JPS60180649A - Production of steel sheet having excellent resistance to hydrogen induced cracking - Google Patents
Production of steel sheet having excellent resistance to hydrogen induced crackingInfo
- Publication number
- JPS60180649A JPS60180649A JP3685884A JP3685884A JPS60180649A JP S60180649 A JPS60180649 A JP S60180649A JP 3685884 A JP3685884 A JP 3685884A JP 3685884 A JP3685884 A JP 3685884A JP S60180649 A JPS60180649 A JP S60180649A
- Authority
- JP
- Japan
- Prior art keywords
- casting
- cavity
- induced cracking
- excellent resistance
- steel sheet
- 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.)
- Pending
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
- B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
- B22D11/06—Continuous casting of metals, i.e. casting in indefinite lengths into moulds with travelling walls, e.g. with rolls, plates, belts, caterpillars
- B22D11/0605—Continuous casting of metals, i.e. casting in indefinite lengths into moulds with travelling walls, e.g. with rolls, plates, belts, caterpillars formed by two belts, e.g. Hazelett-process
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Continuous Casting (AREA)
Abstract
Description
【発明の詳細な説明】
コノ発明は、API規格のX−5,2,X−60゜X−
65,X−70級の各鋼に代表されるラインパイプ用鋼
板等、耐水素誘起割れが必要とされる鋼板の該特性を一
層向上させることを可能にした、耐水素誘起割れ性に一
段と優れた鋼板の製造方法に関するものである。[Detailed description of the invention] This invention is based on API standard X-5, 2, X-60°X-
It has even better hydrogen-induced cracking resistance, making it possible to further improve the properties of steel plates that require hydrogen-induced cracking resistance, such as line pipe steel plates such as 65 and X-70 class steels. The present invention relates to a method for manufacturing steel sheets.
〈産業上の利用分野〉
益々悪化する近年のエネルギー事情を背景として、最近
では、従来は放置されていたようなサワー環境下の油田
や゛ガス田にまで開発の目が向けられるようになってき
た。<Industrial Application Fields> Against the backdrop of the increasingly deteriorating energy situation in recent years, development has recently begun to turn to oil and gas fields in sour environments, which had previously been neglected. Ta.
ところが、硫化水素等の腐食性の強いガスを含む上記サ
ワー環境下では、使用する各種銅相の腐食対策が大きな
問題となっており、特にラインパイプ材等のような比較
的強度の低い鋼材においては、水素脆性の一種である水
素誘起割れ(以下、HIO”と略称する)に強い関心が
集まシ、ラインパイプ等の製造素材たる鋼板の耐H工C
性能の向上が強く叫ばれるようになってきた。However, in the above-mentioned sour environment containing highly corrosive gases such as hydrogen sulfide, countermeasures against corrosion of the various copper phases used have become a major problem, especially for relatively low-strength steel materials such as line pipe materials. Hydrogen-induced cracking (hereinafter abbreviated as "HIO"), which is a type of hydrogen embrittlement, has attracted strong interest.
There is a strong demand for improved performance.
このHICは、硫化水素等による腐食で発生した水素が
鋼材中へ侵入し、非金属介在物の界面等に集積したとき
の内圧で生じるものであり、外部応力無しでも発生する
ことが知られている。This HIC occurs due to internal pressure when hydrogen generated by corrosion due to hydrogen sulfide, etc. enters the steel material and accumulates at the interface of non-metallic inclusions, and it is known that it can occur even without external stress. There is.
〈従来技術〉
従来、このようなラインパイプ用材等の鋼板製造には、
まず、オシレーション方式を採用した通常のスラブ連続
鋳造法にて200〜30(1++on程度の厚さの鋳片
を湾曲半径:1′0〜12m程度で鋳込み、次いでこの
鋳片を圧延素材とした熱間圧延を行うと言う工程が普通
に採用されていた。<Prior art> Conventionally, in the production of steel plates such as line pipe materials,
First, a slab with a thickness of about 200 to 30 (1++ on) was cast with a bending radius of about 1'0 to 12 m using the normal continuous slab casting method that adopted the oscillation method, and then this slab was used as a rolling material. A process called hot rolling was commonly used.
しかしながら、このようにして製造された鋼板には、連
続鋳造鋳片の偏析に伴う内部欠陥が持ち来たされ、耐H
I’C性能に悪影響を及ぼしているとの指摘がなされる
ようになってきたのである。However, steel sheets manufactured in this way have internal defects due to segregation of continuously cast slabs, and have high resistance to H.
