JPH0711484A - Method and equipment for manufacturing tin plated steel sheet - Google Patents

Abstract

PURPOSE:To obtain a steel sheet with attractive and stable bright surface at high speed, without requiring reflow and quenching treatments, by applying temper rolling at specific draft after Sn plating. CONSTITUTION:A steel sheet, prepared by performing cold rolling, annealing, primary temper rolling if necessary, and successively Sn plating, is temper-rolled at 0.1-40% draft. By this method, the necessity of reflow and quenching as means to improve surface brightness can be obviated and the color tone and brightness of the surface of the plated steel sheet can remarkably be improved, and the Sn plated steel sheet having attractive bright surface can be obtained. Further, the necessity of equipment for reflow and quenching treatments and heating energy for them can be obviated, and manufacturing costs can be reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a tin (Sn) plated steel sheet and a manufacturing facility.

[0002]

2. Description of the Related Art Sn-plated steel sheets are widely used as materials for cans such as beverage cans and gallon cans. The manufacturing process is cold rolling, annealing, temper rolling, and then Sn plating in an electric Sn plating facility.
It is generally plated. In the electric Sn plating equipment, a so-called reflow process is performed to melt the electrodeposited Sn by raising the temperature of the steel sheet after Sn plating to a temperature equal to or higher than the melting point of Sn, and further perform a quenching process in which the molten Sn is immersed in hot water and solidified. There are cases. By this reflow and quench treatment, it is possible to obtain a beautiful glossy surface, which is one of the features of Sn plated steel sheets.

On the other hand, the manufacturing cost of Sn-plated steel sheet is lowered,
Proposals have been made to make the manufacturing process continuous in order to shorten the lead time. Japanese Unexamined Patent Publication (Kokai) No. 4-32559 discloses an equipment row in which these equipments are arranged in series in order to integrate the steps of continuous annealing, temper rolling and Sn plating, which have been conventionally performed separately. .

[0004]

However, when reflowing and quenching a Sn-plated steel sheet at a high speed, a surface defect called quenching stainless steel becomes a problem.
Quenching Sten is a phenomenon in which when a steel sheet is cooled in warm water, an abnormal boiling phenomenon occurs at the steel sheet interface, and this impact causes Sn to solidify while being distorted irregularly. Presents an appearance like. Generally, it is difficult to obtain a steel sheet surface without quenching as the passing speed is higher, and in order to obtain a steel sheet surface without quenching stainless steel,
There is no choice but to reduce the passing speed. That is, it was one of the main factors that reduce the productivity of Sn-plated steel sheets.

Even when the Sn-plated steel sheet is manufactured by the equipment disclosed in Japanese Patent Laid-Open No. 4-32559, the reflow rather than the continuous annealing, temper rolling, and Sn plating ability (Ton / Hr) for the above-mentioned reason. In many cases, the quenching capacity is significantly inferior, and in such a case, the capacity of the entire equipment is limited by reflow and quenching. That is, even if the number of steps is minimized and the lead time is shortened, there is a large dilemma that the manufacturing cost is increased because the processing capacity is low.

The present invention solves the above-mentioned problems and easily manufactures a Sn-plated steel sheet having a beautiful and stable glossy surface even at a high speed, particularly continuous annealing, temper rolling, and Sn plating are integrated. It is an object of the present invention to provide a method for producing a Sn-plated steel sheet and a facility therefor in which a means for obtaining a beautiful glossy surface does not rate-control other processes.

[0007]

According to the present invention, in order to obtain a beautiful glossy surface, a steel sheet that has been cold-rolled and annealed is tin-plated, and then subjected to a temper treatment in a range of 0.1 to 40%. A method for producing a tin-plated steel sheet, which comprises rolling,
Further, the present invention is characterized in that the steel sheet that has been cold-rolled and annealed is subjected to the first temper rolling, tin-plating, and then the second temper rolling. The present invention also provides a method for producing a tin-plated steel sheet, which comprises subjecting each of the temper-rolled tin-plated steel sheets obtained above to electrolytic chromate treatment.

Further, the present invention is a tin-plated steel sheet manufacturing facility characterized in that a continuous annealing furnace, a tin plating facility, a temper rolling facility, and an electrolytic chromate facility are arranged in this order,
Alternatively, the present invention provides a tin-plated steel sheet manufacturing facility characterized in that a continuous annealing furnace, a first temper rolling mill, a tin plating facility, a second temper rolling mill, and an electrolytic chromate facility are arranged in this order. Is.

