JPH06170431A - Manufacture of wide flange shape without web wave - Google Patents
Manufacture of wide flange shape without web waveInfo
- Publication number
- JPH06170431A JPH06170431A JP3036076A JP3607691A JPH06170431A JP H06170431 A JPH06170431 A JP H06170431A JP 3036076 A JP3036076 A JP 3036076A JP 3607691 A JP3607691 A JP 3607691A JP H06170431 A JPH06170431 A JP H06170431A
- Authority
- JP
- Japan
- Prior art keywords
- flange
- web
- cooling
- rolling
- temperature
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Landscapes
- Metal Rolling (AREA)
- Control Of Metal Rolling (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明はウェブ波のないＨ形鋼の
製造方法に関し、特にフランジの冷却処理条件をフラン
ジとウェブとのの温度差によって決定する製造方法に関
するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing an H-section steel without web waves, and more particularly to a method for producing a cooling treatment condition for a flange by the temperature difference between the flange and the web.
【０００２】[0002]
【従来の技術】Ｈ形鋼の断面形状は、図１に示すよう
に、通常フランジ１の厚さがウェブ２の厚さよりも厚く
なっているため、熱延過程でウェブ２の冷却速度がフラ
ンジ１に比較して速くなり、仕上圧延終了時にはフラン
ジ温度がウェブ温度よりも２００℃以上も高くなる場合
がある。この圧延終了時のフランジ１とウェブ２との仕
上温度差のため、室温まで冷却された状態においてはフ
ランジ１がウェブ２に比べて相対的に短かくなり、図２
に示すようにフランジ１に引張り残留応力が発生し、ウ
ェブ２に圧縮残留応力が発生する。そして、ウェブ２の
圧縮残留応力が座屈応力を越えるとウェブ波が発生して
形状不良となり、製品として使用できなくなる。従っ
て、このようなウェブ波を防止するためには、ウェブの
圧縮残留応力を座屈応力以下に抑制しなければならな
い。2. Description of the Related Art As shown in FIG. 1, the cross-sectional shape of H-section steel is such that the thickness of the flange 1 is usually thicker than the thickness of the web 2. In some cases, the flange temperature becomes higher than that in Example 1, and the flange temperature becomes 200 ° C. or more higher than the web temperature at the end of finish rolling. Due to the difference in finishing temperature between the flange 1 and the web 2 at the end of rolling, the flange 1 becomes relatively shorter than the web 2 in a state where the flange 1 and the web 2 are cooled to room temperature.
As shown in (1), tensile residual stress is generated in the flange 1 and compressive residual stress is generated in the web 2. Then, when the compressive residual stress of the web 2 exceeds the buckling stress, a web wave is generated, resulting in a defective shape and unusable as a product. Therefore, in order to prevent such web waves, the compressive residual stress of the web must be suppressed below the buckling stress.
【０００３】ウェブ波の発生原因となる残留応力を軽減
させる方法が従来種々開示されているが、作業能率の点
ですぐれている製造方法としては、圧縮時にフランジを
冷却する特公昭４１−２０３３６号公報に開示された製
造方法、及び仕上げ圧延後フランジを冷却する特公昭４
７−３１４８１号公報に開示された製造方法がある。こ
れらの方法においてはいずれもＨ形鋼が高温の状態にあ
るうちフランジを冷却し、残留応力の発生原因となるフ
ランジとウェブとの温度差を縮小するようにしている。Various methods for reducing the residual stress that causes the generation of web waves have been disclosed in the past, but as a manufacturing method which is superior in work efficiency, Japanese Patent Publication No. 41-20336 which cools the flange during compression is disclosed. Manufacturing method disclosed in the publication and Japanese Patent Publication No. Sho 4 for cooling flange after finish rolling
There is a manufacturing method disclosed in JP-A 7-31481. In all of these methods, the flange is cooled while the H-section steel is in a high temperature state to reduce the temperature difference between the flange and the web, which causes residual stress.
【０００４】しかし、これらの方法を実施するには、圧
延時にフランジを冷却する場合にはフランジ及びウェブ
の仕上温度又はその温度差を、圧延後にフランジを冷却
する場合には冷却後のフランジ及びウェブの温度又はそ
の温度差を具体的に設定する必要があるが、これについ
ては従来の方法においては明確にされていなかった。However, in order to carry out these methods, when the flange is cooled during rolling, the finishing temperature of the flange and the web or the temperature difference thereof is used. When cooling the flange after rolling, the flange and the web after cooling are used. It is necessary to specifically set the temperature or the temperature difference thereof, but this has not been clarified in the conventional method.
【０００５】ところで、フランジの厚さとウェブの厚さ
との比が３程度になる薄肉ウェブＨ形鋼では、フランジ
を冷却しない場合には延終了時にフランジ温度はウェブ
温度よりも２００℃以上高くなるのが普通である。この
温度差を１回のフランジ冷却で縮小するには強いフラン
ジ冷却を行ってフランジ温度の降下量を大きくする必要
がある。本発明者らは、１回の冷却でのフランジ温度の
降下量が大き過ぎるとその冷却中にウェブ波が発生する
ことを発見した。この現象は、フランジが強く冷却され
て大きく収縮するとその反力としてウェブに大きな圧縮
応力が発生し高温状態にあって降伏応力が低下している
ウェブは容易に塑性して座屈するという謂ゆる塑性座屈
に起因している。このようにフランジ冷却中に発生する
ウェブの座屈を冷却中座屈と云う。これに対して、前述
のごとくフランジを冷却した後室温近くまで冷却された
状態で発生するウェブの座屈を冷却後座屈と云う。冷却
中座屈は冷却後座屈と同様に形状不良の原因となるが、
それを防止する冷却条件はまだ明らかでない。By the way, in the thin web H-section steel in which the ratio of the thickness of the flange to the thickness of the web is about 3, if the flange is not cooled, the flange temperature becomes 200 ° C. or more higher than the web temperature at the end of rolling. Is normal. In order to reduce this temperature difference with one flange cooling, it is necessary to perform strong flange cooling and increase the amount of flange temperature drop. The present inventors have discovered that if the amount of decrease in the flange temperature in one cooling is too large, a web wave is generated during the cooling. This phenomenon is because when the flange is strongly cooled and contracts greatly, a large compressive stress is generated in the web as a reaction force, and the yield stress is reduced due to high temperature, so the web easily plasticizes and buckles. Caused by buckling. The buckling of the web generated during flange cooling is called buckling during cooling. On the other hand, as described above, buckling of the web that occurs after cooling the flange and then cooling to near room temperature is called buckling after cooling. Buckling during cooling causes shape defects as well as buckling after cooling,
The cooling conditions to prevent it are not clear yet.