It has begun to be pointed out that this has an adverse effect on I'C performance.
即ち、圧延に供するスラブ鋳片を製造する際、鋳片厚さ
が200〜300閣程度であると゛中心偏析″と呼ばれ
る内部欠陥がどうしても発生してしまう。そして、この
内部欠陥は熱間圧延によっても消失することがなく、例
えばラインパイプ等の製品としてサワー環境下で使用さ
れたシすると、前記欠陥部に水素が侵入畜積することと
なってH工O’z引き起すのである。That is, when manufacturing slab slabs for rolling, if the thickness of the slab is about 200 to 300 mm, internal defects called "center segregation" inevitably occur.This internal defect is removed by hot rolling. For example, when used in a sour environment as a product such as a line pipe, hydrogen enters and accumulates in the defective parts, causing hydrogen oxidation.
このような中心偏析は、柱状晶として発達してきた凝固
シェルの最終凝固位置付近で発生する空隙、即ち凝固収
縮やバルジング等の機械的要因によって生ずる空隙部に
デンドライトの枝の間の濃化溶鋼が流入して起きること
が解明されている。Such center segregation is caused by the presence of concentrated molten steel between the branches of dendrites in the voids that occur near the final solidification position of the solidified shell that has developed as columnar crystals, that is, the voids that are caused by mechanical factors such as solidification shrinkage and bulging. It has been clarified what happens when the inflow occurs.
そこで、このような中心偏析の防止策として、○ 低温
鋳込み、RE、M(希土類元素)や鋼線の添加、或いは
電磁攪拌の手段によって鋳片中心部の等軸晶域を拡大し
、濃化溶鋼の移動抵抗を大きくする方法、
O濃化溶鋼を等軸晶間へ積極的に分散せしめ、線状の集
積とならないようにする方法、O最終凝固位置でのバル
ジングを防止する方法、
O凝固収縮を補う程度の軽圧下を施す方法、等が試みら
れているが、いずれもかなυの費用を必要とする上、そ
れでも十分な効果が期待できず、鋼板段階での超音波探
傷にてはねられる場合も時としてあったのである。Therefore, as a measure to prevent such center segregation, the equiaxed crystal region at the center of the slab is expanded and concentrated by low-temperature casting, addition of RE, M (rare earth elements), steel wire, or electromagnetic stirring. A method of increasing the movement resistance of molten steel, a method of actively dispersing O-enriched molten steel between equiaxed crystals to prevent linear accumulation, a method of preventing bulging at the final O solidification position, O solidification Attempts have been made to apply light reduction to compensate for shrinkage, but all of these methods require a cost of around υ and are not expected to be sufficiently effective. There were times when they were hit.
〈発明の目的〉
本発明者等は、上述のような観点から、中心偏析等に基
づく内部欠陥が無く、優れた耐HIC性を有する鋼板を
、工程数少なく、高能率かつ低コストで、安定して製造
すべく研究を重ねた結果、以下に示される如き知見を得
たのである。<Purpose of the Invention> From the above-mentioned viewpoint, the present inventors have created a steel plate that is free from internal defects due to center segregation and has excellent HIC resistance, with a small number of processes, high efficiency, low cost, and a stable process. As a result of repeated research in order to manufacture it, we obtained the knowledge shown below.
く知見事項〉
(a) 最近、第1図(ツインベルトキャスター)或い
は第2図(相対する一対のリング状回転体の内外周に接
したベルトラ回転体と同期回転させながら鋳込むもの)
に示したような同期式ベルトキャスターにより、融点が
比較的高い鋼等の薄鋳片を連続的に鋳造する方法が開発
され、実用化のための多数の報告がなされているが、特
に、キャビティ厚さ’f: 60 m以下に設定した同
期式べ化トキャスターにて溶鋼を鋳造すると、鋳片の中
心部付近でも凝固シェルの成長速度が低下せず、従って
極めて微細な凝固組織が得られること。(a) Recently, casters as shown in Fig. 1 (twin belt caster) or Fig. 2 (caster caster while being rotated synchronously with a belt roller rotating body that is in contact with the inner and outer peripheries of a pair of opposing ring-shaped rotating bodies)
A method for continuously casting thin slabs of steel, etc. with a relatively high melting point, using a synchronous belt caster as shown in Figure 1, has been developed, and numerous reports have been made regarding its practical application. Thickness 'f: When molten steel is cast using a synchronous type beta caster set to 60 m or less, the growth rate of the solidified shell does not decrease even near the center of the slab, and an extremely fine solidified structure can therefore be obtained. thing.
