JP2000288628A - Large unit weight coil of ultra thin steel strip and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a large unit weight coil of ultra thin steel strip capable of executing a slitting work excellent in the accuracy of width and a sticking work at the time of manufacturing a three-piece can be the film laminating method by preventing defect in shape of a coiled coil. SOLUTION: At the time of making the large unit weight coil by coiling the ultra thin steel strip having thickness of <=0.20 mm and width of >=950 mm, after starting coiling the strip on a sleeve having a diameter of 400-600 mm and coefficient of rigidity of >=0.05 kgf/mm, the strip is coiled taking the tension in the position at 5 m from the begining end of coiling as 2.0-4.0 kgf/mm2 and also the tension in the position at 10 m from the terminal as 1.2-4.0 kgf/mm2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention mainly relates to a film-laminated steel strip (plated or filmed) suitable for use in a three-piece weld can (hereinafter simply referred to as a weld can) obtained through an electric seam welding process. Ultra-thin steel strip large single coil that is excellent in the accuracy of the lamination position, especially during film lamination, and that enables stable and high-speed seam welding. And a method of manufacturing the same. In addition, the film lamination method includes a method of directly attaching to a large coil,
There is a method in which a large coil is formed into a slit coil in advance and then pasted, and the present invention can be applied to any of these.

[0002]

2. Description of the Related Art A steel plate for a can is subjected to various platings such as Sn, Cr, and Ni on the surface and processed into a three-piece can or a two-piece can. . Above all, the three-piece can consists of three parts: the top lid, the bottom lid and the seam-welded shell plate. Have.

[0003] With the recent mass consumption of beverage cans, can-making technology has progressed, and efforts have been made to rationalize the use of thinner steel plates for cans to reduce the weight of cans. I have. Along with this, as a means to reinforce the decrease in strength of the can due to the decrease in plate thickness, in addition to adopting a steel plate for can with a high degree of tempering, a change in the processing shape, for example, from a conventional simple cylindrical shape to a can head In addition, methods such as neck-in processing, multi-stage neck-in processing, change to smooth large neck-in processing at the bottom of the can, and overhanging to the barrel shape, unevenness processing, and change to bead processing at the body part will be adopted. Became. The manufacturing method is, for example, the magazine "TH
E CANMAKER ”Feb. 1996, pages 32 to 37, first form a steel strip into a cylinder, weld it, and then apply a precision split mold, hydrostatic press, etc. to join the cylinder. It consists of a process of imparting circumferential expansion strain to the body (can expansion). Therefore, the welded portion is required to have a quality that does not cause a defect even when the can expanding process is performed.

[0004] When a three-piece can is made from a thin steel plate as described above, the temperature of the steel plate rises due to a rise in the temperature of the steel plate due to a small amount of heat carried away by the body of the weld can during seam welding. And the contact resistance also increases, resulting in frequent scattering. For this reason, an appropriate welding current range in which scattering can be avoided stably is narrowed, and high-speed welding is becoming difficult.

[0005] Along with the above-mentioned material thinning, recent advances in can-making technology include advances in coating and printing methods for can body plates. In other words, instead of the conventional sheet coating method (4 to 6 rows x 5 to 6 rows with wide sheet)-baking method using a heating oven (210 ° C x 20 minutes high temperature and long time baking), gravure printing is performed in advance. Laminated (150-230 ° C x several seconds at medium temperature, ultra-short-time baking) the resulting film on the outer surface of the can and at the same time, a plain transparent film on the inner surface of the can to impart aesthetic appeal and enhance the flavor of the contents. A secure film lamination method was developed. This method is described in, for example, JP-A-5-3
Japanese Patent No. 1868 discloses that both sides of a long can body blank material (a narrow coil corresponding to the circumferential length of one can) continuously supplied from a coil wound with a can body blank material are welded. A method is disclosed in which a film is thermocompression-bonded while leaving exposed metal portions at corresponding end edges. Since the film laminating method does not use a heating oven in this way, it is not only an environmentally friendly method, but also enables high-speed sheet passing,
This is a technology that contributes to the promotion of high-speed can-making because the printing can be performed on the can body plate by heating only for a short time by changing the film and finishing the printing in one pass even for multicolor printing.

[0006] In addition, while the contents of cans have become diversified and tended to be multi-product, small-volume production, in order to respond to the trend of fluid consumption, inventory has been reduced as much as possible to make cans in just-in-time. Is required. Conventionally, the printing line is stopped according to each type, plate change, color change, and color printing are performed.
Since printing was performed in six rows, it was not suitable for small-lot production. In contrast, in the film lamination method, gravure printing is performed on a film with excellent handleability to the length according to the production plan, and this is pressed to the coil and finished, so it can meet the demand for just-in-time. It can be said to be a production method. In addition, as a laminating method, a large unit weight coil is slit in advance to a width equivalent to the circumferential length of one can, and then a film is attached. The narrow coil method is more suitable for small-quantity just-in-time production. .