【０００６】[0006]
【発明が解決しようとする課題】本発明は、上記従来例
の問題点及び本発明者らにより発見された上記の新らた
な問題点を解決するためになさされたものであり、ウェ
ブに冷却後座屈が発生しないようにするために、仕上圧
延後のフランジとウェブの許容温度差（圧延時のみフラ
ンジを冷却する場合）、仕上圧延後にフランジ冷却を行
った後の許容温度差（仕上圧延後にフランジを冷却する
場合）、ウェブに冷却中座屈が発生しないための１回の
冷却で許容されるフランジ温度の降下量、冷却後座屈及
び冷却中座屈が発生しないための必要条件である最後の
フランジ冷却開始時のフランジとウェブの許容温度差等
を具体的に設定することにより、ウェブ波のないＨ形鋼
を製造すること可能にしたウェブ波のないＨ形鋼を製造
方法を提供することを目的とする。The present invention has been made to solve the problems of the above-mentioned conventional examples and the above-mentioned new problems found by the present inventors. To prevent buckling after cooling, the allowable temperature difference between the flange and the web after finish rolling (when the flange is cooled only during rolling) and the allowable temperature difference after flange cooling after finish rolling (finishing When cooling the flange after rolling), the amount of flange temperature drop allowed for one cooling to prevent buckling of the web during cooling, and necessary conditions for preventing buckling after cooling and buckling during cooling. A method for producing an H-section steel without a web wave, which makes it possible to produce an H-section steel without a web wave, by specifically setting the allowable temperature difference between the flange and the web at the start of cooling the last flange Can provide The interest.
【０００７】[0007]
【課題を解決するための手段】本願の発明の１つの態様
によれば、ウェブの冷却後座屈を防止するために次のよ
うな処理がなされる。すなわち、Ｈ形鋼の圧延時だけに
フランジを冷却するＨ形鋼の製造方法においては、仕上
圧延後の自然放冷開始時において、フランジの平均温度
とウェブの平均温度との差が下記関数式で示される冷却
後座屈の限界温度差ΔＴａ以下となるように圧延時のフ
ランジ冷却を行う。According to one aspect of the present invention, the following processing is performed to prevent buckling of the web after cooling. That is, in the method for manufacturing the H-section steel in which the flange is cooled only during rolling of the H-section steel, the difference between the average temperature of the flange and the average temperature of the web at the start of spontaneous cooling after finish rolling is expressed by the following functional expression. The flange cooling at the time of rolling is performed so that the temperature difference ΔTa of the buckling after cooling is less than or equal to ΔTa.
【０００８】また、Ｈ形鋼の仕上圧延後だけ、又は圧延
時及び仕上圧延後にフランジを冷却するＨ形鋼の製造方
法においては、仕上圧延後のフランジ冷却を行った後の
自然放冷開始時において、フランジの平均温度とウェブ
の平均温度の差が下記関数式で示される冷却後座屈限界
温度差ΔＴａ以下となるように仕上圧延後、又は圧延時
及び仕上圧延後にフランジ冷却を行う。 ΔＴａ＝｛（１＋Ａｗ／Ａｆ）σcr／Ｅ−３×１０-4｝×１０5 …（１） σcr＝Ｍｉｎ｛３．６Ｅ（ｔｗ／Ｈｗ）2 ，σｙ｝ Ａｗ，Ａｆ：ウェブ及びフランジの断面積 Ｅ：常温でのヤング率 ｔｗ：ウェブの厚さ Ｈｗ：ウェブの内幅 σｙ：常温でのウェブの降伏応力 ΔＴａ：単位℃ ここで、フランジの平均温度はフランジ外側面と内側面
の平均温度であり、ウェブの平均温度はウェブ中央の表
面温度又はウェブ表面のいくつかの点の平均温度であ
る。Further, in the method for producing the H-section steel in which the flange is cooled only after the finish rolling of the H-section steel, or during the rolling and after the finish rolling, in the natural cooling after the flange cooling after the finish rolling is started. In the above, flange cooling is performed after finish rolling, or during rolling and after finishing rolling so that the difference between the average temperature of the flange and the average temperature of the web is equal to or less than the buckling limit temperature difference after cooling ΔTa represented by the following functional expression. ΔTa = {(1 + Aw / Af) σ cr / E−3 × 10 −4 } × 10 5 (1) σ cr = Min {3.6E (tw / Hw) 2 , σ y } Aw, Af: Web and Cross-sectional area of flange E: Young's modulus at room temperature tw: Thickness of web Hw: Inner width of web σ y : Yield stress of web at room temperature ΔTa: Unit ° C Here, the average temperature of the flange is the outer surface and inner surface of the flange. It is the average temperature of the sides, and the average temperature of the web is the surface temperature at the center of the web or the average temperature of several points on the web surface.
