WO2010095154A1 - Modification of the composition of the flux solution for hot-dip batch galvanizing of steel parts - Google Patents

Modification of the composition of the flux solution for hot-dip batch galvanizing of steel parts Download PDF

Info

Publication number
WO2010095154A1
WO2010095154A1 PCT/IT2010/000052 IT2010000052W WO2010095154A1 WO 2010095154 A1 WO2010095154 A1 WO 2010095154A1 IT 2010000052 W IT2010000052 W IT 2010000052W WO 2010095154 A1 WO2010095154 A1 WO 2010095154A1
Authority
WO
WIPO (PCT)
Prior art keywords
steels
flux solution
galvanizing
improved according
hot
Prior art date
Application number
PCT/IT2010/000052
Other languages
French (fr)
Inventor
Ugo Bottanelli
Original Assignee
Ugo Bottanelli
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Ugo Bottanelli filed Critical Ugo Bottanelli
Priority to EP10711936.4A priority Critical patent/EP2430206B1/en
Publication of WO2010095154A1 publication Critical patent/WO2010095154A1/en

Links

Classifications

    • CCHEMISTRY; METALLURGY
    • C23COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23CCOATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C2/00Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor
    • C23C2/04Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor characterised by the coating material
    • C23C2/06Zinc or cadmium or alloys based thereon
    • CCHEMISTRY; METALLURGY
    • C23COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23CCOATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C2/00Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor
    • C23C2/02Pretreatment of the material to be coated, e.g. for coating on selected surface areas
    • C23C2/022Pretreatment of the material to be coated, e.g. for coating on selected surface areas by heating
    • CCHEMISTRY; METALLURGY
    • C23COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23CCOATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C2/00Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor
    • C23C2/02Pretreatment of the material to be coated, e.g. for coating on selected surface areas
    • C23C2/024Pretreatment of the material to be coated, e.g. for coating on selected surface areas by cleaning or etching
    • CCHEMISTRY; METALLURGY
    • C23COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23CCOATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C2/00Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor
    • C23C2/04Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor characterised by the coating material
    • C23C2/12Aluminium or alloys based thereon
    • CCHEMISTRY; METALLURGY
    • C23COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23CCOATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C2/00Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor
    • C23C2/30Fluxes or coverings on molten baths

Definitions

  • the present invention has as object the improvement of the surface preparation of pre-fabricated steel parts to be hot-dip galvanized and more specifically it refers to the influence of the flux solution composition on the coating quality obtained in batch galvanizing processes where molten Zinc baths containing up to 0,1 wt% Al are used.
  • Steels that my be galvanized include those so-called: reactive. Steels reactivity depends on a critical concentration of Si and P in the steel (Sandelin effect) which may vary not only among the steels but also in the same steel where they may be unevenly distributed. Coatings obtained with reactive steels are gray and dull, the interface with the steel is fragile, the thickness of the coating is high causing excessive Zinc consumption and therefore an economical damage.
  • the fragile interface contains Zn-Fe phases that may reach the outer surface of the coating which due to its fragility may flake after a mechanical deformation.
  • the flux solution which traditionally contains a mixture of salts among which ZnC12 is, according to its concentration, a potential source of danger for the environment and thus must be carefully monitored.
  • the present invention aims at contributing to the solution of potential problems arising from the presence of ZnC12 in the galvanizing shop, by means of a procedure for the preparation of surface of pre-fabricated steel pieces to be hot-dip galvanized in a Zn-Al-alloy, according to which the concentration of ZnC12 into the flux solution is maintained below the limit prescribed by the law and preferably down to zero.
  • the steel pieces, after pickling are immersed into an aqueous solution containing: 0-50 g/L Of ZnCl 2 , preferably 0-25, and more preferably 0-10, 20-300 g/L OfNH 4 Cl, 0.1-1 g/L Of Bi 2 O 3 , at a pH ranging from 0.1 e 1.5, preferably between 0.5 e 1, maintained in the optimum interval by means of HCl 0. IN or KOH 0. IN additions; pieces are immersed in the flux solution at a temperature between 4 and 50 0 C, preferably between 10 and 30 0 C and more preferably between 15 and
  • the salts from the flux solution remain adherent to the steel pieces and have a fusion temperature well below the temperature of the molten galvanizing bath and are therefore easily eliminated upon immersion forming ashes and dross.
  • Mn, and/or P i.e. steels commercially known as Sandelin or Iper-sandelin steels
  • the flux solution according to the present invention obtaining coating with uniform thickness, with no surface defects and with a smooth surface without non-homogeneous areas.
  • Table 1 contains the symbols with which the surface quality of coatings was assessed according its coating homogeneity & continuity, uniformity of the colour. Table 1.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Coating With Molten Metal (AREA)
  • Cleaning And De-Greasing Of Metallic Materials By Chemical Methods (AREA)