However, by adopting the above-described technology,
When laminating a film on a thin strip steel strip and performing high-speed welding, even with the same sheet thickness, the appropriate welding current range was large with the conventional sheet coat material, and stable welding was achieved. (Splash) occurs,
In the can-expansion test, peeling occurred at the welded portion, and there was a problem that a wide suitable welding current range could not be obtained. The cause of the scattering is basically that an overcurrent flows,
Peeling is because a sufficient current does not flow. As described above, in the case where the appropriate welding current range is narrow, peeling occurs when the current value is reduced in order to prevent the occurrence of spattering, and conversely, spattering occurs when the current value is increased so that the peeling does not occur. However, to date, the reason why the film lamination method using a slit coil cannot perform high-speed stable welding has not been elucidated, and the technical development of high-speed stable operation using this method is strongly expected. I was

While the thinning of the can material and the film lamination method using a slit coil bring new problems, the technology of seam welding of the can body itself has been further developed. First, comparing the welding speed,
For example, for a 340g beverage can, conventionally 500 cans / min (can height 10
What was about 8 mm x 500 cans / min = 54 m / min) has recently become 1100 cans / min (can height 108 mm x 1100 cans / min = 119 m / min)
A high-speed welding machine of the order has also been developed, and process production is beginning. In addition, efforts have been made to reduce the welding width in order to improve the material yield, and the welding width has been reduced from about 1.0 mm in the past to a narrow range of 0.8 mm or less. With the improvement of such welding technology, there is an increasing demand for improved quality of welded parts under high-speed welding. Inevitably, the lamination method using thin-walled slit steel strips is faster and more sound. There is a demand for the appearance of a body plate material that can be easily welded. In addition, when a plurality of films having a width equivalent to the circumferential length of one can are arranged on a wide large single coil at intervals in the coil width direction and directly pasted simultaneously in the coil longitudinal direction, a gap between adjacent films may be obtained. Is a position where welding is performed. Therefore, in this part,
When a film or an adhesive is present, there is a problem that defects due to the burning of organic substances occur during welding, and a body plate material that has good bonding accuracy and can withstand such a direct bonding method is required.

[0009]

As described above, a wide single coil having a large width is slit into a narrow width corresponding to the circumferential length of the can body. At the edge, the film is laminated leaving the exposed metal part, and when the body plate is seam-welded, multiple films are simultaneously pasted in the coil longitudinal direction directly on the wide large single coil, and then slit. When welding the body plate, a wide and large single coil is required, which has a wide appropriate welding current range, enables high-speed, stable welding, without causing scattering during welding or peeling off during the can-expansion test. ing.

The present inventors have conducted intensive studies and researches in order to meet the above-mentioned demands of the prior art, and as a result, have strictly controlled the slit conditions and the like to improve the width accuracy (dimensional accuracy) of the slit steel strip. Was found to be effective in improving high-speed weldability in film lamination and the like (Japanese Patent Application Nos. 10-54970 and 11-48129). However, even if the conditions of the slitting step are strictly controlled, sufficient width accuracy may not be obtained in some cases. The present inventors have found that this is due to a defective coil shape. In particular, in an ultra-thin steel strip large single weight coil having a plate thickness of 0.200 mm or less and a coil single weight (coil weight) of 9 tons or more, the coil shape is reduced. It has been found that strict control of the winding conditions is necessary to keep good. A main object of the present invention is to provide an ultra-thin steel strip large single coil capable of preventing the above-mentioned defective coil shape and capable of performing slitting and sticking operations with good width accuracy.

[0011]

Means for Solving the Problems The inventors have conducted research and studies to achieve the above object. As a result, they found the following. It is important to increase the slit width accuracy in the method of slitting in advance, and to increase the accuracy of the sticking position in the method of slitting after sticking the film in a plurality of strips. When the ultra-thin steel strip large unit weight coil is slit while being unwound, or when lamination is performed, the coil has a telescope, poor roundness, or buckling. Or that the coil is meandering if the tension at the time of winding is unstable, and the width direction accuracy of the slit steel strip and the accuracy of the bonding position are deteriorated, and to maintain the state of the coil properly. Conditions were found. The present invention is based on the above findings, and the gist configuration thereof is as follows.

(1) A coil having a thickness of 0.20 mm or less, a width of 950 mm or more, and a weight of 9 tons or more, wherein the coil has a diameter of 40 tons.
An ultra-thin steel strip large unit weight coil wound around a sleeve having a hardness of 0 to 600 mm and a rigidity coefficient of 0.05 kgf / mm or more.

(2) A coil having a thickness of 0.20 mm or less, a width of 950 mm or more, and a weight of 9 tons or more, wherein the coil has a diameter of 40 tons.
Wound on a sleeve with a hardness of 0 to 600 mm and a stiffness coefficient of 0.05 kgf / mm or more, and the tension at a position 5 m from the inner diameter side end of the steel strip is 2.0 to 4.0 kgf / mm ² , and a 10 m position from the outer diameter side end of the coil ultrathin strip large unit weight coil, wherein the tension in is 1.2 ~4.0 kgf / mm ^2.

(3) The tension in the section sandwiched between the two positions is substantially constant, or the tension is gradually reduced from the inner diameter side to the outer diameter side of the coil. Ultra-thin steel strip large unit weight coil.

In the above (1) to (3), the steel strip may have a surface treatment layer on at least one surface, and the surface treatment layer may include a film laminate layer.

(4) When winding an ultra-thin steel strip having a thickness of 0.20 mm or less and a width of 950 mm or more into a large single coil of 9 tons or more, a diameter of 400 to 600 mm and a rigidity coefficient of 0.05 kgf / mm
Winding is started on the above sleeve, and the tension at the position 5 m from the beginning of the winding is 2.0 to 4.0 kgf / mm ² and the tension at the position 10 m from the end is 1.2 to 4.0 kg.
A method for producing an ultra-thin steel strip large single-weight coil, characterized in that the coil is wound as f / mm ² .

(5) The winding is performed so that the winding tension in the section sandwiched between the two positions is substantially constant or the coil is gradually reduced from the inner diameter side to the outer diameter side of the coil. )).