【０００９】本発明者らの研究により、圧延時だけにフ
ランジを冷却する場合には仕上圧延後の自然放冷開始時
におけるフランジ平均温度とウェブ平均温度の差、或い
は仕上圧延後、又は圧延時及び仕上圧延後にフランジを
冷却する場合には仕上圧延後の冷却を行った後の自然放
冷開始時におけるフランジ平均温度とウェブ平均温度の
差が、Ｈ形鋼の形状と材料定数から決まる冷却後座屈の
限界温度差ΔＴａ以下であればウェブの冷却後座屈は発
生しないことが判明した。自然放冷開始時におけるフラ
ンジの平均温度とウェブの平均温度との差が冷却後座屈
の限界温度差以下となるように、圧延時、仕上圧延後又
は圧延時と仕上圧延後に、図３に示すようにフランジ水
冷装置３を使用してフランジ水冷を行うことにより、ウ
ェブ波のないＨ形鋼を製造することができる。According to the study by the present inventors, when the flange is cooled only during rolling, the difference between the average temperature of the flange and the average temperature of the web at the start of natural cooling after finishing rolling, or after finishing rolling, or during rolling. When cooling the flange after finish rolling, the difference between the average temperature of the flange and the average temperature of the web at the start of natural cooling after cooling after finishing rolling is determined by the shape and material constants of the H-section steel. It has been found that buckling does not occur after cooling the web if the buckling limit temperature difference ΔTa or less. In order to make the difference between the average temperature of the flange at the start of spontaneous cooling and the average temperature of the web less than the critical temperature difference of buckling after cooling, during rolling, after finishing rolling, or during rolling and after finishing rolling, as shown in FIG. As shown, by performing flange water cooling using the flange water cooling device 3, it is possible to manufacture an H-section steel without web waves.
【００１０】また、本発明の他の態様によれば、ウェブ
の冷却中座屈を防止するために次のような処理がなされ
る。すなわち、圧延時、仕上圧延後、又は圧延時及び仕
上圧延後にフランジを冷却する場合に、１回又は複数回
にわたってフランジ冷却するものとし、そして、１回の
冷却によるフランジの平均温度の降下量が下記関数式に
示される冷却中座屈限界温度降下ΔＴｂ以下となるよう
にフランジの冷却を行う。According to another aspect of the present invention, the following treatment is performed to prevent buckling during cooling of the web. That is, when the flange is cooled during rolling, after finish rolling, or during rolling and after finish rolling, the flange is cooled once or plural times, and the amount of decrease in the average temperature of the flange due to one cooling is The flange is cooled so that the buckling limit temperature drop ΔTb during cooling, which is represented by the following functional expression, becomes equal to or less than ΔTb.
【００１１】ｔｆ≦２０mmでＡｆ／Ａｗ≦１．７のと
き、又はｔｆ＞２０mmのとき ΔＴｂ＝２０．４（Ａｆ／Ａｗ）2 −１３９（Ａｆ／Ａｗ）＋２９６ …（２） ｔｆ≦２０mmでＡｆ／Ａｗ＞１．７のとき ΔＴｂ＝１２０ …（３） また、圧延時だけにフランジを冷却するＨ形鋼の製造方
法では、フランジ平均温度降下量は通常仕上圧延直前に
行うフランジ冷却で最も大きく、この冷却でのウェブの
冷却中座屈発生の危険性が高い。仕上圧延後だけに又は
圧延時と仕上圧延後にフランジを冷却するＨ形鋼の製造
方法では、仕上圧延後に行う冷却でのフランジ温度降下
量が通常最も大きく、この冷却での冷却中座屈発生の危
険性が高い。本発明者らは、これらの冷却中座屈の危険
性が高い冷却において、フランジの平均温度の降下量
が、Ｈ形鋼のフランジとウェブの断面積比とフランジ厚
みから決まる前記冷却中座屈限界温度降下ΔＴｂより小
さければ冷却中座屈は発生しないことを見出した。すな
わち、圧延時だけにフランジを冷却する場合には仕上圧
延直前のフランジ冷却において、仕上圧延後だけに、又
は圧延時及び仕上圧延後にフランジを冷却する場合には
仕上圧延後のフランジ冷却において、図３に示す如くフ
ランジ水冷を行う際、フランジの平均温度の降下量が冷
却中座屈の限界温度降下以下の範囲内で冷却を行えばウ
ェブの冷却中座屈を防止できる。When tf ≦ 20 mm and Af / Aw ≦ 1.7, or when tf> 20 mm ΔTb = 20.4 (Af / Aw) 2 -139 (Af / Aw) +296 (2) When tf ≦ 20 mm When Af / Aw> 1.7 ΔTb = 120 (3) Further, in the manufacturing method of the H-section steel in which the flange is cooled only during rolling, the average flange temperature drop is usually the most in flange cooling performed immediately before finish rolling. Large, there is a high risk of buckling during web cooling during this cooling. In the manufacturing method of the H-section steel in which the flange is cooled only after finish rolling or during and after rolling, the amount of flange temperature drop in the cooling performed after finish rolling is usually the largest, and buckling occurs during cooling in this cooling. High risk. In the cooling in which there is a high risk of buckling during cooling, the inventors have decided that the amount of decrease in the average temperature of the flange is determined by the sectional area ratio of the flange and the web of the H-section steel and the flange thickness during cooling. It was found that buckling does not occur during cooling if it is smaller than the limit temperature drop ΔTb. That is, when cooling the flange only during rolling, in the flange cooling immediately before finish rolling, only after finish rolling, or in the flange cooling after finish rolling when cooling the flange during rolling and after finish rolling, As shown in FIG. 3, when the flange water cooling is performed, the buckling during cooling of the web can be prevented if cooling is performed within a range in which the amount of decrease in the average temperature of the flange is less than the limit temperature drop of buckling during cooling.
【００１２】これは一例であって、１回又は複数回行う
すべてのフランジ冷却において、フランジの平均温度の
降下量は冷却中座屈の限界温度降下以下となる範囲内に
なければならない。そして、この範囲内の冷却を行うこ
とにより前述の如く仕上圧延後又は仕上圧延後の冷却を
行った後のフランジ平均温度とウェブ平均温度との差を
冷却後座屈の限界温度差以下とすればウェブの冷却後座
屈も防止でき、ウェブ波のないＨ形鋼を製造することが
できる。This is an example, and in all the flange cooling performed once or a plurality of times, the amount of decrease in the average temperature of the flange must be within a range that is less than the critical temperature drop of buckling during cooling. Then, by performing cooling within this range, the difference between the average temperature of the flange and the average temperature of the web after the finish rolling or after the finishing rolling is cooled as described above is less than the critical temperature difference of buckling after cooling. For example, buckling of the web after cooling can be prevented, and H-section steel without web waves can be manufactured.