[0009]

The function of the present invention is to perform cold rolling, annealing and, if necessary, the first temper rolling, and then Sn-plated steel sheet,
By temper rolling in the rolling reduction range of 0.1-40%,
The color tone and gloss of the steel sheet surface after plating are remarkably improved, and a beautiful glossy surface can be easily obtained.

The upper limit of the rolling reduction of the temper rolling after Sn plating is 40%
The reason is as follows. When temper rolling with a rolling reduction of more than 40%, the peeling of the plated Sn increases, and the peeled Sn accumulates on the work roll, creating fine irregularities on the surface layer of the work roll. The effect of improving the color tone and gloss due to is weakened. When temper rolling with a reduction rate of more than 40% is performed, the damage of the plating layer becomes large, and the corrosion resistance and other properties deteriorate as compared with the case where no temper rolling is performed.

Further, the lower limit of the rolling reduction of the temper rolling after Sn plating is set to 0.1% because the rolling reduction of less than 0.1% cannot obtain sufficient effect of improving the color tone and gloss. When the Sn-plated steel sheet is applied to a material for a can, it is often seen that electrolytic chromate treatment is carried out as a post-treatment after Sn plating.
What was limited after temper rolling after plating is that the chromate film formed by electrolytic chromate treatment is generally hard and brittle, so if the temper rolling is performed after electrolytic chromate, the chromate film is likely to peel off, similar to the above reason. This is because the effect of improving the color tone and gloss is weakened.

In the present invention, after annealing, temper rolling may be performed, Sn plating may be performed, and then the second temper rolling may be performed. Generally, in temper rolling after cold rolling / annealing, there is often a case where a material having high hardness is manufactured by taking a reduction rate of 40% or more as a second cold rolling. In the case of Sn for the above reasons
It is difficult to apply a process that reduces the reduction rate of temper rolling after plating to 40% or more. In such a case, a large reduction rate is obtained in the temper rolling (second cold rolling) after annealing and Sn
After plating, it is desirable to apply a process that takes a small reduction rate in the second temper rolling.

As described above, according to the present invention, since the gloss of the Sn-plated steel sheet is adjusted by temper rolling, it is possible to avoid the rate-limiting of the strip-passing speed associated with quenching.

[0014]

EXAMPLES FIGS. 1 and 2 schematically show the equipment arrangement of the continuous annealing / surface treatment equipment of the present invention. In FIG. 1, the steel strip that has left the continuous annealing furnace 1 is plated on the Sn plating equipment 5, then temper-rolled on the skin pass equipment 3 via the intermediate looper 2 and, if necessary, on the electrolytic chromate equipment 7 via the intermediate looper 4. It is chromated and wound on the take-up reel 9 via the exit side looper 8.

In FIG. 2, the steel strip exiting the continuous annealing furnace 1 is temper-rolled by the first temper rolling equipment 3 via the intermediate looper 2 and then passed through the intermediate looper 4 and Sn plating equipment 5.
After being subjected to the tempering rolling in the second tempering rolling equipment 6, it is passed through the electrolytic chromating equipment 7, passed through the exit side looper 8, and taken up by the take-up reel 9. On the other hand, FIG. 3 is an equipment sequence diagram disclosed in Japanese Patent Laid-Open No. 4-32559, which is a conventional technique shown for comparison. An annealing furnace 1 is followed by a temper rolling facility 3 and a plating facility 5, followed by a reflow and quench treatment facility 10.

FIG. 4 is a schematic view of the equipment array shown in FIG.
The relationship between the rolling reduction of the Sn-plated steel sheet after plating and the gloss is shown. The weight per unit area during Sn plating was 1.2 g / m ² . The glossiness was measured by GS20 based on JIS G8741. Moreover, in FIG. 5, Sn manufactured using the equipment row shown in FIG.
The relationship between the rolling reduction and the luster of a plated steel sheet after plating is shown. The weight per unit area during Sn plating was 1.6 g / m ² . The reduction ratio of temper rolling before Sn plating was 1.0%.

