JPS603912A - Method for removing scale of surface layer of hot rolled sheet - Google Patents

Abstract

PURPOSE:To improve remarkably a descaling effect by regulating a rate of different speeds between opposing rolls to a specific value or more as well as regulating a rate of elongation to a specific value or less, in rolling a hot rolled sheet at the different speeds of rolls as a preceding process before a pickling or mechanical descaling process. CONSTITUTION:As a preceding process before a pickling or mechanical descaling process, a hot rolled sheet 1 is rolled by a high speed roll 2 and a low speed roll 3 which rotates at a lower peripheral speed than that of the roll 2. At that time, a rate of different speeds between the opposing rolls 2, 3 is regulated to >=1.2%, and a rate of elongation is regulated to lower than the rate of different speeds and preferably to <=0.5%.

Description

【発明の詳細な説明】 めの異周速圧延方法に係る。[Detailed description of the invention] This relates to a different circumferential speed rolling method.

（従来技術） 通常、熱間圧延機により圧延された熱延板は、板厚をよ
り薄くするために冷間圧延機により圧延されるが、その
際、熱延板にスケールが付着していると圧延及び製品に
問題を生じる。このため、熱延板は冷間圧延を行なう前
に、塩酸等の酸によるスケール除去（酸洗）やショツト
ブラスト等機械的な方法でスケール除去が行なわれる。(Prior art) Usually, a hot-rolled plate rolled by a hot-rolling mill is rolled by a cold-rolling machine to make the plate thinner, but at that time, scale is attached to the hot-rolled plate. This causes problems with rolling and products. For this reason, before hot-rolled sheets are cold-rolled, scale is removed by mechanical methods such as removal of scale with an acid such as hydrochloric acid (pickling) or shot blasting.

又この酸洗作業或いは機械的脱スケールの前に、予じめ
熱延板に曲げ加工を加えたり軽圧延を実施したりするこ
とにより、熱延板表面のスケールをはく離しやすい状態
にし、酸洗時間の短縮が可能な事が知られている。この
中でも軽圧延の効果が大きく、特に板をロールに巻き付
ける所謂異周速圧延の効果が大きい事が知られている。In addition, before this pickling work or mechanical descaling, the hot rolled sheet is bent in advance or subjected to light rolling to make it easier to peel off the scale on the surface of the hot rolled sheet. It is known that washing time can be shortened. Among these, it is known that light rolling has a great effect, and in particular, so-called different circumferential speed rolling, in which the plate is wound around rolls, has a great effect.

この異周速圧延の例としてｐｖ圧延による板の状況を第
１図に示すが、ｐｖ圧延では板１がｒｆ．Ｑを受けてい
る圧延領域４での板の表裏面に作用する摩擦力の方向が
、ロールの高速側２と低速側３で異なり、これによりス
ケールのはく離が促進されることが知られている。As an example of this rolling at different circumferential speeds, the state of a plate subjected to PV rolling is shown in FIG. It is known that the direction of the frictional force acting on the front and back surfaces of the plate in the rolling region 4, which is subjected to Q, is different between the high speed side 2 and the low speed side 3 of the rolls, which promotes scale peeling. .

而して、Ｐｖ圧延においては、」１下ロールの真速率は
２〜７％、又伸び率は真速率と等しい２〜７％程度で操
業されるのが通例である。こ＼で真速率は〔（高速ロー
ル周速）／（低速ロール周速）−ｉ）、又伸び率は（　
（ｔ　１／ｌＱ　）−１　３と定義される。但しｔｏ＝
圧延圧延長板長ｔｌ：圧延後仮長さである。In Pv rolling, the true speed of the first lower roll is usually 2 to 7%, and the elongation rate is about 2 to 7%, which is equal to the true speed. Here, the true speed rate is [(high speed roll circumferential speed)/(low speed roll circumferential speed) - i), and the elongation rate is (
It is defined as (t 1/lQ )-1 3. However, to =
Rolling extension plate length tl: Temporary length after rolling.

