JPH02153059A - Manufacture of highly corrosion resistant cr-containing steel sheet aluminized with al or al alloy excellent in uniform coating property and adhesive strength of coating layer - Google Patents

Abstract

PURPOSE:To manufacture a Cr-containing steel sheet hot dip aluminized with Al and Al alloy excellent in the uniform coating property and adhesive strength of a plating layer and having high corrosion resistance by forming a plating layer of Ni, Co, etc., on a Cr- containing steel sheet and then applying hot dip aluminizing with Al and Al alloy to the above plating layer. CONSTITUTION:At the time of applying hot dip aluminizing with Al or Al alloy to the surface of a steel sheet containing <25wt.% Cr, the steel sheet is subjected to cathodic electrolytic treatment in an aqueous solution containing one or two kinds among metal ions, such as Ni<2+> and Co<2+>, so that the weight ratio to So<2-> ion concentration satisfies the relation in 1/50<=(metal ion concentration)/(total SO4<2-> ion concentration)<=1/5 and also containing free sulfuric acid in 75-350g/l concentration at 7.5A/dm<2> current density for 1-15sec, and successively, a coating layer of Ni, Co, and Fe or a coating layer of alloy of two or more kinds among these metals is formed to 0.01-1mu thickness on the above steel sheet in a plating bath of <pH3.0 containing one or >=2 metal ions among Ni<2+>, Co<2+>, and Fe<2+> by >=50% by weight ratio to the sum total of SO4<2-> ions and C<-> ions. Finally, a hot dip aluminizing layer with Al or Al alloy is formed on the above coating layer.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for producing a steel plate containing highly corrosion-resistant hot-dip Al and Al alloy plating C with excellent uniform coverage and adhesion of the plating layer.

(Prior art) C: As a method of applying Al and Al alloy plating with excellent corrosion resistance to steel sheets, for example, Japanese Patent Publication No. 52-33579
No. 1, JP-A-60-245727, JP-A-61
There are those described in Publication No.-6261, etc.

In Japanese Patent Publication No. 52-33579, A
As a method for applying a l or Al alloy plating layer, heat treatment of annealing and reduction is performed without oxidizing the plating original plate using a plating pretreatment method, or if the steel surface is oxidized, the oxide film can be removed by means such as grinding. A method of removing and performing Al plating treatment is disclosed.

On the other hand, JP-A-60-245727 and JP-A-61
Publication No. 6261 discloses that NiC is added to the surface of a Cr-containing steel plate.
A method is disclosed for producing an excellent Al-plated steel sheet by applying a base plating layer such as O to prevent oxidation in a heat treatment furnace and improving wettability with a plating bath.

However, when we examine these methods in detail, we find that they are not stable manufacturing technologies and are not suitable for industrial use! a!
There were the following problems in terms of design and performance. That is, in the heat treatment step before Al plating, a strong oxide film is formed on the surface of the Cr-containing steel sheet due to trace amounts of 02 or H20 that inevitably enter the heating furnace. Once an oxide film is formed on the surface of a Cr-containing steel sheet, it is not easily reduced or removed by mechanical means such as grinding in a heating furnace. For this reason, the wettability of the plating bath is inhibited, and the grinding forms microscopic protrusions on the original plate, causing oxides floating on the surface of the plating bath to adhere, inhibiting the uniform coverage of the plating layer, and causing pinholes. However, there was a problem in that a large amount of unplated material was generated, which seriously deteriorated the corrosion resistance. In addition, since the oxide film formed on the surface of the Cr-containing steel sheet is difficult to remove with the activation treatment using the normal pickling method, it is difficult to remove the oxide film formed on the surface of the Cr-containing steel sheet. &
There was a phenomenon in which the coating properties and adhesion of the layer deteriorated and the layer peeled off due to roll abrasion during the heat treatment process. For this reason, the Al plating layer also has many unplated spots and pinholes, and if the Al plating w4 is subjected to advanced processing, there is a problem that it may peel off from the interface between the steel surface and the base plating layer or from the base plating layer.

(Problems to be Solved by the Invention) When performing Al or Al alloy hot-dip plating, the plating original plate is generally subjected to annealing to adjust the material quality and activation treatment by reducing the surface of the original plate at the same time as pretreatment. However, in this step, the surface of the Cr-containing steel sheet is easily oxidized in the presence of trace amounts of oxygen or water vapor, and it is difficult to reduce the surface of the Cr-containing steel sheet if oxidation is formed. For this reason, in these annealing and reduction steps before plating, it is difficult to uniformly and sufficiently activate the surface of the Cr-containing steel sheet, and the Al
Or the Al alloy plating layer has no pinholes or defects! etc., resulting in deterioration of uniform coverage and adhesion.

In order to prevent oxidation during such annealing and reduction processes and increase wettability with the Al-based plating bath, even if the cold-rolled material is coated with a base plating such as Ni or Co in advance, the plating original plate is already coated. Because a stable and strong oxide film is formed on the surface, the surface cannot be sufficiently activated by conventional methods such as pickling, resulting in the formation of a base coating layer with many pinholes.

Therefore, in the annealing and reduction steps, the base coating layer is peeled off by the transport rolls in the heating furnace, and the peeled portions or pinhole portions are oxidized to form an oxide film. As a result, the adhesion and corrosion resistance of the Al or Al-gold plating layer deteriorate.

The present invention deals with the production of t8 Al-plated steel sheets containing Cr as an essential component and Al alloy-plated steel sheets.
Al and Al alloy plating with excellent uniform coverage, adhesion of the plating layer, and corrosion resistance by solving the above-mentioned problems caused by r concentrating on the steel surface and forming strong oxide groups. C “The purpose is to provide a manufacturing method for steel sheets containing
Ru.

