JPH079029B2 - Manufacturing method of ultra-thin hard tin plate in continuous annealing equipment - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for manufacturing an ultrathin hard tin plate in a continuous annealing facility.

[Prior Art] Generally, when surface-treated original plates such as tin plate and tin-free steel plates are annealed, soft materials with tempers T-1 to T-3 are annealed in a box and Hard materials 4 to T-6 are annealed by continuous annealing.

And the tempering rate, when continuously annealing the hard surface-treated original plate of T-4 or more, the maximum speed that can be taken in the continuous annealing work is, except for the heating capacity of the annealing furnace, whether or not the heat buckle of the steel sheet occurs. It depends. That is, a large number of hearth rolls are provided in the upper and lower parts of the furnace in the continuous annealing furnace, and the surface-treated original plate is subjected to a predetermined heat treatment while being sequentially wound around these hearth rolls. In order to prevent the original plate from meandering, the hearth roll is provided with a so-called crown whose diameter is slightly increased from both ends of the roll toward the center. And in particular, in the cooling zone of the continuous annealing furnace that cools the original plate heated to a high temperature, the part in contact with the original plate of the hearth roll keeps the high temperature, and the both ends which are not in contact are the low temperature, so the thermal crown Occurs, the total crown of the hearth roll increases. Therefore, the force acting in the width direction of the original plate becomes large, and as a result, the original plate buckles in the width direction and a so-called heat buckle is generated. This situation is more likely to occur as the plate passing speed increases and the plate thickness decreases.
The frequency of occurrence is especially high for ultra-thin original plates with a thickness of 0.2 mm or less.

Here, in the continuous annealing work of ultra-thin steel plates, there is no known data that clearly arranges the maximum speed of the threading in relation to the plate thickness and the material, but in general, low carbon, which is a general material for tinplate, is used. Steel has a thickness of about 0.200 mm and a maximum speed of about 650 to 720 m / min.

[Problems to be Solved by the Invention]

In the conventional manufacturing method as described above, heat buckle is more likely to occur as the plate thickness becomes thinner, and even if there is a margin in the heating capacity of the furnace, it becomes a major factor that hinders manufacturing efficiency. There was a problem.

This invention is made in view of such conventional problems, the plate thickness on the inlet side of the continuous annealing furnace is 25% or more thicker than the product plate thickness carbon content 100ppm or less ultra low carbon steel plate The purpose is to solve the above-mentioned problems by using it.

[Means for Solving the Problems]

This invention uses a continuous annealing facility with a line speed of 800 m / min or more to achieve a product sheet thickness of 0.170 mm or less and a temper of T-4.
In producing the above ultra-thin hard tin plate, the continuous annealing furnace has a plate thickness on the inlet side of the continuous annealing furnace that is 25% or more thicker than the product plate thickness, and an ultra-low carbon steel sheet with a carbon content of 100 ppm or less is continuously annealed. A method for producing an ultra-thin hard tin plate in a continuous annealing equipment, characterized by rolling with a reduction rate of 20% or more by a cold rolling mill having two or more stands arranged on the outlet side of is there.

[Action]

As already mentioned above, the occurrence of heat buckle during continuous annealing is based mainly on the fact that the plate thickness of the original plate depends on the thinness of the plate thickness in addition to the plate passing speed of the original plate. By increasing the size, it is possible to prevent the occurrence of this problem.

Therefore, if the sheet passing speed is limited to 800 mpm or more, in order to obtain an ultrathin hard tin plate with a product plate thickness of 0.170 mm or less and a temper of T-4 or more, a master plate that is 25% or more thicker than the product plate thickness To prevent heat buckle by passing it through a furnace, and using ultra-low carbon steel with a carbon content of 100 ppm or less as the raw material of this original plate, which has two or more stands arranged on the outlet side of the furnace. When temper rolling is performed by applying a reduction rate of 20% or more by a rolling machine, the above-mentioned predetermined product sheet thickness and temper degree by work hardening can be obtained.

