JPS6334237B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a steel plate for cans with excellent weldability and a method for manufacturing the same.

In recent years, welded cans have been attracting attention due to advances in wire seam welding methods, and Ni-plated or Ni-Sn
New materials such as alloy-plated steel sheets are being used. These materials are required to have excellent corrosion resistance after painting, and therefore it is essential to perform chromic acid-based electrochemical conversion treatment. In other words, as shown in Figure 1, conventional steel plates used for can materials have had their surfaces plated with Ni (or Ni-Sn alloy plated), rinsed with water, and subjected to chemical conversion treatment (electrolytic chromic acid treatment). After that, the treatment solution is rinsed again in a water washing tank, etc., and then dried. However, the chemical conversion coating (one or two types of metallic chromium and chromium oxide) produced by this electrolytic chromic acid treatment requires a large current to melt the welding point due to the high welding point, or the welding current is too high. This reduces electrical conductivity and causes welding defects. Also, because current flows locally and causes local heat generation,
Partial over-melting of the iron causes "dust" to occur, making uniform welding impossible and significantly deteriorating weldability.

The present invention has been made to solve the above-mentioned problems of the prior art, and the first invention is to improve the weldability of steel plates for cans by applying Ni plating or coating without a chemical conversion coating to the portions of the steel plates to be welded. It is characterized by exposing the Ni-Sn alloy plating layer. Further, a second invention is a method for manufacturing a steel sheet for cans according to the first invention, in which an organic resin is applied to a portion of a Ni-plated steel sheet or the like to be welded in the can manufacturing process to perform a chemical conversion treatment, and then the organic resin is applied to a portion to be welded. It is characterized by the removal of

Next, the present invention will be explained in detail based on the drawings.

FIG. 2 is a plan view showing the steel plate for cans according to the first invention, and FIG. 3 is a sectional view taken along line AA in FIG. In Fig. 2, 2 is the part to be welded which will become a can joint during the can manufacturing process, and in Fig. 3, that part is Ni or Ni-Sn alloy plating provided on the base steel plate 1. Layer 3 is exposed. Further, in other parts, a chemical conversion coating 4 is formed on the plating layer 3.

It is preferable to shift the position of the portion 2 to be welded on the front and back sides of such a steel plate for cans. That is, as shown in Fig. 3, on the surface side of the steel plate, the welding area 2 is to the right of the perpendicular line α.
, and on the back side, a portion 2 to be welded is provided on the left side of the perpendicular line α. During can manufacturing, the steel plate is cut along each perpendicular line α, and the parts 2, 2 to be welded on the front and back sides of the steel plate are joined by welding. Since the Ni or Ni-Sn alloy plating layer 3 is exposed on the joint surface, welding can be performed reliably.

In addition, as shown in FIG. 2, the width W of the part 2 to be welded is
Usually, about 2 to 5 mm is sufficient, and the length L of each cut of the steel plate is determined depending on the type of canned goods.

Next, the second invention will be explained in detail based on the drawings.

As shown in FIG. 1, the present invention involves coating a predetermined portion of the plated steel plate with an organic resin after the conventional Ni or Ni-Sn alloy plating, and then chemical conversion treatment as in the normal manufacturing process. After that, the organic resin is removed.

The part to be coated with this organic resin is only the part 2 to be welded in the can manufacturing process, and if a stepped roll having steps is applied to the surface of the moving steel plate and rotated, the organic resin is applied by roll transfer at that time. good. In addition, as the organic resin, phenol-based, epoxy-based, and epoxy-phenol-based resins are preferable, and as a means for removing these resins, it is preferable to dissolve them using an organic solvent such as thinner in order to improve workability. preferable.

FIG. 4 is a schematic diagram of a manufacturing process showing an embodiment of the second invention method.

That is, Ni plating is performed in plating tanks 14, 14,
The strip 10 rinsed in the water washing tank 15 is
The organic resin is guided to the coating rolls 11, 11 side, and the organic resin is applied to the portions to be welded during can manufacturing. Next, this is led to chemical conversion treatment tanks 12, 12 for chromium oxidation treatment, and then the coated organic resin is dissolved and removed in a dissolution tank 13 containing an organic solvent.