【００１３】また、本発明の他の態様によれば、ウェブ
の冷却後座屈及び冷却中座屈を防止するためには次の処
理がなされる。すなわち、圧延時、又は圧延時及び仕上
圧延後にフランジを冷却する際に、複数回行うフランジ
冷却のうち最後の冷却の開始時において、フランジの平
均温度とウェブの平均温度との差が冷却後座屈の限界温
度差ΔＴａと前記冷却中座屈の限界温度降下ΔＴｂの和
であるΔＴａ＋ΔＴｂより小さくなるように粗圧延中又
は仕上圧延以前にフランジを冷却する。According to another aspect of the present invention, the following treatment is performed to prevent buckling of the web after cooling and buckling during cooling. That is, at the time of rolling, or at the time of rolling and cooling the flange after finish rolling, at the start of the final cooling of the flange cooling performed a plurality of times, the difference between the average temperature of the flange and the average temperature of the web is after cooling. The flange is cooled during rough rolling or before finish rolling so that it becomes smaller than ΔTa + ΔTb, which is the sum of the critical temperature difference ΔTa for buckling and the critical temperature drop ΔTb for buckling during cooling.
【００１４】前述したように、自然放冷開始時のフラン
ジの平均温度とウェブの平均温度との差がΔＴａ以下で
あればウェブの冷却後座屈は発生しない。更に、前述し
たように、１回のフランジ冷却でのフランジの平均温度
の降下量が全てのフランジ冷却でΔＴｂ以下であればウ
ェブの冷却中座屈は発生しない。従って、最後のフラン
ジ冷却開始時においてフランジの平均温度とウェブの平
均温度との差がΔＴａ＋ΔＴｂより小さければ、フラン
ジの平均温度をウェブの冷却中座屈が発生しないΔＴｂ
よりも小さい範囲内で降下させ、かつ自然放冷開始時の
フランジの平均温度とウェブの平均温度との差を冷却後
座屈の発生しないΔＴａ以下とすることができる。すな
わち、最後のフランジ冷却開始時におけるフランジの平
均温度とウェブの平均温度との差がΔＴａ＋ΔＴｂより
小さくなるように粗圧延中間又は仕上圧延以前に図３に
示す如くフランジ水冷を行い、最後のフランジ冷却にお
いて図３に示す如くフランジ水冷により、冷却後の自然
放冷開始時のフランジの平均温度とウェブの平均温度と
の差がΔＴａ以下となるように、フランジの平均温度の
降下量がΔＴｂ以下となる範囲内でフランジを冷却する
ことにより、冷却中座屈も冷却後座屈も防止できてウェ
ブ波のないＨ形鋼を製造することができる。As described above, if the difference between the average temperature of the flange at the start of spontaneous cooling and the average temperature of the web is ΔTa or less, buckling of the web after cooling does not occur. Further, as described above, buckling does not occur during cooling of the web if the average temperature drop of the flange in one flange cooling is ΔTb or less in all flange cooling. Therefore, if the difference between the average temperature of the flange and the average temperature of the web at the start of the final flange cooling is smaller than ΔTa + ΔTb, the average temperature of the flange does not cause buckling during cooling of the web ΔTb.
The temperature can be lowered within a smaller range, and the difference between the average temperature of the flange at the start of spontaneous cooling and the average temperature of the web can be set to ΔTa or less at which buckling does not occur after cooling. That is, flange water cooling is performed as shown in FIG. 3 before the rough rolling intermediate or finish rolling so that the difference between the average temperature of the flange at the start of the final flange cooling and the average temperature of the web becomes smaller than ΔTa + ΔTb, and the final flange cooling is performed. In Fig. 3, the amount of decrease in the average temperature of the flange is ΔTb or less so that the difference between the average temperature of the flange and the average temperature of the web at the start of natural cooling after cooling is equal to or less than ΔTa by the flange water cooling. By cooling the flange within the range, buckling during cooling and buckling after cooling can be prevented, and an H-section steel without web waves can be manufactured.
【００１５】[0015]
【実施例】表１は鋼種ＳＳ４１のＨ形鋼を製造したとき
の結果を示しており、表中の温度はすべて平均温度であ
る。EXAMPLES Table 1 shows the results when H-section steels of steel type SS41 were manufactured, and the temperatures in the table are all average temperatures.
【００１６】[0016]
【表１】 [Table 1]
【００１７】ケース１，２ケースのＨ形鋼のサイズで
は、自然放冷時の温度差が９５℃で、冷却後座屈の限界
温度差ΔＴａ＝１１３℃，冷却中の限界温度降下ΔＴｂ
＝１６３℃である。ケース１に示すように、このサイズ
では仕上圧延後にフランジ水冷を行いフランジ温度を８
１℃降下させてウェブ波のないＨ形鋼が製造できた。フ
ランジの温度降下がΔＴｂより小さい８１℃とし自然放
冷時のフランジとウェブの温度差をΔＴａより小さい９
５℃としたため冷却中座屈及び冷却後座屈を防止でき
た。Regarding the sizes of the H-section steels of cases 1 and 2, the temperature difference during natural cooling is 95 ° C., the limit temperature difference ΔTa = 113 ° C. of buckling after cooling, and the limit temperature drop ΔTb during cooling.
= 163 ° C. As shown in Case 1, with this size, the flange temperature is set to 8 by water cooling the flange after finish rolling.
A H-section steel without web waves could be manufactured by lowering by 1 ° C. The temperature drop of the flange is 81 ° C, which is smaller than ΔTb, and the temperature difference between the flange and the web during natural cooling is smaller than ΔTa 9
Since the temperature was 5 ° C, buckling during cooling and buckling after cooling could be prevented.
