JPH02220735A - Production of high tensile strength steel for welding and low temperature including titanium oxide - Google Patents
Production of high tensile strength steel for welding and low temperature including titanium oxideInfo
- Publication number
- JPH02220735A JPH02220735A JP3950789A JP3950789A JPH02220735A JP H02220735 A JPH02220735 A JP H02220735A JP 3950789 A JP3950789 A JP 3950789A JP 3950789 A JP3950789 A JP 3950789A JP H02220735 A JPH02220735 A JP H02220735A
- Authority
- JP
- Japan
- Prior art keywords
- oxide
- low
- steel
- toughness
- deoxidation
- 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
- 229910000831 Steel Inorganic materials 0.000 title claims abstract description 41
- 239000010959 steel Substances 0.000 title claims abstract description 41
- 238000004519 manufacturing process Methods 0.000 title claims description 8
- 238000003466 welding Methods 0.000 title abstract description 11
- OGIDPMRJRNCKJF-UHFFFAOYSA-N titanium oxide Inorganic materials [Ti]=O OGIDPMRJRNCKJF-UHFFFAOYSA-N 0.000 title description 2
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 title 1
- 229910045601 alloy Inorganic materials 0.000 claims abstract description 13
- 239000000956 alloy Substances 0.000 claims abstract description 13
- 238000009749 continuous casting Methods 0.000 claims abstract description 12
- 239000008187 granular material Substances 0.000 claims abstract description 7
- ATJFFYVFTNAWJD-UHFFFAOYSA-N Tin Chemical compound [Sn] ATJFFYVFTNAWJD-UHFFFAOYSA-N 0.000 claims abstract description 6
- 229910004353 Ti-Cu Inorganic materials 0.000 claims abstract description 5
- 229910052748 manganese Inorganic materials 0.000 claims abstract description 5
- 229910052757 nitrogen Inorganic materials 0.000 claims abstract description 5
- 238000005096 rolling process Methods 0.000 claims abstract description 5
- 229910052717 sulfur Inorganic materials 0.000 claims abstract description 5
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims abstract description 4
- 239000012535 impurity Substances 0.000 claims abstract description 4
- 229910052760 oxygen Inorganic materials 0.000 claims abstract description 4
- 239000001301 oxygen Substances 0.000 claims abstract description 4
- 229910052698 phosphorus Inorganic materials 0.000 claims abstract description 4
- 239000002245 particle Substances 0.000 claims description 17
- 238000000034 method Methods 0.000 claims description 11
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 10
- 239000002244 precipitate Substances 0.000 claims description 8
- 238000002844 melting Methods 0.000 claims description 6
- 230000008018 melting Effects 0.000 claims description 6
- 239000002131 composite material Substances 0.000 claims description 5
- 229910052758 niobium Inorganic materials 0.000 claims description 5
- 229910011212 Ti—Fe Inorganic materials 0.000 claims description 4
- 229910052804 chromium Inorganic materials 0.000 claims description 4
- 229910052742 iron Inorganic materials 0.000 claims description 4
- 229910052750 molybdenum Inorganic materials 0.000 claims description 4
- 229910052720 vanadium Inorganic materials 0.000 claims description 4
- 229910052796 boron Inorganic materials 0.000 claims description 3
- 229910052802 copper Inorganic materials 0.000 claims description 3
- 229910052759 nickel Inorganic materials 0.000 claims description 3
- 229910004337 Ti-Ni Inorganic materials 0.000 claims 2
- 229910011209 Ti—Ni Inorganic materials 0.000 claims 2
- KHYBPSFKEHXSLX-UHFFFAOYSA-N iminotitanium Chemical compound [Ti]=N KHYBPSFKEHXSLX-UHFFFAOYSA-N 0.000 claims 2
- 229910052799 carbon Inorganic materials 0.000 abstract description 4
- 239000000203 mixture Substances 0.000 abstract description 4
- 229910052719 titanium Inorganic materials 0.000 abstract description 4
- 229910001208 Crucible steel Inorganic materials 0.000 abstract 3
- 230000001376 precipitating effect Effects 0.000 abstract 2
- 239000010936 titanium Substances 0.000 description 45