As can be seen from this, by performing temper rolling after Sn plating, it was possible to obtain gloss equivalent to that of the reflow material without performing reflow and quench treatment. Compared with the reflow and quench treatments that have the problem of quenching, temper rolling after plating can obtain a beautiful glossy surface stably and easily even if the stripping speed increases. Regarding the method of temper rolling after plating, it may be performed with only one pair of work rolls or with two or more pairs of work rolls, but any method is applicable. Further, in order to reduce the peeling of the plating layer, wet type temper rolling is preferable, but dry type may be used.

Further, in the equipment row of the above-mentioned embodiment, the annealing-surface treatment equipment having the electrolytic chromate treatment equipment was explained, but the present invention is not necessarily limited to this. That is, it is not necessary to perform chromate treatment, for example, continuous annealing, temper rolling, when performing Sn plating in separate lines, or when performing phosphoric acid treatment as post-treatment after Sn plating, further after Sn plating It can also be applied when the post-treatment is not performed.

Regarding the provision of surface treatment equipment immediately after the continuous annealing furnace, there is an example of JP-A-61-149492, which is to perform the surface treatment immediately after the annealing so that the corrosion resistance of the plated surface and the chemical conversion treatment can be improved. The purpose is to improve the property and is completely different from the present invention.

[0020]

EFFECTS OF THE INVENTION According to the present invention, as a means for increasing the surface gloss of Sn-plated steel sheet, temper rolling is performed without using reflow or quench treatment, so that it has a beautiful and stable gloss surface even at high speed. Sn-plated steel sheets can now be easily obtained, which has greatly contributed to the improvement of productivity.

Also, unlike reflow and quench treatments,
Since the energy for heating the steel sheet is unnecessary, the effect of reducing the manufacturing cost is great. Furthermore, when constructing the continuous annealing-surface treatment line of the present invention, reflow equipment is not required, and therefore, a merit that the construction cost can be reduced by that amount can be expected.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing an equipment row in a continuous annealing-surface treatment equipment of the present invention.

FIG. 2 is a schematic diagram showing an equipment row in the continuous annealing-surface treatment equipment of the present invention.

FIG. 3 is a schematic diagram showing an equipment row in a conventional continuous annealing-surface treatment equipment.

FIG. 4 shows the relationship between the reduction ratio of temper rolling and the glossiness (no skin pass before plating).

FIG. 5 shows the relationship between the rolling reduction of the temper rolling and the glossiness (there is a skin pass before plating).

[Explanation of symbols]

 1 Annealing furnace 2 Intermediate looper 3 1st temper rolling equipment 4 Intermediate looper 5 Sn plating equipment 6 2nd temper rolling equipment 7 Electrolytic chromating equipment 8 Ejection side looper 9 Winding reel 10 Reflow and quench treatment equipment

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Fumio Furukaku, 1 Kawasaki-cho, Chuo-ku, Chiba-shi, Chiba Inside the Chiba Works, Kawasaki Steel (72) Makoto Himeno 1 Kawasaki-cho, Chuo-ku, Chiba, Chiba Prefecture Kawasaki Steel Works Co., Ltd. Chiba Steel Works (72) Inventor Kazuo Akaoka 1 Kawasaki-cho, Chuo-ku, Chiba-shi, Chiba Kawasaki Steel Works Chiba Works

Claims (6)

[Claims] 1. A method for producing a tin-plated steel sheet, which comprises performing tin-plating on a steel sheet that has been cold-rolled and annealed and then temper-rolling in a rolling reduction range of 0.1 to 40%. 2. A tin-plated steel sheet which is obtained by subjecting a cold-rolled and annealed steel sheet to a first temper rolling, tin plating, and then a second temper rolling. Manufacturing method. 3. A tin-plated steel sheet, characterized in that a cold-rolled and annealed steel sheet is tin-plated, temper-rolled in a rolling reduction range of 0.1 to 40%, and electrolytically chromated. Method. 4. A steel sheet that has been cold-rolled and annealed is subjected to a first temper rolling and tin plating, and then a second temper rolling and electrolytic chromate treatment. Method for producing tin-plated steel sheet. 5. A tin-plated steel sheet manufacturing facility comprising a continuous annealing furnace, a tin plating facility, a temper rolling facility, and an electrolytic chromate facility arranged in this order. 6. A continuous annealing furnace, a first temper rolling equipment,
A facility for manufacturing tin-plated steel sheets, characterized in that a tin-plating facility, a second temper rolling facility, and an electrolytic chromate facility are arranged in this order.