JPS5947323A - Production of high tension steel having excellent toughness in weld zone and property for stopping propagation of brittle fracture - Google Patents
Production of high tension steel having excellent toughness in weld zone and property for stopping propagation of brittle fractureInfo
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- JPS5947323A JPS5947323A JP15679682A JP15679682A JPS5947323A JP S5947323 A JPS5947323 A JP S5947323A JP 15679682 A JP15679682 A JP 15679682A JP 15679682 A JP15679682 A JP 15679682A JP S5947323 A JPS5947323 A JP S5947323A
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- steel
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Classifications
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
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- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Crystallography & Structural Chemistry (AREA)
- Mechanical Engineering (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Heat Treatment Of Articles (AREA)
- Heat Treatment Of Steel (AREA)
Abstract
Description
【発明の詳細な説明】
本発明は母材においては脆性（、ｒ、ｌけＣ，Ｘ伝１「
１７停止１−！−１テ性にすぐれ、また溶接部において
＆Ｊ： Ｉ＋！抗性抗性破壊発性特性ぐれた高張力鋼の
製造法＆Ｕかかわるものである。DETAILED DESCRIPTION OF THE INVENTION The present invention is characterized in that the base material is brittle (, r, l, C,
17 stop 1-! -1 Excellent thermal properties, and also in welded parts &J: I+! This relates to the manufacturing method of high-strength steel with excellent resistance and fracture resistance properties.
ＬＰＧ ＋ ＬＮＧ 等のエネルギー源を貯蔵する低温
容器用で［−・９材や寒冷曲で使用に供せられるう・ｆ
ン・ぐイブ用：１４ ＡＡｉ’こけ、その構造物として
の安全性を確保するために脆性破壊伝播停止特性に関す
る高いＩ）性値が必要とされている。匝１月の使用され
るＪＳ（境が厳しくなるにつれて、より高い靭性値が必
要となる傾向は今後捷ず１す強くなるであイ）う。この
ような趨勢に対処するために、鋼に合金元素、特にＮｉ
を添加したり、”また熱間圧延方法あるいは熱処哩方法
に工夫をこらしているのが実状である。For use in low-temperature containers for storing energy sources such as LPG + LNG.
For 14 AAi' moss, a high I) property value regarding brittle fracture propagation arresting properties is required to ensure safety as a structure. The JS used in January (as the boundaries become stricter, the tendency to require higher toughness values will become stronger in the future). To address this trend, alloying elements, especially Ni, have been added to steel.
The reality is that the hot rolling method or heat treatment method has been devised.
ところで一般に川（１り遺物、とりわけ大７，６普ｒ′
Ｉ４構造物では主要部利は主として溶接によって製作さ
れ、これらの構造物で１１危性破壊の発生のおそれがあ
るとすれば、それは殆んどの場合溶接ｌＸ１５であり、
しだがって＋ｔ％い溶接部靭性（脆性破壊発生に対する
↓１（抗）を桐材に付与することは重要である。大型、
、１１１＋、１７７造物の安全性、すなわち脆性破壊に
よる崩壊のＩ（ｂ市を２枚図するならけ、浴接部におい
ては主として１６ｚ、性破壊ざ［１生に対する抵抗、す
なわち溶接部靭性にすぐれ、丼た母、（Ａにおいてυ；
１、−たひ発生しだ脆性亀裂の伝播を阻止する性１止、
ず々わち、１Ｉ６１：性破壇伝播停止特性にすぐれた４
・：（４を曲用に供することがＪＩｆ安である。し７か
［７なが゛ら、イ「ｌ−来］支ト１；工においては両！
［口、性を高い木葉てＪＪ、、 １１１１１ ｌ−ｙ
、かつ入；バ団用を可能ならしめる程＋＋Ｃの＋ｉ（，
４１ｊ’ｉコストで↓・」造するには困難が太きかった
。プことえｌ；ｌ’、Ｎｌ添加によって脆性破壊伝播停
止特性を向上さ＋Ｊ、 （ｔｉるものの、Ｎｉ添加二肌
の増加と共に溶接部の７．壺高１便さけ高くなり、溶接
部の靭性、竹に脆性（・皮壊５１・５生の指（巳ツであ
る限界ＣＯＤか低下することが知らｔｌ−こいる（５失
と′：ｉ。By the way, in general, rivers (11 relics, especially large 7th and 6th century
In I4 structures, the main parts are mainly manufactured by welding, and if there is a risk of 11 dangerous failure occurring in these structures, it is mostly welding IX15,
Therefore, it is important to give paulownia material +t% higher weld joint toughness (↓1 (resistance) against brittle fracture occurrence.
, 111+, 177 The safety of structures, that is, the collapse due to brittle fracture I (If you draw two pictures of b), in the bath welding area, it is mainly 16 , rice bowl mother, (υ in A;
1. - Ability to prevent the propagation of brittle cracks caused by cracks,
Zuzuwachi, 1I61: 4 with excellent ability to stop the spread of sexual failure
・:(It is JIf cheap to use 4 for declension. Then 7 or [7 Nagara, I "l-come"] branch 1; In engineering, it is both!
[Koha Te JJ,, 11111 l-y
, and enter;+i(,
It was extremely difficult to build it at a cost of 41j'i. (Although the addition of Nl improves the brittle fracture propagation arresting property, the weld height increases by 7.1 cm with the addition of Ni, and the toughness of the weld increases.) It is known that bamboo has brittleness (51.5 raw fingers) and the limit COD decreases.
