JPS61213393A - Aluminum alloy plated steel material - Google Patents

Abstract

PURPOSE:To produce easily a plated steel material having superior corrosion resistance and workability by electroplating a steel material with an Al alloy contg. a specified amount of Mn. CONSTITUTION:A steel material is electroplated with an Al alloy contg. 0.1-9wt%, preferably 1-5wt% Mn in a molten salt bath. The resulting Al alloy film has superior workability and satisfactory corrosion resistance. When the plated steel material is temper-rolled at about 0.1-0.5% draft, a fine glossy surface is obtd. without deteriorating the workability or corrosion resistance.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention has the characteristics that the plating film is highly ductile, has excellent workability, and has high corrosion resistance when applied to steel materials using the molten salt electroplating method. The purpose is to provide steel materials plated with aluminum alloy.

<Prior art> Steel materials coated with aluminum (Ava) have favorable properties such as excellent corrosion resistance, beauty, and non-toxicity, and are expected to be put to practical use. Since this is not possible, they are currently manufactured mainly by the molten metal immersion method, and in some cases by the vacuum evaporation method.

However, in the case of the molten metal immersion method, it is difficult to perform thin plating, the formation of an alloy layer due to the operation temperature exceeding 70 liters, and the negative effects on the base material cannot be ignored, and the vacuum evaporation method cannot be ignored. The reality is that there are problems with productivity and that it has not been fully put into practical use.

<Problems to be Solved by the Invention> The present invention aims to provide an A/ type electroplated steel material that uses a molten salt bath and has excellent corrosion resistance and workability. Methods using two-component or three-component systems such as AtCtJ - At tends to form dendrite or powder-like precipitation, and especially at high current densities of 20 A/dtn' or higher, electrodeposition is poor and electrodeposition efficiency is low, and in this case, the corrosion resistance of the plating film is significantly deteriorated. do.

As methods to improve this, methods such as adding additives to the molten salt bath and electrodepositing alloys with various metal elements have already been proposed.

In the present invention, as a steel material which has sufficiently improved the drawbacks of these conventional methods, (1) the corrosion resistance performance is equivalent to or higher than that of M;

■ Excellent workability.

■ Stable production is possible with high current density of 20A/d♂ or more.

As a result of fundamental studies on At-based alloy plating, we found that Al-M
It was confirmed that plating with n-alloy met the above objectives.

It is known that Deer is an element that improves and strengthens the corrosion resistance of At.
It has been proposed that a glossy plating film can be obtained by setting the content to 5 wt% or more.

However, as a result of more detailed experimental research, the present inventors determined that the amount of blood combined in the above-mentioned plating film was 19wt.
% or more has poor workability because it is significantly inferior in burnability, and because it is merely a protective film without sacrificial corrosion protection, it corrodes on exposed parts of the base material such as end faces and skins. It was discovered that the anti-corrosion performance was insufficient due to this drawback.

Therefore, the present inventors found that a plating film that meets the purpose of the above-mentioned item 0 to 0 has a Mn content of 0.1 to 0 g wt%.
An At alloy in the range of 1 to S is effective, preferably 1 to S.
wt%. However, although the above-mentioned alloy region does not necessarily exhibit an excellent glossy surface, it has excellent workability and sufficient corrosion resistance, and especially when a glossy surface is desired, 0.1 to 0.
By adding temper rolling with a rolling reduction of about 5%,
It was also confirmed that a beautiful glossy surface could be obtained without impairing workability or corrosion resistance.

That is, the present invention provides an At alloy film with 0.1 to s
It is characterized in that it contains wt% of At alloy, and the content of At alloy plating film is 0.
．． 0.0% was limited to 1% to 9%. If it is less than I wt%, it will be difficult to achieve the improvement objectives of ■ to ■ above.
This is because if it exceeds t%, good workability and excellent corrosion resistance cannot be obtained.

In order to fully achieve the above-mentioned improvement objective, it is preferable that the blood content during plating be 1 to 5 wt%.

Next, a specific configuration of the present invention will be described.

The At alloy plating in the present invention is performed by a plating method similar to the commonly used molten salt electrolytic M plating method, but the molten salt bath is a binary or multicomponent mixture of AtCAs-xCA (X: 7 to potassium metal salt). A molten salt anhydrous bath is used. Note that similar baths include baths to which organic amines, fluorides, bromides, alkaline earth metal salts, etc. have been added, and other metal elements may not be present in the film at less than 1 wt%. The same applies to baths in which .