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS First, the present invention will be described based on experimental results. When using an aging steel strip with a thickness of 0.180mm and a tempering degree of T5CA to finish and wind a thin tin-plated steel strip on a tin plating line, a rigidity coefficient of 0.04
kgf / mm (YS 20kgf / mm ² , plate thickness 1mm), 0.05kgf / mm (YS 25k
gf / mm ² , thickness 1 mm), 0.4 kgf / mm (YS 25 kgf / mm ² , thickness 3 m
m)) When using an iron sleeve (diameter: 508 mm) and when not using a sleeve, when winding a coil on these sleeves (reel if there is no sleeve),
While changing the level of the winding tension, the tension change in the coil was changed under the following three conditions, and the state of the coil was investigated. The circularity of the sleeve used was good, with a deviation from the perfect circle (defined in FIG. 1) of 5 mm or less. After winding about 5 m (3 turns) from the beginning of winding, the tension is increased, and then winding is performed with the same tension toward the end of winding. After winding about 5 m (3 turns) from the start of winding, the tension is increased, and then winding is performed while increasing the tension toward the end of winding. After winding about 5 m (3 turns) from the start of winding, the tension is increased, and then winding is performed while gradually decreasing the tension toward the end of winding.

Based on the results obtained by the above experiments, the winding state of the coil and the state of the wound coil are classified as follows and shown in Table 1. Ia: Winding is interrupted because the coil becomes large in telescope shape during winding. Ib: Winding was interrupted because the coil became large in telescope shape during winding and abrasion occurred on the surface. II: The coil was wound up, but when it landed after moving the coil, the coil was crushed and the roundness was poor. III: It was wound up normally by the coil and could reach the slit line (good). IV: Wound on the coil, but kink occurred on the inner diameter of the coil if it landed after moving the coil.

Here, the meanings of the telescope, poor roundness, and kink are as follows. Telescope: As shown in FIG. 1 (a), this refers to a defect in which the coil is spirally wound, but may be a complicated spiral. If there is a telescope, the steel strip meanders when rewinding in the slitting process, so that the dimensional accuracy is reduced.
The definition of the telescope amount is shown in the figure.・ Improper roundness: As shown in Fig. 1 (b), the coil is crushed and flattened. If there is an improper roundness, the steel strip meanders in the slitting process or unwinds in the slitting process. Sometimes the feed speed of the steel strip becomes unstable.・ Kink: Refers to the buckling condition of the inner diameter of the coil shown in Fig. 1 (c).
Similar to the poor roundness, meandering and instability of the feed speed occur.

[0021]

[Table 1]

From Table 1, it can be seen that using a sleeve having a predetermined stiffness coefficient and winding in consideration of winding tension is extremely important for obtaining a normal coil. The reason for the need for a sleeve is explained as follows. The telescope is likely to be generated when the winding tension is low (the meandering correction ability is low at the time of winding, and it is likely to shift sideways at the time of handling, etc.). In addition, poor roundness (collapse of the coil) is more likely to occur when the winding tension is reduced because the plate cannot support its own weight. Can be prevented). According to this fact, when a high winding tension is applied, a telescope is less likely to be generated, but on the other hand, the inner diameter portion of the coil cannot easily support the stress (winding pressure) and tends to buckle. In particular, when the plate thickness is small and the coil unit weight is large, the suitable tension region sandwiched between the tension limits of the two is narrowed, and the shape cannot be maintained well. Therefore, if a sleeve having a predetermined rigidity or more is inserted into the inner diameter portion of the coil, the buckling resistance of the inner diameter portion increases, and the upper limit winding tension determined by the buckling limit is increased.

The present inventors have investigated in more detail, and the conditions of a normal coil are as follows: telescope amount 100 mm or less, deviation from a perfect circle 100 mm or less, kink degree 50 mm or less (all defined in FIG. 1), It was concluded that a reel stiffness coefficient of 0.05 kgf / mm or more was essential to satisfy these conditions. There is no upper limit to the rigidity coefficient of the sleeve, but is preferably 1.5 kgf / mm or less in consideration of cost. From the same point of view, it is important to use a sleeve having a deviation from a perfect circle of 5 mm or less, since a buckling limit is not sufficiently increased in a sleeve having a poor roundness. The error in the inner diameter is preferably set to 1.0% or less. Further, the sleeve must have a diameter of 400 to 600 mm together with the above-mentioned rigidity coefficient. This is because if the inner diameter of the winding coil is smaller than 400 mm, the reel strength is insufficient when winding a large single coil of 9 tons or more. This is because the diameter becomes too large and handling becomes inconvenient, and in particular, it becomes unstable when a slit coil is formed in units of one strip. It is desirable that the deviation of the sleeve from a perfect circle be suppressed to 10 mm or less.

Next, the winding tension will be described. When the winding tension is increased, the frictional force between the steel plates increases, and the steel plates behave in the same manner as when the steel plates are joined together and the plate thickness is increased, and an effect of increasing rigidity appears. For this reason, buckling of the inner diameter at the time of handling the steel strip coil and meandering at the time of rewinding are less likely to occur. On the other hand, when the winding tension is reduced, the tightening pressure is small, which causes buckling due to telescope or crushing. Also, if the thickness is small, the rigidity (thickness x thickness x
Yield point) decreases, the tightening pressure increases, and the coil is easily crushed. Conversely, when the sheet thickness is large, the steel strip does not collapse even if the winding tension is small. FIG. 2 summarizes the effects of the winding tension and the plate thickness on the state of the coil from the results of experiments by the inventors. The winding tension in the present invention was determined on the basis of FIG. 2 from conditions for preventing the occurrence of any of the kink and the telescope.
Therefore, the tension is 2.0 to 4.0 at 5m after winding starts.
increases in kgf / mm ² wound.