６８（１９８２） ８６２９ 、し１２）。68 (1982) 8629, 12).
かかる実状を踏えて本発明者らは１、′ｆ１１月のＩｉ
’Ａ性破端伝播現象について従来の常−＆とｔＪ、全く
異なる現実を発見し、１１１細な冶金的検１；・１を加
えることによって溶接部に粋いてはＣＯＤ １ｌｉ−に
、しって特徴イ・１けられる脆性破壊発生特性、母相に
おい−では脆性１σν壊伝播停止特性の優れた高張カル
ｉｊの７！ ；；”を法を発明するに到ったものである
。In view of this situation, the inventors of the present invention
By discovering a completely different reality regarding the A-type fracture edge propagation phenomenon, and adding 111 detailed metallurgical examination 1;・1, welds can be cooled to COD 1li-. Characteristics (a) - 1-digit brittle fracture initiation property, and - in the matrix, hypertonic Cal ij has excellent brittle 1σν fracture propagation stopping properties. ;;” which led to the invention of the law.
以下に本発明の計器ｊを記述するが初めに成分μｍえ定
の理由を述べる。The instrument j of the present invention will be described below, but first the reason for determining the component μm will be described.
Ｃはテ５ｌｐｉ材の所要強度を確保するためには不可欠
な元素であって、０．０２％未満では強度不足となり、
また０１５チを越えると、溶接部靭性が低下するので添
加晴を０．０２％以上０．１．５ ’１以下に限定した
。C is an essential element to ensure the required strength of Te5lpi material, and if it is less than 0.02%, the strength will be insufficient.
Moreover, if it exceeds 0.015 cm, the toughness of the weld zone decreases, so the addition amount is limited to 0.02% or more and 0.1.5'1 or less.
Ｓｉは溶鋼中の脱酸を促進し、しかも固溶体強化による
強厚−Ｆ昇の効果を期待できる元素であるので０．０１
％以上添加するが、溶接部にしばしば高炭素マルテンサ
イトを発生させ、溶接部靭性を劣化させる傾向が大きい
ので０．３係を上限とした。Si is an element that promotes deoxidation in molten steel and can also be expected to have the effect of increasing the strength -F by solid solution strengthening, so it is 0.01
% or more, but since high-carbon martensite often occurs in the weld zone and has a strong tendency to deteriorate the toughness of the weld zone, the upper limit is set at 0.3%.
Ｍｎ Ｉｔ：を母４４の低温靭性を改善させる元素とし
て有効であるので下限は０．５％としだが、過４１．に
添加するとＹり４接部の硬度を上昇させ冷間割れ性を増
大させ、゛まだ溶接部靭性の低下も招来するので、この
発明では２，０チを上限にした。Since MnIt: is effective as an element for improving the low-temperature toughness of the matrix 44, the lower limit is set to 0.5%, but the lower limit is 0.5%. In this invention, the upper limit is set at 2.0 mm, since adding it to Y-4 increases the hardness of the Y-joint part and increases the cold cracking property, and also causes a decrease in the toughness of the weld zone.
Ａｔは巨く知られているように強力な脱酸剤であり、壕
だ結晶粒の微細化にも効果的に機能するので、基本成分
の一独として不可欠な元素であるが、＋ｌ晶Ｒ：に添加
すると材Ｊｊ、に有害であるアルミナクラスターを形成
するため上限として０１チを設定した。As is widely known, At is a powerful deoxidizing agent, and it also functions effectively to refine trench crystal grains, so it is an essential element as one of the basic components. 01 was set as the upper limit because when added to Jj, it forms alumina clusters that are harmful to the material Jj.
本発明においては適ｈ１の１゛ｌおよびＮの添加は必須
である。ＴｉおよびＮは鋼イ」中でＴｉＮ化合物を１１
ａ威し、適当に分散したＴ １Ｎ１ｆ１ｉｌｌ吻Ｑ；１
、オーステナイト結晶粒の粗大化抑制の機能を有するか
らである。In the present invention, it is essential to add 1 liter of appropriate h1 and N. Ti and N are TiN compounds in steel.
a, properly dispersed T 1N1f1ill snout Q;1
This is because it has the function of suppressing coarsening of austenite crystal grains.
添加Ｔｉｔｉ、が０００５％未満ではこの効果を１ｌＪ
ｊ侍しに＜＜、まだ０．０３０チを超過すると、オース
テナイト結晶粒粗大化防止に無効であるのみなら」゛、
材質、特に溶接部靭性に有害であるような和犬な’ｒｉ
Ｎ化合物生成の傾向が顕層になるので、０．０３０ ％
を上限とした。When the added Titi is less than 0005%, this effect is reduced to 1 lJ.
If it still exceeds 0.030, it will be ineffective in preventing austenite crystal grain coarsening.''
Japanese dog'ri that is harmful to the material, especially the weld toughness.
0.030% because the tendency of N compound formation is in the obvious layer.
was set as the upper limit.
添加する趣旨から明らかなようにＮ ＆、ｌ ＴｉＮを
形成するに必要かつ十分な：１１に制御することが必要
であるが製鋼作業におけるバラツギも考ｒ、ｌｋ、、
ｌ〜で添加ａ・１≧囲を（０，２〜（’１．５）ＸＴｉ
係とした。As is clear from the purpose of adding N&,l, it is necessary to control it to a level of 11 necessary and sufficient to form TiN, but variations in steelmaking operations must also be taken into consideration.
Addition a・1 ≧ (0,2～('1.5)XTi
I was in charge.