(Measures Pi for Solving the Problems) The present invention provides a steel sheet containing 25% or less of Cr at a weight ratio of 181 or 21!JI of the metal ion Ni"Co2◆ to the total SO42"" 1750≦
(Metal ion concentration)/(Total SO42″′ ion concentration)≦
115, i a t* 1 to 15 at a current density of 7.5 A/dm2 or more in an aqueous solution containing 75 to 350 g/I of acid
Cathodic electrolytic treatment is performed for a second, and then a
+ IMi or two or more metal ions as s o ,”−
50% by weight relative to the total of ions and 01- ions
0.01-
1 u thick Ni, Co, Fe coating layer or two of these
After applying 81M of alloy liquid to the coating layer, molten Al and Al alloy plating are applied to the coating layer. This is a method for producing a highly corrosion resistant Al and Al alloy plated CRT steel plate with excellent uniform coating properties and coating layer adhesion.

(Function) In the present invention, the strong oxide film formed on the surface after cold rolling is efficiently removed and activated, and then Ni, which has few pinholes and excellent uniform coverage and adhesion, is formed on the surface. Co
, Fe base! An alloy base plating layer composed of two or more of these types is applied, and this base plating outer layer is annealed and surface activated on the plated original plate in a heating furnace such as an oxidation furnace method or a non-oxidation furnace method. Prevents oxidation and formation of oxide film on the surface of Cr-containing steel. Moreover, even if it is oxidized, it is easily reduced and activated by reducing gas. And it has fewer pinholes and has excellent uniform coverage and adhesion. It becomes possible to manufacture S corrosion-resistant Al and Al alloy plated Cr-containing steel sheets.

In order to efficiently remove and activate the oxide film on the surface of this Cr-containing steel/cold-rolled material, free H2SO is the main component, and one or two types of Ni"Co2" in the form of sulfate are added to this as the main component.
A cathodic electrolytic treatment is performed using a treatment bath containing fi metal ions. By appropriately selecting the amount of metal ions in this treatment bath and setting appropriate electrolytic treatment conditions, efficient removal and activation of the oxide film on the surface of the steel sheet and precipitation of a small amount of metal ions can be performed simultaneously.

The thickness of the oxide film formed on the steel surface, the degree of crank formation, etc. differ depending on the surface properties of the steel plate. The oxide film is peeled off from the parts that are easily removed and activated, and metal ions are precipitated. Then, current is concentrated on other parts that are difficult to be activated, the oxide film is removed and activated, and metal ions are deposited. These actions are repeated one after another, and the surface of the steel plate is plated.

If free HCl or hyperfic+- ions are present in this electrolyte, there is a risk of pitting corrosion in areas where the steel surface can be easily activated.
In the present invention, free Hx SO4, S,
A treatment bath containing O, Z- ions as a main component is used.

In addition, the oxide film on the steel surface is removed by containing a small amount of metal ions compared to the SO, Z- ion concentration in the bath, shortening the treatment time, and optimizing the electrolytic current density.
Activates and simultaneously deposits a small amount of metal. Also, this i
In the present invention, the metal precipitate of t is Ni%Co%Ni-Co
Because we have selected metals with excellent oxidation resistance,
Prevent the regeneration of the open oxide film as much as possible until the next metal plating process.

Next, in the present invention, a base coating layer is applied using a plating bath with a high content of metal ions such as Ni, Co, and Fe, and has excellent electrolytic efficiency, and as a result, the subsequent Al or Al alloy plating layer is It improves uniform coverage and adhesion of the plating layer, making it possible to manufacture steel sheets containing Al and Al alloy plating C with excellent corrosion resistance.

The present invention will be explained in detail below.

A steel plate with a Cr content of 25% or less that is made from molten steel produced in a melting furnace such as a converter or electric furnace and made into a slab by continuous casting, ingot making, or blooming, and then hot rolled, pickled, and cold rolled. Use material 0
In the present invention, the reason why the Cr content of the plated original sheet is restricted is that if the Cr content exceeds 25%, the oxide film on the steel surface is formed by SO42- ions and metal ions (N
It is difficult to remove and activate by cathodic electrolytic treatment for 1 to 15 seconds using a treatment bath consisting of one or two types of ``Co''. This is because it is difficult to obtain an excellent metal plating layer. Further, although the lower limit of the Cr content in the plating original plate is not particularly regulated, it is preferable to use a steel plate containing 2.5% or more of Cr. That is, the Cr content of the plating original plate is 2.5
%, the surface can be easily activated without the treatment of the present invention, and the N1rP metal plating layer can be provided as a plating layer with excellent uniform coverage or adhesion. It is possible. However, no matter how carefully the base plating and IjAl and Al alloy plating operations are performed after the activation treatment, a small amount of pinholes are generated. Alternatively, during the forming process, red rust or perforation corrosion occurs from the occurrence of flaws that reach the base steel, and the corrosion resistance of the plated steel sheet deteriorates. Therefore, in a corrosive environment where the potential of the plating 114 is higher than that of the original plate, such as in a corrosive environment exposed to condensed water or in a commercial temperature humid atmosphere containing sulfite, the potential of the plating 114 will be higher than that of the original plate, and the potential of the plating 114 will be higher than that of the original plate. Causes corrosion. For these reasons, in the present invention, the Cr content of the plating original plate is set to 2.
5 to 25%, preferably 5 to 20%.

In the present invention, it is preferable to use, for example, the following steel plates as the original plate.