At this time, it is preferable to increase the tension toward the inner diameter side to oppose the tightening pressure, and reduce the tension toward the outer diameter side to reduce the tightening pressure. Therefore, it is desirable to reduce the tension from the inner diameter side to the outer diameter side by 0 to 40%, preferably 20 to 40%. For this reason, the lower limit of the outer winding side tension is 1.2
It is lowered to kgf / mm ^2. In addition, since the tensile stress on the coiler side cannot be ensured within 5 m of the beginning of the most winding (corresponding to about 3 windings until it is wound tightly), the end of the most winding
It is physically difficult to pull on the upper process side within 10 m (up to 10 m short), and high tension cannot be applied even if a pinch roll is provided in the immediate vicinity of the coil. In addition, within the range of the above control, the tension is 1.2 to
4.0 shall be managed within the range of kgf / mm ^2. Further, outside the above-mentioned control range, that is, within 5 m from the beginning of winding and within 10 m from the end of winding, tension is applied to such an extent that winding does not shift. FIG. 3 shows an example of a typical tension applying pattern. In the above description, the tension indicates the value at the time of winding, but it is also possible to measure the winding tension with the coil after winding. For example, a method is conceivable in which a force is applied to only a part of the coil in the lateral direction, and a load required to cause a deviation in the wound coil is investigated.

In addition, Table 1 shows that in Table 1, a coil wound under tension under conditions A to J using an iron sleeve having a rigidity coefficient of 0.05 kgf / mm (a deviation from a perfect circle of 5 mm or less) was used. The state of threading while rewinding at the slit line was examined. As a result, C to G were able to pass through the board well by visual observation. On the other hand, in A, B, and H to J, the swing of the pass line during passing was recognized with the naked eye. Next, while measuring the width accuracy of the slit steel strip, a 0.150 mm-thick can body plate (190 g can, circumferentially set length 16
5 mm (including 0.5 mm overlap allowance))
After laminating the film so as to match the direction of 90 ° (width direction of the plate), welding was performed at a welding speed of 120 m / min. In this way, the occurrence of scattering when welding and the peeling in the weld opening test were investigated. Here, the scattering occurrence index was defined as the total length of the scattering occurrence portion in the entire length of the welded portion of one can. The peeling index in the weld can expansion test is the ratio of cans generated to the total number of welded cans that were subjected to the peel test.
(%). The composition of the steel sheet is as follows: C: 0.041 wt%, Si: 0.01 wt%, Mn: 0.24 wt%,
P: 0.012 wt%, S: 0.014 wt%, Al: 0.029 wt%,
N: 0.0088 wt%, O: 0.002 wt%. Further, by setting the coil winding temperature after hot rolling to 600 ° C., a large amount of N solid solution remained, and dry temper rolling was performed under light pressure at a rolling reduction of 1 to 3%. The results are also shown in Table 1.

From Table 1, it was found that for C, E and F, very good weldability was obtained, and the accuracy in the width direction was as small as ± 0.05% or less. On the other hand, in the coils A, B, H to J which generate coils such as a telescope and a kink, welding defects such as generation of scattering and insufficient welding strength occurred. This is probably because the accuracy of the slit width is poor at ± 0.07 to 0.08% of the circumferential length of the weld can (including the overlap allowance). Note that D, G in which the winding tension was increased toward the outer diameter side of the coil.
In this case, scattering and insufficient welding strength occurred slightly. In D and G, the width accuracy was about ± 0.05 to 0.06%, which was better than that of the coil having a bad appearance, and the accuracy was worse than C, E, and F. Such a phenomenon is because the tension was excessive at the time of rewinding the coil, and it was not able to follow to the extent that it could not be recognized by the naked eye, and the width accuracy was poor. A similar experiment was also performed in a method of laminating a slit film on a large unit weight original plate coil. In the case of scatter, the slit width was as narrow as −0.06 to −0.08% of the circumferential length of the weld can (including the overlap allowance). On the other hand, those with insufficient strength were widened from + 0.06% to + 0.08%.

In the course of developing the present invention, the following points were also confirmed. The non-aged steel sheet is poor in scattering, and the aged steel sheet is excellent. In addition, even in the case of aging steel sheets, the circumferential direction of the can body is rolled.
Samples collected in the 90 ° direction tend to be scattered. Particularly, in the case of the aging steel sheet, when the length accuracy in the circumferential direction is shorter than the set value -0.05%, the accuracy becomes extremely poor. The peeling of the weld in the can-expansion test is not as large as the difference between the non-aged steel sheet and the aged steel sheet. However, in both steel sheets, the circumferential length accuracy exceeds + 0.05%. When it becomes long, it deteriorates remarkably.

Based on the above findings, a method of laminating a film on a steel strip for cans, shearing it into a large plate and slitting it into cans in one unit, or slitting the steel strip for cans in advance into a width of one can can be used as a film. In the method of laminating and then shearing to obtain a blank (can body material) per can, the appropriate welding current range narrows in the 90 ° rolling direction where the direction of collecting the can body is disadvantageous for welding. It seems that this is the cause, but it cannot be adopted because it causes a great disadvantage in industrially efficient production. Because, in the slit coil method, in order to make a blank of 1 can unit by laminating and shearing after lamination, as described above, it is necessary to leave exposed metal parts with a width of several mm at both edges corresponding to the welding position. There is. At this time, it is not always easy to laminate the front and back so that the center part with a width of several mm can be slit at high speed. If the operation is performed in accordance with the center portion in the width direction, the laminating operation can be performed continuously, and the position where such a single can is sheared does not correspond to the welding position, so that there is no hindrance to the seam welding operation. Therefore, in the present invention of the slit coil system, as a rational plate removing method, the circumferential direction of the body plate (the circumferential direction of the welding can) is set to the rolling 90 ° direction (the rolling plate width direction). It was assumed to be done.