■は通常は析出強化元素として活用されるが、本発明の
趣旨ではむしろｑ、＋’ｐ、人性向」二の物点から必甥
でろれは添加する。過量添加ｄＸ母旧の脆性破壊伝播停
止特性および溶接部ｒ＆、ｌ １（Ｉを劣化するので０
２％以下に制限した。(2) is normally used as a precipitation strengthening element, but in the spirit of the present invention, it is added if necessary from the point of view of q, +'p, human tendency. The brittle fracture propagation arresting characteristics of the excessively added dX matrix and the weld zone r&, l 1 (I deteriorates, so
It was limited to 2% or less.
Ｎｈは熱間圧延時のオーステナイト結晶粒の微細化に有
効であるが、溶接熱影響部を硬化させ結果的には靭性劣
化を惹起するので、０．０８％以下の添加ｈ１に制限し
た。Although Nh is effective in refining austenite grains during hot rolling, it hardens the weld heat affected zone and eventually causes deterioration of toughness, so the addition h1 was limited to 0.08% or less.
Ｃｒ 、 Ｍｏはいずれも焼入性および母相の強化の観
点では適当畦の使用は有効であるが、焼入性向上機能は
また溶接部を著しく硬化さゼるので、Ｃｒについては１
．０係、ＭＯについては０，５φを峰の上限とした。For both Cr and Mo, the use of appropriate ridges is effective from the viewpoint of hardenability and strengthening of the matrix, but the hardenability improvement function also significantly hardens the welded part, so for Cr, 1
．． For the 0th section and MO, 0.5φ was set as the upper limit of the peak.
Ｎｉは母材の脆性破壊伝播停止特性を著しく向上させる
元素として知られているが、前記したように、（合接部
の硬度上昇をもたらし、浴接部靭性を低下させること、
およ０・本発明の趣旨から添加する場合であっても高々
１．５％とした。Ni is known as an element that significantly improves the brittle fracture propagation arresting properties of the base metal, but as mentioned above, it has the potential to (increase the hardness of the joint, reduce the toughness of the bath weld,
and 0. Even when added for the purpose of the present invention, it is limited to 1.5% at most.
Ｃｕは固浴体強化元素として必リンとあれは添加するこ
とかり能であるが過ｈ１添加は切材、浴接部靭性の劣化
、壕だ熱間脆性の誘発の恐れがあり０．５係以下に制限
した。Cu can be used as a solid bath strengthening element by adding phosphorus, but adding too much phosphorus may cause deterioration of the toughness of the cut material, bath joints, and induction of hot embrittlement in trenches. limited to the following.
＋Ｊ、」−の各元素の個々の添加厩の他に本発明にお本
発明では炭素当Ｉｆと呼ぶ）のイ１１１が０４（）％以
下になることを必須系１′１・とじてい乙。１４ｒ（＄
ｉ、当＋’４が０４０％を超えると、溶接部の１・Ｕ’
−１１５、’！１に：’（：国人ヒ゛ｊ〜が土中ｖ的小
さい場合の硬度が著し、〈高くなり、／ｒ１１及部＋ｌ
！Ｖｊ性、とりわけ脆性破壊発生１１１１件の指標であ
る限界ＣＯＤ値の低下がよりｉ〕１’ｊ沓にｈ゛る電乃
で十限’ｉｆｆ （！−，ｌ。In addition to the individual additions of each element of +J, ``-'', the present invention also includes the essential system 1'1 and B that the amount of 111 of carbon (hereinafter referred to as If) is 04()% or less. . 14r ($
If i, t+'4 exceeds 040%, 1・U' of the welded part
-115,'! 1:'(:When the soil v is small, the hardness becomes extremely high, /r11 and +l
! Vj properties, especially the decrease in the critical COD value, which is an indicator of the occurrence of brittle fracture 1111 cases, is more than 1'iff (!-, l.
て０．４０％を設定した。0.40% was set.
次に製造条件の限定理由について、１已述する。Next, the reasons for limiting the manufacturing conditions will be briefly described.
熱間圧延前に堵片Ａ″だｌ？ｊ′ｒ＋・ηハをΔ帛点以
」二にｉｍ熱するのはく肖片搾んば′、中４片を仝（本
に一４〜ＩＱにオーステナイト化するた？〈）であって
、川＜・：１−後に所・〃の機械的特性値を得るには不
円欠である。加熱（５冒ｉ ＩＩ：を１１５０℃以下に
制限することによ−）て、必頃元紫として添加されてい
るＴｉおよびＮの効能と相すって圧延前のオーステナイ
ト；ｆｊ’を品粒を細粒にがっ整粒に保つことが可能で
あんとの理由により加ｊ塾温度に上限を設定した。時に
、告・れたｌ１ｌ−Ｓ： ｌ／４召４抱停止特性を１％
るには、整粒の側−スーツナイト結晶ｆ）ンを得ること
は必四争件である。本発明に該当する鋼材の化学成分は
低炭素当購であってこれはＡｒ３変帖点が相対的に高い
ことを意味する。したがって、圧舛終了後のオーステナ
イト結晶粒の細粒化全Ｒ１−るだめに９００℃以下での
圧下（１１を３０ ％以」二確保することを必須条件と
する。ただし圧延仕上温度１ｌｊＡ、ｒ３以上とし、初
析フェライトの析出を抑制しなければならない。Before hot-rolling, heat the flakes A'' to a temperature of ∆rolling point. It is austenitized to IQ?〈), and it is irregular to obtain the mechanical property value of 〃 after 〇〉. By heating (by limiting the temperature to 1150°C or less), the austenite before rolling; An upper limit was set on the heating temperature for the reason that it was possible to maintain fine particles and a uniform grain size. At times, I was told l1l-S: l/4 summoning 4 hold stop characteristic by 1%
In order to achieve this, it is essential to obtain a well-sized grained side-suitite crystal f). The chemical composition of the steel material applicable to the present invention is low carbon, which means that the Ar3 transition point is relatively high. Therefore, it is essential to ensure that the austenite crystal grains are refined by 900°C or less (11 by 30% or more) after the completion of rolling. With the above conditions, precipitation of pro-eutectoid ferrite must be suppressed.