Abstract

The present invention aims at contributing to the solution of potential problems arising from the presence of ZnCl2 in the galvanizing shop, by means of a procedure for the preparation of surface of pre-fabricated steel pieces to be hot-dip galvanized in a Zn-Al-alloy, according to which the concentration of ZnC12 into the flux solution is maintained below the limit prescribed by the law and preferably down to zero. According to this procedure, the steel pieces, after pickling are immersed into an aqueous solution containing ZnCl2, NH4Cl and Bi2O3. Using the flux solution according to the present invention it is possible to coat in a batch galvanizing bath containing a Zn-Al-alloy, carbon steels and steels with high Si content, and/or Mn, and/or P (i e. steels commercially known as Sandelin or Iper-sandelin steels), usually considered difficult steels for galvanizing. obtaining coatings with uniform thickness, with no surface defects and with a smooth surface without non-homogeneous areas.

Description

MODIFICATION OF THE COMPOSITION OF THE FLUX SOLUTION FOR HOT-DIP BATCH GALVANIZING OF STEEL PARTS
The present invention has as object the improvement of the surface preparation of pre-fabricated steel parts to be hot-dip galvanized and more specifically it refers to the influence of the flux solution composition on the coating quality obtained in batch galvanizing processes where molten Zinc baths containing up to 0,1 wt% Al are used.
The selection of the appropriate chemical solution composition together with special operating conditions, guarantee the satisfactory wetting of the steel part during the immersion into the molten Zn-alloy and an homogeneous and adherent coating.
State of The Art
Batch hot-dip galvanizing is one of the most important technologies for steels coating against corrosion especially atmospheric. In this process steel parts are immersed into molten Zinc at 440-450°C. Even if improvements have been introduced for single operation in the industrial lines, the sequence of these operations are still the same since many years: a) degreasing followed by water rinsing, b) 10wt% HCl pickling followed by water rinsing, c) fluxing into a water-based saline solution which contains
ZnC12+NH4Cl, followed by drying without rinsing, d) immersion into a molten Zn-based alloy at «440-
4500C.
Steels that my be galvanized include those so-called: reactive. Steels reactivity depends on a critical concentration of Si and P in the steel (Sandelin effect) which may vary not only among the steels but also in the same steel where they may be unevenly distributed. Coatings obtained with reactive steels are gray and dull, the interface with the steel is fragile, the thickness of the coating is high causing excessive Zinc consumption and therefore an economical damage.
The fragile interface contains Zn-Fe phases that may reach the outer surface of the coating which due to its fragility may flake after a mechanical deformation.
The reason of this reactivity has not yet been thoroughly clarified even if many methods for its limitation have been proposed, based on the additions of metallic elements into the molten Zinc-bath, among which the most efficient are Al and Ni. Examples of these modification of the galvanizing baths composition are the so-called Polygalva based on 0.06wt% Al addition, other methods based on less Al additions, or the so-called Technigalva based on
0.05wt% of Ni addition.
It has been suggested also the addition of Sn=2.5%, Ni=0.05% or V=0.04%, Ti=0.05% which are claimed to be able to eliminate the Sandelin effect for steels containing up to Si= 1%. It has also proposed to add
1% Mn or 0.1-0.2% Mg.
The use of Aluminum additions to the Zinc bath has been studied for long time for its promising potentiality either for the inhibition of the interface Zn/Fe reaction either because its low cost compared to that of Ni.
Nevertheless its use has not been possible yet because in the actual process conditions, the presence of Al in the bath causes defects such as not-coated areas which may reduce the corrosion resistance of the coated piece.
