JPS5811488B2 - Manufacturing method of steel plate for easy-open cans with excellent can-opening and lid-forming properties - Google Patents

Description

[Detailed Description of the Invention] The present invention is an excellent material for so-called easy-open cans, in which a score of an appropriate depth is engraved on the can lid or can body, and the can can be opened without tools such as a can opener. The present invention relates to a method of manufacturing a steel plate for easy-open cans having the following properties.

In recent years, easy-open cans have come into use for beer cans, carbonated beverage cans, juice cans, etc.

These easy-open cans include those such as beer cans in which a portion of the can lid is opened (in the present invention, a pull-open type and a can lid) and full-open cans in which the entire can lid is opened, such as canned food cans. There is a type (Full open type).

This easy-open can lid is primarily made of aluminum.

However, aluminum cannot be used in all cases due to the corrosion resistance of the contents, and from the viewpoint of recycling when collecting empty cans, it is preferable that the entire can be made of the same material.

Therefore, easy-open can lids using steel plates have been considered.

However, since steel is inherently tenacious, it cannot be opened as easily as aluminum, and we have not yet reached the stage of making easy-open can lids that can be opened as easily as aluminum easy-open can lids.

In addition, if the steel is incompletely recrystallized (so-called underbaked) by annealing in order to lose its tenacity, the workability will be lost and many cracks will occur when machining rivets for attaching oven tabs. The reality is that there was a problem with the lid.

In view of the above-mentioned circumstances, the inventors of the present invention conducted many experiments with the aim of obtaining a steel plate for easy-open cans that has excellent can-opening properties and good rivet workability.
We have invented a method for producing a steel plate for easy-open cans that has can-opening performance equivalent to that of aluminum easy-open can lids, has excellent lid-forming properties, particularly rivet workability, and does not generate cracks during processing.

The present invention will be specifically explained in detail below.

The steel constituting the method of the present invention has carbon: 0.02 to 0.07
%, silicon 20.1% or less, Mn: 0.1 to 0.5%, and oxygen: 0.02% or less, and 1/ of the carbon content.
The sum of 2 and the amount of oxygen is 0.04% or less, and the remainder consists of iron and inevitable impurities.

The reason for determining the component range as described above is as follows.

As the carbon content increases, carbides increase and cracks occur during riveting, so the upper limit is set at 0.07%.

Furthermore, when the carbon content decreases, the strength of the steel plate decreases, making it difficult to secure the strength necessary for an easy-open can lid, so the lower limit is set at 0.02%.

If the content of silicon is too high, it will deteriorate the corrosion resistance of the can, so the upper limit is set at 0.1%.

Manganese is added to prevent hot embrittlement of the steel sheet due to sulfur present in the steel as an unavoidable impurity, and from this point of view, the content of manganese is required to be 0.1 to 0.5%.

If a large amount of oxygen is contained, oxide inclusions will increase and cracks will easily occur during riveting, so the content should be 0.02% or less.

Furthermore, in order to prevent the occurrence of cracks during riveting, it is insufficient to regulate the upper limits of the carbon and oxygen contents individually; it is necessary to specify the upper limit of the total amount of these two components.

That is, in order to prevent the occurrence of cracks during riveting, the total amount of both components must be 1/2 (capital) + (01<0.04%).

This steel is melted using an appropriate method such as a converter, and then made into a slab by ingot formation and blooming, or continuously cast into a slab, which is then hot-rolled at a temperature of 800°C or higher, and then Cold rolling at a reduction rate of 60% or more, then at a temperature of 600-800°C
Box annealing or continuous annealing is performed.

The annealed steel plate is temper rolled at a rolling reduction of 4 to 20%.

Temper rolling is necessary to improve the opening performance of an easy-open can lid and to improve the rivet workability.

However, if the rolling reduction is less than 4%, both the effect of improving can opening property and the effect of improving rivet workability are lost.