惰の含有成分１ハ：を上記の範囲に制御し、かつ炭素当
１１１を０．／１０％以下に制限することにより、当服
す（１をＡｃ３点以上１１５０℃以下に加熱した後、Ａ
ｒ３点以上で熱間圧延を施し、圧延後空気中に放冷する
ことによって得られる主たる金属組織は厚板材相当の鋼
材厚みの場合にはフェライトとパーライトの混合組織が
主体である。しかるに本発明ＶこおいてはＡｒ３点以上
で熱間圧延した後、Ａｒ３点以」二の〆＃ｉ’を度から
空冷以」二の冷却味瓜で強制的に冷却し、主たる組織を
フェライトと微細に分散したマルテンサイトの混合組織
にし、かつフェライト中に（廿倣細な析出物の析出を可
能な限り抑制することを特徴とするものである。The content of the carbon component 1c: is controlled within the above range, and the carbon content 111 is controlled to 0. /10% or less.
The main metal structure obtained by hot rolling at the r3 point or higher and cooling in the air after rolling is mainly a mixed structure of ferrite and pearlite in the case of a steel material with a thickness equivalent to a thick plate material. However, in the present invention V, after hot rolling at an Ar point of 3 or higher, the main structure is changed to ferrite by forcibly cooling the 2nd #i' from the 3rd Ar point to an air cooling temperature or higher. It is characterized by having a mixed structure of finely dispersed martensite and suppressing the precipitation of fine precipitates in the ferrite as much as possible.
本発明者らは１ｌ岡月の１１れ性破ぐ・ｔ・伝１１１１
停＋ｔ−’ｔに性を支配する冶金因子として、従来から
・１１１られている結晶粒の微細化とＮｉの添加の他に
、ｐｉｔｌｌ目１１出物の少ないフェライトと微、ｉ４
１６）’ｆＦｊ１．シフた一Ｚルデンリ゛イトの混合組
織を生成させることによって脆性（ｄｌ而面成表面エネ
ルギーの増加をはかることができることを発見したもの
であり、このゴｌ： ニー）−４，は本函′：１．！ｌ
−Ｊのｔ、ｌ、！ 「Ｉ、ｊ゛をなすものである。１１
危＋１破」・Ｐｌをイ・′；”市させるに１．Ｌ Ｓ進
展する脆性亀裂の有する１ｌｌｈ萌エネルギーを吸収す
る必要があるが、本発明者はバトｊ（（１な実験とへ祭
を基にして、既存技術の他にさらに２．１ｌｌｌの方Ｍ
′Ｌによって、脆性破面生成表面エネルギーの増加が可
能であることを見出した。即ち、その弔−の明点は脆性
破面がフェライ）＆ｉ品粒を１１ｊ市えて断接する結晶
粒に伝播する際結晶粒界にＶ１ディアリ、ソと呼ばれる
延性破吻部分が形成されるか、そのディアリッジの塑性
変形能を一ヒゲ１芒ぜる力ｌノ５である。The inventors are 1l Okazuki's 11resei break・t・den 1111
In addition to the refinement of crystal grains and the addition of Ni, which have traditionally been considered as metallurgical factors that govern the properties of the
16)'fFj1. It was discovered that it is possible to increase the brittle (dl) surface energy by generating a mixed structure of shifted particles. :1. ! l
-J's t, l,! “I, j゛.11
It is necessary to absorb the 1llh energy of the brittle crack that propagates in order to cause the PL to break down. Based on the existing technology, an additional 2.1 lll M
It has been found that the surface energy for forming a brittle fracture surface can be increased by 'L. In other words, the bright point of the rupture is the brittle fracture surface (ferrite) & when the grain is separated from 11j and propagated to the intersecting grain, a ductile fracture part called V1 diary and so is formed at the grain boundary, The plastic deformability of the deer ridge is 1 no 5.
そのためには塑性変形能の大きい、フェライト結晶粒を
確保する必要がある。その１″葭も効１４′：的な方法
が用１１ξ後の急冷である。圧延後の冷却法度が空冷４
Ｊｌ！度の局舎には校内に無数の炭化物宿が析出し、あ
るいは１１）合体を形成する結果、フェライト結晶わ“
ｌのψ１１ ＋′Ｉ変形能は著しく低下する。For this purpose, it is necessary to secure ferrite crystal grains with large plastic deformability. The most effective method is rapid cooling after rolling.The cooling method after rolling is air cooling 4.
Jl! Numerous carbide deposits precipitate in the central building, or ferrite crystals form as a result of 11) coalescence.
The deformability of ψ11 +'I of l is significantly reduced.
