JP3528504B2 - Manufacturing method of extra thick steel plate - Google Patents
Manufacturing method of extra thick steel plateInfo
- Publication number
- JP3528504B2 JP3528504B2 JP07509497A JP7509497A JP3528504B2 JP 3528504 B2 JP3528504 B2 JP 3528504B2 JP 07509497 A JP07509497 A JP 07509497A JP 7509497 A JP7509497 A JP 7509497A JP 3528504 B2 JP3528504 B2 JP 3528504B2
- Authority
- JP
- Japan
- Prior art keywords
- forging
- rolling
- reduction
- slab
- manufacturing
- 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.)
- Expired - Fee Related
Links
- 229910000831 Steel Inorganic materials 0.000 title description 41
- 239000010959 steel Substances 0.000 title description 41
- 238000004519 manufacturing process Methods 0.000 title description 17
- 238000005096 rolling process Methods 0.000 description 46
- 238000005242 forging Methods 0.000 description 41
- 230000007547 defect Effects 0.000 description 15
- 238000000034 method Methods 0.000 description 11
- 239000011800 void material Substances 0.000 description 9
- 238000012545 processing Methods 0.000 description 8
- 238000009749 continuous casting Methods 0.000 description 6
- 238000012360 testing method Methods 0.000 description 6
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 4
- 238000001514 detection method Methods 0.000 description 4
- 239000000463 material Substances 0.000 description 4
- 238000002788 crimping Methods 0.000 description 3
- 238000005266 casting Methods 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 238000010438 heat treatment Methods 0.000 description 2
- 229910052742 iron Inorganic materials 0.000 description 2
- 239000002994 raw material Substances 0.000 description 2
- 229910000677 High-carbon steel Inorganic materials 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 238000005520 cutting process Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000011156 evaluation Methods 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 238000007711 solidification Methods 0.000 description 1
- 230000008023 solidification Effects 0.000 description 1
- 239000002436 steel type Substances 0.000 description 1
- 230000008719 thickening Effects 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
Landscapes
- Metal Rolling (AREA)
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、厚板圧延における
極厚鋼板（製品板厚150 〜200mm 以上）の製造方法に関
し、特に連鋳鋳片のセンターポロシティを効果的に消滅
（閉鎖−圧着）させて内質特性の良好な極厚鋼板を有利
に製造する方法を提案する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing an extremely thick steel sheet (product sheet thickness of 150 to 200 mm or more) in plate rolling, and in particular, effectively eliminates the center porosity of continuously cast slabs (closed-crimping). Therefore, a method for advantageously manufacturing an extra-thick steel plate with good internal properties is proposed.
【０００２】[0002]
【従来の技術】一般に、厚鋼板は連続鋳造鋳片（以下、
「連鋳鋳片」という）、または、鋳型鋳造したインゴッ
トを分塊圧延した鋼片（以下、「分塊スラブ」という）
を素材としてこれらを圧延することによって製造され
る。2. Description of the Related Art Generally, thick steel plates are continuously cast slabs (hereinafter referred to as
"Continuous cast slab") or steel slab obtained by slab-rolling a cast ingot (hereinafter referred to as "agglomerated slab")
It is manufactured by rolling these using as a raw material.
【０００３】この両者を比較すると、製造コストの点で
は前者の方に魅力があるが、連鋳鋳片の場合、分塊スラ
ブよりも厚みが薄いため、極厚鋼板の製造に際してはセ
ンターポロシティの未圧着部分が発生する割合が高く、
また現状の厚板圧延機の能力では、連鋳鋳片の中心部に
存在するセンターポロシティを安定して消滅させること
は困難である。そのために、連鋳鋳片から製造された極
厚鋼板を超音波探傷試験すると、多くの製品が内質不良
となっていることが多い。Comparing the two, the former is more attractive in terms of manufacturing cost, but in the case of continuous cast slabs, the thickness is smaller than that of the agglomerate slab, so that the center porosity of the extremely thick steel plate is increased. There is a high rate of unbonded parts,
Further, it is difficult to stably eliminate the center porosity existing in the central portion of the continuous cast slab with the capability of the current thick plate rolling mill. Therefore, when an ultra-thick steel plate manufactured from a continuous cast slab is subjected to an ultrasonic flaw detection test, many products often have poor internal quality.