The molten salt bath must be sufficiently dehydrated and harmful components removed beforehand.

The eutectoid component can be either a Mn salt such as MnCAJ or immediate metal dissolution. These Mn ions are added in the bath in an amount of 1 to 2000 I) pm, depending on the amount desired to be eutectoid in the plating film.

The plated base material is steel with a sufficiently cleaned surface.
A steel material that has already been subjected to surface treatment such as Zn plating may be used, and multilayer plating may be used.

Current can be passed through smooth direct current, ripple direct current, superimposed alternating current, Varne direct current, etc. Even when the anode is an insoluble anode, M
Alternatively, an Al-Mn alloy soluble anode is also possible. In addition, it is desirable to provide a plating bath with agitation or a pump.

<Experimental example> Plating condition bath composition: ALClJ-NaCA-KCt (AtCt
J: 62mO4%, NaC4:20moz%, KC
l: l 8m04%) Bath temperature = 200°C Added Mn: MnC1J () 0.1 to 60 in 7kg bath
00ppm) Base material: Cold rolled steel plate (0.8t100mm
70■) Current density = 5-70 Simultaneous liquid flow rate: 0.8 m/sec The test results of steel materials plated with A7 alloy under the above conditions will be explained based on the attached drawings.

FIG. 1 is a graph showing the relationship between the Mn content in the plating bath and the Mn content in the plating film, with the horizontal axis showing the apparent concentration in the bath and the vertical axis showing the incorporated content in the film. As is clear from Figure 1, the dependence of current density is seen at high altitudes, but the amount of metal in the film is determined according to the soil concentration in the bath, and in any current density region, Mn White smooth (matte) at O-B wt%, gray powdery at 8-15 wt%, 15 wt%
% or higher, a glossy film can be obtained.

FIG. 2 is a graph showing the relationship between the amount of carbon in the film and the electrodeposition efficiency, where the horizontal axis shows the Mn content in the film and the vertical axis shows the electrodeposition efficiency. The adhesion efficiency is the best when the amount of blood combined in the film is around 5 wt%, and corresponding to Figure 1, the amount of combined blood in the film is 8 to 1%.
The electrodeposition efficiency deteriorated in the 5 wt % gray powdery part. Further, it is clear that at around 5 wt%, the electrodeposition efficiency is good even at a current density of roA76-, and that the electrodeposition efficiency is high even when the inner layer content of the film is 1 wt% or less.

Figure 3 is a graph showing the relationship between Mn content in the coating and processing adhesion. ), and the adhesion of the plating film to the tape was evaluated by the value of t in the adhesive tape peeling test after bending. It is clear that the workability deteriorates.

Figure 4 is a graph showing the relationship between the metal content in the film and the SST red rust generation time, where the horizontal axis shows the Mn content in the film and the vertical axis shows the red rust formation time, and the thickness of the plating film is 2 μm.
A cross-cut flaw reaching the base metal was made on the plated surface to examine the sacrificial corrosion protection ability. The effect of Mn addition on the film can be seen from before and after o and i wt light, and it can be seen that the corrosion resistance improves, but on the other hand, the sacrificial corrosion protection performance deteriorates when the Mn content is around 10 wt%.

<Effects of the Invention> As is clear from FIGS. 1 to 4 showing the results of the above experimental examples, the At alloy plating film, which is a feature of the present invention, contains 0.
Steel materials plated with an At alloy containing 1 to 9 wt% Mn have extremely good electrodeposition efficiency, high ductility, and excellent sacrificial corrosion protection, resulting in excellent workability and corrosion resistance. This method has the effect of easily providing an excellent M alloy plated steel material, which also improves productivity because plating can be performed at a high current density.

[Brief explanation of the drawing]

The figures show the experimental results of the present invention; Fig. 1 is a graph showing the relationship between the amount of blood in the plating bath and the amount of blood combined in the plating film;
Figure 8 is a graph showing the relationship between the amount of blood in the plating film and electrodeposition efficiency, Figure 8 is a graph showing the relationship between the amount of blood in the plating film and processing adhesion, and Figure 4 is the graph showing the relationship between the amount of blood in the plating film and process adhesion. It is a graph showing the relationship between the abundance and the SST red rust occurrence time. Mn in 5Pf 537 (1) 9m) & Mn poisonous amount in membrane (WtS4) Fig. 3 i Mn in Jt (wt@A) Fig. 4

Claims (1)

[Claims] (1) A steel material plated with an aluminum alloy containing 0.1 to 9 wt% of Mn in the plating film.