ｆ（ｒ１２の要点はフェライトと微細分散したマルテン
サイトによって高い加工硬化係数を得ることができ、こ
のことは塑性変形の局在化を抑制し、これはティアリッ
ジの塑性変形能を増加させる効果を有し結果的には、脆
性破面生成エネルギーの増加に寄与するものである。第
１点および第２点の技術思想は相互に独立したものであ
るが本発明の峙；へ法に従えは両方の効果を同時に活用
でき、脆性破壊伝播停止Ｉ−，特性の大幅な向上が可能
なのである。The key point of f(r12 is that ferrite and finely dispersed martensite can obtain a high work hardening coefficient, which suppresses the localization of plastic deformation, which has the effect of increasing the plastic deformability of tear ridges. As a result, this contributes to an increase in the energy for forming a brittle fracture surface.Although the technical ideas of the first and second points are independent from each other, the approach to the present invention is to follow the law. Both effects can be utilized at the same time, making it possible to significantly improve brittle fracture propagation arresting properties.
従来技術においては、微細分散したマルテンサイトは広
義の意味で靭性に悪影響を与えると考えられてきたが、
本発明においてｔよ、その悪影響がでない理由を断明す
る。靭性に対する、＃ｉｉ Ｋ（ｔ１分散し７たマルテ
ンサイトの悪影響は主として従来は溶接部において知ら
れた現象であり、その解析が行なわれてきた。オーステ
ナイトＩ！ｎｉ １１号１・□’ｉ、 ｙ）−Ｉ−１，
て々１５１１に冷却する腸合、主として含有する１１−
学成分によって決するマルテンザイト変態聞始霊１）Ｗ
す、−トでマルテンサイトが形成されるが、生成したマ
ルテンサイトは体積膨張をイ゛（′なうためにＰＪ４さ
しまたファライトに転位が導入される。この事実は；７
ｅ 、ｉ、ｊ旨１り電子＆７Ｑ微埠観壓によって本発明
者は０？ｒ′認し７ている。ｌ−、かるにこのような転
ｆヶが導入され／こ後もさらに急速に冷却を続けること
によりｈｌ１Ｍ中に同浴する炭素あるいは僧素くｔが心
入された転位に拡１１ダし、固着する確率Ｖよ小さく々
る。彼って牢７，１．’、ｌ、 、１；Ｊ、Ｆにオで急
冷を続けた３Ｍ１合に乾し微細分ｌ”）ｔし／辷マルテ
ンザイトが形成されるもののそれに１’４ｒ接している
Ｑｐｊ性変性能形能んだフェライト粒内に自由ノを転位
がＩＸ′Ｉｌｔ付していることが！待機である。この・
１１１だとえ微細分散したマルテンサイトが脆く、外ノ
）によって破Ｊ・（１シ２だとしても１４τ接する自由
転位の移１．ＲＩ３によって、それが脆性破壊発生のθ
スとなるグリフイスｔＩ’％んゼとして働らきにくいこ
とを、蓚、昧している。・１１実、同一成分の！ｆｌ！
１材を、本発明Ｋｒ／〔一つて剌造しだ１船台と圧延後
に空冷した場合（＋１’、１１へはフェライト・・ぐ−
ライト〜！’Ｉ ）とに卦ける、脆性破壊発生特性は殆
んど優劣の７）−はない。ＣＯＤ値について＆Ｊむしろ
本発明１′λてになる４ｉ・補材の方がやや優れてさえ
いる。この結果を帛１図に示す。他力、溶接部に生成さ
れる微＋ｔ：ｌｔｌなマルテンザイトｉｉマルテンザイ
ト変縛後も徐ス″ケされることおよびマルテンサイトに
Ｕ４４１Ｗする金ｉｄ 、ｌｌＬ Ｆｙが多くの、鳴合
靭件の低い、」二部ベーナイトであって、脆弱なマルテ
ンサイトがグリフイス出、裂として作用する可能性が大
きく、結果としてシャルピー試験あるいはＣＯＤ試Ｉ倹
弯°で評価される靭性値を低下させるものと考えられる
。In the conventional technology, it has been thought that finely dispersed martensite has a negative effect on toughness in a broad sense;
Let us clarify the reason why there is no adverse effect in the present invention. The negative effect of martensite dispersed in #ii K(t1) on toughness is a phenomenon known mainly in welds and has been analyzed. y)-I-1,
1511, mainly containing 11-
Martenzite metamorphosis determined by scientific composition 1) W
Martensite is formed in the -t, but in order to achieve volume expansion, dislocations are introduced into the PJ4 and farite. This fact is;
e, i, j effect 1 electron & 7Q Weibu Kanju, the inventor is 0? r' recognized7. 1-, such a dislocation f is introduced, and by continuing to cool it even more rapidly, the carbon or carbon atoms present in the hl1M bath expand into the dislocations inserted, The probability of sticking is smaller than V. He is in prison 7.1. ', l, , 1; J, F were continued to be rapidly cooled in O, and finely divided into 3M1 and 1'), Qpj deformation properties were formed, which formed 1'4r of martenzite. The fact that dislocations are attached to free nodes IX'Ilt in the developed ferrite grains is waiting.
Even if it is 111, the finely dispersed martensite is brittle, and the transfer of free dislocations in contact with 1.RI3 causes the fracture to occur due to θ, which causes brittle fracture.
I am aware that it is difficult to work as a staff member.・11 fruits have the same ingredients! Fl!
When 1 material is air-cooled after rolling with the present invention Kr/[one ship and one platform] (+1', 11 are ferrite...