- 239000000463 material Substances 0.000 description 11
- 230000000694 effects Effects 0.000 description 5
- 239000010953 base metal Substances 0.000 description 4
- 230000015572 biosynthetic process Effects 0.000 description 4
- 150000004767 nitrides Chemical class 0.000 description 4
- 238000012360 testing method Methods 0.000 description 4
- 229910000859 α-Fe Inorganic materials 0.000 description 4
- 238000001816 cooling Methods 0.000 description 3
- 238000010438 heat treatment Methods 0.000 description 3
- 238000012545 processing Methods 0.000 description 3
- 239000000047 product Substances 0.000 description 3
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 2
- 229910000746 Structural steel Inorganic materials 0.000 description 2
- 238000012733 comparative method Methods 0.000 description 2
- 238000005336 cracking Methods 0.000 description 2
- 229910000734 martensite Inorganic materials 0.000 description 2
- 239000011159 matrix material Substances 0.000 description 2
- 150000001247 metal acetylides Chemical class 0.000 description 2
- 238000001556 precipitation Methods 0.000 description 2
- 238000004881 precipitation hardening Methods 0.000 description 2
- 239000006104 solid solution Substances 0.000 description 2
- 238000007711 solidification Methods 0.000 description 2
- 230000008023 solidification Effects 0.000 description 2
- 238000005728 strengthening Methods 0.000 description 2
- 229910000851 Alloy steel Inorganic materials 0.000 description 1
- -1 C: 0.02 to 0.18% Inorganic materials 0.000 description 1
- UCKMPCXJQFINFW-UHFFFAOYSA-N Sulphide Chemical compound [S-2] UCKMPCXJQFINFW-UHFFFAOYSA-N 0.000 description 1
- 229910001069 Ti alloy Inorganic materials 0.000 description 1
- 229910009973 Ti2O3 Inorganic materials 0.000 description 1
- 229910003079 TiO5 Inorganic materials 0.000 description 1
- 238000000137 annealing Methods 0.000 description 1
- 229910001566 austenite Inorganic materials 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 230000000052 comparative effect Effects 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 230000000593 degrading effect Effects 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 230000004927 fusion Effects 0.000 description 1
- 238000010191 image analysis Methods 0.000 description 1
- 230000006698 induction Effects 0.000 description 1
- SOQBVABWOPYFQZ-UHFFFAOYSA-N oxygen(2-);titanium(4+) Chemical class [O-2].[O-2].[Ti+4] SOQBVABWOPYFQZ-UHFFFAOYSA-N 0.000 description 1
- 238000005204 segregation Methods 0.000 description 1
- 238000009628 steelmaking Methods 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- GQUJEMVIKWQAEH-UHFFFAOYSA-N titanium(III) oxide Chemical compound O=[Ti]O[Ti]=O GQUJEMVIKWQAEH-UHFFFAOYSA-N 0.000 description 1
- 230000009466 transformation Effects 0.000 description 1
- 230000007704 transition Effects 0.000 description 1
- RMLPZKRPSQVRAB-UHFFFAOYSA-N tris(3-methylphenyl) phosphate Chemical compound CC1=CC=CC(OP(=O)(OC=2C=C(C)C=CC=2)OC=2C=C(C)C=CC=2)=C1 RMLPZKRPSQVRAB-UHFFFAOYSA-N 0.000 description 1
- 238000009849 vacuum degassing Methods 0.000 description 1
- 239000002699 waste material Substances 0.000 description 1
Abstract
Description
（産業上の利用分野）
本発明は、溶接性の優れた強靭性高張力鋼に係わり、特
に、溶接熱影響部（以下ＨＡＺと称する）の低温靭性の
優れた構造用鋼の製造法に関するものである。
（従来の技術）
低合金鋼の溶接部のＨＡＺ靭性は、（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）母相の硬さ及び靭性（フェラ
イト中の固溶Ｃ，Ｎ）等の冶金学要因によって支配され
ている。
これらの中でＨＡＺ靭性の向上策として、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。
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、５０ｋ
ｇ−ｆ ／ ＠Ｊ高張力鋼の大入熱溶接時のＨＡＺ靭性
を改善する手段がとられている。
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靭性を劣化させるという欠点が存在する。
一方、本発明者の一部は、溶鉄のＡｆｉ脱酸に替わるＴ
ｉ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
ＩＦＰと称する）を発達させることにより、ＨＡＺ靭性
を著しく改善できることを、特開昭８０−２４５７６８
号、特開昭［ｉｏ −７９７４５号、特開昭８１−１１
７２４５号、特開昭６２−１８４２号において示した。
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靭性が向上する
ことを出願番号８３−１３８１３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靭性を確保するため