Next, from the results of the above, it can be said that it is preferable to use an aging steel sheet in order to enable high-speed seam welding without causing scattering or welding peeling.
The reason why the occurrence of scattering is reduced when the aging steel sheet is used is explained as follows. That is, the material obtained by shearing the slit steel strip in can units is subjected to a mild bending-bending process by a kind of leveler mechanism called a flexor immediately before the welding operation in the can making process, and immediately thereafter. It is forcibly bent by colliding with an edge set at a specific angle to form a cylindrical can body. When an aged steel sheet is subjected to bending-bending back (usually about 0.1 to 1.5% in terms of surface strain) by this flexor,
Yield strength is significantly reduced. For this reason, the material can be formed without bending in the form of a broken line, and the welding of the both edges of the material is accurately associated with each other, and there is no scattering or peeling even by high-speed welding. In addition, since the aging steel sheet is subjected to baking at about 230 ° C. or less after the subsequent welding heat or repair of the paint of the welded part, it hardens by age hardening, which is advantageous in securing the strength of the can. The aging steel sheet is defined as a pre-strain of 7.5%, accelerated aging treatment at 100 ° C for 30 minutes with an aging index AI of 3 kgf / mm.
^It refers to a steel sheet having aging characteristics of ² or more.
On the other hand, non-aging steel sheets strengthened by the work hardening method have the same hardness and do not show the same softening as the aging steel sheets even through the flexor. Becomes larger. For this reason, it is considered that an extremely narrow welding width of 0.8 mm or less could not be obtained stably, and the welding current locally flowed to increase the melting of the steel sheet, resulting in scattering.

Further, when the width of the slit steel strip was shorter than the set length of the circumferential length by more than 0.05%, the occurrence of scattering in high-speed welding increased extremely. The reason is,
It is considered that the welding current locally flowed and scattered when the width of the steel strip was shortened due to the variation in width accuracy during the production of the slit steel strip for a welding width of 0.8 mm or less. Conversely, when the width of the slit steel strip became larger than the set value of the length in the circumferential direction by more than 0.05%, the peeling of the weld in the can open test increased remarkably. It is considered that the reason for this is that if the width is excessively larger than the set value, the welding width also increases, and the current flows in a wide range, so that sufficient welding strength cannot be obtained. Note that the width accuracy of the slit steel strip is ±
In order to be within the range of 0.05%, in addition to using the steel strip coil of the present invention described above, it is necessary to control dimensions with high precision as described later.

In order to ensure the welding width with high accuracy, in addition to the above-mentioned definition of the slit coil width accuracy, a material having a small yield strength at the time of welding (after passing through the flexor) is excellent. In this regard, the aging steel sheet is advantageous as described above. Further, in the rolling direction of 90 ° and the rolling direction, the yield strength in the former direction was higher, and this is considered to have led to the above result. It has also been found that such a tendency becomes larger as the work-hardening is increased by increasing the tempering reduction rate after the continuous annealing. The inventors further conducted experiments on the amount of decrease in yield strength by the flexor, that is, the amount of decrease in yield strength after bending-unbending, and found that the amount of decrease in yield strength was 5 kgf / mm.
^When it is ² or more, it has been found that the formability of the can body becomes good, the welding width can be secured with high accuracy, and the stabilization of high-speed welding is further facilitated. Of course, it has been confirmed that this decrease in yield strength is almost recovered by subsequent strain age hardening (by baking paint or standing at room temperature) and does not adversely affect the strength of the can.

As described above, in order to perform a high-speed welding and to make a three-piece can in a reasonable manner without causing spattering at the time of welding and peeling of the welded portion in the can-expansion test,
The precision of the circumferential length dimension is within ± 0.05% of the set length (that is, the circumferential length of the can including the overlap allowance) in strip milling where the rolling strip width direction is the circumferential direction of the welding can. It is desirable to use the aging steel sheet. By taking these measures, the springback is reduced due to the softening of the work in the flexor, the can becomes a highly circular can body, a welding width of about 0.8 mm or less can be secured with accuracy as set, and if welding with the set current, Thus, high-speed welding, which has been difficult in the past, can be performed. The reason why the thickness of the slit steel strip is set to 0.20 mm or less is that the effect of the present invention is particularly exhibited in a hard-to-weld thin material of 0.20 mm or less, and the unit weight of the coil is 9 tons or more. This is because the size is necessary for improving process productivity (eliminating unnecessary time for coil preparation, setup, acceleration, deceleration, etc.). Further, the reason why the plate width is set to 950 mm or more is a value set from the viewpoint of slitting efficiency, and it is not realistic to manufacture a coil of 9 tons or more with a width smaller than this.

Next, the desirable composition of the steel strip in the present invention will be described together with the main reasons. C: 0.06 wt% or less When the C content is more than 0.06 wt%, the overall crystal grain size is reduced, the cold rolling property is reduced, and the strength of the welded portion is increased to prevent cracking in flange processing. cause. Si: 0.03% by weight or less Si is an element that hardens the material in addition to deteriorating the corrosion resistance as a food can and should be suppressed. Mn: 0.05 to 0.5 wt% or less Mn is an element necessary to prevent edge cracking due to S in the hot-rolled steel strip, and is desirably added according to the S content. To increase the yield strength,
Excessive addition is not preferred. P: 0.02 wt% or less If P is contained excessively, it hardens the steel, deteriorates the rollability, and also deteriorates the corrosion resistance, so that it is suppressed. S: 0.02 wt% or less If S is excessively contained in relation to the Mn content, it causes not only edge cracking of the hot-rolled steel strip due to red hot embrittlement, but also lowers ductility and deteriorates corrosion resistance.

