JPH0642979B2 - Manufacturing method of high strength steel for welding and low temperature containing titanium oxide - Google Patents
Manufacturing method of high strength steel for welding and low temperature containing titanium oxideInfo
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- JPH0642979B2 JPH0642979B2 JP1039507A JP3950789A JPH0642979B2 JP H0642979 B2 JPH0642979 B2 JP H0642979B2 JP 1039507 A JP1039507 A JP 1039507A JP 3950789 A JP3950789 A JP 3950789A JP H0642979 B2 JPH0642979 B2 JP H0642979B2
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Description
【発明の詳細な説明】 （産業上の利用分野） 本発明は、溶接性の優れた強靱性高張力鋼に係わり、特
に、溶接熱影響部（以下ＨＡＺと称する）の低温靱性の
優れた構造用鋼の製造法に関するものである。TECHNICAL FIELD The present invention relates to a toughness and high strength steel having excellent weldability, and particularly to a structure of a weld heat affected zone (hereinafter referred to as HAZ) having excellent low temperature toughness. The present invention relates to a manufacturing method of steel for use.
（従来の技術） 低合金鋼の溶接部のＨＡＺ靱性は、(1)有効結晶粒の大
きさ（オーステナイト粒径、ミクロ組織）、(2)硬化相
の粒径及び体積分率（炭化物、高炭素マルテンサイト、
介在物）、(3)母相の硬さ及び靱性（フェライト中の固
溶Ｃ，Ｎ）等の冶金要因によって支配されている。(Prior Art) HAZ toughness of a welded portion of low alloy steel is (1) effective grain size (austenite grain size, microstructure), (2) grain size and volume fraction of hardened phase (carbide, high Carbon martensite,
Inclusions), (3) hardness and toughness of matrix (solid solution C, N in ferrite) and other metallurgical factors.
これらの中でＨＡＺ靱性の向上策として、ＨＡＺ組織を
微細化し、有効結晶粒を細粒化する方法が簡便であり、
高温で安定な種々の析出物を活用した各種の方法が提案
されている。Among these, as a measure for improving the HAZ toughness, a method of refining the HAZ structure and making effective crystal grains fine is simple,
Various methods utilizing various precipitates that are stable at high temperatures have been proposed.
例えば、昭和54年６月発行の鉄と鋼，第65巻第８号1232
頁においては、ＴｉＮを微細分散させ、50kg・ｆ／mm2
高張力鋼の大入熱溶接時のＨＡＺ靱性を改善する手段が
とられている。For example, Iron and Steel, June 65, 1979, Volume 65, No. 1232
In the page, finely disperse TiN, 50kgf / mm 2
Measures have been taken to improve the HAZ toughness during high heat input welding of high strength steel.
しかし、これらの析出物は、大入熱溶接においては大部
分が溶解され、ＨＡＺ組織の粗粒化と固溶Ｎの増加を生
じ、ＨＡＺ靱性を劣化させるという欠点が存在する。However, most of these precipitates are melted in high heat input welding, resulting in coarsening of the HAZ structure and increase of solute N, which deteriorates HAZ toughness.
一方、本発明者の一部は、溶鉄のＡ脱酸に替わるＴｉ
脱酸により、鋼中にＴｉ酸化物を微細分散させ、溶接時
のＨＡＺ部において、粒内フェライト変態組織（以下Ｉ
ＦＰと称する）を発達させることにより、ＨＡＺ靱性を
著しく改善できることを、特開昭60-245768号、特開昭6
0-79745号、特開昭61-117245号、特開昭62-1842号にお
いて示した。On the other hand, some of the inventors of the present invention
The Ti oxide is finely dispersed in the steel by deoxidation, and the intragranular ferrite transformation structure (hereinafter I
(Referred to as FP), the HAZ toughness can be remarkably improved.
No. 0-79745, JP-A-61-117245 and JP-A-62-1842.
さらに、本発明者らはＴｉ酸化物含有鋼においては鋼中
のＴｉ酸化物個数の増加にともないＨＡＺ靱性が向上す
ることを出願番号63-13613号で明らかにした。しかし、
連続鋳造で溶製すると、スラブ中央部においてＴｉ酸化
物個数が減少し、大入熱ＨＡＺ靱性を確保するために必
要な個数を得られない場合が生じた。Further, the inventors of the present invention have revealed in the application number 63-13613 that the HAZ toughness of the Ti oxide-containing steel increases as the number of Ti oxides in the steel increases. But,
When melted by continuous casting, the number of Ti oxides was reduced in the central portion of the slab, and there were cases where the number required to secure high heat input HAZ toughness could not be obtained.