ところでかかるｐｖ圧延等の圧延によるスケール除去方
法で問題となるのは、スケールが付着している板を圧延
しているため、通常圧延より大きなロール摩耗を伴なう
が、このようなロールにより圧延を継続すると、Ｉｌｌ
狭材を通板した後に巾広材を通板した場合、＋＋］狭材
によるロール摩耗のため、ロールプロフィルが変化して
いるので巾広材の形状を悪化させ、通板作業に問題を生
じる。このため１１］広材からｌＪ狭材へと酸洗の通板
スケジュールを組む必要があり、生産効率を低下させて
いる。By the way, the problem with scale removal methods by rolling such as PV rolling is that since the plate with scale attached is rolled, it is accompanied by greater roll wear than normal rolling. Continuing, Ill
When passing a wide material after passing a narrow material, the roll profile changes due to roll wear caused by the narrow material, which worsens the shape of the wide material and causes problems in threading work. . For this reason, it is necessary to set up a pickling schedule from 11] wide timber to lJ narrow timber, which reduces production efficiency.

（発明の目的） 本発明者等はこの点について種々研究の結果、板形状に
影響を及ぼす基本的因子は勿論伸び率にあるが、この伸
−率を非常に小さくしても真速率を一定値以上に保つこ
とにより、酸洗性などの脱スケール効果を大ｒ１１に向
上させ得ることを知見し、これにより前記板形状悪化の
問題を解決したもので、これによりロールの長期使用、
即ち交換頻度面して本発明は、酸６Ｌ或いはメカニカル
なスケール除去工程の前工程として熱延板を異周速圧延
するにあたって、相対するロールの真速率を１．２チ以
上とするとともに、伸び率を前記真速率より小さく、且
つ帆５％以下とすることを要旨とするものである。(Purpose of the Invention) As a result of various studies on this point, the present inventors have found that the fundamental factor that affects the plate shape is, of course, the elongation rate, but even if this elongation rate is extremely small, the true velocity rate remains constant. By keeping the value above this value, we found that descaling effects such as pickling properties could be improved to a large degree of R11.This solved the problem of deterioration of the plate shape, and this enabled long-term use of the rolls.
In other words, in terms of the replacement frequency, the present invention is advantageous in that when rolling a hot rolled sheet at different circumferential speeds as a pre-process of an acid 6L or mechanical scale removal process, the true speed rate of the opposing rolls is set to 1.2 inches or more, and the elongation is The gist is to make the speed smaller than the true speed and 5% or less.

（発明の構成・作用） 以下本発明を図面に示す実施例に基づいて具体的に説明
する。(Structure and operation of the invention) The present invention will be specifically described below based on embodiments shown in the drawings.

第２図は熱延板ｌが高球ロール２に巻きつけられ、高速
ロール２の周速度と同速度にて通板される型式の異周速
圧延を示しており、高速ロール２より少し遅い周速で回
転する低速ロール３により、ロールの真速率より小さい
、はＸ′零に近い伸び率で圧延を受け、その後酸洗設備
に送られる。Figure 2 shows a type of mixed circumferential speed rolling in which a hot rolled sheet l is wound around a high ball roll 2 and passed at the same speed as the circumferential speed of the high speed roll 2. The material is rolled by a low-speed roll 3 rotating at a high speed at an elongation rate smaller than the true velocity of the roll and close to zero X', and then sent to a pickling facility.

本発明の圧延においては、伸び率をはＸ零に近いもい、
よ零アあ、６えあ仲。。ヨ１ゆヵ１ゎ、板。　１形状を
悪化させる原因が俣り除かれ、又高速ロール２と低速ロ
ール３にて圧下力を加えられ、その圧下部では板の表裏
逆方向に剪断力を生じるため、前記ｐｖ圧延とほぼ同等
のスケールはく離を行なう事が＝Ｉ能である。In the rolling of the present invention, the elongation rate is close to X zero,
Yo Zero Ah, 6 Ah Naka. . Yo 1 Yuka 1ゎ, board. 1. The cause of deterioration of the shape is removed, and rolling force is applied by high-speed roll 2 and low-speed roll 3, and shearing force is generated in the opposite direction of the front and back of the plate at the rolling part, so it is almost equivalent to the above-mentioned PV rolling. It is possible to perform scale peeling of

