JPH0625392B2 - High-toughness and high-strength steel with a yield strength of 60 kgf / ▲ mm2 ▼ and above with excellent electron beam weldability - Google Patents
High-toughness and high-strength steel with a yield strength of 60 kgf / ▲ mm2 ▼ and above with excellent electron beam weldabilityInfo
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- JPH0625392B2 JPH0625392B2 JP1097480A JP9748089A JPH0625392B2 JP H0625392 B2 JPH0625392 B2 JP H0625392B2 JP 1097480 A JP1097480 A JP 1097480A JP 9748089 A JP9748089 A JP 9748089A JP H0625392 B2 JPH0625392 B2 JP H0625392B2
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- electron beam
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Description
【発明の詳細な説明】 （産業上の利用分野） 本発明は電子ビーム溶接性の優れた降伏強度60kgｆ／mm
2以上の高靭性高張力鋼に関するものである。DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention has a yield strength of 60 kgf / mm with excellent electron beam weldability.
It relates to high toughness and high strength steel of 2 or more.
（従来の技術） 近年、エネルギー需要の増加にともない、海洋構造物、
圧力容器、水圧鉄管および海定調査艇などの構造物は大
型化、厚肉化の傾向にあり、これらに使用される鋼材は
高強度でかつ高靭性の要求となっている。(Prior Art) In recent years, with the increase in energy demand, offshore structures,
Structures such as pressure vessels, penstocks, and oceanographic research boats are becoming larger and thicker, and the steel materials used for them are required to have high strength and high toughness.
その要求は当然、構造物の一部を構成する溶接部に対し
てもなされており、電子ビーム溶接を利用し、溶接部の
特性向上と同時に施工効率の向上を図ろうという動きが
盛んである。Needless to say, this requirement is also made for the welded part that constitutes a part of the structure, and there is an active movement to improve the characteristics of the welded part and simultaneously improve the construction efficiency by using electron beam welding. .
従来、これらに使用される鋼板の溶接は、被覆アーク溶
接（ＳＭＡＷ）、潜弧溶接（ＳＡＷ）、又は、ＭＩＧ溶
接が主体である。これらの溶接では、板厚が厚くなるに
つれ加速度的に積層数が増加して、施工時間が膨大なも
のとなり、かつブローホール、スラグ巻き込み等の溶接
欠陥も発生しやすく、信頼性に欠ける。Conventionally, the welding of steel plates used for these is mainly covered arc welding (SMAW), latent arc welding (SAW), or MIG welding. In these weldings, as the plate thickness increases, the number of laminated layers increases at an accelerating rate, the construction time becomes enormous, and welding defects such as blowholes and slag entrainment easily occur, resulting in poor reliability.
又、従来の高強度材においては、溶接施工時に水素によ
る低温割れ防止のための予熱を実施しており、特に被覆
アーク溶接を行なう場合には、鋼管構造物の内面側溶接
等においては作業能率が極めて低下する。In addition, conventional high-strength materials are preheated to prevent cold cracking due to hydrogen during welding. Especially, when performing covered arc welding, work efficiency is improved in the welding of the inner surface of steel pipe structures. Is extremely low.
これらの溶接施工の能率向上と信頼性の向上および厳し
い靭性要求等に応えるために電子ビーム溶接の適用が考
えられるようになってきた。The application of electron beam welding has come to be considered in order to improve the efficiency and reliability of these welding processes and meet strict toughness requirements.
電子ビーム溶接は、従来の溶接（被覆アーク溶接、ＳＡ
Ｗ溶接、ＭＩＧ溶接）と比べて、主に一層で溶接を行な
うため、板厚40mmを越える範囲ではコスト的に有利な領
域となり、板厚が厚くなるほどその効果は大きくなる。
又、電子ビーム溶接は従来の溶接と異なり、鋼板そのも
のを溶融させ接合するものであるため、鋼板の製造にあ
たっては、この溶接部の強度及び靭性を考慮した成分設
計を行なう必要がある。Electron beam welding is the conventional welding (covered arc welding, SA
Compared with W welding and MIG welding), welding is mainly performed in a single layer, so that in a range where the plate thickness exceeds 40 mm, it becomes a cost-effective region, and the thicker the plate, the greater the effect.
Also, unlike conventional welding, electron beam welding involves melting and joining the steel sheet itself, and therefore, in the production of the steel sheet, it is necessary to perform a component design in consideration of the strength and toughness of the welded portion.
従来の降伏強度60kgｆ／mm2級以上の高張力鋼では、こ
の点の配慮は全くなされていなかったといっても過言で
はない。It is no exaggeration to say that no consideration was given to this point in the conventional high-strength steel with a yield strength of 60 kgf / mm 2 or higher.