（発明が解決しようとする課題） 連続鋳造における鋼塊中央部のＴｉ酸化物個数の減少は
主にＴｉ酸化物が凝固時に二次脱酸生成物として析出す
るため、徐冷されるスラブ中央部では凝集粗大化するこ
とに原因することが判明した。(Problems to be Solved by the Invention) The decrease in the number of Ti oxides in the central portion of the steel ingot in continuous casting is mainly due to the precipitation of Ti oxides as a secondary deoxidation product during solidification. Then, it was found to be caused by the coarsening of aggregation.
スラブ中央部においても必要なＴｉ酸化物個数を確保
し、ＨＡＺ靱性を改善するために、二次脱酸生成物に加
え、溶鋼段階で析出する一時脱酸Ｔｉ酸化物を活用す
る、連続鋳造のモールドでのＴｉ脱酸方法が有効である
との結論に達し、本発明を成したものである。In order to secure the required number of Ti oxides even in the central part of the slab and to improve the HAZ toughness, in addition to the secondary deoxidation product, the temporary deoxidation Ti oxide that precipitates in the molten steel stage is utilized for continuous casting. The present inventors have reached the conclusion that the Ti deoxidation method using a mold is effective.
（課題を解決するための手段） 本発明は、以上の知見に基づいてなされたものであり、
その要旨は、溶鉄を予備脱酸により溶存酸素を重量％で
0.0030〜0.0100％に溶製し、合金添加による成分調整に
より、Ｃ：0.02〜0.18％、Ｓｉ：0.03〜0.25％、Ｍｎ：
0.4〜2.0％、Ｓ：0.0007〜0.0060％、Ｎ：0.0010〜0.00
40％を含有させ、Ｐ≦0.015％、Ａ≦0.003％に制限
し、Ｃｒ≦1.0％、Ｎｉ≦3.0％、Ｍｏ≦0.5％、Ｖ≦0.1
％、Ｎｂ≦0.05％、Ｂ≦0.002％、Ｃｕ≦1.5％の１種ま
たは２種以上を含有し、残部はＦｅ及び不可避不純物か
らなる溶鋼を溶製、さらに、最終脱酸として連続鋳造の
モールドで低融点のTi-Cu、Ti-Ni、Ti-Fe合金のワイヤ
ー、または粒体を添加し、重量％でＴｉ：0.005〜0.030
％を含有させ、スラブ中央部において、主に粒子径が0.
1〜3.0μｍにあるＴｉ酸化物及びＴｉ酸化物とＴｉＮ，
ＭｎＳの複合析出物粒子の合計で40〜170個／mm2を含有
する鋼塊を圧延して製造することを特徴とする溶接部低
温靱性の優れた低温用高張力鋼の製造法である。(Means for Solving the Problems) The present invention has been made based on the above findings,
The gist is that the dissolved iron is pre-deoxidized and the dissolved oxygen is
Melted to 0.0030-0.0100%, and by adjusting the composition by adding an alloy, C: 0.02-0.18%, Si: 0.03-0.25%, Mn:
0.4 to 2.0%, S: 0.0007 to 0.0060%, N: 0.0010 to 0.00
40% content, P ≦ 0.015%, A ≦ 0.003%, Cr ≦ 1.0%, Ni ≦ 3.0%, Mo ≦ 0.5%, V ≦ 0.1
%, Nb ≦ 0.05%, B ≦ 0.002%, Cu ≦ 1.5%, one or more, and the balance consists of molten steel consisting of Fe and unavoidable impurities, and a continuous casting mold for final deoxidation. And low melting point Ti-Cu, Ti-Ni, Ti-Fe alloy wires or particles are added, and Ti: 0.005 to 0.030% by weight.
%, And the particle size is mainly 0 in the central part of the slab.
Ti oxide and Ti oxide and TiN at 1 to 3.0 μm,
A method for producing a low-temperature high-strength steel having excellent low-temperature toughness at a welded portion, which is characterized in that a steel ingot containing 40 to 170 pieces / mm 2 in total of MnS composite precipitate particles is rolled and produced.
（作用） 以下、本発明について詳細に説明する。(Operation) Hereinafter, the present invention will be described in detail.
最初に本発明鋼の基本成分範囲の限定理由について述べ
る。First, the reasons for limiting the basic composition range of the steel of the present invention will be described.
まず、Ｃは鋼の強度を向上させる有効な成分として添加
するもので、0.02％未満では構造用鋼として必要な強度
が得られず、また0.18％を超える過剰の添加は、溶接割
れ性、ＨＡＺ靱性などを著しく低下させるので、上限を
0.18％とした。First, C is added as an effective component for improving the strength of steel. If it is less than 0.02%, the strength required for structural steel cannot be obtained, and if it is added in excess of 0.18%, weld crackability, HAZ Since the toughness is significantly reduced, the upper limit is
It was 0.18%.
