| 摘要 |
PCT No. PCT/JP91/01802 Sec. 371 Date Aug. 26, 1992 Sec. 102(e) Date Aug. 26, 1992 PCT Filed Dec. 27, 1991 PCT Pub. No. WO92/12271 PCT Pub. Date Jul. 23, 1992.It is an object to provide a process for manufacturing galvannealed steel sheets having high anti-powdering property as required when they are press formed, and stabilized frictional properties in a coil. Steel sheets are plated in a bath having a low aluminum content, while they have, when entering the bath, a low temperature as defined in relation to the aluminum content of the bath, so that an alloying reaction may be prevented. Then, the sheets are heated for alloying in a high-frequency induction heating furnace so that the sheets leaving the furnace may have a temperature of from over 495 DEG C. to 520 DEG C. to yield galvannealed consisting mainly of a delta 1 phase. An iron or iron-alloy top coating having an appropriate iron content can be applied onto the plated steel surface to improve its paintability. |