【０００４】このことから、従来、極厚鋼板の製造に当
たっては、圧下比（鋼片厚み÷製品厚み）に下限値を設
け、その下限値を下まわるような加工条件で極厚鋼板を
製造しなければならないときは、分塊スラブを素材とし
て用いることが普通である。例えば、圧力容器用鋼板の
製造条件を規定したASTM A20では、この圧下比の下限値
を３以上としているし、JIS 規格ではこのような規定は
ないが、鋼板製造業者が自主的に管理して製造を行って
いるのが、実情である。Therefore, in the past, in the production of extra-thick steel plates, a lower limit value was set for the reduction ratio (steel thickness / product thickness), and the extra-thick steel plates were produced under processing conditions that were below the lower limit value. When it must be done, it is common to use slabs as the material. For example, in ASTM A20, which specifies the manufacturing conditions for steel plates for pressure vessels, the lower limit of this reduction ratio is set to 3 or more. Although there is no such specification in JIS standard, steel plate manufacturers manage it voluntarily. The fact is that they are manufactured.
【０００５】ただし、分塊スラブの場合、押湯部の濃厚
偏折や沈澱晶部の負偏折などが発生するおそれがあり、
分塊圧延後にこれらの部分を切り捨てることによる歩止
まりの低下、あるいは分塊圧延という中間工程を必要と
するために、コストの増大や生産性低下を招くという問
題があった。However, in the case of a slab of slab, there is a possibility that thick unevenness in the riser portion or negative deviation in the precipitated crystal portion may occur.
There is a problem in that the yield is reduced by cutting off these parts after the slabbing, or an intermediate step of slabbing is required, resulting in an increase in cost and a drop in productivity.
【０００６】このことを考えると、たとえ圧下比が下限
値を下まわるような場合であっても、極厚鋼板の製造に
当たって連鋳鋳片を用いられるようにすることが望まし
く、そのための下記のような幾つかの提案がある。Considering this, it is desirable to use continuous cast slabs in the production of extra-thick steel plates even when the reduction ratio is below the lower limit. Here are some suggestions.
【０００７】[0007]
【発明が解決しようとする課題】
「鉄と鋼」第66年(1980)第２号 201〜210 頁では、セ
ンターポロシティを効果的に消滅させるための圧延条件
を検討し、圧延形状比で定義された値を大きくすること
により内質の良好な鋼板を製造する方法を提案してい
る。しかしながら、この方法の場合、実際の圧延におい
ては圧延機の設備仕様により圧延形状比が大きな制約を
受けるため、圧下比が３未満になるような大幅な圧下比
にまで適用することができないという問題点がある。
特開昭55−114404号公報、特開昭61−273201号公報で
は、連鋳機の出側でロールあるいは面状の圧下手段を設
けて、連鋳スラブのセンターポロシティの閉鎖−圧着を
図る技術を提案している。しかしながら、この技術で
は、厚板素材用連鋳機の設備改良にコストがかかりすぎ
るという問題点がある。
その他、厚板圧延の前に鍛造を行ってセンターポロシ
ティを軽減する方法もある（「第２版 わが国における
最近の圧板製造技術の進歩」(1984)日本鉄鋼協会152 〜
153 頁) 。そして、特願平６−26988 号公報では、下記
式(1) で示される条件を満足するように鋳造圧下率と圧
延圧下率を開示している。
30≧α1 ≧30−0.5 α2 ……(1)
ここに α1 ：鍛造での圧下率（％）
α2 ：圧延での圧下率（％）
しかし、これらの文献には、全圧下率を30％未満で極厚
鋼板を製造する技術についてまでは開示していない。と
くに、鍛造作業コストを極力抑えるためには、鍛造加熱
は１回とすることが望ましく、かつ鋼片の温度低下によ
る鍛造圧下不能を防ぐには、短時間で作業を終える必要
がある。そのためには、圧下比緩和と同時に最小の鍛造
圧下率で前記センターポロシティを閉鎖−圧着して消滅
させることが必要となるが、上記各文献にはその条件が
不明である。[Issues to be Solved by the Invention] In "Iron and Steel", No. 66 (1980) No. 2, pp. 201 to 210, rolling conditions for effectively eliminating center porosity are examined and defined by rolling shape ratio. It proposes a method for producing a steel sheet with good internal quality by increasing the value obtained. However, in the case of this method, in the actual rolling, the rolling shape ratio is greatly restricted by the equipment specifications of the rolling mill, so that it cannot be applied to a large reduction ratio such that the reduction ratio is less than 3. There is a point. In JP-A-55-114404 and JP-A-61-273201, a technique for closing / compressing the center porosity of a continuous casting slab by providing a roll or planar reduction means on the exit side of the continuous casting machine. Is proposed. However, this technique has a problem that it takes too much cost to improve the equipment of the continuous casting machine for thick plate materials. In addition, there is a method to reduce the center porosity by performing forging before thick plate rolling (“The 2nd edition: Recent progress in pressure plate manufacturing technology in Japan” (1984) Iron and Steel Institute of Japan 152-
