JPS62224404A - Hot skin pass installation - Google Patents

Abstract

PURPOSE:To specifically improve the flatness of a steel strip by providing a four high mill which can vary a work roll crown and disposing bridle roll units which apply specific high tension to the steel strip before and behind said mill. CONSTITUTION:The four high skin pass mill 5 which can vary the work roll crown so as to meet the profile of the steel strip is provided and the bridle roll unit 8, 9 respectively disposed before and behind said mill. A connector 10 is further installed behind a shear 4. The steel strip is wound around the bridle rolls 8A, 9A of the units 8, 9 and the rolls are driven to apply the high tension of >=0.3sigmay to the steel strip according to the above-mentioned mechanism. The steel strip is then subjected to skin pass rolling with the rolling mill 5 and the steel strips are connected by the connector 10 such as MAG welding machine. Since the skin pass rolling is executed while the high tension is kept applied to the steel strip, the flatness of the steel strip is made <=0.3% steepness.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to hot skin pass equipment for continuously flattening hot rolled steel strips.

[Prior art and its problems]

Hot-rolled hot-rolled steel strips are temper-rolled in hot skin pass equipment, but in recent years, quality requirements for hot-rolled steel strips have become stricter, and in particular the flatness of the strips has been required for cold-rolled steel mills. There is.

On the other hand, the thickness of steel strips tends to become thinner and the tensile strength thereof increases, making it difficult to obtain flatness.

Conventional hot skin pass equipment, as shown in Figure 4,
A strip steel S-hinch roll 2 unwound from an uncoiler 1;
It passes through a leveler 3 and a shear 4, undergoes straightening rolling in a four-layer skin pass mill 5, passes through a deflector roll 6, and is wound onto a tension reel 7.

In such equipment, the steel strip is skin-passed one by one, and the tension applied to the steel strip during the skin-pass is generated by an uncoiler and a tension reel, and its value is small at most 0.1σy (σy is It has been impossible to stably produce a flat steel strip with a steepness of 0.3 or less from the leading edge to the trailing edge.

This invention was proposed in view of the above circumstances, and its purpose is to cover the entire length of a hot rolled steel strip, that is, from the leading edge to the end of one steel strip (2 km in length) in the longitudinal direction. To provide hot skin pass equipment capable of stably producing a flat steel strip with a steepness of 0.3 inches or less up to the edge.

[Means for solving problems]

The hot skin pass equipment according to the present invention includes a four-layer rolling mill in which a roll bender and/or a variable crown roll roll, and a work roll crown are variable in accordance with the strip steel profile; Placed in the front and rear, 0.3σy on the steel strip
The inlet/outlet priddle roll unit imparts the above high tension, and the
Equipped with connecting machines such as AG welding machines and plasma welding machines, it performs skin passes under high tension of 0.3σy or more and changes the crown of the work roll according to the strip profile to achieve good flatness. It is designed so that it can be obtained.

Furthermore, by connecting the steel strips with a connecting machine, the above conditions can be obtained also at the most and rearmost ends in the longitudinal direction of one steel strip, and a steel strip that is flat over the entire length can be obtained.

〔Example〕

The present invention will be described below based on an illustrated embodiment.

Note that the same reference numerals are given to parts that are the same as or correspond to the conventional ones.

As shown in Figure 1, an entry side priddle roll unit 8 and an exit side priddle roll unit 9 are provided before and after the 4-type skin pass mill 50, and a connecting machine l is installed at the rear stage of the shear 4.
O. A shear 11 is provided in front of the deflector roll 6.

With this configuration, the strip steel S is wound around the priddle rolls 8 Ae 9 A of the priddle roll units 8 and 9,
This roll is driven by a motor to apply high tension.

Experiments have shown that the relationship between steepness λ and unit tension is as shown in Fig. 2, and the skin pass is applied when the unit tension, which is the tension per cross-sectional area in the width direction of the steel strip, is 0.3σy or more. If steepness λ (= h/e x 10
0%) 0.3% or less flatness comparable to that of cold-rolled steel sheets can be obtained.