(1) In weight%, C; 0.20% or less, acid-soluble AI;
Steel plate (2) consisting of 0,005-0.10%, Cr; 2,5"25%, balance Fe and unavoidable impurities (Si, P%S, Mn, etc.) /174Jfi with the composition of (1) above Additional elements: Ni: 0.05-10%, Cu: 0.05
-1%, Mo; 0.05-1%, Si; 0.2-1%,
P; 0.02-0.05%, Al; 0.1-5%, B
;0,0001 to 0.005% of one or more types of steel plate (3) 1! In mass%, C: 0.02% or less, acid-soluble Al
: o, 005-0.10%, Cr; 2.5-25%, further Ti; 0.01-0.8%, Nb; 0
．． 01-0.8%, V; 0.01-0.8%, Z r
; Steel plate containing 0.01 to 0.8% of one or more kinds, with the balance consisting of Fe and unavoidable impurities (4) Above (3)
) Ni; 0.05-10 as an added element to the steel plate with the composition
%, Cu; 0.05-1%, Mo: 0.05-1%, S
i; 0.2-1%, P; 0.02-0.05%, Al
: 0.1 to 5%, B ; 0,0001 to 0.005% of 111g Steel plate containing one or more of these cold-rolled plated materials containing Cr are manufactured through normal manufacturing processes. It is used in the present invention after being subjected to a degreasing treatment (such as electrolytic treatment in a solution of orsilicate or phosphoric acid solute with a surfactant added thereto).

First, Ni” was added as a metal ion to these steel plates.
The weight ratio of one or two types of Co" to 80.2-ions is 1150≦(metal ion concentration)/(s o ,"
- ion concentration)≦115, free sulfuric acid 75-350g/l
'IIL of 7.5 A/dm'' or more in an aqueous solution consisting of
A cathodic electrolytic treatment is performed for 1 to 15 seconds at a tlL density, that is, this treatment involves surface activation to remove the strong oxide film formed on the surface of the Cr-containing steel sheet, and Ni, Go.
, and Ni-Co alloy precipitation treatment at the same time.

This treatment bath may be a (sulfuric acid-nickel sulfate), (sulfuric acid-cobalt sulfate), (sulfuric acid-nickel sulfate-cobalt sulfate) bath that satisfies the above conditions, or a bath containing sodium sulfate, etc. to increase conductivity. A treatment bath is used.

If the free sulfuric acid concentration in the treatment bath is less than 75 g/1, it is difficult to uniformly remove the oxide film on the surface of the original plate and activate the surface, and it is also impossible to sufficiently prevent the simultaneous precipitation of Ni, etc. On the other hand, if the concentration of free sulfuric acid exceeds 350 g/l, the effect will be saturated, and the economic loss due to taking out the treatment bath will increase, and more mist will be generated in the treatment bath, resulting in deterioration of the working environment and damage to the treatment equipment. It is industrially disadvantageous, such as increased wear and tear. Therefore, in the present invention, the free sulfuric acid concentration is 75 to 350 g/l, preferably 100 to 300 g/l.
It is l.

For this free sulfuric acid, in the treatment bath of the present invention, metal ions, that is, Ni"
Co" or (Ni" ten Co") is added in the range of 1150≦(metal ion concentration)/(304"-ion concentration)≦115. By using a treatment bath containing these metal ions, the oxide film on the surface of the original plate is efficiently removed, and metals such as Ni and CO with good adhesion are simultaneously precipitated in small amounts. In other words, the oxide film on the surface of the Cr-containing steel is not uniform, and by the cathodic electrolytic treatment in this treatment bath, the oxidized group is removed and activated from the parts where it is easy to be removed, and the metal ions in the bath first precipitate in these parts. Then, current is concentrated on the unpeeled portions of the other oxide films to remove the oxide films.
Metal ions precipitate. Such reactions are repeated in sequence, and the surface of the Cr-containing steel on which a strong oxide film has been formed is activated, and metals such as Ni, which have excellent adhesion, are simultaneously precipitated.

In addition, the effect of the deposited metal prevents the oxide film from being regenerated after the treatment and before electroplating, improving the adhesion of plating ffi in the next step.

(Ni"Co"(Ni"+Co") metal ions) If the backing layer is less than 1750 compared to the total SO1'- ion concentration in the treatment bath, the metal ion content is too small and the removal of the oxide film and the metal ions If the metal ion concentration exceeds 115 compared to the total 504z″′ ion concentration, the metal ion content in the treatment bath is too high, and the unactivated surface of the plating original plate is difficult to occur. The plating layer with poor adhesion or the hydroxides, oxides, etc. of the contained metals will precipitate and the adhesion will deteriorate, and in any case, the object of the present invention will not be achieved.Therefore, in the present invention, the metal ion concentration and the total The ratio of SO42- ion concentration is 1150 to 11
5, preferably 1/25 to 1/10.

The cathodic electrolytic treatment is carried out at a current density of 7.5 A/di2 or more and a treatment time of 1 to 15 seconds. When the current density is less than 7.5 A per 1 dm2 of steel plate, it is difficult to remove the oxide film and simultaneously precipitate the 4r group in a short time. Or 10A/d+a
The upper limit of the current density is not particularly regulated, but if the current density becomes too high, the resistivity of the Cr-containing steel sheet will be high, and the resistance of the steel sheet during threading will decrease. Depending on the plate thickness, the steel plate may generate heat between the conductor cool and the treatment bath, promoting oxidation of the steel. Therefore, in the present invention, a current density of 35 A/da2 or less is preferable, and in that case, the treatment time However, if the cathodic treatment is performed for a time longer than 15 seconds, the effect will be saturated and the effect will be saturated. ,
Metal ions are further precipitated over the precipitated areas of metal ions such as Ni, resulting in metal plating with partially different thicknesses! A layer is created, and the thickness of the subsequent metal plating is also non-uniform. Therefore, the treatment time of the present invention is 1 to 15 seconds, preferably 1.5 to 7.5 seconds.