に必要な個数を得られない場合が生じた。
（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。
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靭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。
（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
ｏ、ｏｏａｏ〜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％、Ｓ
ｊ：０．０３〜０．２５％、Ｍｎ：０．４〜２．０％、
Ｓ ： ０．０００７〜０．００８０％、 Ｎ
： ０．００１０−０．００４０％を含有させ、Ｐ≦
０．０１５％、Ａｌ ５０．００３％に制限し、Ｃｒ≦
１．０％、Ｎｌ≦３．０％、Ｍｏ≦０．５％、■≦０．
１ ％、 Ｎｂ ５０．０５％、 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−ＣｕＳＴｉ−Ｎｌ 、Ｔｉ−Ｆｅ合金のワイヤ
ー、または粒体を添加し、重量％でＴｉ：０．００５〜
ｏ、ｏａｏ％を含有させ、スラブ中央部において、主に
粒子径が０．１〜３．０μｓ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／ｌｌｌ１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靭性の優れた低温用高張
力鋼の製造法である。
（作 用）
以下、本発明について詳細に説明する。
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。
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、１８９６を超える過剰の添加
は、溶接割れ性、ＨＡＺ靭性などを著しく低下させるの
で、上限を口、１８％とした。
次に、Ｓｌ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、靭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、Ｓ１含有量をこの範囲に
制限した。
Ｍｎは母材の強度、靭性の確保には０．４％以上の添加
が必要であるが、溶接部の靭性、割れ性などの許容でき
る範囲で上限を２．０％とした。
Ｓについては、複合体のＭｎＳを析出させるために０．
０００７％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、０．０００７〜０．０
０８０％とした。
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Ｔｉ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、靭性低下をもたらすため、０．０
３％以下とした。
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、靭性を低下させる。
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、ＩＦＰ組織の生成量が減少し靭性が低下
する。
Ｐは、凝固偏析による溶接割れ性、靭性などの低下を防
止する上から、極力低減すべきであり、上限を０．旧５
％に制限した。
Ａｐは強力な脱酸元素であり、０．００３％以上の添加
はＴｉ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、靭性の低下がもたらされる
ので、０．００３％以下に制限した。
以上が本発明鋼の基本成分であるが、母材強度の上昇、
及び母材の靭性向上の目的で、Ｃｒ。
Ｎｉ 、Ｍｏ、Ｖ、Ｎｂ、Ｂ、Ｃｕの１種または２種以
上を含有することができる。
まず、Ｎｉは、母材の強靭性を為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
されることにより靭性の低下をもたらすため、上限を３
．０％とした。
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、母材の低温靭性の、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、靭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。
Ｖ、Ｎｂは母材の強靭化、粒界フェライトの生成抑制な
どによる靭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、靭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。
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靭性向上が
期待されるが、０．００２％を超える添加は、Ｆｅ
（ＣＢ）ｅの析出による靭性低下と急冷処理での硬化を
招くため、上限を０．００２％とした。
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。
次に、ＨＡＺにＩＦＰを生成し組織を微細化しＨＡＺ靭
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。
ＩＦＰは主に粒子径が０．１〜３．０μｍにある数％の
Ｍｎを固溶したＴｉ２Ｏ３，Ｔｉａ ｏ５のチタン酸化
物及びこれらの酸化物とＴｔＮ、ＭｎＳの複合体、Ｔｉ
Ｎ＋ＭｎＳの複合体から生成する。該粒子径が０．１−
未満ではＩＦＰ生成効果は極めて弱く、また、３．０ａ
ｍ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靭性の低下をも
たらす。
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／−以上存在させることが必要である。
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１７０８／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／ｌＩＩ！でなければならな
い。
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次脱酸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。
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
−Ｎｌ 、Ｔｉ −Ｆｅ合金が優れていることが
判明した。
その合金の組成は［Ｌ％でＴｉ：４Ｑ〜６０％、残部は
Ｃｕ １Ｔｉ：６０〜８０％、残部はＮｉ 、Ｔｉ：８
５〜７５％、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。
またＴｉ脱酸前の(Industrial Application Field) The present invention relates to strong, high-strength steel with excellent weldability, and particularly to a method for manufacturing structural steel with excellent low-temperature toughness of the weld heat-affected zone (hereinafter referred to as HAZ). It is. (Prior art) The HAZ toughness of a welded joint of low alloy steel is determined by: (1) effective grain size (austenite grain size, microstructure); (2)
It is governed by metallurgical factors such as the grain size and volume fraction of the hardened phase (carbides, high carbon martensite, inclusions), (3) the hardness and toughness of the matrix (solid solution C, N in ferrite). There is. Among these methods, a simple method to improve HAZ toughness is to refine the HAZ structure and refine the effective crystal grains.
