To manufacture Cr-containing bar steel capable of improving scale peelability and having excellent surface property even when the steel contains Cr exerting adverse effect on the scale peelability.
In a method for manufacturing Cr-containing bar steel containing 0.10-2.0% Cr in which a steel slab containing 0.10-2.0% Cr is taken out from a heating furnace, and the steel slab is subjected to descaling, and hot-rolled, (a) the steel slab is heated in the heating furnace for ≥15 minutes in the temperature range in which the surface temperature of the steel slab is ≥800°C and ≤1,150°C, and then, the steel slab having its surface temperature (the extraction temperature) in the temperature range is taken out of the heating furnace, and (b) immediately, in the atmosphere of O2 concentration of ≥10 vol.%, (b-1) the steel slab is rapidly heated at the temperature-rising rate of ≥5 °C/sec till the surface temperature of the steel slab reaches the temperature (reaching temperature) within the range of ≥1,200°C and ≤1,350°C, (b-2) the steel slab is held at the reaching temperature for ≥0.1 second and ≤60 seconds, and (c) the steel slab is subjected to the descaling.
NAKAKUBO SHOHEI
ONISHI TAKASHI
TAHIRA TOMOHIDE
| JP2007330984A | 2007-12-27 | |||
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Tadashi Sugakawa
Osamu Futakuchi
Hiroaki Ito
Hisahiko Ueki
Uemura Junko
Next Patent: METHOD FOR MANUFACTURING Cr-CONTAINING BAR-STEEL MATERIAL