When it exceeds 20%, the ductility deteriorates due to an increase in heat reduction reduction more than the effect of improving riveting workability, and cracks frequently occur during riveting.

The shaft plate manufactured by the above method is then subjected to surface conditioning such as degreasing and pickling, followed by plating with various metals such as tin, nickel, chromium, and aluminum, phosphate treatment, and other chemical conversion treatments. , used as steel plate for easy-open cans.

It can also be used as a steel plate for easy-open cans without being subjected to plating or chemical conversion treatment.

Examples of the present invention will be described below.

Example 1 Steel having the components shown in Table 1 was melted in a converter.

These were cast according to a conventional strip process, hot-rolled, cold-rolled, and continuously annealed at a temperature of 690°C.

These annealed coils were temper rolled at a reduction rate of 10%, and
It was made of a 4 mm steel plate.

Next, tin plating was applied using a regular electroplating line.

After painting and baking the tin plate manufactured in this process, the remaining score thickness is 0.07 mm.
) type easy-open can lid, and measured the can opening force and investigated the occurrence of cracks during rivet processing.

These results are shown in Table 2.

As is clear from Table 2, steels A and B produced by the manufacturing method of the present invention
, C have a small can opening force, which is almost equal to the can opening force of the currently used full open type aluminum can lid (manufacturing standard max 8.0 kg).

Furthermore, none of the steels A, B, and C cracked during riveting, indicating that they had extremely excellent riveting properties.

In addition, the steels E and F other than those of the present invention have a high opening force and have problems in opening the can, or they often crack during riveting.
It is inferior to the steel plate for easy-open cans manufactured by the present invention.

Example 2 Steel C in Table 1 was hot-rolled and then cold-rolled at different cold rolling reductions, followed by box annealing at 650° C. for 2 hours.

These annealed coils have rolling reduction rates of 2.5%, 5%, 10%,
At 17% and 25%, temper rolling was performed using hydraulic rolling.
．． A 24mM steel plate was used.

Next, tin plating was applied using a regular electroplating line.

After painting and baking the tin plate manufactured in this process, the score remaining thickness is 0.07 mm.
) type of easy-open can lid, the can opening force was measured, and the occurrence of rivet cracking was investigated.

These results are shown in Table 3.

As is clear from Table 3, steels C-2, C-3, and C-4 subjected to skin pass rolling at the rolling reduction of the present invention all have a small can-opening force, and can be opened with a fully open aluminum can lid. The force is equal to g, and no cracks occur during riveting.

However, steel C that was skin pass rolled at a downstream rate lower than that of the present invention
-1 has a high can opening force and also cracks occur during riveting.

In addition, steel C-5 was skin-pass rolled at a rolling reduction rate higher than that of the present invention.
cracks frequently occur during riveting and are inferior to steel sheets manufactured by the present invention as steel sheets for easy-open cans.

In Example 1.2, the can opening force measurement results were shown for a fully open type easy-open can lid that opens the entire surface of the can lid.
Even in the case of easy-open can lids,
The steel sheet manufactured by the present invention had a can-opening force as low as that of an aluminum can lid, and no cracking occurred during riveting.

Furthermore, the steel sheet manufactured according to the present invention does not generate cracks during scoring (this makes it an excellent steel sheet for easy-open cans).

As shown in the above examples, the steel plate for easy-open cans manufactured by the method of the present invention has excellent can-opening properties and riveting properties, and has performance comparable to that of aluminum easy-open ends.

Claims (1)

[Claims] 1 Carbon: 0.02% to 0.07%, Silicon: 0.1%
Below, Mn: 0.1 to 0.5% and oxygen: 0.02%
A can opening property characterized by performing skin pass rolling at a reduction rate of 4 to 20% on a steel sheet for cans containing the following and 1/2C + 0 < 0.04% or less with the balance being iron and unavoidable impurities. A method for producing steel plates for easy-open cans with excellent lid-forming properties.