈001〉 texture, and retain a deformation-hardened sublayer. A surface layer to 200 nm thick is enriched with oxygen, nitrogen, and carbon. X-ray diffraction has been used to study austenite lattice strains caused by residual stresses. The mechanical and heat treatment has been found to reduce the friction-induced elastic lattice contraction along the normal to the surface. The direction [100] is most sensitive to the effect of residual stresses and can serve as a marker when analyzing the nature of residual stresses in steels with structurally-changed plastically-undeformed surface layers.