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2. National Standard of P.R. China, GB/T 223. 17-89, p.104.
3. H.Z. Wang: Steel and Iron (in Chinese), Vol 35(1) (2000), p.73.
4. H.Z. Wang: Metallurgy in China (in Chinese), Vol38 (6) (2002), p.20.
5. Z.J. Yang, M.L. Li, J.W. Chen: Iron and Steel (in Chinese), Vol 38(3) (2003), p.61.