JPH01319628A - Production of extremely thin and hard black plate in continuous annealing equipment - Google Patents

Abstract

PURPOSE:To produce the extremely thin and hard black plate at a high speed without generating a heat buckle by continuously annealing a cold rolled steel sheet consisting of an extra-low carbon steel thicker than the target thickness, then subjecting the sheet to temper rolling at the time of producing the extremely thin and hard black plate. CONSTITUTION:The extremely low carbon cold-rolled steel sheet which is produced by hot rolling and cold rolling a raw material steel slab to the thickness larger by about 25% than the final target value of 0.20mm and has <100ppm C is drawn out of a pay-off reel 1 and is welded by welder to the terminal end of the preceding steel sheet and thereafter, the surfaces are cleaned by cleaning equipment 4 at the time of producing the extremely thin and hard black plate having <0.20mm thickness and >T-4 degree of tempering. The steel sheet is then passed at >800m/min line speed in a continuous annealing furnace consisting of a preheating zone 6, heating zones 7, 8, a soaking zone 9, and a cooling zone 10 and is thereby continuously annealed. This steel sheet is temper-rolled at >=20% draft by >=2 stands of cold rolling mills 12. The steel sheet for the extremely thin and hard black plate having <0.20mm thickness and >T-4 degree of tempering is thus produced at a high speed without generating the heat buckle.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] This invention relates to a method for producing ultra-thin hard tin plate blanks in continuous annealing equipment.

(Prior art) Generally, when annealing a surface-treated original plate such as a tin plate or a steel plate for tin-free steel, the degree of tempering is T-] to T.
Soft materials such as T- are box annealed, with a range of 1゛-4 to T-
The hard material No. 6 was subjected to continuous annealing.

When continuously annealing a hard surface-treated original sheet with a thermal refining degree of T-4 or higher, the maximum speed that can be achieved in the continuous annealing operation is approximately the same as that of the steel sheet, except for the heating capacity of the annealing furnace. It depends on the presence or absence. In other words, a large number of hearth rolls are installed in the upper and lower parts of the continuous annealing furnace, and the surface-treated original sheet is sequentially wound around these hearth rolls and subjected to a predetermined heat treatment. The hearth roll is provided with a so-called crown whose diameter is slightly enlarged from both ends of the roll toward the center in order to prevent the original sheet from meandering. In particular, in the cooling zone of a continuous annealing furnace that cools the original sheet heated to a high temperature, the part of the hearth roll that is in contact with the original sheet remains at a high temperature, while the two ends that are not in contact are at a low temperature. Crown occurs, and Hearth roll's 1-tal crown becomes popular. Therefore, the force acting in the width direction of the original plate increases, and as a result, the original plate buckles in the width direction, resulting in so-called heat buckling. This situation is more likely to occur as the threading speed of the original plate increases and as the plate thickness becomes thinner.
The occurrence frequency is particularly high in extremely thin original plates with a thickness of 0.2 mm or less.

In continuous annealing of ultra-thin steel sheets, there is no publicly known data clearly arranging the maximum speed for threading in relation to the thickness and material quality, but it is generally For carbon steel, the plate thickness is about 0.200n,
The maximum speed is approximately 650 to 720 m/min.

[Problems to be solved by the invention] In the conventional manufacturing method as described above, the thinner the plate, the more likely it is that heat occlusion will occur, and even if the furnace has sufficient heating capacity, There was a problem that it became a major factor that hindered manufacturing efficiency.

This invention was made in view of these conventional problems, and the present invention has been made in view of the above-mentioned conventional problems.
The aim is to solve the above problems by using ultra-low carbon steel sheets with a carbon content of 00 pp or less.

[Means for Solving the Problems] This invention uses continuous annealing equipment with a line speed of 800 m/min or more to produce ultra-thin products with a thickness of 0.200 mm or less and a tempering degree of "T'-4 or more." In producing a hard tin plate, an ultra-low carbon steel plate with a carbon content of 1100 pp or less is continuously annealed, and the plate thickness at the entrance side of the continuous annealing furnace is 25% or more thicker than the product plate thickness, and at the same time, at the exit side of the continuous annealing furnace This is a method for manufacturing extremely γ!■ hard tin plate blanks in continuous annealing equipment, which is characterized in that rolling is performed with a rolling reduction of 20% or more using a cold rolling mill having a configuration of two or more stands.

[Effect]

As already mentioned above, the occurrence of heat I and heat cracks during continuous annealing is mainly affected by the thinness of the sheet as well as the speed at which the sheet passes through the furnace. By increasing the plate thickness, it is possible to prevent this problem from occurring.