P. 153). Further, Japanese Patent Application No. 6-26988 discloses a casting reduction rate and a rolling reduction rate so as to satisfy the condition represented by the following formula (1). 30 ≧ α 1 ≧ 30−0.5 α 2 (1) where α 1 : Rolling ratio in forging (%) α 2 : Rolling ratio in rolling (%) However, in these documents, the total rolling ratio is It does not disclose the technology for manufacturing extra-thick steel plates with less than 30%. In particular, in order to suppress the cost of forging work as much as possible, it is desirable to perform the forging heating once, and it is necessary to finish the work in a short time in order to prevent the inability of the forging reduction due to the temperature decrease of the steel slab. For that purpose, it is necessary to close-press and eliminate the center porosity with a minimum forging reduction rate at the same time as the reduction of the reduction ratio, but the conditions are unknown in the above-mentioned documents.
【０００８】一般に、連鋳鋳片のセンターポロシティ
は、主として鋳片幅方向の両端から連鋳鋳片厚相当の部
分を除いたその幅方向の中央部に分布することが知られ
ている。ただし、連続鋳造機での鋳造条件によっては、
鋳片幅方向両端部に生成する空隙性欠陥の方が、上記の
中心部に生成するセンターポロシティより比較的大き
く、そのために、通常の鍛造圧下処理ではセンターポロ
シティのみならずこの空隙性欠陥の閉鎖−圧着ができな
い場合があった。It is generally known that the center porosity of a continuous cast slab is mainly distributed in the center in the widthwise direction of the slab, except both ends in the widthwise direction of the slab, except for portions corresponding to the thickness of the continuous cast slab. However, depending on the casting conditions in the continuous casting machine,
The void defects generated at both ends in the width direction of the slab are relatively larger than the center porosities generated at the above-mentioned center part.Therefore, in normal forging reduction processing, not only the center porosity but also the closure of these void defects is generated. -Sometimes crimping was not possible.
【０００９】本発明の主たる目的は、内質特性の優れた
極厚鋼板の製造技術を提案することにある。本発明の他
の目的は、空隙性欠陥を確実に消滅させるのに有効な、
鍛造圧下に供すべき鋼片の望ましい形状を究明するとこ
ろにある。本発明のさらに他の目的は、センターポロシ
ティを消滅させるのに有効な、全圧下率と鍛造圧下率と
の望ましい関係を究明するところにある。[0009] A main object of the present invention is to propose a manufacturing technique for an extra-thick steel sheet having excellent internal properties. Another object of the present invention is to effectively eliminate void defects,
This is to find out the desirable shape of the steel slab to be subjected to forging pressure. Still another object of the present invention is to investigate a desirable relationship between the total rolling reduction and the forging rolling reduction, which is effective in eliminating the center porosity.
【００１０】[0010]
【課題を解決するための手段】上掲の目的に適う極厚鋼
板製造技術について鋭意研究するうちに、発明者らは、
鍛造に供すべき加工出発鋼片の形状と、全圧下率に対す
る鍛造圧下率との望ましい関係を特定すれば、内質特性
の優れた極厚鋼板が得られることを知見し、本発明を完
成した。[Means for Solving the Problems] As a result of earnest research on an extremely thick steel plate manufacturing technique which meets the above-mentioned purpose, the inventors have
The present invention has been completed by finding that the shape of the processing starting steel piece to be subjected to forging and the desired relationship between the forging reduction rate and the total reduction rate can provide an extremely thick steel sheet with excellent internal properties. .