Light! There is almost no superiority or inferiority in brittle fracture occurrence characteristics compared to 7). Regarding the COD value, the 4i supplementary material made from the 1'λ of the present invention is even slightly better. The results are shown in Figure 1. In addition, the slight +t:ltl martenzite generated in the welded part ii. This is a bipartite bainite, and there is a strong possibility that the brittle martensite acts as griffin cracks and cracks, which results in a decrease in the toughness value evaluated by the Charpy test or COD test I degree. It will be done.
以上性ｉ（！１に述べてきた本発明の技術界（ｊｌに基
すき・）１々造した剣例の母４１０脆性破壊伝１番停止
特性および（誓１）′：部をシミュレートしたン餐４゛
路内Ｊ′Ｍ、熱ザイクルをが口した出合の１１１；λ性
破」賢之発生’ｔ’ｉｒ性を従来法との比較において１
毛１喪に示す。脆性破壊伝播停止時性は１ｒ４ｆ ｇ型
のＤＷＴＴ （Ｄｒｏｐ Ｗｅｉｇｈｔ Ｔｅａｒ Ｔ
ｅ５ｔ ）を使用し、試＋１．４片（Ｊｊｌ而が脆性破
面率５０チを示す温度をその（旨−とした。試陥片形状
は厚み１４１１Ｉ＋ＩＸ長さ１８０ｍｍ、幅４５爺であ
り、１′１′さ５ ＋ｎｍのノッグ一部は脆性破胞発生
を容易１／（：Ｌ、、かつｊｆｌｌ破而をＭ面するだめ
、局所的に脆化プ」イーでいる。溶ｊアｊ％におりる脆
性破壊発生！ｈ性（’ｊ、’ Ｂ Ｓ ！’ｉ ７６２
にイ（，１・１ρししたＣＯＤ小ｔ７験によって劇！価
した。’ｊ ｆｒ、 ｔｌ’＋ ０：出１ｐ（、燻−ナ
イクルを施しだ噴材のヴイッカース１ｌｉｌｊ黒を荷Ｅ
Ｉ＋、’、 ２０ ｋｑで測定した。The technical world of the present invention (preferably based on jl) which has been described in the above characteristics i (!1) was created by simulating the mother 410 brittle fracture first stopping characteristic and (vow 1)': part. In a comparison of the occurrence of 't'ir' with the conventional method, 111;
Shown in 1 mourning. The brittle fracture propagation stop time is 1r4f g-type DWTT (Drop Weight Tear T
e5t) was used, and the temperature at which the sample +1.4 piece (Jjl) showed a brittle fracture ratio of 50 was set as the temperature (-).The test piece shape was 1411I+IX in thickness, 180mm in length, and 45mm in width. '1' A part of the nog with a thickness of 5 +nm is easy to cause brittle rupture. brittle fracture occurs!
(, 1.1 rho COD small t7 experience! 'j fr, tl' + 0: out 1 p (, smoked - Nycle treated spray wood Vickers 1 lilj black loaded E
I+,', was measured at 20 kq.
第１萩から明らかなように、本発明による′ｉ’ｌＹｔ
：Ｉ−１；１は２％Ｎｉ含有鋼と６１に同勢の！１ぐ
・、１′目ｊｌｌｆ ｊ史伝ｌｉｔ？停止特１生を有し
、溶接部についてはそのＩＩ【Ｑ ｌ現は倶く、また／
？′７接部靭性の指標である限界ＣＯＤ ＆；Ｉ、はる
かにされていることが明らかである。ｌｒｒ ４ｇ′部
の硬１１１か低いことは溶接冷間割れイウ・るいＱＪ、
心１）；部の応カイ１ｉｊｉ化物１１ｇ食割れ特性にも
ｉ、ｔ：ｒれているとｒ１′乏よう。As is clear from the first bush, 'i'lYt according to the present invention
:I-1;1 is the same as 2% Ni-containing steel and 61! 1gu・, 1′ jllf j history lit? It has a stopping characteristic 1, and for welded parts, its II
? '7 It is clear that the limit COD &;I, which is an index of joint toughness, is much higher. If the hardness of lrr 4g' part is 111 or lower, it means weld cold cracking.
Mind 1); If the eclipse characteristics of the compound 11g are also i, t:r, then r1' will be poor.
なお本発明は主として脆性破り伝＋１１９停止特性につ
いて記１１ｉしてきたが、母材のＩＬＩＬ性値が大きい
ことＱ」、主としてガスラインノクイゾで問題となる不
安定ｊｄ性被破壊抑制にも有効に機能にするものである
。不安定延性破壊とＤｗＴＴでの吸収エネルギーには相
関のあることが知られているか、本発明法によろく？４
利の方が従来法によるそれより高い吸収エネルギーを示
しているからである。Although the present invention has mainly been described with respect to the brittle breakage resistance +119 stopping property, the large ILIL property value of the base material is also effective in suppressing unstable JD damage, which is a problem mainly in gas line nozzles. It is what makes it functional. Is it known that there is a correlation between unstable ductile fracture and absorbed energy in DwTT? 4
This is because the method shows higher absorbed energy than the conventional method.
本発明においては浴接部については脆性破壊発生！ｔｌ
Ｉ性を・主たる対象にしているが浴接法あるいはその後
の−７へ処鯉に工夫をこらして浴接部における１Ｆｌｉ
性１伎」自伝１８ｉ停＋１：！ｌ、”１件の向上に本発
明の技術思想を活用−１′ることも可能である。In the present invention, brittle fracture occurs in the bath contact part! tl
The main target is the I-type, but the bath-wetting method or the subsequent -7 method is applied to the 1Fli in the bath-wetting part.