次に、Ｓｉは母材の強度確保、溶鋼の予備脱酸などに必
要であるが、0.25％を超えると熱処理組織内に硬化組織
の高炭素マルテンサイト（以下Ｍ＊と称す）を生成し、
靱性を著しく低下させる。また、0.03％未満ではＴｉ酸
化物の分散に必要な溶鋼の予備脱酸ができないため、Ｓ
ｉ含有量をこの範囲に制限した。Next, Si is necessary for securing the strength of the base material, pre-deoxidizing molten steel, etc., but if it exceeds 0.25%, high carbon martensite (hereinafter referred to as M * ) with a hardened structure is formed in the heat-treated structure,
Remarkably reduces toughness. If it is less than 0.03%, the preliminary deoxidation of molten steel necessary for dispersion of Ti oxide cannot be performed, so S
The i content was limited to this range.
Ｍｎは母材の強度、靱性の確保には0.4％以上の添加が
必要であるが、溶接部の靱性、割れ性などの許容できる
範囲で上限を2.0％とした。Mn needs to be added in an amount of 0.4% or more in order to secure the strength and toughness of the base material, but the upper limit was made 2.0% within the allowable range of the toughness and crackability of the welded portion.
Ｓについては、複合体のＭｎＳを析出させるために0.00
07％以上必要であるが、0.0060％超の過剰の添加は、粗
大な硫化物系介在物を形成し、母材の延性低下と異方性
の増加を招くため、0.0007〜0.0060％とした。For S, 0.00 to precipitate MnS in the composite.
07% or more is required, but excessive addition of more than 0.0060% forms coarse sulfide-based inclusions, which leads to a decrease in ductility and anisotropy of the base material, so the content was made 0.0007 to 0.0060%.
ＴｉはＴｉ酸化物とＴｉ窒化物の形成に必須の元素であ
り、0.005未満では必要とするＴｉ酸化物とＴｉ窒化物
量が得られず、ＩＦＰ生成量が低減するため0.005％以
上の添加が必要であるが、0.03％超の添加は、過剰なＴ
ｉ炭化物の析出をともない、析出硬化により硬さを上昇
させ、靱性低下をもたらすため、0.03％以下とした。Ti is an essential element for the formation of Ti oxide and Ti nitride. If less than 0.005, the required amount of Ti oxide and Ti nitride cannot be obtained, and the amount of IFP produced is reduced, so 0.005% or more must be added. However, if more than 0.03% is added, excess T
With precipitation of i-carbide, the hardness is increased by precipitation hardening and the toughness is reduced, so the content was made 0.03% or less.
Ｎは含有量が0.0040％を超えるとＭ＊が存在しない条件
でも母相を脆化させ、靱性を低下させる。また、Ｎが0.
0010％未満では鋼中にほとんど窒化物を生成せず、ＩＦ
Ｐ組織の生成量が減少し靱性が低下する。When the content of N exceeds 0.0040%, the matrix becomes brittle and the toughness deteriorates even under the condition that M * does not exist. Also, N is 0.
If it is less than 0010%, almost no nitride is formed in the steel, and IF
The amount of P structure produced decreases and the toughness decreases.
Ｐは、凝固偏析による溶接割れ性、靱性などの低下を防
止する上から、極力低減すべきであり、上限を0.015％
に制限した。P should be reduced as much as possible in order to prevent deterioration of weld cracking and toughness due to solidification segregation, and the upper limit is 0.015%.
Limited to.
Ａは強力な脱酸元素であり、0.003％以上の添加はＴ
ｉ脱酸により形成されるＴｉ酸化物が形成されなくな
り、ＩＦＰが形成されず、靱性の低下がもたらされるの
で、0.003％以下に制限した。A is a strong deoxidizing element, and the addition of 0.003% or more is T
The Ti oxide formed by i-deoxidation is not formed, IFP is not formed, and the toughness is reduced. Therefore, the Ti oxide content is limited to 0.003% or less.
以上が本発明鋼の基本成分であるが、母材強度の上昇、
及び母材の靱性向上の目的でＣｒ，Ｎｉ，Ｍｏ，Ｖ，Ｎ
ｂ，Ｂ，Ｃｕの１種または２種以上を含有することがで
きる。Although the above are the basic components of the steel of the present invention, the increase of the base metal strength,
And Cr, Ni, Mo, V, N for the purpose of improving the toughness of the base material.
One, two or more of b, B and Cu may be contained.
まず、Ｎｉは、母材の強靱性を高める極めて有効な元素
であるが、3.0％を超す添加は、焼き入れ性の増加によ
り、ＩＦＰ組織の形成が抑制されること、Ｍ＊が生成さ
れることにおり靱性の低下をもたらすため、上限を3.0
％とした。First, Ni is an extremely effective element that enhances the toughness of the base material, but addition of more than 3.0% suppresses the formation of the IFP structure due to the increase in hardenability, and M * is generated. In particular, it lowers the toughness, so the upper limit is 3.0.