【００１１】即ち、本発明は連鋳鋳片から、鍛造と厚板
圧延とを併用して全圧下率が20〜60％の範囲内の加工条
件で125mm厚以上の極圧鋼板を製造する方法において、
前記連鋳鋳片の端部を幅方向から圧下し、該鋳片幅方向
の両端部を150mm以上減尺させると共に肥厚化させるこ
とにより、幅方向の断面形状がドッグボーン状を呈する
鋼片とした後実体鍛錬し、これを被鍛造材として厚板圧
延を行うことを特徴とする極厚鋼板の製造方法である。
本発明において、全圧下率を20〜25％とする加工に当た
っては、鍛造時の圧下率を11 ％以上とすることが好まし
い。本発明において、全圧下率を25超〜60％とする加工
に当たっては、鍛造時の圧下率を16 ％以上とすることが
好ましい。That is, the present invention is a method for producing an extreme pressure steel plate having a thickness of 125 mm or more from a continuous cast slab by using forging and plate rolling together under processing conditions in which the total reduction ratio is in the range of 20 to 60%. At
By rolling down the end of the continuous cast slab from the width direction, and by thickening together with the both ends of the slab width direction are reduced by 150 mm or more, a steel slab having a dogbone-shaped cross-sectional shape in the width direction. After that, substantial forging is performed, and the plate is rolled using this as a material to be forged.
In the present invention, it is preferable to set the rolling reduction at the time of forging to 11 % or more in the processing for setting the total rolling reduction to 20 to 25%. In the present invention, it is preferable to set the rolling reduction at the time of forging to 16 % or more in the processing in which the total rolling reduction is more than 25 to 60%.
【００１２】[0012]
【発明の実施の形態】本発明は、連続鋳造鋳片につい
て、これを鍛造加工に供すのに望ましい鋼片形状とはど
んなものかについて研究した。その結果、連鋳鋳片の幅
方向の両端部、特に鋳片厚み相当の部分には、通常の鍛
造圧下によって鋳片幅方向の中央部に生成するセンター
ポロシティを消滅させるに足りる圧下量）では圧着する
ことのできない空隙性欠陥が発生し、センターポロシテ
ィとともにこの部分が圧着不良（未圧着）を起こして内
質欠陥となることをつきとめた。BEST MODE FOR CARRYING OUT THE INVENTION The present invention investigated a continuously cast slab and what a desirable slab shape is to be subjected to forging. As a result, the widthwise ends of the continuous cast slab, especially the part corresponding to the thickness of the slab, is an amount of reduction sufficient to eliminate the center porosity generated in the central part of the slab width direction by normal forging reduction). It was found that void defects that could not be crimped were generated, and that this part together with center porosity caused crimping defects (not crimped) and became internal defects.
【００１３】そこで、本発明では、上記の鋳片幅方向の
端部に生成する空隙性欠陥を、図１に示すような通常の
鍛造圧下工程において確実に圧着封塞するために、この
部分（両端部）を肥厚化させた鋼片とすることを考え
た。つまり、両端部Ｅだけが肥厚化した、いわゆる断面
形状がドッグボーン状である鋼片を製造し、これを通常
の加工条件を付与して鍛造したのである。その結果、上
述したセンターポロシティや空隙性欠陥などの未圧着部
分、とくに幅方向両端部に生成する空隙性欠陥は完全に
消滅することがわかった。Therefore, in the present invention, in order to surely press-bond and seal the void defect generated at the end portion in the width direction of the cast piece in a normal forging reduction step as shown in FIG. It was considered to use thickened steel pieces at both ends. In other words, a steel piece having a so-called dogbone-shaped cross-section, in which only both end portions E are thickened, is manufactured, and this is forged under normal working conditions. As a result, it was found that the above-mentioned unbonded portions such as center porosity and void defects, particularly void defects generated at both ends in the width direction, disappeared completely.
