JPH01129993A - Band steel and its production - Google Patents

Abstract

PURPOSE:To easily and surely produce the title band steel free of rusting and excellently finished by forming an org. resin film on a wide steel sheet plated on both sides, slitting the sheet into a band steel having specified width, and further forming an electroplating layer on the cutting end face. CONSTITUTION:A hot coil 1 is cold-rolled into a wide steel sheet, a primary plating layer 5 is continuously formed on both sides of the sheet by hot-dip galvanization, etc., and a nonconductive org. resin film 7 is formed on both sides of the wide plated steel sheet 1a by roll coating, etc. The wide plated steel sheet 1a having the plating layer 5 and the film 7 on both sides is passed between a couple of upper and lower cutters 8, and slitted to a specified width to form a band steel 2. The band steel 2 is electroplated by continuous electrogalvanization, etc., to form a secondary plating layer 12 on both cutting end faces 10 where the bare surface of the band steel 2 is exposed. As a result, the entire periphery of the band steel 2 is covered with the plating layers 5 and 12, and the band steel 2 having excellent corrosion resistance and free of rusting can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a steel strip obtained by slitting a wide double-sided plated steel plate into a predetermined width, and a method for manufacturing the same.

In particular, it is characterized by the anti-corrosion treatment of the cut end surface that occurs during slitting.

[Conventional technology]

This type of steel strip is generally made from a wide hot coil obtained by hot rolling a steel ingot. Namely.

To explain with reference to FIG. 1 showing an embodiment of the present invention, a hot coil 1 or a hot coil 1 is rolled in a cold rolling process 3.
The wide cold-rolled coil rolled in step 4 is plated in plating step 4. After this, post-treatments such as chemical conversion treatment such as chromate treatment and oil coating treatment are performed on the surface of the plating layer to form the wide plated steel sheet 1.
get a. Then, this wide plated steel plate 1a is passed through a slitting process 9, where it is slit to a predetermined width to form a strip steel plate 2.
It is known to form.

[Problem that the invention seeks to solve]

In a conventional steel strip 2 obtained by slitting a wide plated steel sheet 1a, the base steel is exposed at the cut end surface 10 at the time of slitting, as shown in FIG. However, in the band steel sheet 2 obtained from a galvanized steel sheet, the corrosion resistance of the cut end surface 10 is also improved due to the sacrificial anticorrosive action of zinc on the steel sheet base. Therefore, although the steel band plate 2 is used as it is for packaging bands, etc., it does not cause much problem.

However, 9. For example, when used as a forming material for spiral tubes (cable armor) for electrical wiring.

Rust on the cut end surface 10 becomes a problem. In addition, when the steel band plate 2 is used as a tension band for the interior parts of a television receiver, not only does it rust itself, but it also rusts away from other electrical components and circuits that are densely mounted. There is a risk of damage from the pieces.

More perfect treatment of the cut end surface 10 has become highly desirable.

Therefore, the inventor of the present invention aimed to prevent rust from forming on the cut end surface 10 of a steel strip 2 obtained by slitting the most common double-sided galvanized steel sheet.

We considered using electroplating, which can be processed at low temperatures. However, in that case, the primary plating layer 5 on the front and back surfaces applied prior to the slitting is eluted and the surface is eroded, and zinc is precipitated on the plated surface and adheres in the form of powder. As a result, it has been found that the rust prevention performance deteriorates and the appearance is damaged, and furthermore, when processing the steel strip, the precipitated powder adheres to equipment and the like, causing problems such as scratches on the surface.

In addition, if the steel strip 2 that has been electrogalvanized instead of the previous hot-dip galvanizing is further electroplated for the same purpose,
It has been found that because an extra secondary plating layer is laminated not only on the cut end surface 10 but also on the primary plating N5, practical problems arise such as the steel strip itself becoming too thick than desired.

The present invention has been proposed in view of the above situation, and an object of the present invention is to obtain a steel strip plate that is free from even one rust and has a good finish.

An object of the present invention is to provide a method that can easily and reliably produce a steel strip plate that is free from rust and has a good finish.