The solution for this problem is described in the Italian Patent RM2002A000589 and AL2008A000020 in which it is declaimed that by the use of a flux solution containing ZnCl2 + NH4Cl + BiCl3 it is possible the use of Zn in which low amount of Al may be added in order to obtain a significant reactivity reduction for the so-called reactive steel and coatings without surface defects.
Nevertheless this innovation does not take into account of the environmental restrictions introduced by the so-called Seveso law. In fact, in Italy, in the D.Lgs No. 65 dated March, 14, 2003 complying with the
Directive 1999/45/CE & 2001/60/CE Art.6 Annex π, ZnC12 is classified as dangerous toxic compound because may cause long-term adverse effects in the aquatic environment.
Its presence into the galvanizing shop has been therefore restricted and must be as low as possible.
The flux solution which traditionally contains a mixture of salts among which ZnC12 is, according to its concentration, a potential source of danger for the environment and thus must be carefully monitored.
Description of the invention
The present invention aims at contributing to the solution of potential problems arising from the presence of ZnC12 in the galvanizing shop, by means of a procedure for the preparation of surface of pre-fabricated steel pieces to be hot-dip galvanized in a Zn-Al-alloy, according to which the concentration of ZnC12 into the flux solution is maintained below the limit prescribed by the law and preferably down to zero. According to this procedure, the steel pieces, after pickling are immersed into an aqueous solution containing: 0-50 g/L Of ZnCl2, preferably 0-25, and more preferably 0-10, 20-300 g/L OfNH4Cl, 0.1-1 g/L Of Bi2O3, at a pH ranging from 0.1 e 1.5, preferably between 0.5 e 1, maintained in the optimum interval by means of HCl 0. IN or KOH 0. IN additions; pieces are immersed in the flux solution at a temperature between 4 and 500C, preferably between 10 and 300C and more preferably between 15 and
25°C, for an immersion time between 10s and 10 minutes, preferably between20s and 2 min. and more preferably between 30s and 1 min. After extraction from the flux solution, the steel pieces are dried at 60-
1200C for a maximum time of 60 min.
The salts from the flux solution remain adherent to the steel pieces and have a fusion temperature well below the temperature of the molten galvanizing bath and are therefore easily eliminated upon immersion forming ashes and dross.
Using the flux solution according to the present invention it is possible to coat in a batch galvanizing bath containing a Zn-Al-alloy, both carbon and high strength steels. Also steels with high Si content, and/or
Mn, and/or P (i.e. steels commercially known as Sandelin or Iper-sandelin steels), usually considered difficult steels for galvanizing for the excessive growth of the a fragile interface, may be easily coated using the flux solution according to the present invention obtaining coating with uniform thickness, with no surface defects and with a smooth surface without non-homogeneous areas.
Some preferred embodiments
The following Examples demonstrate certain preferred embodiments of the present invention, without in any way limiting the scope and objects of the invention.
Many hot-dip galvanizing experiments were made, with different flux mode and different galvanizing baths. Table 2 summarizes the obtained results.
Steels were processed according to the following procedure: a. degreasing into an acidic aqueous commercial solution 10wt% concentrated, at room temperature for 10 minutes; b. tap water rinsing; c. HCl 10wt% pickling at room temp, for 15 minutes; d. Tap water rinsing; e. Fluxing according to Table 2; f. Drying at 80°C in dry air; g. Immersion into a molten Zn.0,03 wt% Al at 45O0C .
The following Table 1 contains the symbols with which the surface quality of coatings was assessed according its coating homogeneity & continuity, uniformity of the colour. Table 1.
Figure imgf000005_0001
Table 2
Figure imgf000005_0002
Figure imgf000006_0001
(*) specimes maintained for 1 hr in air after pickling and tap water rinsing (**) tap water rinsing