上述のように、第1図及び第2図は同期式ベルトキャス
ターのそれぞれ別の例を示す概略構成図であるが、第1
図に示されるものでは、2つの水冷鋳造ベルト1,1の
間隔部分に形成されている鋳造区域(キャビティ)にオ
ーバーフロー樋で、また第2図で示されるものでは、2
つの水冷鋳造ベルト1.1とリング状回転体8との間隔
部分に形成されている鋳造区域(キャビティ)にノズル
9で、それぞれタンディツシュ4からの給湯を行うが、
鋳込まれた溶鋼は水冷鋳造ベルト1に接して凝固シェル
6を形成し、それらとともに移動しながら短時間に薄鋳
片7となって無理なく引き抜かれるのである。なお、第
1図及び第2図において、符号3で示されるものはプー
リー、5は溶融金属プールである。As mentioned above, FIGS. 1 and 2 are schematic configuration diagrams showing different examples of synchronous belt casters.
In the case shown in the figure, the casting area (cavity) formed in the space between the two water-cooled casting belts 1, 1 is provided with an overflow trough, and in the case shown in FIG.
Hot water is supplied from the tundish 4 to the casting area (cavity) formed in the space between the two water-cooled casting belts 1.1 and the ring-shaped rotating body 8 through the nozzles 9, respectively.
The cast molten steel forms a solidified shell 6 in contact with the water-cooled casting belt 1, and while moving together with the solidified shell 6, it becomes a thin slab 7 in a short time and is easily drawn out. In addition, in FIGS. 1 and 2, the reference numeral 3 indicates a pulley, and the reference numeral 5 indicates a molten metal pool.
ちなみに、同期式ベルトキャスターで鋳込んだAI)工
規格のX−60級鋼鋳片のキャスター向凝固係数is添
加法によって調査したところ、22〜26 (tan
/ ” )と言う、水冷銅鋳型による従来法での15〜
21 (1ffl/mmz )よりもかなり大きい値を
示しておシ、鋳片の中心部付近でもシェル成長速度が落
ちないであろうことが確認された。By the way, when we investigated the caster solidification coefficient of X-60 class steel slab according to the AI) engineering standard cast using a synchronous belt caster using the IS addition method, we found that it was 22 to 26 (tan).
15~ by the conventional method using a water-cooled copper mold.
21 (1 ffl/mmz), and it was confirmed that the shell growth rate would not decrease even near the center of the slab.
(b) 同期式ベルトキャスターで溶鋼の鋳造を行うと
、最終凝固位置での溶鋼静圧は溶鋼高さにして0.5〜
2m程度と、従来の10〜12mに比して相当に小さく
なり、しかも多くはキャスターの中(即ち鋳型中)で凝
固を完了することとなるので、鋳片のバルジング量をゼ
ロ又は極めて僅かな量に抑えられること。(b) When molten steel is cast using a synchronous belt caster, the static pressure of the molten steel at the final solidification position is 0.5 to 0.5 to the height of the molten steel.
The length of the slab is approximately 2m, which is considerably smaller than the conventional length of 10 to 12m, and most solidification is completed inside the caster (that is, inside the mold), so the amount of bulging of the slab can be reduced to zero or extremely small. Being able to keep the amount down.
(C) 従って、キャビティ厚さを特に60祁以下に設
定した同期式ベルトキャスターにて耐HIC鋼を鋳造す
ると、中心偏析の殆んど無い微細凝固組織鋳片が高能率
で得られ、更に該鋳片の熱間圧延によって一段と優れた
耐HIO特性を備えた熱延鋼板を実現できること、
〈発明の構成〉
この発明は、上記知見に基づいてなされたものであフ、
耐H工0鋼板の製造方法において、まず、キャビティ厚
さ:60胴以下
に設定した同期式ベルトキャスターにて溶鋼を連続的に
薄鋳片となすとともに、該薄鋳片を圧延素材として用い
ることにより、中心偏析が殆んど無く、耐HIC性の極
めて優れた鋼板を安定して量産し得るようにした点、
に持金を有するものである。(C) Therefore, when HIC-resistant steel is cast using a synchronous belt caster with a cavity thickness of 60 mm or less, a finely solidified slab with almost no center segregation can be obtained with high efficiency, and the The present invention has been made based on the above findings, and it is possible to realize a hot-rolled steel sheet with even better HIO resistance by hot rolling a cast slab. In the manufacturing method, first, molten steel is continuously formed into thin slabs using a synchronous belt caster with a cavity thickness of 60 mm or less, and by using the thin slabs as rolling stock, center segregation is almost eliminated. The advantage lies in the fact that it is possible to stably mass-produce steel sheets with extremely high HIC resistance without any hassle.