Furthermore, the place J! ! ! The bath temperature is not particularly regulated, and the treatment is carried out within the range of room temperature to 90°C.

As the electrode used in this treatment, any of insoluble electrodes such as Pb-8n electrodes, stainless steel electrodes, titanium/platinum plated electrodes, and soluble electrodes such as nickel and cobalt may be used. However, in order to perform industrially stable processing operations, soluble electrodes are required to be used for electrolytic metal ions from the electrodes, and it is difficult to maintain the above ratio of metal ions in the bath. It is advantageous to use an electrode to replenish the metal ions in the form of a carbonate such as nickel carbonate in accordance with the rate of reduction of metal ions due to the treatment, so as to maintain the content ratio m.

Free hydrochloric acid or CI- ions are not preferable because they can cause perforation corrosion of the plating original plate depending on the constituent materials of the processing equipment or the composition of the original plate, but they may be contained as unavoidable impurities in the processing bath used in the present invention. There is no particular effect in the amount that is used.

In addition, when Fe"+ ions are contained in the treatment bath as impurity elements, the content is preferably 5 g/l or less, since it prevents the precipitation of other Ni"Co" ions.
5[1/I or less is more preferable.

Next, after wiping off the excess treatment bath in the above treatment or washing with water, Ni, Co%Fe, Ni-Co.

Undercoat II treatment of Ni--Fe, Co--Fe, and Ni Co--Fe'A is performed. The base coating plating layer is to prevent oxidation peeling during the heat treatment process of At and Al alloy plating Ii, and it is important that it has excellent uniform coverage, small amount of pinholes, and excellent adhesion. Therefore, in order to obtain a plating layer with excellent electrolytic efficiency and good uniform coverage after cathodic electrolytic treatment, metal ions N12+,
A plating bath containing at least 50%, preferably at least 60% of all SO4'-10 C1- ions, which are involved in electrolytic efficiency in the plating bath, contains one or more of Co2◆Fe'10. The thickness of the base coating plating layer used to form the base plating layer is 0.01 to 1 μm. The thickness of this base coating layer is 0.
If it is less than 01μ, it is difficult to prevent the surface of the Cr-containing steel sheet from oxidizing during the heating process, and the effect of improving wettability with Al and Al alloy plating baths is also small, making it difficult to prevent Al and Al alloy plating, which is the objective of the present invention. However, if the thickness of the base coating layer exceeds 1 μm, the effect becomes saturated and becomes uneconomical, and in some cases, the thickness of the base coating layer exceeds 70 μm.
In the heat treatment process at about 0 to 1000°C, peeling may occur due to abrasion by a roll or the like or thermal shock due to rapid heating. Therefore, in the present invention, the thickness of the base coating waste is 0.01 to 1 .mu.m, preferably 0.03 to 0.5 .mu.m.

In addition, in the present invention, this base plating bath has a pH of 3.
．． Use a low pH bath below 0. In other words, if the pH of the plating bath is 3.0 or less, oxidation of the surface of precipitates such as Ni during the plating process after base coating layer treatment, or re-oxidation of This has the effect of removing. As a result, a base coating such as Ni1Co can be obtained which has a more uniform coating property, a smaller amount of formed holes, and has excellent adhesion. Especially pH 2.5
The following are preferred.

Furthermore, in order to improve the uniform coverage of the base coating layer, metal ions were added at a temperature of 5% to all 80.2-ions and all CI-ions in the base coating layer.
A plating bath containing 0% or more, preferably 60% and having an electrolytic efficiency of 1 is used.

For example, nickel sulfate 240g/I, nickel chloride 45g/I
g/l, boric acid 30 B/l (N i”/ (S
A plating bath is used in which the pH is adjusted to 3.0 or less by adding H, SO, and the composition is 65%).

Next, after applying this base plating layer, it is washed with water, dried, and introduced into a heat treatment furnace for annealing to adjust the material quality and screening of the surface.

This heat treatment method, conditions, etc. are not particularly restricted in the present invention. In the case of Al or Al alloy plating, this heat treatment furnace is generally used to burn off residual oils and fats on the surface of the plating original plate, such as rolling oil, in an oxidizing atmosphere and perform preheating.
An oxidation furnace method is used in which annealing and reduction is performed in a reduction furnace, and a non-oxidation furnace method is used in which residual oils and fats on the surface are vaporized and removed in a weakly oxidizing or non-oxidizing atmosphere, preheated, and then annealed and reduced in a reduction furnace. It will be done. Although both methods are used in the present invention, heat treatment using a non-oxidizing furnace method is preferable because residual oils and fats do not adhere to the surface of the base plating layer as described above.・In this heat treatment process, since the base plating layer of the present invention which has excellent performance characteristics is applied, oxidation of the Cr-containing steel surface hardly occurs, and the surface of the base plating layer is not oxidized. However, it is easily reduced and activated by reducing gas, and the plating of Al and Al alloys is easily performed. This reducing atmosphere furnace generally uses N2-containing 1
It is preferable to use a mixture of 10% or more, preferably 15% or more of N2 and N2, ammonia decomposition gas, or the like.

Although it varies depending on the steel composition of the plated original plate used and the required material properties, the temperature is 600 to 1050℃.
After being annealed and screened for about 10 to 180 seconds at a heating temperature of After introducing it into a light bath and performing immersion plating, the amount of plating is adjusted by wiping means such as high-pressure fluid.

In the present invention, Al and Al alloy plating baths are not particularly restricted, but the following plating margins are used. For example, Al and Al-6iSAl-Cr, AlMg1Al
Al and Al alloy plating baths containing Si Cr, Al Sl-Mg alloys, etc. and impurities unavoidably contained therein from plating equipment, plating original plates, etc., such as Fe, are used.