【００１８】ケース２に示すように無水冷ではウェブ波
が生じたが、これは自然放冷時のフランジとウェブとの
温度差がΔＴａより大きい１６７℃となり、このため冷
却後座屈が発生したのである。As shown in Case 2, the water wave was generated in the anhydrous cooling, but the temperature difference between the flange and the web during natural cooling was 167 ° C., which was larger than ΔTa, and buckling occurred after cooling. Of.
【００１９】ケース３〜６のＨ形鋼のサイズでは、ΔＴ
ａ＝９３℃，ΔＴｂ＝１２０℃、仕上圧延後のフランジ
水冷開始時の限界温度差はΔＴａ＋ΔＴｂ＝２１３℃で
ある。ケース３に示すように、このサイズでは、圧延中
にフランジ水冷を行ってフランジ温度を６０℃降下させ
て仕上圧延後の水冷でフランジ温度を１０２℃降下させ
て、ウェブ波のないＨ形鋼が製造できた。圧延中のフラ
ンジ水冷により仕上圧延後のフランジ水冷開始時のフラ
ンジとウェブの温度差をΔＴａ＋ΔＴｂより小さい１７
８℃とし、仕上圧延後の水冷によるフランジの温度降下
量をΔＴｂより小さい１０２℃として自然放冷時のフラ
ンジとウェブの温度差をΔＴａより小さい８７℃とした
ため、冷却中座屈及び冷却後座屈を防止できた。因みに
ケース４，ケース５に示す如く無水冷の場合及び仕上圧
延後だけの水冷によりフランジ温度を１０３℃降下させ
た場合にはウェブ波が生じた。自然放冷時の温度差がΔ
Ｔａを越えたための冷却後座屈が発生したのである。For the H-section steel sizes of Cases 3 to 6, ΔT
a = 93 ° C., ΔTb = 120 ° C., and the limit temperature difference at the start of flange water cooling after finish rolling is ΔTa + ΔTb = 213 ° C. As shown in Case 3, in this size, flange water cooling is performed during rolling to lower the flange temperature by 60 ° C., and water temperature after finishing rolling lowers the flange temperature by 102 ° C. I was able to manufacture. Due to the water cooling of the flange during rolling, the temperature difference between the flange and the web at the start of water cooling of the flange after finishing rolling is smaller than ΔTa + ΔTb.
Since the temperature drop of the flange due to water cooling after finish rolling was 8 ° C., which was smaller than ΔTb, and the temperature difference between the flange and the web during natural cooling was 87 ° C., which was smaller than ΔTa, the buckling during cooling and the post-cooling buckling were performed. I was able to prevent buckling. Incidentally, as shown in Case 4 and Case 5, web waves were generated in the case of anhydrous cooling and in the case of lowering the flange temperature by 103 ° C. by water cooling only after finish rolling. The temperature difference during natural cooling is Δ
Buckling occurred after cooling due to exceeding Ta.
【００２０】ケース６に示すように、仕上圧延後だけの
水冷によりフランジ温度を１５５℃降下させた場合にも
ウェブ波が生じた。自然放冷時の温度差はΔＴａより小
さいが１回の水冷でのフランジの温度降下量がΔＴｂを
越えたため冷却中座屈が発生したのである。As shown in Case 6, web waves were generated even when the flange temperature was lowered by 155 ° C. by water cooling only after finish rolling. Although the temperature difference during natural cooling is smaller than ΔTa, the amount of temperature drop of the flange in one water cooling exceeds ΔTb, so buckling occurred during cooling.
【００２１】[0021]
【発明の効果】上記の実施例からも明らかなように、本
発明によれば１回のフランジ冷却によるフランジの平均
温度の降下量がΔＴｂより小さくなるように冷却を制限
しながら、最後のフランジ冷却開始時においてフランジ
の平均温度とウェブの平均温度の差がΔＴａ＋ΔＴｂよ
り小さくなるように、また仕上圧延の後の又は仕上圧延
後のフランジ冷却を行った後の自然放冷開始時において
フランジの平均温度とウェブの平均温度の差がΔＴａよ
り小さくなるように圧延中又は仕上圧延後のフランジ冷
却を行うことにより、ウェブ波のないＨ形鋼が製造でき
る。As is apparent from the above-described embodiments, according to the present invention, the cooling is limited so that the average temperature drop of the flange by one cooling of the flange becomes smaller than ΔTb, while the last flange is cooled. The difference between the average temperature of the flange and the average temperature of the web at the start of cooling is smaller than ΔTa + ΔTb, and the average of the flange at the start of natural cooling after flange cooling after finish rolling or after finish rolling. By performing flange cooling during rolling or after finish rolling so that the difference between the temperature and the average temperature of the web is smaller than ΔTa, an H-section steel without web waves can be manufactured.
【図１】Ｈ形鋼の断面図である。FIG. 1 is a sectional view of an H-section steel.
【図２】Ｈ形鋼の残留応力の分布を示す断面図である。FIG. 2 is a cross-sectional view showing the distribution of residual stress of H-section steel.
【図３】本発明によるＨ形鋼のフランジの水冷状況を示
す断面図である。FIG. 3 is a cross-sectional view showing a water cooling state of a flange of H-section steel according to the present invention.