なお、ここで言う「耐HIC鋼」とは、ラインパイプ用
鋼等として知られているところの、c:o、01〜0.
31(以下係は重量係とする)、Si:0.61以下、
Mn : 0.5〜2.0 qb。The term "HIC-resistant steel" used herein refers to c:o, 01-0.
31 (hereinafter referred to as weight), Si: 0.61 or less,
Mn: 0.5-2.0 qb.
P:0.015%以下、S:0.005%以下、M :
’0.003〜0.06 %
程度を含むとともに、必要に応じて、更に0.01〜0
.14のNbや、C!u、 Ni、 Cr、 Mo、V
、 Ti、REM(希土類元素) 、 Oa、 Zrの
1種以上を含有し、残部が実質的にFeから成る成分組
成の鋼に代表されるものを指す。P: 0.015% or less, S: 0.005% or less, M:
' Contains approximately 0.003 to 0.06%, and if necessary, further 0.01 to 0.
.. 14 Nb and C! u, Ni, Cr, Mo, V
, Ti, REM (rare earth element), Oa, and Zr, and the remainder is essentially Fe.
また、「同期式ベルトキャスター」とは、第1図で示し
たツインベルトキャスターや、例えば特開昭55−83
11号公報に記載されているような、相対する一対のリ
ング状回転体の内外周に接したベルトラ回転体と同期回
転させながら鋳込むキャスター(第2図)等の、鋳造用
ベルトラ背面から水冷しながら回転させるキャスターを
意味するものである。そして、これらのキャスターは、
ント及びマクロ・エッチによるマクロ偏析評価全実施し
た。In addition, "synchronized belt caster" refers to the twin belt caster shown in Fig. 1, for example,
Water cooling is applied from the back side of a casting belt truck, such as a caster (Fig. 2) that is cast while rotating synchronously with the belt truck rotating body that is in contact with the inner and outer peripheries of a pair of opposing ring-shaped rotating bodies, as described in Publication No. 11. This refers to casters that can be rotated while moving. And these casters are
All macro segregation evaluations were carried out using etchants and macro etch.
一方で、それぞれの鋳片を熱間圧延によって10mm厚
(圧下比:1.5〜10)とし、との熱延鋼板から10
0 X 1.00−の試験片を切り出して耐HIC性能
試験を行った。耐HIC性能試験は、BP条件(人工海
水%H2S飽和)に96時間浸漬後、超音波非破壊検査
によりHI C割れ率を調査すると言う方法を採用した
。On the other hand, each slab was hot rolled to a thickness of 10 mm (rolling ratio: 1.5 to 10), and
A test piece of 0 x 1.00- was cut out and subjected to an HIC resistance test. The HIC resistance performance test adopted a method in which the HIC cracking rate was investigated by ultrasonic non-destructive testing after being immersed in BP conditions (artificial seawater % H2S saturated) for 96 hours.
このときの鋳片マクロ偏析評価結果、及びHN3割れ率
を第2表に示した。Table 2 shows the macro segregation evaluation results of the slab and the HN3 cracking rate.
第2表に示される結果からも明らかなように、鋳片厚さ
くキャビティ厚さ)が60祁以下では、△Tに関係なく
、マクロ偏析評価が十分に満足し得る結果であることが
明らかである。そして、HN0割れ率も、割れ発生ゼロ
或いは極めて低い値であった。As is clear from the results shown in Table 2, it is clear that when the slab thickness multiplied by the cavity thickness is 60 or less, the macro segregation evaluation results are sufficiently satisfactory regardless of △T. be. The HN0 cracking rate was also zero or extremely low.
また、鋳片厚さくキャビティ厚さ)が6(1mm’i越
えたものは、△Tを20℃以下にしないとマクロ偏析評
価が実用上好ましく無い程度にまで低下し、HzclI
Jh率が20係を越えてしまうことから、何らかの伺加
的な対策を講じる必要のあることがわかる。In addition, if the slab thickness multiplied by the cavity thickness exceeds 6 (1 mm'i), unless △T is lowered to 20°C or less, the macro segregation evaluation will drop to a level that is not desirable for practical use, and HzclI
Since the JH rate exceeds 20, it is clear that some additional measures need to be taken.