Various methods have been proposed that utilize various precipitates that are stable at high temperatures. For example, in Tetsu to Hagane, Vol. 65, No. 8, page 1232, published in June 1971, TiN was finely dispersed and 50k
Measures have been taken to improve the HAZ toughness of g-f/@J high-strength steel during high heat input welding. However, most of these precipitates are dissolved in high heat input welding, resulting in coarse graining of the HAZ structure and increase in solute N, which has the disadvantage of degrading the HAZ toughness. On the other hand, some of the inventors of the present invention have proposed that T
Unexamined Japanese Patent Application Publication No. 2003-110022 has shown that HAZ toughness can be significantly improved by finely dispersing Ti oxides in steel through deoxidation and developing an intragranular ferrite transformation structure (hereinafter referred to as IFP) in the HAZ during welding. Showa 80-245768
No., JP-A-Sho [io-79745, JP-A-81-11
No. 7245 and JP-A-62-1842. Furthermore, the present inventors revealed in Application No. 83-13813 that in Ti oxide-containing steel, HAZ toughness improves as the number of Ti oxides in the steel increases. However, when continuous casting is used, Ti is formed in the center of the slab.
There were cases where the number of oxides decreased and the number necessary to ensure high heat input HAZ toughness could not be obtained. (Problem to be solved by the invention) The decrease in the number of Ti oxides in the central part of the steel ingot during continuous casting is mainly due to the fact that Ti oxides precipitate as secondary deoxidation products during solidification. It was found that this was caused by coarsening of agglomerates. In order to secure the necessary number of Ti oxides even in the central part of the slab and improve HAZ toughness, in addition to secondary deoxidation products, temporary deoxidation Ti oxides precipitated during the molten steel stage are utilized.
It was concluded that a Ti deoxidizing method using a continuous casting mold is effective, and the present invention was completed. (Means for solving the problem) The present invention has been made based on the above findings,
The gist is that molten iron is pre-deoxidized to reduce dissolved oxygen to o, ooao to 0.0100% by weight, and by adjusting the components by adding alloys, C: 0.02 to 0.18%, S.
j: 0.03-0.25%, Mn: 0.4-2.0%,
S: 0.0007-0.0080%, N
: Contains 0.0010-0.0040%, P≦
0.015%, Al 50.003%, Cr≦
1.0%, Nl≦3.0%, Mo≦0.5%, ■≦0.
1%, Nb 50.05%, B≦0.002
%, Cu ≦1.5%, and the remainder is Fe and unavoidable impurities.Furthermore, as final deoxidation, low melting point Ti-CuSTi- is used in a continuous casting mold for final deoxidation. Add Nl, Ti-Fe alloy wire or particles, Ti: 0.005 to 0.005% by weight
Ti oxide and Ti with a particle size of 0.1 to 3.0 μs are mainly contained in the central part of the slab.
The total of composite precipitate particles of oxide, TiN, and MnS is 40
This is a method for producing high-strength steel for low temperature use with excellent low-temperature toughness of welds, which is characterized by producing by rolling a steel ingot containing -170 pieces/lll1. (Function) The present invention will be explained in detail below. First, the reason for limiting the basic component range of the steel of the present invention will be described. First, C is added as an effective component to improve the strength of steel. If it is less than 0.02%, the strength necessary for structural steel cannot be obtained, and if it is added in excess of 0.1896, it may cause weld cracks. The upper limit was set at 18% because it significantly lowers the hardness, HAZ toughness, etc. Next, Sl is necessary to ensure the strength of the base metal and to preliminarily deoxidize molten steel, but if it exceeds 0.25%, a hardened structure of high carbon martensite (hereinafter referred to as M*) will be formed in the heat-treated structure. and significantly reduce toughness. Further, if it is less than 0.03%, preliminary deoxidation of molten steel necessary for dispersing Ti oxide cannot be performed, so the S1 content was limited to this range. Although it is necessary to add Mn in an amount of 0.4% or more to ensure the strength and toughness of the base metal, the upper limit was set to 2.0% within an allowable range such as the toughness and crackability of the welded part. Regarding S, in order to precipitate MnS of the complex, 0.