【００１４】そのために、本発明では、鋳片幅方向の両
端に肥厚化した部分を形成するために、図２に示すよう
に、連鋳鋳片１の幅方向の両端部を、鍛造上・下金敷
２，３にて幅方向から圧下することにした。この鋳片幅
方向からの圧下によって、該鋳片１の両端部Ｅの厚さ
は、元厚にほぼ比例して肥厚化した部分を形成すること
ができるが、発明者らが行った数々の試験によれば、幅
方向圧下による減尺代（ｒ）が150mm 以上／両側であれ
ば、センターポロシティおよび端部空隙性欠陥の消滅に
必要な端部の膨らみが得られることをつきとめた。Therefore, in the present invention, in order to form thickened portions at both ends in the width direction of the cast piece, as shown in FIG. We decided to use the lower anvils 2 and 3 to reduce the width. By the reduction in the width direction of the cast piece, the thickness of both end portions E of the cast piece 1 can form a thickened portion almost in proportion to the original thickness. According to the test, if the reduction amount (r) due to the reduction in the width direction is 150 mm or more / both sides, the center porosity and the end bulge necessary for eliminating the end void defect are obtained.
【００１５】即ち、本発明では、鋳片幅方向からの圧下
する量は、その両端部を幅方向に150mm 以上減尺させて
厚み方向に膨らませることにより肥厚化する程度とし、
この圧下によって、鋳片の断面形状がドッグボーン状と
なる被鍛造材とすることができる。このような鍛造用鋼
片を用いて鍛造を行うと、上述した内質欠陥の発生を確
実に阻止することができるようになる。That is, in the present invention, the amount of reduction from the width direction of the slab is such that both ends are reduced by 150 mm or more in the width direction and expanded in the thickness direction to thicken.
By this reduction, it is possible to obtain a forged material in which the slab has a dogbone cross-sectional shape. When forging is performed using such a forging steel piece, it becomes possible to reliably prevent the occurrence of the above-mentioned internal defects.
【００１６】本発明は、また、上述したセンターポロシ
ティの効果的な消滅を図るために、鍛造と厚板圧延とを
併用することにより極厚鋼板を製造する方法である。と
くに、上述したセンターポロシティの消滅を図るため
に、鍛造と厚板圧延との加工割合を制御する方法であ
る。すなわち、本発明においては、上記の２つの加工
(鍛造、圧延) の割合は、最終板厚にするための全圧下
率を20〜60％の範囲内として、鍛造時の圧下率を11 ％以
上とする。好ましくは、前記全圧下率が20〜25％のとき
は11 ％以上とし、この全圧下率25超〜60％のときは16 ％
以上とする加工制御を行う。The present invention is also a method for producing an extremely thick steel sheet by using forging and thick sheet rolling together in order to effectively eliminate the above-mentioned center porosity. In particular, in order to eliminate the above-mentioned center porosity, it is a method of controlling the processing ratio of forging and plate rolling. That is, in the present invention, the above two processes
The ratio of (forging and rolling) is such that the total reduction ratio for achieving the final plate thickness is within the range of 20 to 60%, and the reduction ratio during forging is 11 % or more. Preferably, it is 11 % or more when the total rolling reduction is 20 to 25%, and 16 % when the total rolling reduction is over 25 to 60 %.
The above processing control is performed.
【００１７】このことに関し、発明者らは、310mm 厚の
連鋳鋳片を用いて、鍛造及び厚板圧延の圧下率を変化さ
せて、製品の内質特性を超音波探傷試験により調査し
た。その結果を表１に示す。また、鍛造圧下率と厚板圧
延圧下率で整理したものを図３に示す。ここで、図３に
おいて、○はJIS G 0801に規定された鋼板の超音波探傷
試験において合格の品質レベルであり、×は不合格レベ
ルを示す。With respect to this, the inventors investigated the internal properties of the product by ultrasonic flaw detection test by using a continuous cast slab having a thickness of 310 mm and changing the reduction ratio of forging and plate rolling. The results are shown in Table 1. Moreover, what was arranged by the forging reduction rate and the plate rolling reduction rate is shown in FIG. Here, in FIG. 3, ∘ indicates a quality level that passed in the ultrasonic flaw detection test of the steel sheet specified in JIS G 0801, and x indicates a fail level.