Claims

Claims
1. An improved process for the preparation of a steel parts surface for batch hot-dip galvanising comprising the immersion of these parts into an aqueous flux solution based on chlorides and containing Bismuth Chloride, having a pH ranging from 0.5 and 1.5 and a temperature in the range 4 - 500C, preferably between 10 and 3O0C and, more preferably between 15 and 250C, for an immersion time between 10 seconds and 10 minutes, preferably between 20 s and 2 minutes, and more preferably between 30 s and 1 minute.
2. An improved according to claim 1, in which the steel part for hot-dip galvanizing into an alloy containing mainly Zinc and 0.01wt% - 0.1 wt% of Aluminum is (a) degreased into a commercial acidic aqueous 10wt% solution, at room temperature for 10 minutes; (b) tap water rinsed; (c) pickled into HCl 10wt% at room temperature for 15 minutes; (d) again rinsed into tap water; (e) fluxed into 0-50 g/L ZnCl2, 20-300 g/L NH4Cl, 0,1-1 g/L Bi2O3, 10-100 g/L KCl, whose pH is between 0.5 and 1.5 and the temperature between 3 and 500C; (f) dried in warm air at 60 - 1200C.
3. An improved according to claim 2 in which the pH is between 0.5 and 1, adjusted within the optimum range adding HCl or KOH 0. IN and the temperature is between 4 and 400C.
4. An improved according to claim 3 in which the temperature is between 4 and 25°C.
5. An improved according to claim 2 in which the pH is between 0.5 and 1, adjusted within the optimum range adding HCl or KOH 0. IN, and the immersion time of steel parts is between 30 s and 2 min.
6. An improved according to claim 5 in which the immersion time of steel parts in the flux solution is between 20 s and 1 min.
7. An improved according to claim 5 in which the immersion time into the flux solution is between 30 s and lmin.
8. An improved according to claim 2 in which the steel parts are dried, after immersion in the flux solution, at 60-1200C for a maximum time of 60 minutes.
PCT/IT2010/000052 2009-02-19 2010-02-17 Modification of the composition of the flux solution for hot-dip batch galvanizing of steel parts WO2010095154A1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
EP10711936.4A EP2430206B1 (en) 2009-02-19 2010-02-17 Modification of the composition of the flux solution for hot-dip batch galvanizing of steel parts

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
ITAL2009A000002A IT1392855B1 (en) 2009-02-19 2009-02-19 NEW FORMULATION OF FLUSHING SOLUTION IN GENERAL STEEL HOT GALVANIZING PROCESSES
ITAL2009A000002 2009-02-19

Publications (1)

Publication Number Publication Date
WO2010095154A1 true WO2010095154A1 (en) 2010-08-26

Family

ID=41055106

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/IT2010/000052 WO2010095154A1 (en) 2009-02-19 2010-02-17 Modification of the composition of the flux solution for hot-dip batch galvanizing of steel parts

Country Status (3)

Country Link
EP (1) EP2430206B1 (en)
IT (1) IT1392855B1 (en)
WO (1) WO2010095154A1 (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
RU2646303C2 (en) * 2016-07-12 2018-03-02 Акционерное общество "Уралэлектромедь" Flux for hot galvanizing of steel products
DE102021111089A1 (en) 2021-04-29 2022-11-03 Seppeler Holding Und Verwaltungs Gmbh & Co. Kg Process, system and use of these in batch galvanizing