[Means for solving problems]

The manufacturing method of the present invention includes a step of forming a non-conductive organic resin film 7 on the primary plating layer 5 of a wide-width plated steel sheet 1a on which a primary plating layer 5 is continuously formed on the front and back surfaces, and a subsequent wide-width A plated steel plate 1a is slit to a predetermined width to form a strip steel plate 2.
and the process of forming.

This process consists of a step of electroplating the steel strip 2 to form a secondary plating layer 12 on the cut end surface 10 thereof.

The thus obtained steel strip 2 of the present invention has a primary plating N5 on the front and back surfaces, a non-conductive organic resin film 7 is laminated on the primary plating layer 5, and a cut end surface 10 when slit is formed. Secondary plating layer 12 by electroplating
It has a cross-sectional structure in which

The primary plating layer 5 may be formed by either hot-dip plating or electroplating depending on the use of the steel strip 2. for example,
For hot dip zinc or hot dip zinc alloy plating, set the plating thickness to 30 to 365 g/d per side, and for electrolytic zinc or zinc alloy plating, set the plating thickness to 5 to 20 g/d per side.
g/m2. The reason why the plating thickness in the case of hot-dip plating is set to 30 to 365 g/m2 is that it is easy to form a good plating on nine surfaces. Furthermore, the plating thickness in the case of electroplating was set at 5 to 20 g/m2.

This is because it can be easily formed in manufacturing. In particular, the above-mentioned hot-dip plating is suitable for steel strips that require corrosion resistance because of their thicker coating. Zinc is the plating metal.

Examples include nickel, tin, aluminum, and alloys of each metal.

The wide plated steel sheet 1a after being coated with the organic resin film 7 is generally wound up into a roll.

The next slitting process 9 is then carried out. Of course, the wide plated steel sheet 1a may be continuously passed through the slitting step 9 after the resin film forming step 6.

Furthermore, it is desirable to leave the organic resin film 7 on the front and back surfaces of the product steel strip 2 as an alternative to conventional chemical conversion treatment, but it may peel off in some cases.

〔Example〕

1 and 2 show an embodiment of the invention.

FIG. 1 shows the main steps for continuously producing steel strips 2 from hot coils 1 in the order of steps from top to bottom.

A wide cold rolled coil obtained by rolling the hot coil 1 or the hot coil 1 to a predetermined thickness in a cold rolling process 3 is annealed in a heat treatment process not shown, and further temper rolling is performed appropriately, and a wide steel plate is formed in a plating process 4. A primary plating layer 5 is formed on both the front and back sides by a known continuous hot-dip galvanizing method.

Wide plated steel sheet 1a with primary plating layer 5 formed on the front and back sides
will guide you to the tertiary resin film forming step 6.

Here, a non-conductive organic resin film 7 is laminated on the primary plating layer 5 on the front and back surfaces.

This organic resin film 7 can be formed by a roll coating method as shown in FIG. 9, or by a one-way spray method, and the film thickness is preferably set to 5 to 20 g/rrf.

This coating 7 is applied to a water-dispersible or water-soluble resin having an acid value of 10 to 200 at a weight ratio of 1/1 to the solid content of the resin.
400-1/10 hexavalent chromium compound is blended, pH
It can be formed from a resin composition having a ratio of 3 to 10. Examples of water-dispersible or water-soluble resins used here include polyvinyl acetate emulsion, vinyl acetate-acrylic ester emulsion, acrylic ester copolymer emulsion, vinylidene chloride copolymer, vinyl chloride copolymer, epoxy resin emulsion, butadiene-acrylonitrile latex, etc. It is a resin in which a monomer containing a carboxyl group such as acrylic acid, methacrylic acid, and maleic acid is introduced.

Moreover, as a compound for blending hexavalent chromium, potassium chromic anhydride (9 dichromate), sodium dichromate, potassium chromate, sodium chromate, etc. can be used. One or more of these hexavalent chromium compounds are added to the water-dispersible or water-soluble resin described above, and the amount of hexavalent chromium added is 1) 500 to 500 by weight relative to the solid content of the resin. 1/10. That is, resin solid content 10
It is blended in a range of 0.3 to 10 parts by weight to 0 parts by weight.