%.
Ｃｒ，Ｍｏは焼き入れ性の向上と析出硬化により、母材
の強化に有効である。また、ＴＭＣＰのような適切なプ
ロセスを付加することにより、母材の低温靱性の向上に
有効である。しかし、各成分の上限を超える過剰の添加
は、靱性及び硬化性の観点から有害となるため、Ｃｒ，
Ｍｏの各々について、上限を1.0％，0.5％とした。Cr and Mo are effective in strengthening the base material due to improvement in hardenability and precipitation hardening. Also, by adding an appropriate process such as TMCP, it is effective in improving the low temperature toughness of the base material. However, excessive addition of each component exceeding the upper limit is harmful from the viewpoint of toughness and hardenability.
The upper limits were set to 1.0% and 0.5% for each of Mo.
Ｖ，Ｎｂは母材の強靱化、粒界フェライトの生成抑制な
どによる靱性の改善などに有効であるが、各成分の上限
を超える過剰の添加は、靱性及び硬化性の観点から有害
となるため、Ｖ，Ｎｂのそれぞれについて、上限を0.1
％，0.05％とした。V and Nb are effective for improving the toughness of the base material and improving the toughness by suppressing the generation of grain boundary ferrite, but excessive addition of each component exceeding the upper limit is harmful from the viewpoint of the toughness and hardenability. , V, Nb, the upper limit is 0.1
% And 0.05%.
Ｂは焼き入れ性の向上による母材強度の上昇と粒界フェ
ライトの成長の抑制による高温熱処理鋼材の靱性向上が
期待されるが、0.002％を超える添加は、Ｆｅ２３（Ｃ
Ｂ）６の析出による靱性低下と急冷処理で硬化を招くた
め、上限を0.002％とした。B is expected to increase the strength of the base metal by improving the hardenability and to improve the toughness of the high temperature heat-treated steel material by suppressing the growth of grain boundary ferrite. However, addition of more than 0.002% results in Fe 23 (C
B) Lowering of toughness due to precipitation of 6 and hardening caused by quenching treatment, so the upper limit was made 0.002%.
Ｃｕは母材の強化のわりには、ＨＡＺの硬化が少なく、
有効な元素であるが、応力除去焼鈍による焼き戻し脆
性、溶接割れ性などを考慮して、上限を1.5％とした。Cu is less hardened in the HAZ for strengthening the base material,
Although it is an effective element, the upper limit was set to 1.5% in consideration of temper embrittlement due to stress relief annealing and weld cracking.
次に、ＨＡＺにＩＦＰを生成し組織を微細化しＨＡＺ靱
性を向上させる基となるＩＦＰ核析出物について以下に
説明する。Next, IFP nucleus precipitates that form IFP in the HAZ to refine the structure and improve the HAZ toughness will be described below.
ＩＦＰは主に粒子径が0.1〜3.0μｍにある数％のＭｎを
固溶したＴｉ２Ｏ３，Ｔｉ３Ｏ５のチタン酸化物及びこ
れらの酸化物とＴｉＮ，ＭｎＳの複合体、ＴｉＮ＋Ｍｎ
Ｓの複合体から生成する。該粒子径が0.1μｍ未満では
ＩＦＰ生成効果は極めて弱く、また、3.0μｍ超になる
とＩＦＰ生成能は有するものの、それ自身が破壊の発生
箇所となり易くなり、ＨＡＺ靱性の低下をもたらす。IFP is mainly composed of titanium oxide of Ti 2 O 3 , Ti 3 O 5 in which a few percent of Mn having a particle diameter of 0.1 to 3.0 μm is dissolved, and a complex of these oxides with TiN and MnS, TiN + Mn.
It is generated from the complex of S. If the particle size is less than 0.1 μm, the effect of producing IFP is extremely weak, and if it exceeds 3.0 μm, it has an ability to produce IFP, but tends to become a site of fracture itself, resulting in a decrease in HAZ toughness.
連続鋳造のスラブ中央部におけるその該粒子数について
は、Ｔｉ酸化物及びＴｉ酸化物とＴｉＮ＋ＭｎＳの複合
体の粒子数が少ないと、大入熱ＨＡＺ部において十分に
ＩＦＰを生成させることが出来ないので、それらの合計
で40個／mm2以上存在させることが必要である。Regarding the number of particles in the central part of the continuously cast slab, if the number of particles of the Ti oxide and the composite of Ti oxide and TiN + MnS is small, it is not possible to sufficiently generate IFP in the high heat input HAZ part. It is necessary that the total of them be 40 pieces / mm 2 or more.