【００１８】[0018]
【表１】 [Table 1]
【００１９】表１および図３ところから明らかなよう
に、全圧下率が25％以上の場合、No.３のように、圧延
圧下率を31％としても鍛造圧下率が６％しかなければ製
品の内質の状態は不健全である。逆に、鍛造圧下率が16
％の場合には、No. ５に示すように、圧延圧下率12％で
あっても内質欠陥は見られない。また、圧下率が25％以
下20％以上の場合は、No. ６に示すように、鍛造圧下率
11％、圧延圧下率11％としても製品の内質欠陥はなく、
一方、No. １に示すように、鍛造圧下率６％、圧延圧下
率14％では不健全な内質となつた。As is clear from Table 1 and FIG. 3, when the total reduction is 25% or more, as in No. 3, if the rolling reduction is 31% and the forging reduction is only 6%, the product The quality condition of is unhealthy. Conversely, the forging reduction rate is 16
In the case of%, as shown in No. 5, no internal defect is observed even if the rolling reduction is 12%. When the rolling reduction is 25% or less and 20% or more, as shown in No. 6, the forging rolling reduction is
Even if the rolling reduction rate is 11%, there is no internal defect in the product,
On the other hand, as shown in No. 1, the forging rolling reduction of 6% and the rolling reduction of 14% resulted in unsatisfactory internal quality.
【００２０】次に、鋳片幅方向両端部圧下の有無が与え
る影響について調べた。その結果、No. ４、No. ６に示
すように、鍛造圧下率を11％、圧延圧下率を11％付与し
て、同じ条件にて製品内質の状態を比較したところ、幅
方向端部を圧下しない場合（No.4）は、鋳片両端部の内
質状態が悪く不合格となった。Next, the influence exerted by the presence or absence of rolling reduction at both ends of the slab width direction was examined. As a result, as shown in No. 4 and No. 6, a forging reduction rate of 11% and a rolling reduction rate of 11% were applied, and the product quality was compared under the same conditions. When the slab was not rolled down (No. 4), the internal quality of both ends of the slab was poor and it was rejected.
【００２１】以上の試験結果から、圧下率が25％超60％
以下の場合は、先ず、連鋳鋳片の幅方向端部の圧下量を
150mm以上とすることにより鋳片幅方向両端部の厚みを
大きくし、その後、鋳片幅方向の中央部の鋳片厚みに対
して、16 ％以上の鍛造を行い、その後、製品板厚までの
残厚を厚板圧延を行った。ここで、この加工範囲におけ
る鍛造時の圧下率を16 ％以上にした理由は、実験結果に
もよるが鍛造加熱回数から見た経済性の点からも十分に
圧下可能であるからである。From the above test results, the rolling reduction is more than 25% and 60%.
In the following cases, first, set the reduction amount at the widthwise end of the continuous cast slab.
By increasing the thickness of both ends of the slab in the width direction of the slab by setting it to 150 mm or more, forging is performed by 16 % or more with respect to the thickness of the slab at the center in the width direction of the slab, and then the product sheet thickness The remaining thickness was subjected to plate rolling. Here, the reason why the reduction rate at the time of forging in this working range is set to 16 % or more is that it can be sufficiently reduced from the viewpoint of economical efficiency in terms of the number of times of forging heating, although it depends on the experimental results.
【００２２】一方、圧下率が20％以上25％以下の場合
は、鍛造時での圧下率は11 ％以上を確保すれば、残厚の
厚板圧延により、内部欠陥を十分に解消することができ
る。On the other hand, when the reduction ratio is 20% or more and 25% or less, if the reduction ratio at the time of forging is 11 % or more , internal defects can be sufficiently eliminated by rolling the remaining thick plate. it can.