0.0007% or more is necessary, but excessive addition of more than 0.0060% will form coarse sulfide inclusions, leading to a decrease in ductility and an increase in anisotropy of the base material, so 0.0007 to 0. .0
080%. Ti is an essential element for the formation of Ti oxide and Ti nitride, and if it is less than 0.005%, it will not be possible to form the necessary Ti oxide and Ti nitride.
0.0 because the amount of nitrides cannot be obtained and the amount of IFP generated is reduced.
It is necessary to add 0.05% or more, but addition of more than 0.03% causes precipitation of excessive Ti carbides, increases hardness due to precipitation hardening, and reduces toughness.
It was set to 3% or less. When the content of N exceeds 0.0040%, the matrix becomes brittle even in the absence of M*, reducing the toughness. Further, if N is less than 0.0010%, hardly any nitrides are generated in the steel, the amount of IFP structure generated is reduced, and the toughness is lowered. P should be reduced as much as possible to prevent deterioration of weld cracking properties, toughness, etc. due to solidification segregation, and the upper limit should be set at 0. Old 5
%. Ap is a strong deoxidizing element, and if it is added in an amount of 0.003% or more, Ti oxide formed by Ti deoxidation will not be formed, IFP will not be formed, and the toughness will decrease. % or less. The above are the basic components of the steel of the present invention.
and Cr for the purpose of improving the toughness of the base material. It can contain one or more of Ni, Mo, V, Nb, B, and Cu. First, Ni is an extremely effective element that improves the toughness of the base metal, but adding more than 3.0% increases hardenability and suppresses the formation of IFP structure. The upper limit was set to 3 to reduce toughness due to the formation of
．． It was set to 0%. Cr and Mo are effective in strengthening the base material by improving hardenability and precipitation hardening. Furthermore, adding an appropriate process such as TMCP is effective in improving the low-temperature toughness of the base material. However, excessive addition exceeding the upper limit of each component is harmful from the viewpoint of toughness and hardenability, so Cr
, Mo, the upper limits were set to 1.0% and 0.5%, respectively. V and Nb are effective in improving toughness by strengthening the base material and suppressing the formation of grain boundary ferrite, but excessive addition exceeding the upper limit of each component is harmful from the viewpoint of toughness and hardenability. , V, and Nb, the upper limit is set to 0.
1% and 0.05%. B is expected to improve the toughness of high-temperature heat-treated steel materials by increasing the strength of the base material by improving hardenability and suppressing the growth of grain boundary ferrite, but addition of more than 0.002%
The upper limit was set at 0.002% because the precipitation of (CB)e causes a decrease in toughness and hardening during rapid cooling treatment. Although Cu strengthens the base material, it hardens the HAZ less.
Although it is an effective element, the upper limit was set at 1.5% in consideration of temper embrittlement caused by stress relief annealing, weld cracking resistance, etc. Next, the IFP nuclear precipitates that form the basis of IFP generation in the HAZ, refinement of the structure, and improvement of HAZ toughness will be described below. IFP mainly consists of titanium oxides such as Ti2O3 and TiO5 with a particle size of 0.1 to 3.0 μm and a few percent of Mn as a solid solution, and composites of these oxides with TtN and MnS, and Ti.
It is produced from a complex of N+MnS. The particle size is 0.1-
Below 3.0a, the IFP generation effect is extremely weak.
If it exceeds m, although it has the ability to generate IFP, it itself tends to become a point where fracture occurs, resulting in a decrease in HAZ toughness. Regarding the number of particles in the central part of the continuous casting slab, if the number of particles of Ti oxide and the composite of Ti oxide and TiN + MnS is small, sufficient IFP cannot be generated in the high heat input HAZ part. , it is necessary that a total of 40/- or more of them be present. As the number of particles increases, the number of IFPs also increases,
The presence of an excessive number of particles exceeding 1708/mm2 in total tends to cause a decrease in the ductility of the base metal and welded part.