Al: 0.10 wt% or less If Al is added in a large amount, it is necessary to increase the amount of solid solution N in order to secure the strength of the can by heating after the flexure processing in the welding step. N: 0.005 to 0.015 wt% N promotes aging and adjusts the yield strength, but when added in a large amount, yield strength becomes too large. O: 0.01 wt% or less O forms an oxide and causes cracking or deterioration of corrosion resistance during can-making. Nb, Ti: 0.05 wt% or less for each Nb and Ti can be added for the purpose of preventing skin roughness due to fine graining. However, can strength and aging can be achieved by solid solution strengthening with solid solution C and especially solid solution N. Excessive addition is not preferred for the purpose of ensuring the properties.

The method for producing the steel strip coil of the present invention will be briefly described below. The slab for hot rolling is heated above 1200 ° C. In particular, heating at 1200 ° C. or higher is necessary to secure the solute N required for obtaining aging properties. The finish temperature of the hot finish rolling is Ar ₃ or more. At the edge portion where the temperature is apt to decrease, the crystal grains become coarse when the temperature is less than the Ar ₃ transformation point,
A uniform material cannot be obtained due to softening. Further, the winding temperature should be 650 ° C or less. Winding temperature
If the temperature exceeds 650 ° C., once decomposed AlN precipitates again, and it becomes difficult to secure aging properties. The rolling reduction of the cold rolling is desirably 85% or more from the viewpoint of productivity. A particularly preferred range is 88-92%. Prior to the cold rolling, the oxide scale adhering to the hot rolled sheet surface is removed by pickling or the like, if necessary.

As the annealing method, continuous annealing is preferable from the viewpoint of excellent material uniformity and high productivity.
The annealing temperature in continuous annealing is the recrystallization end temperature (usually 60
(Approximately 0 ° C) is necessary.However, if it is too high, the crystal grains become abnormally coarse and the surface roughness after processing becomes large. growing. Therefore, the upper limit of the annealing temperature is desirably 760 ° C. The aging effect by solid solution N is hardly reduced even when the overaging treatment is performed, but from the viewpoint of productivity, it is preferable not to involve the overaging treatment. In the temper rolling performed after annealing, light reduction rolling is used, and the elongation is set to 3 in order to suppress the large introduction of movable dislocations and obtain aging properties.
% Or less.

At the stage of a cold-rolled steel strip before slitting (that is, a steel strip generally subjected to cold rolling, annealing and temper rolling), the thickness variation of the cold-rolled steel strip in the strip width direction is reduced. It is preferable that the average sheet thickness is within ± 3%, and that the antinode growth height and the ear growth height of the cold-rolled steel strip are each 3 mm or less. If the variation in the thickness of the cold-rolled steel strip in the width direction exceeds ± 3% of the average thickness, even if the slitter operation conditions are optimized as described later, the unevenness of the steel sheet affects the slitting. In some cases, the target slit width accuracy may not be obtained. Also, when the height of the antinode or the height of the ear of the cold-rolled steel strip exceeds 3 mm, the plate may not be flat, and similarly, the slitting accuracy may not be ensured. In this way, in the cold-rolled steel strip before slitting, the thickness variation in the strip width direction is controlled within ± 3% of the average sheet thickness, and the antinode extension height and the ear extension height of the cold-rolled steel strip are controlled. In order to control the thickness to 3 mm or less, high-precision rolling such as work roll shift rolling or work roll cross rolling is performed during cold rolling, and the dimensions of the steel sheet immediately after cold rolling are controlled within the above target values. do it. In addition, since both ends of the cold-rolled steel strip are often cut off at least in the slitting step, about 5% of both ends in the sheet width direction (about 2.5% per side),
The target value may be deviated. In the longitudinal direction, if at least 95% of the entire length of the coil satisfies the target value, there is no problem in practical use.

Here, belly extension and ear extension are 3 m in length.
Cut a steel sheet of the appropriate degree from a steel strip, leave it on a flat surface plate, stretch the belly (irregular convex deformation near the center of the width of the plate) and extend the ear (irregular convex deformation at the end of the width of the plate). ) Shall be obtained from the maximum height. The average thickness of the cold-rolled steel strip is
The median value obtained by measuring about 10 points in the longitudinal direction of the central portion of the steel sheet cut out as described above was used. Although the steel sheet was sampled from several places on the coil, except for 5% at both ends in the longitudinal direction, the variation in the thickness in the longitudinal direction is generally small. There is no. It is preferable in terms of working efficiency that the cold-rolled steel strip be a large single-weight coil with a weight of 9 tons / coil or more. Also, the width of the steel strip is usually
A width of 950 mm or more is preferable from the viewpoint of increasing slitting efficiency and productivity.

When the cold-rolled steel strip thus obtained is finished into a steel sheet which has been subjected to a surface treatment such as thin tin plating by a conventional method, it is wound around a sleeve having a diameter of 400 to 600 mm.
The stiffness coefficient of the sleeve used should be 0.05 kgf / mm or more.
It should be made with attention to roundness, placed inside the coil and wound up. At the point 5 m from the end of the steel strip on the inner diameter side of the coil (about 3 turns from winding), apply tension to 2.
Winding is performed under a controlled tension such that the amount of decrease in tension decreases (including a constant) in the range of 0 to 40% of the tension toward the end of winding, increasing to 0 to 4.0 kgf / mm ² . And
The tension at 10m from the steel strip end on the coil outer diameter side is 1.2
Finish up as ~4.0 kgf / mm ^2. The reasons for these limitations are as described above.