しかしながら、従来の溶接法を使用する場合でも、溶接
性の改善ははかられている。高強度鋼においては、溶接
により溶接熱影響部が硬化し、そこに溶接金属部及び溶
接雰囲気から水素が拡散し、割れ感受性を高める。However, even when the conventional welding method is used, the weldability is improved. In high-strength steel, the welding heat affected zone is hardened by welding, and hydrogen diffuses from the welded heat affected zone and the welding atmosphere to increase crack susceptibility.
このため、溶接熱影響部の割れ感受性低減のため、Ｎ
ｉ，Ｃｒ，Ｍｏ等の焼入性増大元素を極力低減し、その
代わり〔Ｂ（ボロン）〕の焼入性向上効果を利用し、Ａ
ｌ-Ｂ処理により母材の強度、靭性を高めている。例え
ば、特公昭60-30724号「高靭性高張力鋼板の製造方
法」、特公昭60-20461号「高強度高靭性を有する厚肉高
張力鋼板」がある。Therefore, in order to reduce the crack susceptibility of the weld heat affected zone, N
The hardenability-increasing elements such as i, Cr, and Mo are reduced as much as possible, and instead the hardenability-enhancing effect of [B (boron)] is used.
The LB treatment enhances the strength and toughness of the base material. For example, there is JP-B-60-30724 "Method for producing high toughness and high strength steel sheet" and JP-B-60-20461 "Thick and high strength steel sheet with high strength and toughness".
しかしながら、このＡｌ-Ｂ処理鋼は炭素が0.10％以上
と比較的高く、又、Ｂの焼入性向上効果を十分に発揮す
るため、Ｎの固定を図るべくＡｌが多量添加されてい
る。Ｃが高い場合には、冷却速度が速い電子ビーム溶接
部においては粗粒のマルテンサイト組織となり靭性が著
しく低下する。However, this Al-B treated steel has a relatively high carbon content of 0.10% or more, and since it exerts the effect of improving the hardenability of B sufficiently, a large amount of Al is added to fix N. When C is high, a coarse grain martensite structure is formed in the electron beam welded portion where the cooling rate is high, and the toughness is significantly reduced.
一方、Ｂを使わない高張力鋼としては ASTM A543圧力容
器用焼入焼戻しＮｉ-Ｃｒ-Ｍｏ鋼及びASTM A710 系低炭
素析出硬化Ｎｉ-Ｃｕ-Ｍｏ-Ｎｂ鋼等があり、いずれも
溶接熱影響部の硬化性の点についての配慮がなされてい
る。On the other hand, as high-strength steels that do not use B, there are ASTM A543 quenching and tempering Ni-Cr-Mo steels for pressure vessels and ASTM A710 series low carbon precipitation hardening Ni-Cu-Mo-Nb steels. Consideration is given to the curability of the parts.
しかし、この鋼の電子ビーム溶接部は、前者の場合Ｃが
高いため粗粒のマルテンサイト組織となり靭性低下し、
後者は低Ｃのため粗粒の上部ベイナイト組織となり強
度、靭性共低下する。However, in the case of the former, the electron beam welded portion of this steel has a high martensite structure of coarse grains because of the high C, and the toughness decreases
Since the latter is low C, it becomes a coarse grained upper bainite structure, and both strength and toughness decrease.
このように、従来の鋼は、従来の溶接法で溶接すること
を前提としているため電子ビーム溶接による溶接部に関
する配慮は全くなされていない。As described above, since the conventional steel is premised on welding by the conventional welding method, no consideration is given to the welded portion by electron beam welding.
（発明が解決しようとする課題） 本発明は以上の問題点を解決するためのもので、電子ビ
ーム溶接による溶接を行なっても、溶接部の強度、靭性
の良好な電子ビーム特性の優れた降伏強度60kgｆ／mm2
級以上の高張力鋼を提供するものである。(Problems to be Solved by the Invention) The present invention is to solve the above-mentioned problems, and even if welding by electron beam welding is performed, the strength and toughness of the welded portion are excellent and the yield is excellent in electron beam characteristics. Strength 60kgf / mm 2
It provides high-strength steel of a grade or higher.
（課題を解決するための手段） 本発明は重量％で、Ｃ；0.02〜0.10％、Ｓｉ；0.02〜0.
50％、Ｍn;0.5〜1.5％、Ｐ;0.005％以下、Ｓ;0.010％以
下、Ｎi;0.2〜4.5、Ｃr;0.2〜1.0％、Ｍo;0.1〜0.8％、
Ａｌ;0.005〜0.0035％、Ｂ;0.0003〜0.0010％、Ｎ；0.0
050％以下を含有し、残部が鉄および不可避的不純物か
らなる鋼および上記鋼に更にＣu0.1〜1.5％、Ｖ;0.005
〜0.10％、Ｎb;0.005％〜0.05％、Ｔi;0.005〜0.03％か
らなる強度改善元素群の１種または２種以上を含有し、
電子ビームによって溶接された部分が下部ベンナイト組
織あるいはマルテンサイト＋下部ベンナイトとの混合組
織を形成することを特徴とする電子ビーム溶接性の優れ
た降伏強度60kgｆ／mm2級以上の高靭性高張力鋼であ
る。(Means for Solving the Problems) In the present invention, the weight% is C: 0.02 to 0.10%, Si: 0.02 to 0.