In the method of the present invention, as described above, these Al and V
Molten Al and Al are applied to the surface of the base plating layer, which has excellent wettability to the A+ alloy plating bath and has an activated surface.
Alloy plating is applied. Therefore, A with excellent uniform coverage of Al and Al alloy plating and layers, a small amount of pinholes, excellent plating adhesion, and excellent corrosion resistance.
A steel plate plated with L and Al alloys is obtained. In addition, although the case where the present invention is applied to a cold-open rolled material has been explained above, the same effect can be obtained even if it is applied to a fully finished material after cold-open rolling and annealing. That is, the method of the present invention may be applied to a full finish material and subjected to the heat treatment described above to perform hot-dip plating using the JL oxidation method, or the same effect can be achieved by applying the method to a plating method using the blacks method. There is.

(Example Al) Al and Al alloy plated steel sheets were manufactured by using cold-open rolled materials having the steel components shown in Table PJ1 as plating original sheets and applying the treatment method shown below.

Actually, Ike” Masuko! "-...Cathode electrolytic treatment using 1iGIAl> 80g/lH, so, -10g/1CoSO, -78,
0 system aqueous solution (metal ion concentration/S0.2-ion concentration (
Cathode treatment for 1.2 seconds at a current density of 8 A/dm2 in M/5) = 1.3150) (bath temperature 25°C, stainless steel electrician used) <Undercoat layer treatment> 340FI/1cos O4.7 Hzo 45g/
1 cocI2.6H,O-boric acid 45 g/I (weight ratio of metal ions to the sum of ``- ions and CI- ions (M/I) = 63.7%) H2SO in an ice bath.
1) In a plating bath with a total C1- ion concentration of 13.4 g/l adjusted to H2.8 by adding 4, the current density was 10 A/d.
Co plating ratio of 0.1 μ in a+2 (cathodic electrolytic treatment using Al) 80 g/IH2S in an O-bath for 1.2 seconds at a current density of 8 A/dm2 Cathode treatment (bath fA 25°C, using stainless steel electrodes) Base coating layer treatment> Same treatment as Example Al - Cathode electrolytic treatment using steel A2> 120g/IH2S O<-60g/IN iS O4
φ7H,O water-soluble iffl (M/S = 4.5515
0) at a current density of 15 A/da2 for 8 seconds (bath temperature 35°C, 10 Pt plated outer electrode used) <Undercoating layer treatment> 240 g/IN iS O4.7 H20-30H /
IN iC12・6H20-boric acid 30 g/I (M/
I = 70%) Add H, SO, to the ice bath to adjust the pH to 2.
, 0.0 at a current density of 7.5 A/d+a2 using a plating bath with a total CI- ion concentration of 8.91 g/l adjusted to 4.
Ni plating ratio of 6μ "Mackerel" A2-...Cathode electrolytic treatment using steel A2> 100g/IH2-8O-250g/IN iS O4
-7HxO ice water solution M/S=1,42515)
Cathode treatment for 8 seconds at a current density of 0 A/dI 112 (bath temperature 35°C, using a 10pt plating electrode) Base coating layer treatment> Same as Example A2 - Treatment 1j [Δ5LL1] - Steel Cathode electrolytic treatment using A3> 150g/IH2S O4-30g/IN is O4
・7 20 in H20 aqueous solution (M/5=2150)
Cathode treatment for 4 seconds at a current density of A/d+a2 (bath temperature 40°C, Pb-Sn electrode used) Base coating layer treatment> 240g/lN15O, 7 H2O-45g/1Ni
c12・6 H20-Ho7 FM! 40 g/l (
M/I = 64, 2%) Total CI ion concentration adjusted to pH 1.8 by adding H, So, 13.
0 at a current density of 15 A/dm2 in a 4 g/l bath
．． 12μ Ni-plated fruit - Arashi" Masu A3-Jin U-...g
Cathodic electrolytic treatment using AA3 - Same treatment as Example A3 (1) (ground covering [1 treatment]) 125g/1NisO4.7 H2O-125g/lF
e50.・7 H2O-20g/1NiCL-6H2O
-20g/lFeC1゜・6 H2O-Ho7ria, 3
0 g/l (M/I = 62.2%) H,SO in an ice bath
, and adjusted the pH to 1.5 using a plating bath with a total C1- ion concentration of 12.0 g/I, and a current density of 12.0 g/I.
Ni-85%Fe alloy plating ratio of 0.03μ at 5A/d+i2” isan “ΔjiL Eyu” - cathodic electrolytic treatment using steel A3> 150g/IH2So, -5g/lN15O-・7H2
0 series aqueous solution (M/S=O, '35150) at 20A/
Cathode treatment for 4 seconds at a current density of dI*2 (bath temperature 40°C,
Undercoating layer treatment (using Pb-8nt electrode) Same treatment ratio as Example Al (Cathode electrolytic treatment using steel A3) Current density 4A/dI using the same bath
112 for 4 seconds (bath temperature 40°C, P b -S
n electrode used) <Undercoating layer treatment> Same treatment ratio as Example A2 - Cathode electrolytic treatment using steel A3 > Same bath as Example A3 (1) using a current density of 4A/dI
I! Cathode treatment for 4 seconds (bath temperature 40°C, Pb-8n electrode used) <Undercoating layer treatment> Example A 3 Same treatment as in (2) Electrolytic treatment> 200g/lI (zSO--210g/IN iSO
3 in a 4.7H20 aqueous solution (M/S=8.2150)
Undercoat layer treatment> 120g/l NiSO4・7H,0180g
/1coso<・7 H20-12g/IN iC12
・6H2018g/l CoCl.