Next, at the time of slitting, 0.8 ± 0.
5 kgf / mm ² , temperature fluctuation of slitter housing ± 3
It is preferable to perform slitting while maintaining the temperature within the range of ° C. If the tension deviates from the above range, the steel strip becomes C-warped, so the width after the slit becomes positive,
If it is lower, it will not reach the tension that can be wound without loosening the coil. If the amount of temperature fluctuation of the slitter housing is out of the above range, the positional relationship between the upper and lower axes changes due to the thermal expansion of the cutter shaft, and the target slit setting interval is deviated. In order to keep the tension within the above range, it is required to manage the tension more than conventionally performed.However, there are various known methods for concrete tension control methods. There is no problem in realizing if it operates. The temperature of the housing also fluctuates due to various factors such as a seasonal temperature difference, a daily temperature difference, and a temperature difference between the time of startup and the time of steady operation, so that intentional management / control is necessary. In order to minimize the error from the target width dimension, it is preferable to always operate at the same temperature (for example, 30 ° C) ± 3 ° C, but after adjusting the slit width to the target value, adjust the temperature fluctuation in a series of operations. The temperature may be suppressed to ± 3 ° C. Temperature management includes management of equipment heat generation, cooling water management,
It can be realized by appropriately combining known methods such as management of the ambient temperature. In addition, in order to improve the width accuracy of the slit steel strip, the roundness of the take-up reel is set to high precision to prevent flapping of the steel strip, and the gap between the upper and lower holding rubbers is reduced to reduce the gap when slitting. It is more effective to take measures such as preventing the steel strip from bending.

[0042]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described below based on embodiments. Steel having the composition shown in Table 2 was melted by a 270-ton bottom-blowing converter, and extruded while adding Al to obtain low-carbon and medium-carbon Al-killed steel. Then, after passing through a 75-ton large capacity tundish, a slab was obtained by a continuous casting machine. These slabs were heated and hot-rolled under the conditions shown in Table 3 and wound up to form a hot-rolled steel strip, which was descaled by pickling with hydrochloric acid. Subsequently, it was cold rolled to various ultrathin sheet thicknesses by a 6-stand tandem continuous cold rolling mill having a work roll cloth and a shift function. Thereafter, some of them were subjected to nickel diffusion treatment by nickel plating and continuous annealing, and the rest were simply subjected to continuous annealing without nickel plating to obtain cold-rolled annealed steel strips. here,
The thermal cycle was performed at a low temperature (680 to 750) ° C. × 10 seconds simple cycle or 450 ° C. × 1 minute overage treatment cycle. The atmosphere for continuous annealing is NHX gas atmosphere (10% H ₂ +90
% N ₂ ).

[0043]

[Table 2]

[0044]

[Table 3]

Next, after temper rolling was performed on each of these steel strips, a surface treatment such as tin plating, thin tin plating, and Cr plating was performed. For those not subjected to Ni diffusion treatment, various types of tin plating are applied in the halogen type electric tin plating process.
Those subjected to the Ni diffusion treatment were subjected to thin tin plating, and all of them were continuously subjected to reflow treatment (smelting treatment) and chromate treatment to finish tinplate and thin tin plated steel sheets, respectively.
From these surface-treated steel sheets, sipes are collected and
(HR30T) was measured, and it was confirmed to be T5. Whether the tin shape was an island-shaped tin distribution or whether the tin shape was flat as in the prior art was determined by observation with an electron microscope. Tin free steel plate (TFS) is an electroplating line, CrO ₃ ; 180g / l, H ₂ SO
₄ ; The amount of metallic chromium is 30 to 120 mg /
After plating of m ² , CrO ₃ ; 60 g / l, H ₂ SO ₄ ; 0.2 g / l
Chromium hydrated oxide (1 chromium equivalent)
3030 mg / m ² ) for plating. Samples were also taken from these surface-treated steel sheets, and the hardness (HR30T) was measured to confirm that it was T5.

The conditions of the used Ni plating bath, Sn plating bath, reflow and chromate treatment are as follows.

The surface-treated wide steel strips (996 mm width) of various thicknesses manufactured by the above-mentioned method were applied to an iron sleeve having a rigidity coefficient of 0.05 kgf / mm and a deviation from a perfect circle of 3 mm or less. To form a coil having an inner diameter of 508 mm and a single weight of 12 tons. From this coil, the tension during slitting is 0.7
kgf / mm ² (0.4 to 1.0 kgf / mm ² )
It was manufactured by 6 strips of 165 mm width so that the circumferential direction of the can body of the 190 g can was in the plate width direction on a slitter line maintained at a temperature of ~ 33 ° C. Note that 0.5 mm out of 165 mm is the overlap allowance. For comparison, the steel strip whose composition and production conditions from hot rolling to plating are the same as No. 1 in Tables 2 and 3 are shown below.
Telescope amount exceeds 100 mm (No. 10), roundness is 100 mm
Exceeding (No.11), the coil with a kink exceeding 50mm (No.12) was also made. The width of each slit steel strip was measured in μm. With respect to the obtained slit steel strip, the aging index AI (increase in yield strength after aging at 100 ° C for 30 minutes from the stress at the time of 7.5% prestrain) was measured, and the width accuracy of the slit steel strip was measured with a laser. Method Determined with a plate width measurement meter. In addition, the width | variety precision set the deviation amount from the target value of the part which deviated most from the target value (165 mm) in the whole coil length as the representative value.