第３図はロールの異速率毎の板の伸び率と酸洗性向上率
との関係を示すものである。実線は真速率３％の例、点
線は異速率キ伸び率である通常のｐ　’ｖ圧延の例、一
点鎖線は真速率０％即ち通常圧延の場合に相当する。FIG. 3 shows the relationship between the elongation rate of the plate and the pickling performance improvement rate at different speeds of the rolls. The solid line corresponds to an example of a true speed rate of 3%, the dotted line corresponds to an example of normal p'v rolling with a different speed rate and elongation rate, and the dashed line corresponds to a case of a true speed rate of 0%, that is, normal rolling.

これから明らかなことは、ｐｖ圧延では伸び率の」１昇
とともに酸洗性向上率が上昇し、又通常圧延の場合には
伸び率を大きくしないとそれが向上しないが、真速率３
％の例では既に伸び率が０％でも、ｐｖ圧延の伸び率は
ｖ　１．５％（異速率キ１．５％）に相当する酸洗性向
上率をもつということである。What is clear from this is that in PV rolling, the pickling property improvement rate increases as the elongation rate increases by 1, and in the case of normal rolling, it does not improve unless the elongation rate increases, but the true speed rate increases by 3.
% example, even if the elongation rate is already 0%, the elongation rate of PV rolling has an improvement rate of pickling property equivalent to v 1.5% (different speed rate ki 1.5%).

このことはｐｖ圧延と比較した場合、真速率は酸１５１
Ｅ性向上率に対し、伸び率よりも効果は小さいが相当な
影響をもっており、むしろ後述する伸び率の形状悪化に
及ぼす影響の大きさを考慮し、真速率を調整することに
よって、酸洗性を向上させることの必要性を示している
。This means that when compared with PV rolling, the true speed rate is 151
Although the effect is smaller than that of elongation, it has a considerable influence on the E-property improvement rate.Rather, by adjusting the true speed rate, taking into consideration the magnitude of the effect of elongation on shape deterioration, which will be described later, pickling property can be improved. It shows the need to improve.

こ＼で酸洗性向上率とは（前処理板酸６し速度）／（未
処理板酸洗速度）であり、前処理板とはかかるｐｖ圧延
等のスケールブレーキングを行なった板のことをいう。Here, the pickling property improvement rate is (pretreated plate acid 6 rate) / (untreated plate pickling rate), and the pretreated plate is a plate that has undergone scale breaking such as PV rolling. means.

而して本発明においてはこの真速率は１．２％以上とさ
れる。これは第３図から明らかなように、従来のｐｖ圧
延に比し、充分な酸洗性向上率を確保するための下限で
あり、これ以下では真速率による酸洗向上率は小さく、
実操業における効果はほとんどなくなる。In the present invention, this true speed ratio is set to 1.2% or more. As is clear from Fig. 3, this is the lower limit for ensuring a sufficient pickling performance improvement rate compared to conventional PV rolling, and below this, the pickling improvement rate due to true speed is small.
There will be almost no effect in actual operation.

一方第４図には＋１］狭材を通板し、摩耗したロールで
広巾月な通板した時の板の伸び率と形状（急峻度）の関
係を示したもので、伸び率が帆５％くらいより急激に形
状が、悪化していることが判る。On the other hand, Figure 4 shows the relationship between the elongation rate and the shape (steepness) of the board when the board is passed through +1] narrow material and the board is passed wide with worn rolls, and the elongation rate is 5. It can be seen that the shape has deteriorated more rapidly than about 20%.