該粒子数の増加にともないＩＦＰの個数も増加するが、
該粒子数の合計で170個／mm2を超える過剰な存在は、母
材及び溶接部の延性低下を招く傾向があるので、該粒子
数の上限は170個／mm2でなければならない。As the number of particles increases, the number of IFPs also increases,
Excessive presence of the total number of particles exceeding 170 particles / mm 2 tends to reduce ductility of the base metal and the welded portion, so the upper limit of the number of particles must be 170 particles / mm 2 .
上記における本発明の基本となるスラブ中央部でＴｉ酸
化物数を増加させるためには、二次脱酸生成物に加え、
溶鋼段階で析出する一時脱酸Ｔｉ酸化物を活用しなけれ
ばならない。従って、最終脱酸としてのＴｉ添加後、で
きる限り短時間に出鋼、凝固させる必要がある。それに
は連続鋳造においてＴｉをモールド添加する方法が最も
有効であり、その方法について説明する。In order to increase the number of Ti oxides in the central portion of the slab, which is the basis of the present invention, in addition to the secondary deoxidation product,
Temporary deoxidized Ti oxide that precipitates in the molten steel stage must be utilized. Therefore, it is necessary to tap steel and solidify as soon as possible after adding Ti as the final deoxidation. The method of adding Ti to the mold in continuous casting is the most effective for that, and the method will be described.
連続鋳造のモールドでＴｉ脱酸するには、添加したＴｉ
を溶鋼中に、できる限り短時間に均一拡散させる必要が
ある。それには融点の低いＴｉ合金が有効であり、加工
性、経済性を加味し、選択した結果、Ｔｉ‐Ｃｕ，Ｔｉ
‐Ｎｉ，Ｔｉ‐Ｆｅ合金が優れていることが判明した。Added Ti to deoxidize Ti in a continuous casting mold.
Need to be uniformly dispersed in molten steel in the shortest possible time. A Ti alloy with a low melting point is effective for that, and as a result of selecting workability and economic efficiency, Ti-Cu, Ti
-Ni, Ti-Fe alloys were found to be superior.
その合金の組成は重量％でＴｉ：40〜60％，残部はＣ
ｕ、Ｔｉ：60〜80％，残部はＮｉ、Ｔｉ：65〜75％，残
部はＦｅからなるもので何れも純Ｔｉに比べ低融点の合
金である。添加はこれらの合金をワイヤー及び粒状に加
工し、連続しモールド添加する方法である。The composition of the alloy is wt% Ti: 40-60%, the balance is C
u, Ti: 60 to 80%, the balance is Ni, Ti: 65 to 75%, and the balance is Fe. Both are alloys having a lower melting point than pure Ti. Addition is a method in which these alloys are processed into wires and granules and continuously added to the mold.
またＴｉ脱酸前の〔Ｏ〕濃度が0.0100％を超える場合に
は、他の条件を満たしていても、Ｔｉ酸化物が粗粒化し
脆性破壊の起点となり、靱性は向上しない。Further, when the [O] concentration before Ti deoxidation exceeds 0.0100%, the Ti oxide becomes coarse grains and becomes a starting point of brittle fracture even if other conditions are satisfied, and the toughness is not improved.
以下に実施例によりさらに本発明の効果を示す。The effects of the present invention will be further shown in the following examples.
（実施例） 第１表は、試作鋼の化学成分を示し、鋼１〜６まではＴ
ｉ合金によるモールド添加した本発明法によるもので、
鋼７，８は製鋼の真空脱ガス装置内でスポンジＴｉによ
り脱酸する従来法で溶製した比較鋼である。(Example) Table 1 shows the chemical composition of the trial steels, and steels 1 to 6 have T
According to the method of the present invention in which a mold is added by an i alloy,
Steels 7 and 8 are comparative steels produced by the conventional method of deoxidizing with sponge Ti in a vacuum degassing apparatus for steelmaking.
第２表は添加Ｔｉ合金の組成、添加形状、鋳片厚、スラ
ブ中央部のＴｉ酸化物個数、溶接再現ＨＡＺ靱性を表し
た。なお、Ｔｉ酸化物はＴｉ，Ｏ元素の特性Ｘ線をコン
ピュータにより画像解析処理（ＣＭＡ装置）し求めた。Table 2 shows the composition of the added Ti alloy, the added shape, the thickness of the cast piece, the number of Ti oxides in the central portion of the slab, and the HAZ toughness of the weld reproduction. The Ti oxide was obtained by subjecting the characteristic X-rays of Ti and O elements to image analysis processing (CMA apparatus) using a computer.
これらの試作鋼は300mm厚スラブを圧延により50mm鋼板
とし、板厚1/2ｔから12×12×60mmの試験片を採取し、
溶接再現熱サイクル試験によりＨＡＺ靱性を評価した。These trial steels are made by rolling a 300mm thick slab into a 50mm steel plate and collecting test pieces of 12 × 12 × 60mm from a sheet thickness of 1 / 2t.