゛ The connecting machine 10 connects the leading steel strip and the trailing steel strip,
The condition is to obtain a connecting portion that can withstand the above unit tension, and although a MAG welding machine was used in the implementation of the present invention, a method such as plasma welding may also be used.

In addition to the rolling down mechanism for rolling down the steel strip, the skin pass mill needs to have a function of bending the work roll 5A so that it corresponds to the plate profile of the steel strip.

As a concrete method for this function, role bending is the most suitable method. The roll bender has an increase function that creates a convex crown by applying force between the chocks of the upper and lower work rolls, and an increase function that applies force between the chocks of the upper and lower work rolls, as well as an increase function that applies pressure between the chocks of the upper and lower work rolls, and an increase function that applies pressure between the chocks of the upper and lower work rolls to create a convex crown.
Between the chocks of B and/or between the chocks of the lower work roll and the lower back-up roll 5B, there is a defreezing function that applies force between the chocks to create a concave crown.

Further, the present invention is not limited to this, and a VC (barrier pull crown) roll whose crown is variable by introducing high pressure oil into a hydraulic chamber provided in the roll may be used as the backup roll 5B.

In carrying out the present invention, a four-layer skin bath mill having all of the above-mentioned functions as a work roll crown control function was used.

Further, a flatness measuring device 12 is installed on the exit side of the skin pass mill to measure the flatness, and feedback is sent to the crown control mechanism to adjust the crown.

Incidentally, the shear 11 is for cutting the leading end and the trailing end of the steel strip.

Next, the board thickness is 1.6 m11, and the board width is 100011. length 1
560m, a large number of steel strips with a yield stress σ'l of 40 kgf/km.The skin pass unreduced rate is the percentage of the part that could not be rolled down by the skin pass mill, and the flat defect rate is the steepness rate) 0.3% occurrence rate. It is about.

From the above, it is clear that according to the present invention, hot rolled steel strips of good flat quality can be stably obtained.

〔Effect of the invention〕

As described above, according to the present invention, rolling is performed using a four-layer skin pass mill with variable work roll crowns while applying a high tension of 0.3σy or more using priddle rolls, and further, the strip is connected using a connecting machine. Because of this configuration, the flatness of a thin hot-rolled high-strength steel strip having a plate thickness of 5 nm or less can be reduced to a steepness of 0.3% or less, which is comparable to that of a cold-rolled steel sheet.

Furthermore, good flatness can be obtained over the entire length of the steel strip.

[Brief explanation of drawings]

Figure 1 is a schematic diagram showing the hot skin pass equipment according to the present invention, Figure 2 is a graph showing the relationship between steepness and unit tension, Figure 6 is a schematic diagram showing the steepness, and Figure 4 is a conventional hot skin pass. It is a schematic diagram of the equipment. 1... Uncoiler, 2... Vinty roll, 3... Leveler, 4... Shear,
5...4 is the formula skin pass mill, 5A...
・Work roll, 5B...Backup role, 6・
... Deflector roll, 7... Tension reel, 8... Entry side priddle roll unit, 9... Output side priddle roll unit,
10... Connection machine, 11... Shear, 1
2...Flat measuring instrument.

Claims (1)

[Claims] (1) Hot-skin pass equipment that rolls the hot-rolled steel strip uncoiled from the uncoiler to flatten it while applying tension, and then winds it onto a tension reel, where the work roll is rolled using a roll bender and/or a variable crown roll. A four-layer rolling mill whose crown is variable according to the strip profile; A hot spring characterized by comprising an exit bridle roll unit and a connecting machine that is arranged on the exit side of the uncoiler and that connects the leading steel strip and the trailing steel strip and forms a connection that can withstand high tension. Skin pass equipment.