ISIJ International
Online ISSN : 1347-5460
Print ISSN : 0915-1559
ISSN-L : 0915-1559
Regular Article
Effect of Additional Boron Amount on Surface Roughness after Lathe Turning in h-BN Dispersed Type 304 Stainless Steels
Masahiro KawajiriSatoshi Emura Xiaohua MinShigeo YamamotoKazuyuki SakurayaKaneaki Tsuzaki
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2016 Volume 56 Issue 6 Pages 1031-1037


The authors have reported that the machinability (lathe turning, drilling and sawing) of SUS304 (Type 304) austenitic stainless steel is improved by precipitating hexagonal boron nitride (h-BN). In this study, we investigated the surface roughness after lathe turning in the h-BN precipitated SUS304 steels, where the nitrogen content was fixed at 0.2% and the boron content was changed as 0, 0.03, 0.05, and 0.1% (mass%). Surface roughness increased as the boron content increased, especially at a lower cutting speed of 22 m/min. However, SUS304 steel with boron content of up to 0.05 mass% had similar or smaller surface roughness compared with a commercial SUS304 steel, and the SUS304 steel containing 0.1 mass% boron had smaller surface roughness compared with a SUS303 (Type 303) sulfur-added free-cutting steel. Precipitation of h-BN increased the size of the build-up edge and increased the surface roughness. On the other hand, solute nitrogen increased the Vickers hardness, leading to decreased separation size of the build-up edge and decreased surfaced roughness.

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© 2016 by The Iron and Steel Institute of Japan
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