JPS6333103A - Continuous pickling treatment line for steel strip - Google Patents

Abstract

PURPOSE:To efficiently assure the uniformization of surface roughness and thorough descaling and to improve workability by subjecting a steel strip pickled in a pickling tank to a skin pass with a surface light draft mill provided on the down stream thereof. CONSTITUTION:The surface black scale of the hot rolled steel sheet 1 is removed by a descaling line 8 and is then between skin pass rolling rolls 12. The relatively coarse surface roughness is preliminarily imparted to the surface of the rolling rolls. The preferable surface roughness of the rolls is 5-20mum Ra and 10-100mum Rmax. The steel strip having excellent surface conditions is obtd. by the device constituted in the above-mentioned manner.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a continuous pickling treatment line for steel strips, and relates to an apparatus for producing steel plates that require surface roughness, such as surface-coated steel plates.

[Conventional technology]

Conventionally, steel plates or steel strips that require paintability, such as container materials, have poor paintability on the as-rolled surface. It was manufactured by obtaining roughness.

Shot blasting is a method of projecting shot grains or grid grains onto the surface while moving the plate at a constant speed to obtain a surface roughness of 1. Therefore, it is necessary to perform the operation by changing the size of the shot particles depending on the required level of surface roughness. In addition, shot grains are used in circulation, but when they are projected onto a plate, one grain is destroyed and the shot grains gradually become smaller. Therefore, shot grains are sequentially replenished, but the grain size naturally varies, resulting in unevenness in roughness.

Shotblasting hits particles like this.

B) It takes a lot of energy to project, B) The line speed cannot be increased due to the shot blast mechanism, C) It is necessary to replace the shot particles to match the required roughness, B) ) There is a large variation in the roughness of the plate surface.

There was a problem.

In addition, in the case of hot-rolled sheets, shot blasting often doubles as descaling at the same time, but since shot grains are applied to the steel sheet, it is difficult to completely remove scale, and problems such as decarburization occur during the next annealing. was there. For this reason, it has been common practice for steel plates with such strict quality requirements to undergo at least one descaling process, such as pickling, after or before shot blasting.

[Problem that the invention seeks to solve]

An object of the present invention is to provide an apparatus that solves these problems and can easily produce steel plates with a large surface roughness.

[Means for solving problems]

The present invention includes: (1) A continuous pickling treatment line for steel strips in which the surface of the steel strip that is continuously fed is descaled through a pickling tank; (2) A light surface reduction mill is installed downstream of the pickling tank. This is a continuous pickling treatment line for steel strips.

[Function] According to the line of the present invention, after the black scale on the surface of the hot-rolled coil is completely removed by pickling, etc., roll reduction is performed using specially processed rolls. A steel plate having the required surface roughness without variation can be easily obtained.

〔Example〕

FIG. 1 schematically shows 4: Example of the invention. The steel plate l unwound from the uncoiler 2 is flattened by a leveler 3, the leading end is cut by a shear 4, and then connected to the preceding steel plate by a welder 5, and guided to a pickling tank 8 via a looper 6. Next, it is washed with water in a water washing tank 9 to complete the pickling. The steel plate that comes out of the pickling process is 1. It is conveyed through the looper 7 and past the skin pass rolling roll 12 by the priddle roll 10.11,
It is wound up on the tension reel 14. The shear 13 cuts the steel plate l into an appropriate length. The rolling reduction ratio in skin pass rolling is measured by a tensioner 15 on the elongation wheel side.

In the present invention, a skin pass rolling roll 12 is provided after a descaling line (pickling) 8 for removing black scale on the surface of a hot rolled steel sheet l, and this skin pass roll is equipped with a roll having a large surface roughness. A predetermined surface roughness is obtained by applying surface pressure to the surface.

In this case, the problem is how much roughness can be given to the roll surface, but with the conventional method of shot blasting the roll surface, the roll roughness obtained is Ra: 3 to 4ILm, Rmax. :10-20 lm. Therefore, the roughness of the plate surface is large (Ra≧5JL
m, Rmax≧20#Lm) was not obtained.

To solve this problem, the roll is subjected to laser dull processing or discharge layer 1, and the roll surface roughness Ra: 5 to 20 gm,
Rmax: 10-100 ILm (7) A roll was manufactured, and using this roll, the steel plate after descaling was rolled down at a downstream ratio of 1-5%, making it possible to obtain a predetermined steel plate surface roughness. .

When changing the roughness, it is only necessary to change the rolls, so it only takes a few minutes, and unlike shot blasting, it does not require several tens of minutes of shot installation time.

Roll reduction to obtain surface roughness is preferably carried out immediately after descaling.

FIG. 2 shows a comparison of the roughness of a steel plate produced by shot blasting and a steel plate produced by laser dulling rolls, and the surface roughness is almost the same.

〔Effect of the invention〕

According to the device of the present invention, there are the following excellent effects.

(a) Unlike shot blasting, large equipment for projecting shots is not required, and large projecting equipment and energy are not required.

(b) The processing line speed is 20 to 30 mpm for the shot blast line, whereas the processing line speed for the method of the present invention is 200 to 300 mpm, which is the same as for the normal skin pass line.
It will be raised to m p m.

(C) It takes less time to change the roll compared to the 17-person staffing process for shot blasting.

(d) Complete descaling and surface roughening can be performed in the l line.

(e) Roughness variations can also be reduced.

[Brief explanation of the drawing]

FIG. 1 is a schematic side view of a rolling line that imparts surface roughness to a descaling line, and FIG. 2 is a chart comparing the surface roughness obtained under various manufacturing conditions. l... Steel plate 2... Uncoiler 3...
Leveler 4,13... Shear 5... Welding machine 6.7... Looper 8... Pickling 4't'l
9...Washing tank 10.11...Pridle roll 12...Skin pass roll 14...Tension reel 15...Extension wheel side ruler

Claims (1)

[Claims] 1. A continuous steel strip pickling treatment line in which the surface of a steel strip that is continuously fed is descaled through a pickling tank, and a surface light reduction mill is disposed downstream of the pickling tank. Continuous pickling treatment line for strips.