PROCESS FOR GALVANIZING - NIPPON STEEL CORP

Title:

PROCESS FOR GALVANIZING

Document Type and Number:

WIPO Patent Application WO/2006/112517

Kind Code:

A1

Abstract:

A process for galvanizing by which hot-rolled steel sheets, cold-rolled steel sheets, and basis sheets having various compositions can be galvanized without bare spots, specifically, a process which comprises subjecting a basis sheet to surface cleaning and preplating with Ni, heating the resulting basis sheet rapidly in a non-oxidizing or reducing atmosphere to a sheet temperature of 430 to 500ºC at a temperature rise rate of 20°C/sec or above, and then subjecting the sheet to hot-dipping in a zinc plating bath, wherein the following requirements (a) to (d) are satisfied: (a) when the basis sheet is an acid-pickled hot-rolled steel sheet having an Si content of 0.2% or above, the build-up of Ni in the preplating is controlled to be 0.5g/m² or above, (b) when the basis sheet is an acid-pickled hot-rolled steel sheet having an Si content of less than 0.2 %, the build-up of Ni in the preplating is controlled to be 0.2g/m² or above, (c) when the basis sheet is an annealed cold-rolled steel sheet having an Si content of 0.2% or above, the build-up of Ni in the preplating is controlled to be 0.3g/m² or above, and (d) when the basis sheet is an annealed cold-rolled steel sheet having an Si content of less than 0.2%, the build-up of Ni in the preplating is controlled to be 0.05g/m² or above.

Inventors:

ISHIZUKA KIYOKAZU (JP)
NISHIMURA KAZUMI (JP)
KIKUCHI IKUO (JP)

Application Number:

PCT/JP2006/308371

Publication Date:

October 26, 2006

Filing Date:

April 14, 2006

Export Citation:

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Assignee:

NIPPON STEEL CORP (JP)
ISHIZUKA KIYOKAZU (JP)
NISHIMURA KAZUMI (JP)
KIKUCHI IKUO (JP)

International Classes:

C23C2/02; C23C2/06; C23C2/28

Foreign References:

JPH04147953A	1992-05-21
JPH04333552A	1992-11-20
JP2001064759A	2001-03-13
JP2003268519A	2003-09-25
JP2003293108A	2003-10-15

Attorney, Agent or Firm:

Aoki, Atsushi (Toranomon 37 Mori Bldg. 5-1, Toranomon 3-chom, Minato-ku Tokyo 23, JP)

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