50%, Mn; 0.5-1.5%, P; 0.005% or less, S; 0.010% or less, Ni; 0.2-4.5, Cr; 0.2-1.0%, Mo; 0.1-0.8%,
Al; 0.005-0.0035%, B; 0.0003-0.0010%, N; 0.0
Steel containing 050% or less, the balance being iron and unavoidable impurities, and the above steels further having Cu 0.1 to 1.5%, V; 0.005
.About.0.10%, Nb; 0.005% to 0.05%, Ti; 0.005 to 0.03%, and contains one or more members of a strength improving element group,
A high toughness and high strength steel with a yield strength of 60 kgf / mm 2 or higher, which has excellent electron beam weldability, characterized in that the portion welded by the electron beam forms a lower bentonite structure or a mixed structure of martensite and lower bentonite. Is.
（作 用） 以下本発明について詳細に説明する。(Operation) The present invention will be described in detail below.
電子ビーム溶接は、従来の溶接法のように溶接部に別の
材料を供給し、溶接部の特性向上を図るのではなく、鋼
板そのものを溶融させ溶接するものである。そのため鋼
板製造にあたっては、オーステナイト粒の細粒化等の方
法により高靭性を有する鋼板に調整されるが、電子ビー
ム溶接部においては、溶融・凝固組織のためオーステナ
イト粒は粗粒となる。In the electron beam welding, unlike the conventional welding method, another material is supplied to the welded portion and the characteristics of the welded portion are not improved, but the steel sheet itself is melted and welded. Therefore, in manufacturing a steel sheet, a steel sheet having high toughness is adjusted by a method such as grain refinement of austenite grains, but in the electron beam welded portion, the austenite grains become coarse grains due to the melting / solidifying structure.
このとき焼入性が著しく高い粗粒のマルテンサイト組
織、あるいは焼入性が低下した粗粒の上部ベイナイト組
織が生成した場合は、両組織共著しく靭性を低下させ
る。At this time, if a coarse-grained martensite structure having a significantly high hardenability or a coarse-grained upper bainite structure having a reduced hardenability is formed, both structures significantly reduce the toughness.
発明者らは、ここにおいて電子ビーム溶接部で良好な強
度、靭性を有する鋼板を種々検討した結果、0.10％以下
の低炭素鋼をベースに、低Ａｌと低Ｎに微量Ｂを添加す
ることにより電子ビーム溶接部の焼入性が改善され、靭
性の良好な下部ベイナイト組織が得られ高強度、高靭性
が得られることを知見した。As a result of various investigations on steel plates having good strength and toughness in electron beam welding, the inventors have found that by adding a trace amount of B to low Al and low N based on low carbon steel of 0.10% or less. It has been found that the hardenability of the electron beam welded portion is improved, a lower bainite structure having good toughness is obtained, and high strength and high toughness are obtained.
第１図は電子ビーム溶接部の靭性に及ぼすＢとＮ量との
関係について示した図である。FIG. 1 is a diagram showing the relationship between B and N content that affects the toughness of electron beam welds.
Ｎ量を0.0025％でＢを0.0003〜0.0010％の範囲で著しく
靭性が改善できる。又、更に、電子ビーム溶接部の靭性
は下部ベイナイト組織にマルテンサイト組織が混合した
場合には、Ｐ量によって著しく影響されることも知見し
た。The toughness can be remarkably improved when the N content is 0.0025% and the B content is 0.0003 to 0.0010%. Further, it was also found that the toughness of the electron beam welded portion is significantly affected by the P content when the martensite structure is mixed with the lower bainite structure.
第２図は電子ビーム溶接部の靭性に及ぼすＰ量の影響に
ついて示した図である。FIG. 2 is a diagram showing the effect of the P amount on the toughness of the electron beam welded portion.
マルテンサイト＋下部ベイナイトの混合組織において
は、Ｐ量を 0.005％以下にすることにより靭性が向上す
ることが分かる。It can be seen that in a mixed structure of martensite and lower bainite, toughness is improved by setting the P content to 0.005% or less.
一方、Ａｌは電子ビーム溶接部の靭性のためには、第３
図に示すごとく低い方が望ましいことが分かる。On the other hand, Al is the third material because of the toughness of the electron beam weld.
As shown in the figure, it is understood that the lower the better.
