PURPOSE: To improve ductility, toughness, and salt resistance under an alkaline environment by coating a steel material with an Fe-base Al solid solution layer in which the amount of solid-solution Al is specified.
CONSTITUTION: After hot rolling, a pickled and descaled steel material is subjected to Al pack cementation. Halides, etc., are used as a diffusion agent, and the surface of the steel material is coated with an Fe-base Al solid solution layer in which the amount of solid solution Al is regulated to 5-15wt.%. The concentration of solid solution Al is reduced in the coating, and the steel material excellent in salt resistance under an alkaline environment can be obtained. This steel material can be used, e.g., for reinforcing bar for concrete structure to be subjected to the influence of salt.
KANISAWA HIDEO
YAMAMOTO AKIO