The wide plated steel sheet 1a, on which the primary plating layer 5 and the organic resin film 7 are laminated on the front and back sides, is first wound into a roll. Next, the roll-wound wide-width plated steel sheet 1a is continuously fed out and passed through a slitting process 9 equipped with a pair of upper and lower cutter groups 8, where it is continuously slit to a predetermined width to form a strip steel sheet 2. Note that after the cutter group 8, a burr removal device 9 is installed.
A is provided to remove burrs on the end surface that occur during slitting. At this stage, the base steel of the steel strip 2 is exposed at the cut end surface 10 at the time of slitting, as shown in FIG. 2 fa).

In order to prevent corrosion of the cut end surface 10 described above, an end surface plating step 1) is provided following the slitting step 9. In this plating step 1), the steel strip 2 is plated by continuous electroplating, and secondary plating IJ12 is formed on both cut end faces 10 of the strip. At this time.

The plating solution spreads over the entire outer surface of the steel strip 2.

Since the surface of the primary plating layer 5 is completely covered with the insulating organic resin film 7, it is not subjected to electrolytic action and is protected from the plating solution. Therefore, the secondary plating layer 12 is formed only on the cut end surface 10 generated in the slitting process as shown in FIG.
The entire circumference is completely covered with the plating layers 5 and 12.

Thereafter, after performing a rinsing treatment and the like, the steel strip 2 is wound up into a roll using a winding machine to complete the processing.

[Example 1] Hot coil 1 was cold-rolled to form a plate having a thickness of 0.51 mm and a width of 1 mm.
A 235 mm wide steel plate was passed through the plating step 4, and a primary hot dip galvanized layer 5 with a thickness of 60 g/m'' was formed on both sides by continuous hot dip galvanizing.

This double-sided hot dip galvanized steel sheet 1a is coated with resin film forming step 6
Acrylic acid ester, ethyl methacrylate, acrylic acid copolymer (resin solid content 40% by weight, acid value 40)
500 g/l and a mixture of chromic anhydride and 5 g/l with aqueous ammonia and a resin composition adjusted to PI (6.5). An organic resin film 7 with a film thickness of 10 g/m" is roll coated on both the front and back surfaces of the steel plate 1a. It was formed by coating according to the method.

Next, the wide double-sided galvanized steel sheet 1a coated with the organic resin film 7 is slit to create a strip steel sheet 2 with a width of 221)I.
This steel strip 2 was passed through the end face plating step 1), and a secondary electrogalvanized layer 12 having a thickness of Log/m'' was formed on both cut end faces 10 of the steel strip 2 by continuous electrogalvanizing.

[Example 2] Plate thickness 1. Ovm, cold-rolled wide steel plate with a width of 1.235m.

55%A 1-43.4%Zn- as primary plating layer 5
The same procedure as in Example 1 was carried out except that a 1.6% Si aluminum-zinc alloy plating layer was formed with a thickness of 150 g/m''.

[Comparative Example 1] Using the double-sided galvanized steel sheet 1a in Example 1,
The cut end surface 10 of the steel strip 2 obtained by slitting the steel sheet after chromate treatment without coating it with the organic resin film 7
Also, the secondary plating layer 12 was not formed.

[Comparative Example 2] A steel strip 2 obtained by using the double-sided aluminum-zinc alloy plated steel sheet 1a in Example 2, subjecting it to chromate treatment without coating it with the organic resin film 7, and then slitting it.
The secondary plating layer 12 was not formed on the cut end surface 10 of the sample.

Regarding the steel strips obtained in Examples 1 and 2 and Comparative Examples 1 and 2, a performance test regarding the rust prevention properties of both cut end faces was conducted.

As a result, Comparative Example 1 was left indoors at room temperature for one month.
- Although red rust was observed on the cut end surface of the steel strip of Example 2, no red rust was observed on the steel strip of Examples 1 and 2 even after 3 months.

Further, the rusting state on the cut end surface of each steel strip was observed over time under conditions of a temperature of 50° C. and a humidity of 95%, and the results were as shown in Table 1.