〔Example〕

Hereinafter, the present invention will be described 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, reference numeral 1 is a pay-off reel in which a coil having a plate thickness 25% or more thicker than the plate thickness of the ultra-thin hard tin plate 15 as a product is mounted, and the tip of the coil (original plate) dispensed from this is the preceding coil. The end and the welder 2 are joined. Even at this time of joining, the preceding original plate is sent from the No. 1 looper 3 on the inlet side to the No. 2 looper 5 on the inlet side through the cleaning equipment 4 such as degreasing, pickling, and washing with water without stopping the passage of the sheet. Next, from No. 2 looper 5, pre-tropical zone 6, No. 1 heating zone 7, No. 2
A continuous annealing furnace consisting of heating zone 8, soaking zone 9, and cooling zone 10 is passed through at a speed that maintains a line speed of 800 mpm, but since the original plate is thick, heat buckle does not occur on the way and Sent to side looper 11 and two more stands 12,1
In a cold rolling machine (temper rolling mill) consisting of 2 rolling at a reduction rate of 20% or more, hardness by work hardening with a tempering degree of T-4 or more is imparted, and after passing through the refining equipment 13, It becomes a thin hard tin plate 15, and is wound around a tension reel 14. Also, the line speed of the original plate from the pay-off reel 1 to the tension reel 14 is 800 m / min.
The above is maintained.

Here, the above-mentioned cold rolling mill is generally used, for example, JP-A-51-4.
The difference from the skin pass mill for tinplate disclosed in Japanese Patent No. 9116 is that the present invention uses (1) an emulsion type rolling oil, whereas (2) uses a solution type refining liquid. In the invention, at least the No. 1 stand 12 is driven by the upper and lower work rolls or is driven by the upper and lower pack-up rolls, whereas the skin path is often driven by the lower work roll only or the lower backup roll only. There is a feature such as.

Next, the product plate thickness 0.200 mm or less shown in the present invention,
For example, the reduction rate (reduction, thickness reduction rate) for manufacturing products with a tempering degree of T-4 or higher with plate thicknesses of 0.170 mm and 0.150 mm,
The plate thickness of the continuous annealing furnace (CAL) is as shown in the table below.

In addition, the above table is an example only for two levels of product sheet thickness of 0.170 mm and 0.150 mm, and similarly for other product sheet thickness requirements, ultra low carbon with carbon content of 100 ppm or less By using steel as the material, the reduction ratio can be adjusted to obtain the desired temper. However, a desired product cannot be obtained from general low carbon steel due to work hardening.

〔The invention's effect〕

As described above, according to the present invention, it is possible to meet the demand for a thinner and harder ultra-thin tin plate which is promoted by the cost reduction in the can manufacturing maker, and the line speed is increased and the heat buckle is reduced. Since the productivity is greatly improved and the cold rolling is performed continuously, the effects of increasing the lead time for the single process and delaying the delivery date can be obtained.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing an example of continuous annealing equipment for carrying out the present invention. 6,7,8,9,10 …… Continuous annealing furnace, 12 …… Cold rolling stand, 15
…… Product (ultra-thin hard tin plate).

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yoshikazu Seino 1 Kawasaki-cho, Chiba-shi, Chiba Inside the Chiba Works, Kawasaki Steel Co., Ltd. (56) References JP 61-69928 (JP, A) JP 61 -207520 (JP, A) JP-A-60-262918 (JP, A)

Claims (1)

[Claims] 1. A continuous annealing facility with a line speed of 800 m / min or more, the product sheet thickness is 0.170 mm or less and the temper is T-4.
In producing the above ultra-thin hard tin plate, the continuous annealing furnace, the plate thickness on the inlet side of the continuous annealing furnace is 25% or more thicker than the product plate thickness, and the ultra-low carbon steel sheet with a carbon content of 100 ppm or less is continuously annealed. A method for producing an ultra-thin hard tin plate in a continuous annealing facility, which comprises rolling with a reduction ratio of 20% or more by a cold rolling mill having two or more stands arranged on the outlet side of the plate.