The HAZ toughness was evaluated by a welding reproduction heat cycle test.
溶接再現熱サイクル試験は試験片の中央部を高周波誘導
加熱により1400℃に急速加熱し、800℃から500℃の冷却
時間161秒の条件で冷却した。この条件は溶接入熱量130
kJ/cmに相当し、加熱温度1400℃は実際のＨＡＺの溶融
線近傍の加熱領域に相当する。さらに靱性はこの試験片
から２mmＶノッチ・シャルピーに加工し、衝撃破面遷移
温度（以下vTrsと称す）を求め評価した。In the welding reproducible heat cycle test, the central part of the test piece was rapidly heated to 1400 ° C by high frequency induction heating, and cooled at a cooling time of 161 seconds from 800 ° C to 500 ° C. This condition is welding heat input 130
It corresponds to kJ / cm, and the heating temperature of 1400 ° C corresponds to the heating region near the actual HAZ melting line. Further, the toughness was evaluated from the impact fracture surface transition temperature (hereinafter referred to as vTrs) by processing this test piece into a 2 mm V notch Charpy.
第２表に示すように、本発明による鋼は鋳片の厚さ中央
部でＴｉ酸化物を40個／mm2以上含み、比較法による鋼
は十数個／mm2に低減し、目的とする40個／mm2以上の粒
子を分散させられない。As shown in Table 2, the steel according to the present invention contains 40 or more Ti oxides / mm 2 at the center of the thickness of the slab, and the steel according to the comparative method is reduced to a dozen or more / mm 2. 40 particles / mm 2 or more cannot be dispersed.
従って、本発明法による鋼の溶接再現ＨＡＺ靱性(vTrs)
は比較法による鋼に比べ、向上し、vTrsで20〜40℃低温
側にシフトする。このように低融点Ｔｉ合金をモールド
添加する方法により、300mm厚の厚鋳片の中央部におい
てもその該粒子数が40個／mm2以上になり、優れた大入
熱ＨＡＺ靱性を示す。Therefore, the weld reproduction HAZ toughness (vTrs) of steel according to the method of the present invention
Is higher than that of the steel by the comparative method, and shifts to a low temperature side of 20-40 ° C in vTrs. By the method of adding the low melting point Ti alloy to the mold as described above, the number of the particles becomes 40 particles / mm 2 or more even in the central portion of the 300 mm thick cast slab, and excellent large heat input HAZ toughness is exhibited.
即ち、本発明の製造法の要件が総て満たされた時に、第
１表に示される鋼６に示すような連続鋳造による鋼板の
1/2部においてもvTers＝−70℃もの優れた大入熱ＨＡＺ
靱性を持つ低温用鋼材の製造が可能になる。 That is, when all the requirements of the manufacturing method of the present invention are satisfied, a steel plate produced by continuous casting as shown in Steel 6 in Table 1 is
Excellent heat input HAZ with vTers = -70 ° C even at 1/2 part
It becomes possible to manufacture low temperature steel products with toughness.
（発明の効果） 本発明により連続鋳造による厚鋼板の板厚1/2部におい
ても優れた大入熱ＨＡＺ靱性を持つ低温用鋼材の製造が
可能になり、北海のような極低温環境で使用される、海
洋構造物、ラインパイプ、低温容器、等の鋼材に適用が
できる。(Effects of the Invention) The present invention makes it possible to manufacture a low-temperature steel material having an excellent large heat input HAZ toughness even in a plate thickness 1/2 part of a thick steel plate by continuous casting, and used in a cryogenic environment such as the North Sea. It can be applied to steel materials such as offshore structures, line pipes, cryogenic vessels, etc.
その結果、構造物の安全性の確保、溶接性能の向上によ
る経済効果等の産業上の効果は極めて顕著なものがあ
る。As a result, industrial effects such as economic effect due to ensuring safety of structures and improvement of welding performance are extremely remarkable.