【００２３】[0023]
【実施例】連続鋳造に製造した、厚み310mm 、幅2400m
m、長さ3000〜4300mmの連鋳鋳片（鋼種：一般用40キロ
級鋼、一般用50キロ級鋼、高炭素鋼）を、鍛造工場に搬
送し、1250℃に加熱した後、6000トン鍛造プレス機にて
金敷幅800mm の金敷を用い、まず150 mmの鋳片幅方向端
部の圧下を行い、次いでこの鋳片の幅方向の中央部を６
〜27％の圧下率範囲で鍛造圧下を行った。その後、鍛造
後の鋼片を厚板圧延工場に搬送し、圧下率11〜38％の厚
板圧延を行って 150〜260 mmの極厚鋼板を製造した。[Example] Thickness of 310 mm and width of 2400 m manufactured by continuous casting
m, length of 3000-4300mm continuous cast slab (steel type: general 40kg class steel, general 50kg class steel, high carbon steel), transported to forging plant, heated to 1250 ℃, then 6000 tons Using an anvil with an anvil width of 800 mm in a forging press, the width of the 150 mm end of the ingot is reduced first, and then the center of the ingot in the width direction is removed by 6 mm.
Forging reduction was performed in a reduction ratio range of up to 27%. After that, the forged steel slabs were transported to a thick plate rolling plant and rolled with a reduction rate of 11 to 38% to produce extremely thick steel plates of 150 to 260 mm.
【００２４】そして、得られた極厚鋼板について、製品
の内質をJIS G0801 に規定された鋼板の超音波探傷試験
を実施して評価した。その結果を図３に示すが、本発明
法に適合するもの、即ち、No.5〜 7, No. 9 〜11の極厚
鋼板の内質はいずれも良好な結果を示した。The ultra-thick steel sheet thus obtained was evaluated by conducting an ultrasonic flaw detection test on the steel sheet whose internal quality was specified in JIS G0801. The results are shown in FIG. 3, and the results of all of the steel sheets conforming to the method of the present invention, that is, No. 5 to No. 7 to No. 9 to 11 are extremely good.
【００２５】[0025]
【発明の効果】以上説明したように、本発明によれば、
製品の板厚中心部に生成する空隙性欠陥（連鋳スラブの
最終凝固時の供給湯不足により生じる）を容易に消滅さ
せることができ、ひいては内質特性の優れた極厚鋼板を
得ることができる。さらに、本発明によれば、次のよう
な効果が得られる。
(1) 連鋳鋳片から極厚鋼板を厚板圧延によって直接製造
する場合の適用可能な圧下比は、従来2.5 程度であり、
また鍛造と厚板圧延を併用する製造プロセスでは、圧下
比は1.5 程度であったのに対し、本発明によれば、その
圧下比を1.25程度にまで拡大することができる。
(2) また、本発明法によれば、既設の6000ton 鍛造プレ
ス機を用いることにより、従来の分塊スラブを素材とし
て製造していた極厚の鋼板を連鋳鋳片により確実かつ容
易に製造でき、コスト的にも有利である。As described above, according to the present invention,
It is possible to easily eliminate the void defects (generated by the lack of hot water supplied during the final solidification of the continuous casting slab) that occur in the center of the product thickness, and thus obtain an extremely thick steel plate with excellent internal properties. it can. Further, according to the present invention, the following effects can be obtained. (1) The applicable reduction ratio when directly manufacturing extra-thick steel plates from continuous cast slabs by plate rolling is about 2.5 in the past.
Further, in the manufacturing process using both forging and plate rolling, the reduction ratio was about 1.5, but according to the present invention, the reduction ratio can be expanded to about 1.25. (2) Further, according to the method of the present invention, by using the existing 6000 ton forging press machine, it is possible to reliably and easily manufacture the extremely thick steel plate that was manufactured using the conventional slab as a raw material by continuous cast slab. It is possible and advantageous in cost.
【図１】図１は、連鋳スラブを厚さ方向に鍛造するもよ
うを説明する模式図である。FIG. 1 is a schematic diagram for explaining how a continuous cast slab is forged in the thickness direction.
【図２】図２は、連鋳スラブを幅方向に鍛造するもよう
を説明する模式図である。FIG. 2 is a schematic diagram for explaining how to forge a continuous cast slab in the width direction.
【図３】図３は、鍛造圧下率と厚板圧延圧下率による鋼
板内質特性の評価を示したグラフである。FIG. 3 is a graph showing evaluation of steel plate internal quality characteristics by a forging reduction rate and a thick plate rolling reduction rate.