Strip 10 obtained through such a process
Since a part of the strip 10 is protected from immersion in the chemical conversion treatment water by the organic resin, there is no metallic chromium or chromium oxide in the welded part from which the organic resin has been removed, and the strip 10 is cut and welded into a predetermined can shape. At the same time, the weldability of the welded portion is significantly improved.

When applying the organic resin in this step, the coating rolls 11, 11 are those having a plurality of stages 20 in the length direction of the roll body, each having a pitch corresponding to the outer circumferential length of the can, as shown in FIG. , the organic resin is transferred onto the surface of the step 20 via a roll 22 immersed in an organic liquid tank 21 and an intermediate roll 23, and the coating roll 11 is rotated to apply the organic resin attached to the step 20 onto the surface of the strip 10. ing.

Further, in FIG. 4, 16 is a water washing tank, and 17 is a dryer, by which the surface of the strip 10 is rinsed and dried after the organic resin has been removed.

In addition, by the second invention method detailed above, the first method
Although it is a matter of course that the steel sheet for cans according to the invention is manufactured, it goes without saying that the steel sheet is not manufactured only by this manufacturing method, but can also be manufactured by other methods.

Next, a test was conducted to compare and evaluate the weldability of the steel sheet for cans according to the first invention and the conventional steel sheet for cans, and the results shown in FIG. 6 were obtained. In other words, Figure 6 shows Ni-plated steel sheets and Ni-Sn alloy-plated steel sheets.
The appropriate welding current ranges for materials of the present invention and conventional materials were measured. ● and ▲ in the figure indicate that if more current is applied than necessary during welding, dust may be generated and cause uneven welding, or Fe may adhere to the plating film and Fe may melt from there. The maximum current value that does not generate dust is measured.
In addition, 〇 and △ are the minimum current values required to melt and alloy Fe and Ni in the welded portion in order to give a certain strength to the welded portion. Therefore, the larger the range between ● and ○, and between ▲ and △, the wider the range of appropriate current values during welding and the better weldability. It can be seen from FIG. 6 that the product of the present invention has better weldability for both plated steel plates.

As described above, the steel plate for cans according to the first invention of the present application is
There is no chemical conversion coating in the area to be welded, so there is no Ni or Ni-
Since the Sn alloy plating layer is exposed, weldability in that area is much better than conventional products. Further, according to the second invention, during chemical conversion treatment, the predetermined welded portion is covered with organic resin, which protects it from immersion in the chemical conversion treatment solution and prevents the precipitation of metallic chromium and chromium oxide, which improves weldability. This has the effect that the excellent steel plate for cans of the first invention can be reliably obtained.

[Brief explanation of the drawing]

Fig. 1 is a process diagram showing the steps of the conventional method and the second invention method, Fig. 2 is a plan view showing an embodiment of the first invention, Fig. 3 is a sectional view taken along the line A-A in Fig. 2, and Fig. 4 is the second
FIG. 5 is an explanatory diagram showing the operating status of the applicator roll, and FIG. 6 is a graph diagram showing the appropriate welding current range for the conventional product and the first invention product. . In the figure, 1 is a steel plate, 2 is a part to be welded, 3 is a plating layer, 4 is a chemical conversion coating, 10 is a strip, 1
1 is a coating roll, 12 is a chemical conversion tank, and 13 is a dissolution tank.

Claims (1)

[Scope of Claims] 1 A Ni or Ni-Sn alloy plating layer is provided in the part to be welded, and a Ni or Ni-Sn alloy plating layer is provided in other parts and a chemical conversion coating is formed thereon. A steel sheet for cans with excellent weldability. 2. A can with excellent weldability, characterized in that an organic resin is applied to the welding area of a steel plate having a Ni or Ni-Sn alloy plating layer, the plated steel plate is subjected to chemical conversion treatment, and then the organic resin is removed. Method of manufacturing steel plates.