Table 1 As is clear from Table 1, Comparative Example (Conventional Example) 1.
In No. 2, point-like red rust was already observed on the cut end surface of the steel strip after 12 hours had passed.

In Examples 1 and 2, only some red rust was observed after 48 hours had elapsed, indicating that the secondary plating layer coated on the cut end surface was working effectively.

In addition, in Comparative Example 2, the plate thickness was large and the zinc in the primary plating layer was small, so the sacrificial anticorrosion effect of the zinc was weak.
There was significant rust.

〔Effect of the invention〕

In the present invention, in a wide double-sided plated steel sheet 1a, a non-conductive organic resin film 7 is preliminarily coated on the primary plating layer 5 on the front and back sides thereof. Thus.

A wide plated steel sheet 1a on which the organic resin film 7 has been post-treated is slit to obtain a strip steel sheet 2 of a predetermined width. next.

This steel strip 2 was electroplated to form a secondary plating layer 12 on both cut end faces 10 thereof.

According to the manufacturing method of the present invention, when electroplating the steel strip 2, the organic resin film 7 does not adhere to the secondary plating layer 12 on the primary plating layer 5 on the front and back sides of the steel strip 2, or on the primary plating N5. The steel strip 2
A secondary plating layer 12 is adhered and formed on both cut end surfaces lO. As a result, a steel strip 2 with a good finished appearance can be efficiently obtained.

In addition, the step of forming the organic resin film 7 in the method of the present invention can be replaced with the conventional chemical conversion treatment such as chromate treatment or phosphate treatment, or oil coating treatment, so that the entire surface can be coated without increasing the number of steps. This has the advantage that a plated steel strip 2 can be formed.

Thus, the obtained steel strip 2 of the present invention has the front and back surfaces 7 coated with the primary plating layer 5 and the organic resin film 7, and both cut end surfaces 10 at the time of slitting are also coated with the secondary plating layer 12. Because I'm here.

It has extremely good corrosion resistance and is suitable for applications such as the above-mentioned cable armor and tensilan band for television receivers. Further, the organic resin film 7 on the front and back surfaces of 9 has the advantage of providing lubricity during processing, improving corrosion resistance, and being effective in treating the base for painting.

[Brief explanation of the drawing]

1 and 2 show an embodiment of the invention. FIG. 1 is an explanatory diagram showing the main manufacturing process of a steel strip. FIGS. 2(a) and 2(b) are cross-sectional views of the steel strip in the middle of the process. FIG. 3 is a sectional view of a conventional steel strip. 1...Hot coil. 1a... Wide plated steel plate. 2... Steel band plate. 4...Plating process. 5...Primary plating layer. 6...Resin film formation step. 7...Organic resin film. 9...Slitting process. 10...Cut end surface of steel strip plate. 1)... Edge plating process. 12... Secondary plating layer.

Claims (3)

[Claims] (1) A strip steel sheet obtained by slitting a wide plated steel sheet 1a on which a primary plating layer 5 is continuously formed on the front and back surfaces to a predetermined width, the non-conductive organic resin film 7 on the primary plating layer 5 on the front and back surfaces. is formed, and a secondary plating layer 12 by electroplating is formed on the cut end surface 10 at the time of slitting. (2) The thickness of the primary plating layer 5 per side is 30 to 36
It is a hot-dip zinc or hot-dip zinc alloy plating layer set at 5 g/m^2, and the secondary plating layer 12 has a thickness of 5 g/m^2 per side.
The steel strip according to claim 1, which has an electrogalvanized layer set at ~20 g/m^2. (3) A step of forming a non-conductive organic resin film 7 on the front and back surfaces of the wide-width plated steel sheet 1a on which the primary plating layer 5 is continuously formed on the front and back surfaces, and wide-width plating on which the organic resin film 7 is formed. The process consists of a step of slitting the steel plate 1a to a predetermined width to form a steel band 2, and a process of electroplating the steel band 2 to form a secondary plating layer 12 on the cut end surface 10 of the steel band 2. Characteristic manufacturing method of steel strip.