───────────────────────────────────────────────────── フロントページの続き (56)参考文献 特開 昭58−84603（ＪＰ，Ａ) 特開 昭61−273201（ＪＰ，Ａ) 特開 平７−232201（ＪＰ，Ａ) 特開 平１−241301（ＪＰ，Ａ) (58)調査した分野(Int.Cl.7，ＤＢ名) B21B 1/00 - 1/46 B22D 11/128 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP 58-84603 (JP, A) JP 61-273201 (JP, A) JP 7-232201 (JP, A) JP 1- 241301 (JP, A) (58) Fields surveyed (Int.Cl. 7 , DB name) B21B 1/00-1/46 B22D 11/128
Claims (3)
て全圧下率が20〜60％の範囲内の加工条件で125mm厚以
上の極厚鋼板を製造する方法において、前記連鋳鋳片の
端部を幅方向から圧下し、該鋳片幅方向の両端部を150m
m以上減尺させると共に肥厚化させることにより、幅方
向の断面形状がドッグボーン状を呈する鋼片とした後実
体鍛練し、これを被鍛造材として厚板圧延を行うことを
特徴とする極厚鋼板の製造方法。1. A method for producing an extremely thick steel plate having a thickness of 125 mm or more from a continuous cast slab by using forging and thick plate rolling together under processing conditions with a total reduction ratio of 20 to 60%. The end of the continuous cast slab is pressed down in the width direction, and both ends in the width direction of the slab are 150 m.
Extra-thickness characterized by performing post-material forging into steel pieces with a dogbone cross-sectional shape in the width direction by reducing and thickening them by m or more, and then performing plate rolling using this as a material to be forged. Steel plate manufacturing method.
たっては、鍛造時の圧下率を11 ％以上とすることを特徴
とする請求項１に記載の製造方法。2. The manufacturing method according to claim 1, wherein the rolling reduction during forging is set to 11 % or more in processing within a total rolling reduction within the range of 20 to 25%.
当たっては、鍛造時の圧下率を16 ％以上とすることを特
徴とする請求項１に記載の製造方法。3. The manufacturing method according to claim 1, wherein, when processing is carried out in the range where the total rolling reduction is over 25 to 60%, the rolling reduction at the time of forging is 16 % or more.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP07509497A JP3528504B2 (en) | 1997-03-27 | 1997-03-27 | Manufacturing method of extra thick steel plate |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP07509497A JP3528504B2 (en) | 1997-03-27 | 1997-03-27 | Manufacturing method of extra thick steel plate |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH10263614A JPH10263614A (en) | 1998-10-06 |
| JP3528504B2 true JP3528504B2 (en) | 2004-05-17 |
Family
ID=13566246
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP07509497A Expired - Fee Related JP3528504B2 (en) | 1997-03-27 | 1997-03-27 | Manufacturing method of extra thick steel plate |
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| Country | Link |
|---|---|
| JP (1) | JP3528504B2 (en) |
Families Citing this family (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP4543980B2 (en) * | 2005-03-22 | 2010-09-15 | Ｊｆｅスチール株式会社 | Manufacturing method of extra-thick steel plate with excellent internal properties |
| JP6156455B2 (en) * | 2014-08-25 | 2017-07-05 | Ｊｆｅスチール株式会社 | Slab forging method |
| JP6156459B2 (en) * | 2014-10-02 | 2017-07-05 | Ｊｆｅスチール株式会社 | Method for forging steel material and method for producing steel material using the forging method |
| JP6156321B2 (en) * | 2014-10-22 | 2017-07-05 | Ｊｆｅスチール株式会社 | Hot forging method of slab |
| JP7410369B2 (en) * | 2018-08-22 | 2024-01-10 | 日本製鉄株式会社 | Method for reducing internal defects in slabs and slab manufacturing equipment |
| CN112126758B (en) * | 2020-09-25 | 2022-02-22 | 东北大学 | Toughening regulation and control method for super-thick steel plate |
| KR102452501B1 (en) | 2022-05-09 | 2022-10-07 | 주식회사 남경에스엠 | Forging method for slab |
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1997
- 1997-03-27 JP JP07509497A patent/JP3528504B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH10263614A (en) | 1998-10-06 |
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