The upper limit of the number of particles is 170 pieces/lII! Must. In order to increase the number of Ti oxides in the central part of the slab, which is the basis of the present invention, in addition to the secondary deoxidation product,
The primary deoxidizing Ti oxide that precipitates during the molten steel stage must be utilized. Therefore, after the addition of Ti for final deoxidation, it is necessary to tap and solidify the steel as quickly as possible. The most effective method for this purpose is to add Ti to the mold during continuous casting, and this method will be explained below. To deoxidize Ti in a continuous casting mold, the added Ti
must be uniformly diffused into molten steel in the shortest possible time. Ti alloys with low melting points are effective for this purpose, and as a result of considering processability and economic efficiency, Ti-Cu, Ti
-Nl, Ti-Fe alloys were found to be superior. The composition of the alloy is [L% Ti: 4Q to 60%, the balance is Cu 1Ti: 60 to 80%, the balance is Ni, Ti: 8
5 to 75%, and the remainder is Fe, which is an alloy with a lower melting point than pure Ti. Addition is a method of processing these alloys into wires and granules and continuously adding them in a mold. Also, before Ti deoxidation
〔０〕濃度が０．０１００％を超える
場合は、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、靭性は向上しない。
以下に実施例によりさらに本発明の効果を示す。
（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、
ｆＲ７，８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。
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靭性を表
した。なお、Ｔｉ酸化物数はＴｉ。
Ｏ元素の特性Ｘ線をコンピューターにより画像解析処理
（ＣＭＡ装置）し求めた。
これらの試作鋼は３００■厚スラブを圧延により５０ｕ
ｍｍ鋼板とし、板厚１／２ ｔから１２ Ｘ １２ Ｘ
６０ｕｍ＋ｍの試験片を採取し、溶接再現熱サイクル
試験によりＨＡＺ靭性を評価した。
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、８１］０℃から５
００℃の冷却時間１０１秒の条件で冷却した。
この条件は溶接入熱量１３０ｋＪ／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。さらに靭性はこの試験片から２１１ｍＶノ
ツチ・シャルピーに加工し、衝撃破面遷移温度（以下ｖ
Ｔｒｓと称す）を求め評価した。
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／−以上含み、比較法による鋼
は士数個／ＩＩＩ！に低減し、目的とする４０個／ｆｆ
ｌｌ１以上の粒子を分散させられない。
従って、本発明法による鋼の溶接再現ＨＡＺ靭性（ｖＴ
ｒｓ）は比較法による屑に比べ、向上Ｌ、ｖＴｒｓで２
０〜４０℃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、３００關厚の厚鋳
片の中央部においてもその該粒子数が４０個／−以上に
なり、優れた大人熱ＨＡＺ靭性を示す。
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ｖＴｒｓ −−７０℃もの優れた大
入熱ＨＡＺ靭性を持つ低温用鋼材の製造が可能になる。
（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靭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。
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
。
代 理 人 弁理士 茶野木 立 失笑１頁の続き
［株］Ｉｎｔ、 Ｃ１，’
識別記号
庁内整理番号[0] When the concentration exceeds 0.0100%, even if other conditions are met, the Ti oxide becomes coarse grained and becomes the starting point of brittle fracture, and the toughness is not improved. The effects of the present invention will be further illustrated by Examples below. (Example) Table 1 shows the chemical composition of trial steel, and steels 1 to 6 are T
It is based on the method of the present invention in which mold addition is made of i-alloy.
fR7 and fR8 are comparative steels made by the conventional method of deoxidizing with sponge Ti in a vacuum degassing device for steelmaking. Table 2 shows the composition of the added Ti/alloy, the added shape, the slab thickness, the number of Ti oxides in the center of the slab, and the welding reproduction HAZ toughness. Note that the number of Ti oxides is Ti. Characteristic X-rays of the O element were determined by image analysis processing (CMA device) using a computer. These prototype steels were made by rolling 300mm thick slabs to 50u.
mm steel plate, plate thickness 1/2t to 12 x 12 x
A test piece of 60 um+m was taken, and the HAZ toughness was evaluated by a welding reproduction thermal cycle test. In the welding reproduction thermal cycle test, the central part of the specimen was rapidly heated to 1400°C by high-frequency induction heating, and
Cooling was performed at 00° C. for a cooling time of 101 seconds. This condition corresponds to a welding heat input of 130 kJ/cm, and a heating temperature of 1400° C. corresponds to a heating region near the fusion line of the actual HAZ. Furthermore, the toughness was determined by processing this test piece to a 211 mV Notch Charpy and impact fracture transition temperature (hereinafter referred to as v).