１ フランジ ２ ウェブ ３ フランジ水冷装置 1 flange 2 web 3 flange water cooling system
─────────────────────────────────────────────────────
─────────────────────────────────────────────────── ───
【手続補正書】[Procedure amendment]
【提出日】平成３年５月１４日[Submission date] May 14, 1991
【手続補正１】[Procedure Amendment 1]
【補正対象書類名】明細書[Document name to be amended] Statement
【補正対象項目名】特許請求の範囲[Name of item to be amended] Claims
【補正方法】変更[Correction method] Change
【補正内容】[Correction content]
【特許請求の範囲】[Claims]
【手続補正２】[Procedure Amendment 2]
【補正対象書類名】明細書[Document name to be amended] Statement
【補正対象項目名】０００３[Name of item to be corrected] 0003
【補正方法】変更[Correction method] Change
【補正内容】[Correction content]
【０００３】ウェブ波の発生原因となる残留応力を軽減
させる方法が従来種々開示されているが、作業能率の点
ですぐれている製造方法としては、圧延時にフランジを
冷却する特公昭４１−２０３３６号公報に開示された製
造方法、及び仕上げ圧延後フランジを冷却する特公昭４
７−３１４８１号公報に開示された製造方法がある。こ
れらの方法においてはいずれもＨ形鋼が高温の状態にあ
るうちフランジを冷却し、残留応力の発生原因となるフ
ランジとウェブとの温度差を縮小するようにしている。Various methods for reducing the residual stress that causes the generation of web waves have been disclosed in the past. As a manufacturing method which is excellent in work efficiency, Japanese Patent Publication No. 41-20336, in which a flange is cooled during rolling, is disclosed. Manufacturing method disclosed in the publication and Japanese Patent Publication No. Sho 4 for cooling flange after finish rolling
There is a manufacturing method disclosed in JP-A 7-31481. In all of these methods, the flange is cooled while the H-section steel is in a high temperature state to reduce the temperature difference between the flange and the web, which causes residual stress.
【手続補正３】[Procedure 3]
【補正対象書類名】明細書[Document name to be amended] Statement
【補正対象項目名】０００５[Name of item to be corrected] 0005
【補正方法】変更[Correction method] Change
【補正内容】[Correction content]
【０００５】ところで、フランジの厚さとウェブの厚さ
との比が３程度になる薄肉ウェブＨ形鋼では、フランジ
を冷却しない場合には圧延終了時にフランジ温度はウェ
ブ温度よりも２００℃以上高くなるのが普通である。こ
の温度差を１回のフランジ冷却で縮小するには強いフラ
ンジ冷却を行ってフランジ温度の降下量を大きくする必
要がある。本発明者らは、１回の冷却でのフランジ温度
の降下量が大き過ぎるとその冷却中にウェブ波が発生す
ることを発見した。この現象は、フランジが強く冷却さ
れて大きく収縮するとその反力としてウェブに大きな圧
縮応力が発生し高温状態にあって降伏応力が低下してい
るウェブは容易に塑性して座屈するという謂ゆる塑性座
屈に起因している。このようにフランジ冷却中に発生す
るウェブの座屈を冷却中座屈と云う。これに対して、前
述のごとくフランジを冷却した後室温近くまで冷却され
た状態で発生するウェブの座屈を冷却後座屈と云う。冷
却中座屈は冷却後座屈と同様に形状不良の原因となる
が、それを防止する冷却条件はまだ明らかでない。By the way, in the thin web H-section steel in which the ratio of the thickness of the flange to the thickness of the web is about 3, if the flange is not cooled, the flange temperature becomes 200 ° C. or more higher than the web temperature at the end of rolling. Is normal. In order to reduce this temperature difference with one flange cooling, it is necessary to perform strong flange cooling and increase the amount of flange temperature drop. The present inventors have discovered that if the amount of decrease in the flange temperature in one cooling is too large, a web wave is generated during the cooling. This phenomenon is because when the flange is strongly cooled and contracts greatly, a large compressive stress is generated in the web as a reaction force, and the yield stress is reduced due to high temperature, so the web easily plasticizes and buckles. Caused by buckling. The buckling of the web generated during flange cooling is called buckling during cooling. On the other hand, as described above, buckling of the web that occurs after cooling the flange and then cooling to near room temperature is called buckling after cooling. Buckling during cooling causes shape defects as well as buckling after cooling, but the cooling conditions to prevent it are not clear yet.
【手続補正４】[Procedure amendment 4]
【補正対象書類名】明細書[Document name to be amended] Statement
【補正対象項目名】０００６[Correction target item name] 0006
【補正方法】変更[Correction method] Change
【補正内容】[Correction content]
【０００６】[0006]
【発明が解決しようとする課題】本発明は、上記従来例
の問題点及び本発明者らにより発見された上記の新らた
な問題点を解決するためになされたものであり、ウェブ
に冷却後座屈が発生しないようにするために、仕上圧延
後のフランジとウェブの許容温度差（圧延時のみフラン
ジを冷却する場合）、仕上圧延後にフランジ冷却を行っ
た後の許容温度差（仕上圧延後にフランジを冷却する場
合）、ウェブに冷却中座屈が発生しないための１回の冷
却で許容されるフランジ温度の降下量、冷却後座屈及び
冷却中座屈が発生しないための必要条件である最後のフ
ランジ冷却開始時のフランジとウェブの許容温度差等を
具体的に設定することにより、ウェブ波のないＨ形鋼を
製造すること可能にしたウェブ波のないＨ形鋼を製造方
法を提供することを目的とする。SUMMARY OF THE INVENTION The present invention has been made to solve the problems of the above-mentioned conventional examples and the above-mentioned new problems found by the present inventors. To prevent post-buckling, the allowable temperature difference between the flange and the web after finish rolling (when the flange is cooled only during rolling), the allowable temperature difference after cooling the flange after finish rolling (finish rolling When cooling the flange later), the amount of flange temperature drop allowed in one cooling to prevent buckling of the web during cooling, and the necessary conditions to prevent buckling after cooling and buckling during cooling A method for producing a H-section steel without a web wave, which makes it possible to produce an H-section steel without a web wave, by concretely setting the allowable temperature difference between the flange and the web at the time of starting cooling of the last flange. To provide For the purpose.