``Sex 1ki'' autobiography 18i stop +1:! It is also possible to utilize the technical idea of the present invention to improve one problem.
以」二記！、１≦した事実は主として・・」４板につい
てであったが、本発明の要件を満足していれば、静輔オ
のフ杉状、寸法については何等制約を与えるものではな
い。Two notes! The fact that , 1≦ was mainly concerned with the 4th board, but as long as it satisfies the requirements of the present invention, no restrictions are placed on the cedar shape and dimensions of Shizuo.
４、 図ｉ＋−＋ｉ ノｌｉ！’ｉ ’Ｆ−な説明’Ｊ
’ｒ ］し１は本発明による調料の脆性被験発生を従来
法によって製造したＣ；・４材のそれと比較した図であ
る。区１において○印はｖＴｒｓ （ン−＼、）し・ビ
ー、１＆□・ｉｆ！ｉ ＶＬおける５０係破面遷移温黒
−）、Ｃ゛１叩は１゛δｏ、２（Ｃｏｔ）試）険におい
て限界ＣＯＤが０．２ ｍｍ １．□■で示す岬Ｖ’
ｂ：Ｎ ｌ！＋−６ＣＯＤ試験はＩｔｓ ５７６２ Ｆ
、 ｒｌ／’ｊノ＋、１． ） テあ／、。4. Figure i+-+i Noli! 'i 'F-na explanation'J
'r ] 1 is a diagram comparing the brittleness test occurrence of the preparation according to the present invention with that of C;·4 material manufactured by the conventional method. In Ward 1, the circle mark is vTrs (n-\,)shi・bee, 1&□・if! i VL 50 fracture surface transition (warm black), C゛1 stroke is 1゛δo, 2 (Cot) test) limit COD is 0.2 mm 1. Cape V' indicated by □■
b:Nl! +-6COD test Its 5762 F
, rl/'jノ+, 1. ) Tea/,.
Claims (2)
０１〜０、；３％、Ｍｎ ： ０．５〜２．０ ％、Ａ
７：０．０１〜０１％、Ｔｉ ： ０．００５〜００３
０チ、Ｎ：（０，２〜０．５ ） ＸＴｉｆＪを含有し
、残部Ｆｅおよび不純物から成る鋼鋳片または画片をＡ
ｃ３点以上１１５０℃以下に加熱した後、９００℃以下
Ａ ｒ ３点以上の温度域におりる川下率が３０係以上
となる熱間圧延を施した後、Ａｒ３点以」二から空冷よ
り速い冷却速度でかっＡｒ５点以下での主／ζる金属組
織が析出物含有量の少ないフェライトと微細分散しだマ
ルテンサイトとなる冷却速度で冷却することを特徴とす
る浴接部靭性および脆性破１？、伝播停止！１！ｆ性の
優れた高張力鋼の製造法。(1) Ichitomi C: 0.02-0.15%, Si: 0.
01~0, ;3%, Mn: 0.5~2.0%, A
7: 0.01-01%, Ti: 0.005-003
0chi, N: (0,2~0.5) A steel slab or piece containing XTifJ and the balance consisting of Fe and impurities is
c After heating to 3 points or more and 1150℃ or less, hot rolling is carried out so that the downstream rate in the temperature range of 3 points or more is 30 coefficient or more, and then it is faster than air cooling from 2 points to 900℃ or less. Bath joint toughness and brittle fracture 1 characterized by cooling at a cooling rate at which the main/ζ metal structure becomes ferrite with low precipitate content and finely dispersed martensite at Ar5 points or lower. ? , stop propagation! 1! A method for producing high tensile strength steel with excellent f properties.
．０１〜０３％、Ｍｎ ： ０．５〜２．０ ％、Ａ７
： ０．０１〜０．１％、Ｔｉ ： ０．００５〜
０．（１３０％、Ｎ ：（０，２〜Ｉ）５） Ｘ Ｔｉ
’％を含有し、さらにＶ：０．２％以下 、 Ｎｂ
： ｏ、ｏ ８％以下、Ｃｒ ： １．０ ％ 、’Ｊ
、下、Ｍｏ：０．！’ｉ％以下、Ｃｕ ： ０．５％以
下、Ｎｉ：１．５％以下の一４１′ｉｌ斗だは二ＡΦ以
上をように含有し残部Ｆｅおよび不純物から成る（融′
ｌ、ｉ Ｊ−１゜または鋼片をｋｃ５点以上１１５０
’Ｃ以下に加熱した後、９００℃以下Ａｒ３点以十のｆ
ｌＩｉａｔ １隻域における川下率が３０％以上となる
熱間圧９１１．をＭｔｉ した後、Ａｒ３点以下からへ
！冷より速い冷却・ｊｔｉ度でかつＡｒ３点以下での主
メヒる金属組織が析出物含有（・）の少ないフェライト
と微細分散したマルテンサイトとなる冷却速度で冷却す
ることを！ｒ！ｌ：徴とする＋′Ｈ？ 、１茫部靭件お
よび脆性被塑伝播停止に特１ツ１−の供Ｊ１／仁面張力
鋼の製造法。(2) Tun: A%, C: 0.02-0.15, Sj: 0
．． 01-03%, Mn: 0.5-2.0%, A7
: 0.01~0.1%, Ti: 0.005~
0. (130%, N: (0,2~I)5)
'%, further V: 0.2% or less, Nb
: o, o 8% or less, Cr: 1.0%, 'J
, bottom, Mo: 0. ! Cu: 0.5% or less, Ni: 1.5% or less.