即ちこのことから本発明ではまず伸び率を０．５％以下
好ましくは零又は零近傍に保って形状の悪化を防ぎ、そ
の上で真速率を１．２％以上とするものであり、実際上
の真速率は第３図の酸ｂＩＳ性向」１率と伸び率及び真
速率との関係から選定される。That is, in the present invention, first of all, the elongation rate is maintained at 0.5% or less, preferably at zero or near zero to prevent deterioration of the shape, and then the true velocity rate is set at 1.2% or more. The true speed rate is selected from the relationship between the acid bIS propensity 1 rate and the elongation rate and true speed rate shown in FIG.

（実施例） 実施例１ 熱延板通板速度：　１５０ｍｐｍ 伸び率　二〇〜０．２％ 異通率　：１．５％ 酸６Ｌ性向」１率　：１゜２倍 実施例２ 熱延板通板速度：　２００ｍｐｍ 伸び率　二〇〜０．２％ 異通率　：２．０％ 酸洗性向上率　：　１．２５倍 （発明の効果） 本発明は以」二述べたように、従来異周速圧延では、異
通率及び伸び率をはゾ同じ値で操業することにより脱ス
ケール効果を得ていたが、本発明では両者の関係を杓破
することにより、大ＩＪな酸ｂＬ性向」二と形状悪化の
改牌を図ったもので、工業的効果は極めて大きい。(Example) Example 1 Hot-rolled sheet threading speed: 150 mpm Elongation rate 20-0.2% Distortion rate: 1.5% Acid 6L propensity 1 rate: 1°2 times Example 2 Hot-rolled sheet threading Plate speed: 200 mpm Elongation rate: 20 to 0.2% Distortion rate: 2.0% Pickling property improvement rate: 1.25 times (Effect of the invention) As described below, the present invention In high-speed rolling, the descaling effect was obtained by operating at the same value for the difference ratio and the elongation ratio, but in the present invention, by breaking the relationship between the two, the acid bL propensity with large IJ is improved. This is an attempt to change the shape of the label, and the industrial effect is extremely large.

なお、本発明の説明では、板を高速ロールに巻き伺けた
状態で説明したが、かならずしも板なロールに巻き伺け
る必要はなく、又板を低速ロールに巻き付けても本発明
の範囲を逸脱するものではない。In addition, in the explanation of the present invention, the board is wound around a high-speed roll, but it is not necessarily necessary to wind the board around a roll, and even if the board is wound around a low-speed roll, it is beyond the scope of the present invention. It's not a thing.

さらに本発明の説明では、酸洗作業の前に本発明を実施
する例を示したが、メカニカルなスケール除去法に適用
しても本発明は有効である。Further, in the description of the present invention, an example was shown in which the present invention is implemented before the pickling operation, but the present invention is also effective when applied to a mechanical scale removal method.

【図面の簡単な説明】[Brief explanation of drawings]

第１図は通常のＰＶ圧延の説明図、第２図は本発明を適
用した説明図、第３図は板の伸び率と酸洗性向上率との
グラフ、第４図は板の伸び率と形状とのグラフである。 １：熱延板　２：高速ロール ３：低速ロール 第７　回 第３回 第４０Fig. 1 is an explanatory diagram of normal PV rolling, Fig. 2 is an explanatory diagram to which the present invention is applied, Fig. 3 is a graph of plate elongation rate and pickling property improvement rate, and Fig. 4 is a plate elongation rate. This is a graph of the shape and shape. 1: Hot rolled plate 2: High speed roll 3: Low speed roll 7th 3rd 40th

Claims (1)

【特許請求の範囲】[Claims] 酸洗或いはメカニカルなスケール除去工程の前工程とし
て熱延板を異周速圧延するにあたって、相対するロール
の真速率を１２％以上とするとともに、伸び率を０．５
％以下とすることを特徴とする熱延板表面層のスケール
除去方法。When rolling hot-rolled sheets at different circumferential speeds as a pre-process of pickling or mechanical scale removal, the true speed ratio of opposing rolls is set to 12% or more, and the elongation ratio is set to 0.5.
% or less. A method for removing scale from a surface layer of a hot rolled sheet.