【手続補正５】[Procedure Amendment 5]
【補正対象書類名】明細書[Document name to be amended] Statement
【補正対象項目名】００１４[Correction target item name] 0014
【補正方法】変更[Correction method] Change
【補正内容】[Correction content]
【００１４】前述したように、自然放冷開始時のフラン
ジの平均温度とウェブの平均温度との差がΔＴａ以下で
あればウェブの冷却後座屈は発生しない。更に、前述し
たように、１回のフランジ冷却でのフランジの平均温度
の降下量が全てのフランジ冷却でΔＴｂ以下であればウ
ェブの冷却中座屈は発生しない。従って、最後のフラン
ジ冷却開始時においてフランジの平均温度とウェブの平
均温度との差がΔＴａ＋ΔＴｂより小さければ、フラン
ジの平均温度をウェブの冷却中座屈が発生しないΔＴｂ
よりも小さい範囲内で降下させ、かつ自然放冷開始時の
フランジの平均温度とウェブの平均温度との差を冷却後
座屈の発生しないΔＴａ以下とすることができる。すな
わち、最後のフランジ冷却開始時におけるフランジの平
均温度とウェブの平均温度との差がΔＴａ＋ΔＴｂより
小さくなるように粗圧延中又は仕上圧延以前に図３に示
す如くフランジ水冷を行い、最後のフランジ冷却におい
て図３に示す如くフランジ水冷により、冷却後の自然放
冷開始時のフランジの平均温度とウェブの平均温度との
差がΔＴａ以下となるように、フランジの平均温度の降
下量がΔＴｂ以下となる範囲内でフランジを冷却するこ
とにより、冷却中座屈も冷却後座屈も防止できてウェブ
波のないＨ形鋼を製造することができる。As described above, if the difference between the average temperature of the flange at the start of spontaneous cooling and the average temperature of the web is ΔTa or less, buckling of the web after cooling does not occur. Further, as described above, buckling does not occur during cooling of the web if the average temperature drop of the flange in one flange cooling is ΔTb or less in all flange cooling. Therefore, if the difference between the average temperature of the flange and the average temperature of the web at the start of the final flange cooling is smaller than ΔTa + ΔTb, the average temperature of the flange does not cause buckling during cooling of the web ΔTb.
The temperature can be lowered within a smaller range, and the difference between the average temperature of the flange at the start of spontaneous cooling and the average temperature of the web can be set to ΔTa or less at which buckling does not occur after cooling. That is, during the rough rolling or before the finish rolling, flange water cooling is performed as shown in FIG. 3 so that the difference between the average temperature of the flange and the average temperature of the web at the start of the final flange cooling becomes smaller than ΔTa + ΔTb, and the final flange cooling is performed. In Fig. 3, the amount of decrease in the average temperature of the flange is ΔTb or less so that the difference between the average temperature of the flange and the average temperature of the web at the start of natural cooling after cooling is equal to or less than ΔTa by the flange water cooling. By cooling the flange within the range, buckling during cooling and buckling after cooling can be prevented, and an H-section steel without web waves can be manufactured.
【手続補正６】[Procedure correction 6]
【補正対象書類名】明細書[Document name to be amended] Statement
【補正対象項目名】００１７[Correction target item name] 0017
【補正方法】変更[Correction method] Change
【補正内容】[Correction content]
【００１７】ケース１のＨ形鋼のサイズでは、自然放冷
時の温度差が９５℃で、冷却後座屈の限界温度差ΔＴａ
＝１１３℃，冷却中の限界温度降下ΔＴｂ＝１６３℃で
ある。ケース１に示すように、このサイズでは仕上圧延
後にフランジ水冷を行いフランジ温度を８１℃降下させ
てウェブ波のないＨ形鋼が製造できた。フランジの温度
降下がΔＴｂより小さい８１℃とし自然放冷時のフラン
ジとウェブの温度差をΔＴａより小さい９５℃としたた
め冷却中座屈及び冷却後座屈を防止できた。With the size of the H-section steel of case 1, the temperature difference during natural cooling is 95 ° C., and the critical temperature difference ΔTa of buckling after cooling is ΔTa.
= 113 ° C., the limit temperature drop ΔTb during cooling ΔTb = 163 ° C. As shown in Case 1, with this size, flange water cooling was performed after finish rolling to lower the flange temperature by 81 ° C., and H-section steel without web waves could be manufactured. Since the temperature drop of the flange was 81 ° C smaller than ΔTb and the temperature difference between the flange and the web during natural cooling was 95 ° C smaller than ΔTa, buckling during cooling and buckling after cooling could be prevented.
───────────────────────────────────────────────────── フロントページの続き (72)発明者 槇ノ原 操 東京都千代田区丸の内一丁目１番２号 日 本鋼管株式会社内 (72)発明者 片岡 譲 東京都千代田区丸の内一丁目１番２号 日 本鋼管株式会社内 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Misao Minohara 1-2-2 Marunouchi, Chiyoda-ku, Tokyo Nihon Kokan Co., Ltd. (72) Inventor Yutaka Kataoka 1-2-1 Marunouchi, Chiyoda-ku, Tokyo No. Nippon Steel Tube Co., Ltd.