Next, a slit steel strip was coated with an adhesive in advance by a film laminating line, and a gravure-printed PET film was dried on the outer surface of the can, and a transparent film was formed on the inner surface with a slit of 160 mm width. The film was laminated using a nip roll at a threading speed of 200 mpm, leaving a 2.5 mm metal exposed portion at both ends of the slit steel strip. This film laminate coil was primarily sheared to a length of 8 cans (108 mm x 8 = 864 mm), and then, from this sheet, 8 cans were sheared by a slitter in units of 1 can to complete a can body plate. .

A tensile test specimen in the width direction was obtained from the blank for a welding can body obtained in this manner, yield strength was determined, and a sample after passing through a flexor, and after welding evaluation, a welded portion was obtained. , Tensile test specimens in the width direction were sampled from the sample after passing through the repair painting / baking line, and the yield strength of each specimen was determined. Also, about this can body plate,
Welding was performed under the following conditions, and high-speed weldability was evaluated.・ Welding evaluation conditions Copper wire type ・ Electric resistance heating seam welder (commercial machine) Can type: 190g can body Copper wire diameter: 1.3 mmφ Passing speed: 120 m / min Welding pressure: 40 kg Frequency: 700 Hz The above setting conditions Then, n number of 1000 pieces of welding were performed, and the occurrence state of splash (splash) and the occurrence state of peeling of the welded part when the end of the cylinder after welding was enlarged by a conical punch were investigated. The obtained results were evaluated by an index indicating the ratio (%) of the number of generated cans to the total number of welded cans. In addition, the upper limit current value that does not cause dispersion and the peel welding strength (a peel test in which a cut is made at one end of the welded part and the welded part is peeled off from the body of the can is determined to be sufficient if the entire length of the welded part is torn off) ) Was evaluated as an appropriate welding current range, and if the value was 5 A or more, it was determined that a high-speed welding process was possible, and the weldability was evaluated.

Table 3 summarizes the experimental results obtained.
As can be seen from Table 4, the invention example has a good slit width accuracy, a high roundness, a low yield strength after flexure, and a small springback, so that an appropriate welding width can be obtained, No peeling was observed without occurrence of any. On the other hand, in Nos. 10 to 12 of the comparative examples, the slit width precision was poor, and the lap width was widened when the width was large, the current flowed over a large area, the welding strength was insufficient, and peeling occurred. In addition, current flows locally in a narrow one,
The temperature of the weld became high, and the iron melted out, resulting in poor dispersion.

[0051]

[Table 4]

[0052]

As described above, according to the present invention,
After slitting to the width (including the overlap allowance) of the circumferential length of the welded can body plate and laminating the film, or after laminating the film with the above width and slitting, welding and welding are performed. By improving the width accuracy or sticking accuracy of the slit steel strip when finishing, it is possible to form a body with high roundness, and to perform high-speed welding even with a narrow welding width without scattering or peeling of the welded part. Becomes possible. For this reason, it is possible to manufacture a three-piece can very reasonably.

[Brief description of the drawings]

FIG. 1 is a diagram for explaining an example in which the shape of a winding coil is deteriorated.

FIG. 2 is a diagram showing the influence of winding tension and sheet thickness on coil winding properties.

FIG. 3 is a schematic diagram showing an example of a temporal change in tension during winding of a coil according to the present invention.

Continuing from the front page (72) Inventor Hideo Kukuminato 1 Kawasaki-cho, Chuo-ku, Chiba-shi, Chiba Prefecture Inside the Chiba Works, Ltd. (72) Inventor Masato Iri 1 Kawasaki-cho, Chuo-ku, Chiba-shi, Chiba Pref.Kawasaki Steel Co., Ltd. F-term (reference) in Kawatetsu Techno Research Co., Ltd. 4E026 AA02 AA12 BA04 BA14 FA10

Claims (5)

[Claims] 1. A coil made of a steel strip having a thickness of 0.20 mm or less and a width of 950 mm or more and having a weight of 9 tons or more, wherein the coil has a diameter of 400 to 600 mm and a rigidity coefficient of 0.05 kgf / mm or more. An ultra-thin steel strip large single-weight coil wound around a sleeve. 2. A coil made of a steel strip having a thickness of 0.20 mm or less and a width of 950 mm or more and having a weight of 9 tons or more, wherein said coil has a diameter of 400 to 600 mm and a rigidity coefficient of 0.05 kgf / mm or more. The tension at the position 5 m from the coil inside diameter end of the steel strip is 2.0 to 4.0 kgf / mm ² , and the tension at the 10 m position from the coil outside diameter end is 1.2 to 4.0 kg
An ultra-thin steel strip large unit weight coil characterized by f / mm ² . 3. The pole according to claim 2, wherein the tension in the section sandwiched between the two positions is substantially constant or gradually decreases from the inner diameter side to the outer diameter side of the coil. Thin steel strip large unit weight coil. 4. When winding an ultra-thin steel strip having a thickness of 0.20 mm or less and a width of 950 mm or more into a large single coil of 9 tons or more, a diameter of 400 to 600 mm and a rigidity coefficient of 0.05 kgf / mm. Winding is started on the above sleeve, and the tension at a position 5 m from the start end of the winding is 2.0 to 4.0 kgf / mm ² and the tension at a position 10 m from the end is 1.2 to 4.0 kgf / mm.
A method for producing an ultra-thin steel strip large single-weight coil, characterized in that it is wound as mm ² . 5. The coil is wound so that the winding tension in the section sandwiched between the two positions is substantially constant or gradually decreases from the inner diameter side to the outer diameter side of the coil. The method for producing the ultra-thin steel strip large single-weight coil described in the above.