───────────────────────────────────────────────────── フロントページの続き (72)発明者 粟飯原 周二 神奈川県相模原市淵野辺５―10―１ 新日 本製鐵株式会社第二技術研究所内 (56)参考文献 特開 昭62−1811（ＪＰ，Ａ) 特開 平１−228643（ＪＰ，Ａ) 特開 平１−150453（ＪＰ，Ａ) ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shuji Aiwahara 5-10-1 Fuchinobe, Sagamihara City, Kanagawa Pref., Nihon Nippon Steel Co., Ltd. 2nd Technical Research Institute (56) Reference JP 62-1811 (JP, SHO 62-1811) A) JP-A-1-228643 (JP, A) JP-A-1-150453 (JP, A)
Claims (2)
0.0030〜0.0100％に溶製し、合金添加による成分調整に
より、Ｃ：0.02〜0.18％、Ｓｉ：0.03〜0.25％、Ｍｎ：
0.4〜2.0％、Ｓ：0.0007〜0.0060％、Ｎ：0.0010〜0.00
40％を含有させ、Ｐ≦0.015％、Ａ≦0.003％に制限
し、残部はＦｅ及び不可避不純物からなる溶鋼を溶製、
さらに、最終脱酸として連続鋳造のモールドで低融点の
Ｔｉ−Ｃｕ，Ｔｉ−Ｎｉ，Ｔｉ−Ｆｅ合金のワイヤー、
または粒体を添加し、重量％でＴｉ：0.005〜0.030％を
含有させ、スラブ中央部において、主に粒子径が0.1〜
3.0μｍにあるＴｉ酸化物及びＴｉ酸化物とＴｉＮ，Ｍ
ｎＳの複合析出物粒子の合計で40〜170個／mm2を含有す
る鋼塊を圧延することを特徴とする溶接部低温靱性の優
れた低温用高張力鋼の製造法。1. Dissolved oxygen in wt% by preliminary deoxidation of molten iron
Melted to 0.0030-0.0100%, and by adjusting the composition by adding an alloy, C: 0.02-0.18%, Si: 0.03-0.25%, Mn:
0.4 to 2.0%, S: 0.0007 to 0.0060%, N: 0.0010 to 0.00
40% contained, P ≤ 0.015%, A ≤ 0.003%, the balance is molten steel made of Fe and unavoidable impurities,
Furthermore, as final deoxidation, a wire of low melting point Ti-Cu, Ti-Ni, Ti-Fe alloy in a continuous casting mold,
Alternatively, particles are added to contain Ti: 0.005 to 0.030% by weight, and the particle diameter is mainly 0.1 to
Ti oxide and Ti oxide and TiN, M at 3.0 μm
A method for producing a low-strength high-strength steel having excellent low-temperature toughness at a welded portion, which comprises rolling a steel ingot containing 40 to 170 pieces / mm 2 in total of nS complex precipitate particles.
0.0030〜0.0100％に溶製し、合金添加による成分調整に
より、Ｃ：0.02〜0.18％、Ｓｉ：0.03〜0.25％、Ｍｎ：
0.4〜2.0％、Ｓ：0.0007〜0.0060％、Ｎ：0.0010〜0.00
40％を含有させ、Ｐ≦0.015％、Ａ≦0.003％に制限
し、Ｃｒ＜1.0％、Ｎｉ≦3.0％、Ｍｏ≦0.5％、Ｖ≦0.1
％、Ｎｂ≦0.05％、Ｂ≦0.002％、Ｃｕ≦1.5％の１種ま
たは２種以上を含有し、残部はＦｅ及び不可避不純物か
らなる溶鋼を溶製、さらに、最終脱酸として連続鋳造の
モールドで低融点のＴｉ−Ｃｕ、Ｔｉ−Ｎｉ、Ｔｉ−Ｆ
ｅ合金のワイヤー、または粒体を添加し、重量％でＴ
ｉ：0.005〜0.030％を含有させ、スラブ中央部におい
て、主に粒子径が0.1〜3.0μｍにあるＴｉ酸化物及びＴ
ｉ酸化物とＴｉＮ，ＭｎＳの複合析出物粒子の合計で40
〜170個／mm2を含有する鋼塊を圧延することを特徴とす
る溶接部低温靱性の優れた低温用高張力鋼の製造法。2. Dissolved oxygen in wt% by preliminary deoxidation of molten iron
Melted to 0.0030-0.0100%, and by adjusting the composition by adding an alloy, C: 0.02-0.18%, Si: 0.03-0.25%, Mn:
0.4 to 2.0%, S: 0.0007 to 0.0060%, N: 0.0010 to 0.00
40% contained, limited to P ≦ 0.015%, A ≦ 0.003%, Cr <1.0%, Ni ≦ 3.0%, Mo ≦ 0.5%, V ≦ 0.1
%, Nb ≦ 0.05%, B ≦ 0.002%, Cu ≦ 1.5%, one or more, and the balance consists of molten steel consisting of Fe and unavoidable impurities, and a continuous casting mold for final deoxidation. And low melting point Ti-Cu, Ti-Ni, Ti-F
e alloy wire or particles are added, and T
i: 0.005 to 0.030%, Ti oxide and T mainly having a particle size of 0.1 to 3.0 μm in the central part of the slab
40 in total of i-oxide and composite precipitate particles of TiN and MnS
A method for producing a high-strength steel for low-temperature use, which has excellent low-temperature toughness in a welded part, characterized by rolling a steel ingot containing ~ 170 pieces / mm 2 .