・6 HtO* U11 [i 20 g/l (M/I
= 63%) j1% Add sulfuric acid to F9 to pH 1,
Metsu with a total C1-ion concentration of 8.9g/l, adjusted to 6'I14! Example A4 - Steel A4
Cathode electrolytic treatment using the same treatment as Example A4, base coating layer treatment> 120 g/IN iS O4.7 Hto 30
g/IN iCIt・6H20-Hou @30g/l
p consisting of 250g/IHzSOi (M/I=11%)
0.1μ Ni plating at a current density of 30A/dm2 using a plating bath with H zSO4150g/IN iS O
Cathode treatment for 2.5 seconds at a current density of 12.5 A/dII12 in a 4.7 H, O rice aqueous solution (M/S = 4.55150) (bath temperature 65'C, Pb-Sn-I r electrode used) ) Base coating layer treatment> 280g/IN il, SO, ・7 H□O35g/
IN ic 12.6H20-35g/l boric acid (M
/I = 63.3%) by adding Hz SO4 to an ice bath to
H1,75, i1! Walled total -C+- ion concentration 10
．． 0.08μ Ni plating was carried out in a 411/l plating bath at a current density of 5A/d.
Cathode electrolytic treatment using A5〉 Same treatment as Example A5, base coating layer treatment〉 Same bath component system as Example A5, only pH 3.5 plating b
Ni plating with a thickness of 0.08μ was carried out under the same conditions using the same bath, and the steel sheets produced above were evaluated for the uniform coverage of plating 1-, the ffi adhesion of plating 8 layers, and the use in automobile exhaust systems using the evaluation methods shown below. Regarding corrosion resistance assuming that
The performance was evaluated and the results are shown in Table 2. The evaluation test method and evaluation criteria are as follows.

[Evaluation test method and evaluation criteria] 1. Uniform coverage of the plating coating layer An Al-10,5%Si alloy plated 1M plate with a plating amount of 60 g/a+2 per side was manufactured at a line speed of 100 m/win. The appearance was investigated and evaluated using the following evaluation criteria to examine its uniform coverage.

◎...The wettability of the plating bath is extremely good, and the appearance of the plating is very good. Δ...Due to the slightly inferior wettability of the plating bath, a rough dot-like defect (micro bottom plating of 10
(several dots) occurred.
A large number of rough point-like defects occurred on the evaluation surface 2, adhesion of plating layer 0, Al-8%SiM alloy plating layer was applied to a plate thickness of 6 am at a coating weight of 40 g/m per side. After that, after impact bending with the same radius of curvature as the plate thickness, Sellotape (registered trademark) was applied and peeled off, and the peeling status of the plating Iη was investigated.The evaluation criteria are as follows. be.

◎・・・No peeling of plating layer, Sellotape (registered trademark)
Peeling #1m! + No adhesion ○...The surface of the plating layer has peeled off slightly, and very slight peeling material has adhered to the Cellotape (registered trademark) Δ...Partial separation of the plating layer from the steel plate interface has occurred,
Adhesion of peelable substances to Sellotape (registered trademark) is clearly observed ×... Plating M Full-surface peeling 3, Corrosion resistance performance (1) Evaluation method A For 100 x 1001 size steel plate, in commercial temperature atmosphere 1000 at 700℃ in a floating atmosphere
A continuous heating test for hours was conducted to investigate the occurrence of red rust. In other words, when exposed to a high temperature exhaust atmosphere,
The uniform coverage and high-temperature corrosion resistance of the plating layer were evaluated by investigating the occurrence of red rust caused by plating defects (unplated areas). The evaluation criteria are as follows. ■: At-6%Si40 H/m2, ■: Al-1
0%5160g/m2″C.

◎... No red rust ○... Number of dotted red rust occurrences is 1 to 10 Δ... Number of dotted red rust occurrences is 11 or more or area-shaped red rust spots are 3 or less ×... Area There are 4 or more areas where red rust occurs (2) Evaluation method B 50 x 100 rust + * evaluation material (NH,)2S 0.
11000ra/I-N H4N O5500mg/
Using a corrosion test solution prepared by adjusting the pH to 3 using a 1N H4C1b aqueous solution at 80.2'', the samples were immersed at 80°C for 500 hours, and the occurrence of red rust was investigated. That is, the uniform coverage and corrosion resistance of the plating layer in a wet corrosion atmosphere with respect to wandering condensed water was evaluated. The evaluation criteria are as follows. ■: Al80g/m2, ■: Al-
8%5i-0.5%Co50g/m2.

◎... Number of dotted red rust occurrences is 5 or less ○... Number of dotted red rust occurrences is 6 to 10 or more rΔ... Number of dotted red rust occurrences is 11 or more and 30 or more ×... Dotted red rust occurrence Occurrence of red rust in 31 or more pieces or area (3) Evaluation method C S04''-(10001)plm)-NO
,'''(150ppm)-CI-(300p, pm)-
C032-(400099+1)-N H4(300
0ppm)-f(COOH(1000ppm)-CH3
COOH (1000 ppm) aqueous solution to pH 8 Ij1
A cycle test was conducted under the following conditions using the 4-meter controller. That is, the evaluation material (30X 50+am) was heated at 350°C for 60 minutes → corrosion test solution half-immersion test (using a closed container, 1/2 part of the evaluation material was immersed in the corrosion solution, 8
0"C, 15 hours) → Drying (100"C, 124 hours) → Corrosion test liquid/half immersion test (80℃, 24 hours) → Drying (1
00℃, 24 hours) → Corrosion test liquid/half immersion test) (80'
C124 hours)→Indoor exposure (30℃, 56 hours)>1
As a cycle, we investigated the external corrosion status after the 3-cycle test, and assumed corrosion inside this 77 roller. The effect of uniform coverage of I-chip on corrosion resistance was evaluated. The evaluation criteria are as follows. ■ is Al-7%Si45 g
7m'', ■ is Al-10%5i70H/+o'.