Claims (4)
し、その際、仕仕上圧延した後の自然放冷開始時におい
て前記フランジの平均温度とウェブの平均温度との差が
下記の数式（１）に示されるΔＴａ以下となるように前
記フランジの冷却をすることを特徴とするウェブ波のな
いＨ形鋼の製造方法。 ΔＴａ＝｛（１＋Ａｗ／Ａｆ）σcr／Ｅ−３×１０-4｝×１０5 …（１） σcr＝Ｍｉｎ｛３．６Ｅ（ｔｗ／Ｈｗ）2 ，σｙ｝ Ａｗ，Ａｆ：ウェブ及びフランジの断面積 Ｅ：常温でのヤング率 ｔｗ：ウェブの厚さ Ｈｗ：ウェブの内幅 σｙ：常温でのウェブの降伏応力 ΔＴａ：単位℃1. A flange of H-section steel is cooled only during rolling, and at that time, at the start of natural cooling after finish rolling, the difference between the average temperature of the flange and the average temperature of the web is expressed by the following mathematical formula: A method for producing a H-section steel without web waves, characterized in that the flange is cooled to a value not more than ΔTa shown in 1). ΔTa = {(1 + Aw / Af) σ cr / E−3 × 10 −4 } × 10 5 (1) σ cr = Min {3.6E (tw / Hw) 2 , σ y } Aw, Af: Web and Cross-sectional area of flange E: Young's modulus at room temperature tw: Thickness of web Hw: Inner width of web σ y : Yield stress of web at room temperature ΔTa: Unit ° C
延後にＨ形鋼のフランジを冷却し、その際、仕上圧延後
の該冷却を行った後の自然放冷開始時において前記フラ
ンジの平均温度とウェブの平均温度との差が下記の数式
（１）に示されるΔＴａ以下となるように前記フランジ
を冷却することを特徴とするウェブ波のないＨ形鋼の製
造方法。 ΔＴａ＝｛（１＋Ａｗ／Ａｆ）σcr／Ｅ−３×１０-4｝×１０5 …（１） σcr＝Ｍｉｎ｛３．６Ｅ（ｔｗ／Ｈｗ）2 ，σｙ｝ Ａｗ、Ａｆ：ウェブ及びフランジの断面積 Ｅ：常温でのヤング率 ｔｗ：ウェブの厚さ Ｈｗ：ウェブの内幅 σｙ：常温でのウェブの降伏応力 ΔＴａ：単位℃2. A flange of H-section steel is cooled only after finish rolling, or during rolling and after finish rolling, in which case the average of the flanges at the start of spontaneous cooling after performing the cooling after finish rolling. A method for producing an H-section steel without web waves, characterized in that the flange is cooled so that the difference between the temperature and the average temperature of the web is equal to or less than ΔTa shown in the following formula (1). ΔTa = {(1 + Aw / Af) σ cr / E−3 × 10 −4 } × 10 5 (1) σ cr = Min {3.6E (tw / Hw) 2 , σ y } Aw, Af: Web and Af Cross-sectional area of flange E: Young's modulus at room temperature tw: Thickness of web Hw: Inner width of web σ y : Yield stress of web at room temperature ΔTa: Unit ° C
を冷却し、その際、１回の冷却によるフランジの平均温
度の降下量が下記の数式（２）及び（３）式に示される
ΔＴｂ以下の範囲内になるように前記フランジを冷却す
ることを特徴とする請求項１又は２記載のウェブ波のな
いＨ形鋼の製造方法。ｔｆ≦２０mmでＡｆ／Ａｗ≦１．
７のとき、又はｔｆ＞２０mmのとき ΔＴｂ＝２０．４（Ａｆ／Ａｗ）2 −１３９（Ａｆ／Ａｗ）＋２９６ …（２） ｔｆ≦２０mmでＡｆ／Ａｗ＞１．７のとき ΔＴｂ＝１２０ …（３） ｔｆ：フランジの厚さ ΔＴｂ：単位℃3. The flange is cooled once or a plurality of times, wherein the amount of decrease in average temperature of the flange due to one cooling is equal to or less than ΔTb shown in the following formulas (2) and (3). The method for producing an H-section steel without web waves according to claim 1 or 2, wherein the flange is cooled so as to fall within the range. When tf ≦ 20 mm, Af / Aw ≦ 1.
7 or when tf> 20 mm ΔTb = 20.4 (Af / Aw) 2 -139 (Af / Aw) +296 (2) When tf ≦ 20 mm and Af / Aw> 1.7 ΔTb = 120 (3) tf: Thickness of flange ΔTb: Unit ° C
記フランジを冷却する場合であって、複数回にわたって
前記フランジを冷却する場合に、最後の冷却の開始時に
おいてフランジの平均温度とウェブの平均温度との差が
ΔＴａ＋ΔＴｂより小さくなるように、粗圧延中又は仕
上圧延以前に前記フランジを冷却することを特徴とする
請求項３記載のウェブ波のないＨ形鋼の製造方法。4. The average temperature of the flange and the web of the flange at the start of the final cooling when the flange is cooled during rolling or after rolling and finish rolling, and when the flange is cooled multiple times. The method for producing H-section steel without web waves according to claim 3, wherein the flange is cooled during rough rolling or before finish rolling so that the difference from the average temperature is smaller than ΔTa + ΔTb.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3036076A JP2887921B2 (en) | 1991-03-01 | 1991-03-01 | Method of manufacturing H-section steel without web wave |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3036076A JP2887921B2 (en) | 1991-03-01 | 1991-03-01 | Method of manufacturing H-section steel without web wave |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH06170431A true JPH06170431A (en) | 1994-06-21 |
| JP2887921B2 JP2887921B2 (en) | 1999-05-10 |
Family
ID=12459652
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP3036076A Expired - Fee Related JP2887921B2 (en) | 1991-03-01 | 1991-03-01 | Method of manufacturing H-section steel without web wave |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2887921B2 (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0752286A1 (en) * | 1995-07-07 | 1997-01-08 | DANIELI & C. OFFICINE MECCANICHE S.p.A. | Thermal method to control the deformations of hot-rolled sections and relative device |
| JP2020157364A (en) * | 2019-03-27 | 2020-10-01 | Ｊｆｅスチール株式会社 | Manufacturing method for h section steel |
| JP2021154366A (en) * | 2020-03-27 | 2021-10-07 | Ｊｆｅスチール株式会社 | Method of manufacturing h-section steel |
-
1991
- 1991-03-01 JP JP3036076A patent/JP2887921B2/en not_active Expired - Fee Related
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0752286A1 (en) * | 1995-07-07 | 1997-01-08 | DANIELI & C. OFFICINE MECCANICHE S.p.A. | Thermal method to control the deformations of hot-rolled sections and relative device |
| JP2020157364A (en) * | 2019-03-27 | 2020-10-01 | Ｊｆｅスチール株式会社 | Manufacturing method for h section steel |
| JP2021154366A (en) * | 2020-03-27 | 2021-10-07 | Ｊｆｅスチール株式会社 | Method of manufacturing h-section steel |
Also Published As
| Publication number | Publication date |
|---|---|
| JP2887921B2 (en) | 1999-05-10 |
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