l, i J-1゜or steel billet kc5 points or more 1150
After heating to below 900°C, 3 points or more of Ar
lIiat Hot pressure 911. where the downstream rate in one ship area is 30% or more. After doing Mti, go from Ar3 points or less! Cooling is faster than cooling, and cooling is performed at a cooling rate at which the main metal structure below the Ar3 point becomes ferrite with little precipitate content (・) and finely dispersed martensite! r! l: Sign +'H? , 1. A method for manufacturing J1/face tensile steel, which is specially designed for the prevention of brittle plastic propagation.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP15679682A JPS5947323A (en) | 1982-09-10 | 1982-09-10 | Production of high tension steel having excellent toughness in weld zone and property for stopping propagation of brittle fracture |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP15679682A JPS5947323A (en) | 1982-09-10 | 1982-09-10 | Production of high tension steel having excellent toughness in weld zone and property for stopping propagation of brittle fracture |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS5947323A true JPS5947323A (en) | 1984-03-17 |
| JPS621456B2 JPS621456B2 (en) | 1987-01-13 |
Family
ID=15635495
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP15679682A Granted JPS5947323A (en) | 1982-09-10 | 1982-09-10 | Production of high tension steel having excellent toughness in weld zone and property for stopping propagation of brittle fracture |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS5947323A (en) |
Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6425916A (en) * | 1987-07-21 | 1989-01-27 | Nippon Steel Corp | Manufacture of high-strength steel for electric resistance welded tube excellent in toughness at low temperature |
| JPH02217416A (en) * | 1988-11-08 | 1990-08-30 | Nippon Steel Corp | Production of steel stock excellent in arresting property |
| JP2002361312A (en) * | 2001-06-13 | 2002-12-17 | Kawasaki Steel Corp | Method for cooling thick and high tensile strength hot rolled steel strip |
| EP1717331A1 (en) * | 2004-02-19 | 2006-11-02 | Nippon Steel Corporation | Steel sheet or steel pipe being reduced in expression of baushinger effect, and method for production thereof |
| WO2007119878A1 (en) | 2006-04-13 | 2007-10-25 | Nippon Steel Corporation | High-strength steel plate with superior crack arrestability |
| WO2008108333A1 (en) | 2007-03-05 | 2008-09-12 | Nippon Steel Corporation | Thick high-strength steel plate and process for producing the same |
| JP2014062333A (en) * | 2006-10-06 | 2014-04-10 | Exxonmobil Upstram Research Company | Low yield ratio dual phase steel linepipe with superior strain aging resistance |
| KR20150057998A (en) | 2013-11-19 | 2015-05-28 | 신닛테츠스미킨 카부시키카이샤 | Steel sheet |
| KR20160075927A (en) | 2014-12-19 | 2016-06-30 | 주식회사 포스코 | The steel sheet having excellent strength and toughness at the center of thickness and method for manufacturing the same |
-
1982
- 1982-09-10 JP JP15679682A patent/JPS5947323A/en active Granted
Cited By (13)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6425916A (en) * | 1987-07-21 | 1989-01-27 | Nippon Steel Corp | Manufacture of high-strength steel for electric resistance welded tube excellent in toughness at low temperature |
| JPH02217416A (en) * | 1988-11-08 | 1990-08-30 | Nippon Steel Corp | Production of steel stock excellent in arresting property |
| JP2002361312A (en) * | 2001-06-13 | 2002-12-17 | Kawasaki Steel Corp | Method for cooling thick and high tensile strength hot rolled steel strip |
| JP4677685B2 (en) * | 2001-06-13 | 2011-04-27 | Ｊｆｅスチール株式会社 | Cooling method for thick-walled high-tensile hot-rolled steel strip |
| EP1717331A4 (en) * | 2004-02-19 | 2009-09-23 | Nippon Steel Corp | Steel sheet or steel pipe being reduced in expression of baushinger effect, and method for production thereof |
| EP1717331A1 (en) * | 2004-02-19 | 2006-11-02 | Nippon Steel Corporation | Steel sheet or steel pipe being reduced in expression of baushinger effect, and method for production thereof |
| US8815024B2 (en) | 2004-02-19 | 2014-08-26 | Nippon Steel & Sumitomo Metal Corporation | Steel plate or steel pipe with small occurrence of Bauschinger effect and methods of production of same |
| WO2007119878A1 (en) | 2006-04-13 | 2007-10-25 | Nippon Steel Corporation | High-strength steel plate with superior crack arrestability |
| US7914629B2 (en) | 2006-04-13 | 2011-03-29 | Nippon Steel Corporation | High strength thick steel plate superior in crack arrestability |
| JP2014062333A (en) * | 2006-10-06 | 2014-04-10 | Exxonmobil Upstram Research Company | Low yield ratio dual phase steel linepipe with superior strain aging resistance |
| WO2008108333A1 (en) | 2007-03-05 | 2008-09-12 | Nippon Steel Corporation | Thick high-strength steel plate and process for producing the same |
| KR20150057998A (en) | 2013-11-19 | 2015-05-28 | 신닛테츠스미킨 카부시키카이샤 | Steel sheet |
| KR20160075927A (en) | 2014-12-19 | 2016-06-30 | 주식회사 포스코 | The steel sheet having excellent strength and toughness at the center of thickness and method for manufacturing the same |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS621456B2 (en) | 1987-01-13 |
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