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN115323304B (en) * 2022-08-30 2024-02-09 重庆广仁能源装备股份有限公司 Hot galvanizing method for low-silicon active steel

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20060228482A1 (en) * 2005-04-07 2006-10-12 International Lead Zinc Research Organization, Inc. Zinc-aluminum alloy coating of metal objects
US20070137731A1 (en) * 2005-12-20 2007-06-21 David Leychkis Flux and process for hot dip galvanization
WO2007146161A1 (en) * 2006-06-09 2007-12-21 University Of Cincinnati High-aluminum alloy for general galvanizing

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20060228482A1 (en) * 2005-04-07 2006-10-12 International Lead Zinc Research Organization, Inc. Zinc-aluminum alloy coating of metal objects
US20070137731A1 (en) * 2005-12-20 2007-06-21 David Leychkis Flux and process for hot dip galvanization
WO2007146161A1 (en) * 2006-06-09 2007-12-21 University Of Cincinnati High-aluminum alloy for general galvanizing

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
RU2646303C2 (en) * 2016-07-12 2018-03-02 Акционерное общество "Уралэлектромедь" Flux for hot galvanizing of steel products
DE102021111089A1 (en) 2021-04-29 2022-11-03 Seppeler Holding Und Verwaltungs Gmbh & Co. Kg Process, system and use of these in batch galvanizing

Also Published As

Publication number Publication date
IT1392855B1 (en) 2012-04-02
EP2430206A1 (en) 2012-03-21
EP2430206B1 (en) 2013-07-03
ITAL20090002A1 (en) 2010-08-20

Similar Documents

Publication Publication Date Title
US6921439B2 (en) Flux and process for hot dip galvanization
CN100497717C (en) Hot dip galvanizing method for steel pieces
JP5130226B2 (en) Aqueous reaction solution and method for passivating workpieces with zinc or zinc alloy surfaces
AU2002219142A1 (en) Flux and process for hot dip galvanization
TW201307612A (en) Hot dip Zn-Al based alloy plated steel sheet and manufacturing method thereof
KR20150035342A (en) Flux compositions for steel galvanization
EP2430206A1 (en) Modification of the composition of the flux solution for hot-dip batch galvanizing of steel parts
US3943270A (en) Aqueous flux for hot dip galvanising process
JP2008169478A (en) Hot dip coated steel member and method of producing the same
JP2009256703A (en) Highly corrosion-resistant hot dip galvanized steel
JP5336742B2 (en) Chemical conversion treatment method for forming a trivalent chromium chemical conversion coating having good heat and corrosion resistance on zinc or zinc alloy plating
WO1995004607A1 (en) Lead-free galvanizing technique
KR102231328B1 (en) molten aluminium plating bath
KR102183738B1 (en) Water-soluable flux for melted aluminium plating and flux bath comprising the same
RU2646303C2 (en) Flux for hot galvanizing of steel products
CN115896667A (en) Method for hot dip galvanizing of low-alloy high-strength structural steel
WO2023227402A1 (en) Anti corrosion treating car bracket and preparing method thereof
JP6028165B2 (en) High pH trivalent chromium colored conversion coating solution and processing method
JP2952577B2 (en) Prevention method of peeling of hot-dip galvanized layer of Si low concentration carbon steel.
JPH0739634B2 (en) Method for producing blackened and corrosion resistant hot-dip galvanized steel sheet
JP2000160315A (en) Hot dip galvannealed steel
JP2021031772A (en) Hot-dip galvanizing flux liquid and method for manufacturing hot-dip galvanized steel pipe
CN114959538A (en) Zinc-aluminum in-situ gradient coating on surface of iron alloy and preparation method thereof
JPH04224666A (en) Production of hot-dip galvanized stainless steel strip excellent in adhesive strength of plating and corrosion resistance
JPH0243375A (en) Surface treating liquid for galvanized steel sheet

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 10711936

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: DE

WWE Wipo information: entry into national phase

Ref document number: 2010711936

Country of ref document: EP