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1039507A JPH0642979B2 (en) | 1989-02-20 | 1989-02-20 | Manufacturing method of high strength steel for welding and low temperature containing titanium oxide |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1039507A JPH0642979B2 (en) | 1989-02-20 | 1989-02-20 | Manufacturing method of high strength steel for welding and low temperature containing titanium oxide |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH02220735A JPH02220735A (en) | 1990-09-03 |
| JPH0642979B2 true JPH0642979B2 (en) | 1994-06-08 |
Family
ID=12554958
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP1039507A Expired - Lifetime JPH0642979B2 (en) | 1989-02-20 | 1989-02-20 | Manufacturing method of high strength steel for welding and low temperature containing titanium oxide |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0642979B2 (en) |
Cited By (1)
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|---|---|---|---|---|
| CN108941494A (en) * | 2018-09-25 | 2018-12-07 | 湖南华菱湘潭钢铁有限公司 | A kind of Process of Hot Transfering And Hot Charging of cut deal continuous casting billet |
Families Citing this family (13)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5236521A (en) * | 1990-06-06 | 1993-08-17 | Nkk Corporation | Abrasion resistant steel |
| US5403410A (en) * | 1990-06-06 | 1995-04-04 | Nkk Corporation | Abrasion-resistant steel |
| JP2579842B2 (en) * | 1991-03-08 | 1997-02-12 | 新日本製鐵株式会社 | Method for producing intragranular ferritic section steel with excellent toughness as rolled and excellent weld toughness |
| JP2579841B2 (en) * | 1991-03-08 | 1997-02-12 | 新日本製鐵株式会社 | Method for producing as-rolled intragranular ferritic steel with excellent fire resistance and toughness |
| US5292384A (en) * | 1992-07-17 | 1994-03-08 | Martin Marietta Energy Systems, Inc. | Cr-W-V bainitic/ferritic steel with improved strength and toughness and method of making |
| JP2661845B2 (en) * | 1992-09-24 | 1997-10-08 | 新日本製鐵株式会社 | Manufacturing method of oxide-containing refractory section steel by controlled rolling |
| JP2760713B2 (en) * | 1992-09-24 | 1998-06-04 | 新日本製鐵株式会社 | Method for producing controlled rolled steel with excellent fire resistance and toughness |
| FR2757542B1 (en) * | 1996-12-19 | 1999-01-15 | Der Dillinger Huttenwerke Ag | LOW ALLOYED STRUCTURAL STEEL WITH ACTIVE PARTICLES |
| JP3760144B2 (en) * | 2001-08-07 | 2006-03-29 | 新日本製鐵株式会社 | Ultra-low carbon steel sheet, ultra-low carbon steel slab and method for producing the same |
| US6808550B2 (en) * | 2002-02-15 | 2004-10-26 | Nucor Corporation | Model-based system for determining process parameters for the ladle refinement of steel |
| JP4877085B2 (en) * | 2007-06-15 | 2012-02-15 | 住友金属工業株式会社 | Steel |
| JP6645373B2 (en) * | 2016-07-19 | 2020-02-14 | 日本製鉄株式会社 | Steel plate and its manufacturing method |
| JP6720825B2 (en) * | 2016-10-19 | 2020-07-08 | 日本製鉄株式会社 | Thermal processing control type 590 MPa class H-section steel |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5364621A (en) * | 1976-11-22 | 1978-06-09 | Kawasaki Steel Co | Preventing of center segregation in continuous casting |
| JPS58204117A (en) * | 1982-05-22 | 1983-11-28 | Kawasaki Steel Corp | Production of steel material containing uniformly dispersed fine inclusion |
| JPS59190313A (en) * | 1983-04-09 | 1984-10-29 | Nippon Steel Corp | Manufacture of steel material having superior weldability |
| JPH07824B2 (en) * | 1984-05-22 | 1995-01-11 | 新日本製鐵株式会社 | High toughness steel for welding |
| JPS6179745A (en) * | 1984-09-28 | 1986-04-23 | Nippon Steel Corp | Manufacture of steel material superior in welded joint heat affected zone toughness |
| JPS621842A (en) * | 1985-06-26 | 1987-01-07 | Nippon Steel Corp | Tough, high tension steel having superior toughness in weld zone |
-
1989
- 1989-02-20 JP JP1039507A patent/JPH0642979B2/en not_active Expired - Lifetime
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108941494A (en) * | 2018-09-25 | 2018-12-07 | 湖南华菱湘潭钢铁有限公司 | A kind of Process of Hot Transfering And Hot Charging of cut deal continuous casting billet |
| CN108941494B (en) * | 2018-09-25 | 2020-07-07 | 湖南华菱湘潭钢铁有限公司 | Hot-feeding and hot-charging process for medium-thickness plate continuous casting billet |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH02220735A (en) | 1990-09-03 |
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