なお、第2表中の「従来法」とは、水冷銅鋳型−(r使
用したオンレーション方式による、従来の連続鋳造法を
採用し、圧延時の圧延比を10としたものであるが、マ
クロ偏析評価、HIC割れ率ともに極めて悪い結果にな
っていることが確認できる。In addition, the "conventional method" in Table 2 refers to the conventional continuous casting method using the onration method using a water-cooled copper mold, and the rolling ratio during rolling was 10. It can be confirmed that both the macro segregation evaluation and the HIC cracking rate are extremely poor.
そして、相対する一対のリング状回転体の内外周に接し
たベルトラ前記回転体と同期回転させながら鋳込むキャ
スターも、水冷ベルトによる凝固冷却と言う点ではツイ
ンベルトキャスターと変わるところが無く、また最終凝
固位置での溶鋼静圧も、溶鋼高さで2m程度と小さくて
バルジング量が極めて僅かであり、実試験によっても、
ベルト間隔(キャビティ厚さ)が同じであれば第2表に
示されると同様の結果が得られることも確認された。Casters that are cast while rotating in synchronization with the belt rollers that are in contact with the inner and outer peripheries of a pair of opposing ring-shaped rotating bodies are no different from twin-belt casters in that they are solidified and cooled by a water-cooled belt, and the final solidification The static pressure of the molten steel at the molten steel position is also small, at about 2 m at the molten steel height, and the amount of bulging is extremely small.According to actual tests,
It was also confirmed that similar results can be obtained as shown in Table 2 if the belt spacing (cavity thickness) is the same.
く総括的な効果〉
上述のように、この発明によれば、耐HIC性が一段と
優れた鋼板を、能率良く低コストで、かつ安定して量産
することが可能となるなど、産業上有用な効果がもたら
されるのである。Overall Effects> As described above, the present invention has industrially useful benefits such as making it possible to mass-produce steel sheets with even better HIC resistance efficiently, at low cost, and stably. It brings about an effect.
第1図はツインベルト形式の同期式ベルトキャスターに
て鋳造を実施している状態金示す概略模式図、第2図は
態形式の同期式ベルトキャスターにて鋳造を実施してい
る状態を示す概略模式図、第3図は実施例において用い
た鋳造装置の概略模式図である。
図面において、
l・・・鋳造用ベルト、
2・・・オーバーフロー樋、
3・・・プーリー、 4・・・小タンディツシュ、5・
・・溶融金属プール、6・・・凝固シェル、7・・・鋳
片、 8・・・リング状回転体、9.11.13・・・
ノズル、
工0・・・取鍋、 12・・・大タンディツシュ。Figure 1 is a schematic diagram showing a state in which casting is carried out using a twin-belt type synchronous belt caster, and Figure 2 is a schematic diagram showing a state in which casting is carried out using a twin-belt type synchronous belt caster. The schematic diagram and FIG. 3 are schematic diagrams of the casting apparatus used in the examples. In the drawings, l... Casting belt, 2... Overflow gutter, 3... Pulley, 4... Small tundish, 5...
... Molten metal pool, 6... Solidified shell, 7... Slab, 8... Ring-shaped rotating body, 9.11.13...
Nozzle, 0...Ladle, 12...Large tanditshu.
Claims (1)
ティ厚さ、60閣以下 に設定シた同期式ベルトキャスターにて溶鋼を連続的に
薄鋳片となすとともに、該薄鋳片を圧延累月として用い
ることを特徴とする、耐水素誘起割れ性に優れた鋼板の
製造方法。[Claims] In a method for producing a hydrogen-induced cracking-resistant steel plate, first, molten steel is continuously formed into a thin slab using a synchronous belt caster whose cavity thickness is set to 60 mm or less, and the thin casting is A method for producing a steel plate with excellent resistance to hydrogen-induced cracking, characterized by using a piece as a rolled plate.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP3685884A JPS60180649A (en) | 1984-02-28 | 1984-02-28 | Production of steel sheet having excellent resistance to hydrogen induced cracking |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP3685884A JPS60180649A (en) | 1984-02-28 | 1984-02-28 | Production of steel sheet having excellent resistance to hydrogen induced cracking |
Publications (1)
Publication Number | Publication Date |
---|---|
JPS60180649A true JPS60180649A (en) | 1985-09-14 |
Family
ID=12481480
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP3685884A Pending JPS60180649A (en) | 1984-02-28 | 1984-02-28 | Production of steel sheet having excellent resistance to hydrogen induced cracking |
Country Status (1)
Country | Link |
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JP (1) | JPS60180649A (en) |
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1984
- 1984-02-28 JP JP3685884A patent/JPS60180649A/en active Pending
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