Trs) was determined and evaluated. As shown in Table 2, the steel according to the present invention contains 40 Ti oxides/- or more at the center of the thickness of the slab, and the steel according to the comparative method contains Ti oxides at least 40 Ti oxides/III! to the target of 40 pieces/ff.
Particles larger than ll1 cannot be dispersed. Therefore, the welding reproduction HAZ toughness (vT
rs) is improved by L and vTrs by 2 compared to the waste obtained by the comparative method.
Shift to the lower temperature side by 0 to 40°C. In this way, low melting point Ti
By adding the alloy in a mold, the number of particles becomes 40/- or more even in the center of a 300 mm thick slab, showing excellent adult thermal HAZ toughness. That is, when all the requirements of the manufacturing method of the present invention are satisfied, even a half part of a steel plate made by continuous casting as shown in Steel 6 shown in Table 1 can have an excellent large input of vTrs of -70°C. It becomes possible to manufacture low-temperature steel materials with thermal HAZ toughness. (Effects of the invention) The present invention makes it possible to manufacture low-temperature steel materials with excellent high heat input HAZ toughness even at 1/2 part thickness of thick steel plates by continuous casting, and can be used in cryogenic environments such as the North Sea. be done,
It can be applied to steel materials such as marine structures, line pipes, and low-temperature containers. As a result, industrial effects such as ensuring the safety of structures and economic effects due to improved welding performance are extremely significant. Agent Patent Attorney Tate Chanoki Continuing from page 1 [Shares] Int, C1,' Identification code Office reference number
Claims (1)
３０〜０．０１００％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：０．００
０７〜０．００６０％、Ｎ：０．００１０〜０．００４
０％を含有させ、Ｐ≦０．０１５％、Ａｌ≦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：０．００
５〜０．０３０％を含有させ、スラブ中央部において、
主に粒子径が０．１〜３．０ｕｍ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／ｍｍ＾２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靭性の優れた低温用高張力鋼
の製造法。 ２、溶鉄を予備脱酸により溶存酸素を重量％で０．００
３０〜０．０１００％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：０．００
０７〜０．００６０％、Ｎ：０．００１０〜０．００４
０％を含有させ、Ｐ≦０．０１５％、Ａｌ≦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４０〜１
７０個／ｍｍ＾２を含有する鋼塊を圧延することを特徴
とする溶接部低温靭性の優れた低温用高張力鋼の製造法
。[Claims] 1. Preliminary deoxidation of molten iron to reduce dissolved oxygen to 0.00% by weight
C: 0.02-0.18%, Si: 0.03
~0.25%, Mn: 0.4-2.0%, S: 0.00
07-0.0060%, N: 0.0010-0.004
0%, P≦0.015%, Al≦0.003
%, with the remainder consisting of Fe and unavoidable impurities.Furthermore, as final deoxidation, low melting point Ti-Cu, Ti-Ni, Ti-Fe alloy wire or granules are cast in a continuous casting mold. Ti: 0.00 by weight%
Containing 5 to 0.030%, in the central part of the slab,
Rolling a steel ingot containing a total of 40 to 170 particles/mm^2 of Ti oxide and composite precipitate particles of Ti oxide, TiN, and MnS whose particle diameter is mainly 0.1 to 3.0 um. A manufacturing method for low-temperature high-strength steel with excellent low-temperature toughness in welded parts. 2. Preliminary deoxidation of molten iron reduces dissolved oxygen to 0.00% by weight
C: 0.02-0.18%, Si: 0.03
~0.25%, Mn: 0.4-2.0%, S: 0.00
07-0.0060%, N: 0.0010-0.004
0%, P≦0.015%, Al≦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 of them, and the remainder consists of Fe and inevitable impurities.
Furthermore, as final deoxidation, low melting point Ti-Cu, Ti-Ni, Ti-Fe alloy wire,
Or add granules and Ti: 0.005 to 0.00% by weight.
In the central part of the slab, a total of Ti oxide and composite precipitate particles of Ti oxide, TiN, and MnS with a particle size of 0.1 to 3.0 μm are contained in the central part of the slab.