Therefore, when the sheet threading speed is limited to 800 mpm or more,
In order to obtain an ultra-thin hard tin plate with a product thickness of 2.00 mm or less and a tempering level of 1'-4 or higher, the thickness should be 25% of the product thickness.
Heat buckling is prevented by passing thicker original plates through the furnace, and the carbon content of this original plate is 1100p.
A cold rolling mill with two or more stands installed on the exit side of the furnace uses ultra-low carbon steel with a carbon content of 20% or less.
If temper rolling is performed with the following reduction ratio applied, the above-described predetermined product plate thickness and temper degree due to work hardening can be obtained.

〔Example〕

Hereinafter, the present invention will be explained with reference to the drawings. FIG. 1 is a schematic diagram showing an example of continuous annealing equipment for carrying out the present invention.

In the figure, 1 is a payoff reel equipped with a coil that is 25% thicker than the ultra-thin hard tin plate 15 that is the product, and the coil (
The tip of the original plate is joined to the end of the preceding coil by a welder 2. Even during this joining process, the preceding original sheet is degreased, pickled, and washed from the entry side No. 1 looper 3 without stopping the sheet threading.
After passing through cleaning equipment 4 such as washing with water, it is sent to the input side No. 2 looper 5.

Next, from this No. 2 looper 5 to the preheating zone 6. No,
1 heating zone 7. Portion 2 heating zone 8. Soaking zone9. The sheet is passed through a continuous annealing furnace consisting of a cooling zone of 0 at a line speed of 80 Qmpm, but due to the thickness of the original sheet, no heat buckle occurs on the way and the sheet passes through the exit louver 11. It is then rolled in a cold rolling mill (temper rolling mill) consisting of two stands 1.2, 1.2 at a pressure of 20% or more to achieve a temper degree of 'r-4 or higher. It is given hardness by work hardening, becomes an ultra-thin hard tin plate original plate 15 through fine finishing (ifη13), and is wound on a tension reel 14. Also, from the payoff reel 1 to the tension reel 14 The line speed of the blank in between is maintained at 800 rn/min or higher.

Here, a general method of the above-mentioned cold rolling mill, for example, JP-A-51
The difference from the skin pass mill for tinplate disclosed in Publication No. 4.9116 is that (1) the present invention uses an emulsion type rolling oil, but uses a solution type tempering fluid; 2) The present invention is at least No. 1 stand 12 drives the work roll under -L or drives the upper and lower backup rolls, whereas the skin pass drives only the lower work roll or the lower back up roll. It has the characteristic that it is often

Next, the product board WO shown in the present invention, 200 bracken or less, for example, O, ], 70 yrya and 0. ],
Reduction rate (reduction, thickness reduction rate), continuous annealing furnace (
CAL) Thickness of the plate is as shown in the table below.

In addition, Table 1 shows product plate thicknesses of 0.170 and 0.150.
This is only an example of carbon content of 1.2 and 2.0, and other product plate thickness requirements can be similarly applied.
By using ultra-low carbon steel of OOppm or less,
A desired degree of tempering can be obtained by adjusting the rolling reduction rate. However, the desired product cannot be obtained with general low carbon steel due to work hardening.

[Effects of the Invention] As explained below, according to the present invention, the cost reduction is promoted by the can manufacturer Q.
In addition to meeting the demand for ultra-thin tin plate sheets that are thinner and harder, it also significantly improves productivity by increasing line speed and reducing heat rolls.Furthermore, since cold rolling is performed continuously, it is possible to reduce the need for a single process. This has the effect of eliminating problems such as increased lead time and delayed delivery.

[Brief explanation of the drawing]

Figure 1 shows a continuous annealing setup (+!ff) for carrying out the present invention.
FIG. 2 is a schematic diagram showing an example. 6.7, 8, 9.10... Continuous annealing furnace, 12.
...Cold rolling mill stand, 15...Product (ultra-thin hard tin plate). Patent applicant: Kawasaki Steel Corporation Representative Patent attorney: Tetsuya Mori

Claims (1)

[Claims] (1) Continuous annealing equipment with a line speed of 800 m/min or more is used to manufacture ultra-thin hard tin blanks with a product thickness of 0.200 mm or less and a tempering degree of T-4 or higher. An ultra-low carbon steel plate having a carbon content of 100 ppm or less that is 25% or more thicker than the product plate thickness at the side is continuously annealed, and is cold rolled having a configuration of two or more stands arranged on the exit side of the continuous annealing furnace. 20% depending on machine
A method for producing an ultra-thin hard tin plate in a continuous annealing facility, characterized by rolling with a rolling reduction of the above value.