◎... The occurrence of red rust at the gas-liquid interface of the part immersed in the corrosive solution is at or above the micro point M10. Hiroshi or above 20 points or red rust occurrence rate o, i%
The following Δ...A considerable amount of red rust has occurred on the above air-a\i1 surface part or other parts. Example B) A cold-rolled material with the steel composition shown in Table 3 is used as a Metsu B original plate,
Al and Al alloy plating by applying the treatment method shown below! I
Manufactured steel plates.

Actually, Arashi" Masu Bl-←Yoriichi...@Cathode electrolytic treatment using B1> 100g/II (as O4+ 25g/IN iS
Cathode treatment for 1.5 seconds at a current density of 15 A/d so2 in an O4.7H20 aqueous solution (M/S = 2.5750) (bath temperature 30°C, P b -S n electrode used). Layer treatment> 200g/1coso4・7 H2O20g/1co
cI2・6H20-Hou l! 145g/l (M/I
= 63.2%) Mmi, : Add H2SO4, Tep
H2,91,1ml! ! Lf: Total CI-ion concentration 6g
/l in a plating bath with a current density of 12A/d 0.1
3μ CO messa ratio ``bo''``chi'' - 1 jin -... @
Negative fiI electrolytic treatment using B1> 100 g/IHzs 15A/dII in 04 aqueous solution
Undercoat layer treatment using cathode treatment for 3 seconds at a current density of 2> Example B 1 Same treatment as (1) B12 - Cathode electrolysis treatment using steel Blt-> 100g/IH2S On+35g/1cos O+
・7 Cathode treatment for 1.5 seconds at a current density of 15 A/du'' in H20a aqueous solution (M/S = 3.35150) (bath temperature 30''C, stainless steel electrode used) Base coating layer treatment> 180g /1cos O= ・7 H2080g/1F
es O-・7H2020g/1coclz・GHzo
-Log/1Feclz・6H,0-phoric acid 25g/l
(M/I = 62.4%) Total CI-ion concentration 8.98g by adding sulfuric acid to rice temperature and adjusting pH to 1.2
/l's eyes! using a current density of 25 A/da”
．． Co-65%Fe alloy plating ratio of 07μ"4""Danffl"-...Cathode electrolytic treatment using steel B1> 50g/IH, SO, +35 g/1cos O,-
15 in 7820 series aqueous solution (M/S = 6.05150)
Cathode treatment for 1.5 seconds at a current density of A/d+a2 (bath temperature 30°C, stainless steel electrodes used) <Undercoating rIi layer treatment> Example B 1 Same as (2) - Treatment actual - "B2-" ...Cathode electrolytic treatment using steel B2> 150g/IHas 04 +Z5g/1cos O4
・7 H20+25g/IN iS O4” 7 H2
20A/c in 0j% aqueous solution 1 (M/S=3.2150)
Cathode treatment for 2.5 seconds at a current density of 1 m2 (bath temperature 70°C)
, using Ti+Pt plating electrode) Base coating layer treatment>175g/1NisO<・7 HzO-75g/1co
so, 7HzO-28g/1NiCL-6HzO-1
2g/ICoCL・6H20-boric acid 35g/I(M/
I = 64%) Add H, SO, to rice temperature to pH 2
, 0.25 at a current density of 15 A/dt++2 in a plating bath with a total CI-ion concentration of 11.9 g/I adjusted to 4.
μ's Ni 30% Co alloy plating ratio "1" processing...Cathode electrolytic treatment using steel B2> Using the same treatment bath as Example B2, current density 4A/d
Cathode treatment at m2 for 5 seconds (bath temperature 70°C, using 10pt Ti plating electrode) Substrate coating layer treatment> Same treatment as Example B2 - Cathode electrolysis treatment using steel B3 〉 ZOOs/IH2S O, + loog/IN iS
O, 7H20 aqueous solution (M/S = 4, 55
/ 50) at a current density of 25 A/dm2 for 6 seconds (bath temperature 50°C, PB-8N-Ag electrode used).
c12.6 Hzo 25 g/I boric acid (M/I=
63%) Add H2S O4 to rice temperature to adjust pH to 1.8 @
! Cathode electrolytic treatment using AS3 with a total CI-'' ion concentration of 10.4 g/I, Ni plating ratio of 0.11 μ at a current density of 10 A/dm'' Undercoating layer treatment using the same treatment as Example B3> Ni plating ratio of 1.5μ under the same conditions as Example B3 "1 plate" L main 1u-...Cathode electrolytic treatment using steel B3>200g/lH2SO<+10g /1NiSO+φ7
Base m delayer treatment treated in the same manner as Example B3 in Hz Ojlt aqueous solution (M/S = 0,5150) > Same treatment as Example B1 - Cathode 1 electrolytic treatment using f14B4 Jri〉 250g/l) I 2S O4+ 230g/IN i
S O4・7 ((20 series water soluble 1 (M/S=7,5150
) Cathode treatment for 4 seconds at a current density of 30 A/dmz (bath temperature 60°C, pb-S n-A g'IIL electrode used) Substrate coating waste treatment> 240 g/l Ni S 04/7 H ,0-25
FI/IN iCI□・6H,O-boric acid (M/I=6
3%) H, SO to rice temperature.