A method for producing high-strength steel for low temperature use with excellent low-temperature toughness at welds, the method comprising rolling a steel ingot containing 70 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 true JPH02220735A (en) | 1990-09-03 |
| JPH0642979B2 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) |
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| JPH04279247A (en) * | 1991-03-08 | 1992-10-05 | Nippon Steel Corp | Manufacture of transgranular ferrite system rolled shapes with excellent fire resistance and toughness |
| US5236521A (en) * | 1990-06-06 | 1993-08-17 | Nkk Corporation | Abrasion resistant steel |
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| EP0589424A2 (en) * | 1992-09-24 | 1994-03-30 | Nippon Steel Corporation | Shape steel material having high strength, high toughness and excellent fire resistance and process for producing rolled shape steel of said material |
| US5403410A (en) * | 1990-06-06 | 1995-04-04 | Nkk Corporation | Abrasion-resistant steel |
| EP0849372A1 (en) * | 1996-12-19 | 1998-06-24 | A.G. der Dillinger Hüttenwerke | Low alloy construction steel having active particles |
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Citations (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 |
| JPS60245768A (en) * | 1984-05-22 | 1985-12-05 | Nippon Steel Corp | 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
Patent Citations (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 |
| JPS60245768A (en) * | 1984-05-22 | 1985-12-05 | Nippon Steel Corp | 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 |
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| US5403410A (en) * | 1990-06-06 | 1995-04-04 | Nkk Corporation | Abrasion-resistant steel |
| US5236521A (en) * | 1990-06-06 | 1993-08-17 | Nkk Corporation | Abrasion resistant steel |
| JPH04279247A (en) * | 1991-03-08 | 1992-10-05 | Nippon Steel Corp | Manufacture of transgranular ferrite system rolled shapes with excellent fire resistance and toughness |
| JPH04279248A (en) * | 1991-03-08 | 1992-10-05 | Nippon Steel Corp | Manufacture of rolled shapes piersed fine oxide with excellent 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 |
| EP0589435A2 (en) * | 1992-09-24 | 1994-03-30 | Nippon Steel Corporation | Refractory shape steel material containing oxide and process for producing rolled shape steel of said material |
| EP0589424A3 (en) * | 1992-09-24 | 1994-09-14 | Nippon Steel Corp | Shape steel material having high strength, high toughness and excellent fire resistance and process for producing rolled shape steel of said material |
| EP0589435A3 (en) * | 1992-09-24 | 1994-09-14 | Nippon Steel Corp | Refractory shape steel material containing oxide and process for producing rolled shape steel of said material |
| EP0589424A2 (en) * | 1992-09-24 | 1994-03-30 | Nippon Steel Corporation | Shape steel material having high strength, high toughness and excellent fire resistance and process for producing rolled shape steel of said material |
| EP0849372A1 (en) * | 1996-12-19 | 1998-06-24 | A.G. der Dillinger Hüttenwerke | Low alloy construction steel having active particles |
| FR2757542A1 (en) * | 1996-12-19 | 1998-06-26 | Der Dillinger Huttenwerke Ag | CONSTRUCTION STEEL LOW ALLY ACTIVE PARTICLES |
| JP2003119513A (en) * | 2001-08-07 | 2003-04-23 | Nippon Steel Corp | Extra-low carbon steel sheet, extra-low carbon steel slab and manufacturing method therefor |
| WO2003068996A1 (en) * | 2002-02-15 | 2003-08-21 | Nucor Corporation | Model-based system for determining process parameters for the ladle refinement of steel |
| US6808550B2 (en) | 2002-02-15 | 2004-10-26 | Nucor Corporation | Model-based system for determining process parameters for the ladle refinement of steel |
| US6921425B2 (en) | 2002-02-15 | 2005-07-26 | Nucor Corporation | Model-based system for determining process parameters for the ladle refinement of steel |
| US7211127B2 (en) | 2002-02-15 | 2007-05-01 | Nucor Corporation | Model-based system for determining process parameters for the ladle refinement of steel |
| JP2008308737A (en) * | 2007-06-15 | 2008-12-25 | Sumitomo Metal Ind Ltd | Steel, and method for producing the same |
| JP2018012853A (en) * | 2016-07-19 | 2018-01-25 | 新日鐵住金株式会社 | Thick steel plate and manufacturing method therefor |
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| JPH0642979B2 (en) | 1994-06-08 |
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