Total 01-ion concentration adjusted to 981.6 by adding
, 4 g/l plating bath, electric tlL density 8 A
/ 0.8μ Ni plating with dva2 "1] YoW" -...Cathode electrolytic treatment using steel B4> Same treatment as Example B4, base coating layer treatment>240g/1Niso<・7 H2O-45g /lN1
5On・6H20-boric acid 30g/l (M/I = 6
4%) system bath components pH 3.6, total C1- ion concentration 13
．． Current density 8 A/dm using 4 g/l plating bath
FO, 8u Ni plating 19 shadows L...Cathode electrolytic treatment using #BS> 300g/IHzSO++120g/1NisO*・7
Water soluble in HzO1/? [! (M/S=3.75150)
Cathode treatment for 3 seconds at a current density of 35A/da'' (bath temperature 45℃, using PB-8N1 electrode) Undercoat layer treatment> 220g/1Niso, 7 H20-2
0g/lNiC1z・6H20-boric acid 30g
/I (M/r = 63%) total 01'' ion concentration 5 adjusted to pH 1,4 by adding H2S O4 to rice temperature
．． 9g/l weight! In a bath, conduct a Ni plating with a current density of 18 A/d and a current density of 2.
・Cathode electrolytic treatment using steel B5> 250g/IH2S O-+ 500g/IN iS
O<・7H20 water soluble 21 (M/S = 1.25
/ 5) Cathode treatment at a current density of 35 A/dm2 for 7 seconds (bath temperature 45°C, using PB-8N electrode) Base coating layer treatment> Same treatment as Example B5 1ヱ''-...Cathode electrolytic treatment using steel B5〉 Same treatment as Example B2, base coating layer treatment〉 120g/IN iS O, day 7 Hto -30g/
IN iC12・6H20-boric acid 30g/l 1
50g/l H2S O<P% composition (M/I=11
Example B using a pH < 0.5 bath consisting of
Regarding Al and Al alloy plated steel sheets manufactured by Ni plating or above under the same conditions as 5, uniform coverage of the plating layer, adhesion of the outer plating groove, and use in the building material field were estimated using the evaluation methods shown below. Regarding corrosion resistance, performance evaluation was performed and the results are shown in @Table 4. The evaluation test method and evaluation base wall are as follows.

[Evaluation test method and evaluation criteria] 1. Uniform coverage of plating coating R11 Al-3%Si alloy plating with a plating amount of 110 g/Lll" per side at a line speed of 90 m/ωin!
A steel plate was manufactured, its appearance was investigated, and its uniform coverage was examined by evaluating it using the following evaluation criteria.

◎...The final wettability of the plating is very good, and the appearance of the plating is very good. 2 points or less (thick part) occurred Δ...10ds+' due to slightly inferior wettability of the plating bath
Rough outer dot-like defects on the evaluation surface (minor lower plating is 1
0 several points cluster) occurs.
A large number of rough point-like defects occurred on the evaluation surface 2, the adhesion of the plating layer was 0.61, and the plate thickness 1: Al-7.5% Si metal plated final layer was applied on one side. After applying 80 g/m” coating weight,
A 100×10001 evaluation material was subjected to lock 7 ohm processing in the longitudinal direction into a bits pargetite with a cross-sectional shape shown in the f:Al diagram, and the peeling state of the plating layer at the bent portion was investigated. The evaluation criteria are as follows.

◎... Good condition with no abnormality in the plating layer O... Cracks have occurred in the plating layer Δ... Extremely bad plating peeling has occurred ×... No plating @ very severe peeling condition 3, corrosion resistance (1) Evaluation method A Targeting building materials used in industrial areas, 0,8 ms+
An evaluation material with a plate thickness of 75 x 150 mm was extruded to a thickness of 8 mm and subjected to Erichsen processing, and the sulfite concentration was 25.
ppm, exposed for 7 days in an atmosphere of 40° C. and 95% humidity, the occurrence of red rust was investigated, and the performance was evaluated using the following evaluation criteria. ■ is Al100g/m2, (2)
is Al-8%5180g/m"C'J>.

◎...Incidence rate of red rust less than 0.1% O...Incidence rate of red rust 0.1 to less than 1.0% Δ... Occurrence of red rust $1 to less than 1096 ×... Incidence rate of red rust 10
% or more (2) Evaluation method B Plate thickness 0, 6 mm, size X 100 X 200ow
2. While bending the center part of the PF material in the longitudinal direction with the same radius of curvature as the board thickness, we conducted an atmospheric H4 dew test for 5 years in a coastal industrial area and investigated the occurrence of red rust. The following evaluation criteria were used for evaluation. ■ is Al-10%5i-0
,5%Mg80g/,! , ■ is Al-6%5i-1%C
rl 20g/s".

O... No red rust occurrence ○... Red rust occurrence rate less than 0.5% Δ... Red rust occurrence rate 0-. 5 to less than 5%

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the lock 7t-mar processing of the Bits Barge Type. ...Evaluation material.

Claims (1)

[Claims] (1) A steel plate containing 25% or less of Cr is treated with one or both of the metal ions Ni^2^+ and Co^2^+ in all SO
_4^2^- Weight ratio to ion concentration 1/50≦
(metal ion concentration)/(total SO_4^2^-ion concentration)≦1/5, 1 to 15 at a current density of 7.5 A/dm^2 or more in an aqueous solution containing 75 to 350 g/l of free sulfuric acid
Cathodic electrolysis treatment for seconds, then Ni^2^+, Co^2^
+, Fe^2^+, one or more metal ions are S
Ni, Co, Fe coating layer containing 50% or more in weight ratio to the total of O_4^2^- ions and Cl^- ions and having a thickness of 0.01 to 1μ in a plating bath with a pH of 3.0 or less, or two of these. After applying an alloy coating layer consisting of more than one species,
A method for producing a highly corrosion-resistant Al and Al alloy plated Cr-containing steel sheet with excellent uniform coverage and coating layer adhesion, the method comprising applying a hot-dip Al and Al alloy plating layer to the coating layer.