更に、上記のように、Ｎ，Ｂ，Ｐ量及びＡｌ量が適切で
あっても、基本成分が適切でないと降伏強度60kgｆ／mm
2級以上としての優れた強度、靭性が得られない。Further, as described above, even if the amounts of N, B, P and Al are appropriate, if the basic components are not appropriate, the yield strength is 60 kgf / mm.
Excellent strength and toughness as Grade 2 or higher cannot be obtained.
以下に成分の限定理由について説明する。The reasons for limiting the components will be described below.
Ｃ；Ｃは焼入性を向上させ強度を容易に上昇させるのに
有効である。反面、本発明の電子ビーム溶接性に対して
は悪影響与える元素である。すなわち、0.10％超である
とマルテンサイト組織の生成量が増加し靭性を低下させ
る。又、0.02％未満であると目標降伏強度の確保が困難
となる。従ってＣの含有量を0.02〜0.10％とした。C; C is effective in improving hardenability and easily increasing strength. On the other hand, it is an element that adversely affects the electron beam weldability of the present invention. That is, if it exceeds 0.10%, the amount of martensite structure produced increases and the toughness decreases. If it is less than 0.02%, it becomes difficult to secure the target yield strength. Therefore, the content of C is set to 0.02 to 0.10%.
Ｓｉ；Ｓｉは強度向上に有効であるが、高いと低温靭性
及び溶接性を低下させるため上限を0.5％とする。しか
し、製鋼上0.05％は必要である。従ってＳｉ含有量0.05
〜0.50とした。Si; Si is effective for improving the strength, but if it is high, the low temperature toughness and weldability are deteriorated, so the upper limit is made 0.5%. However, 0.05% is necessary for steelmaking. Therefore, the Si content is 0.05
It was set to ~ 0.50.
Ｍｎ；Ｍｎは焼入性を向上させ、強度、靭性確保に有効
であり、その下限は、 0.5％である。しかし、Ｍｎ量が
多過ぎると電子ビーム溶接部は焼入性が増加してマルテ
ンサイト主体の組織となり靭性が低下するため、 1.5％
を上限とした。Mn: Mn improves hardenability and is effective in securing strength and toughness, and its lower limit is 0.5%. However, if the Mn content is too high, the hardenability of the electron beam welded part increases and the structure becomes mainly martensite and the toughness decreases, so 1.5%.
Was set as the upper limit.
Ｐ；Ｐは先に述べたように、電子ビーム溶接部の靭性を
改善させる重要な元素である。特に焼入性が高く、下部
ベイナイト組織にマルテンサイト組織をより多く混合さ
せた組織でも靭性を大きく低下させない。そのためには
0.005％以下に低減することが必要である。P: P is an important element that improves the toughness of the electron beam welded portion, as described above. In particular, the hardenability is high, and even a structure in which a lower bainite structure is mixed with a larger amount of martensite structure does not significantly reduce the toughness. for that purpose
It is necessary to reduce it to 0.005% or less.
Ｓ；Ｓは靭性に有害な元素であり、 0.010％以下に低減
する必要がある。S; S is an element harmful to toughness and needs to be reduced to 0.010% or less.
Ｎｉ；Ｎｉは低温靭性の向上及び焼入性を高めて強度を
向上させるのに有効な元素である。特に低Ｃ領域で下部
ベイナイト組織が生成しやすい。しかし、0.02％未満で
は焼入性が不十分となり強度、靭性が得られない。又、
4.5％を超えるとその効果が飽和する。従ってＮｉの含
有量を0.02〜4.5 ％とした。Ni; Ni is an element effective for improving the low temperature toughness and the hardenability to improve the strength. In particular, a lower bainite structure is likely to be generated in the low C region. However, if it is less than 0.02%, the hardenability becomes insufficient and strength and toughness cannot be obtained. or,
If it exceeds 4.5%, the effect will be saturated. Therefore, the Ni content is set to 0.02 to 4.5%.
Ｍｏ；Ｍｏは焼入性を向上させる元素で強度確保に有効
である。しかし、 0.1％未満ではその効果が減少する。
又、 0.8％を超えるとマルテンサイト組織が増加し、靭
性を低下させる。従ってＭｏの含有量を 0.1〜0.8 ％と
した。Mo; Mo is an element that improves hardenability and is effective in securing strength. However, if less than 0.1%, the effect is reduced.
Further, if it exceeds 0.8%, the martensite structure increases and the toughness decreases. Therefore, the content of Mo is set to 0.1 to 0.8%.
Ａｌ；ＡｌはＮと結合したムオーステナイト粒を微細化
して靭性を向上させる元素である。従って、母材の細粒
化のためには 0.005％必要である。一方、電子ビーム溶
接部においては、溶融後の冷却速度が速いためＡｌを多
量添加してもＮとＡｌは結合せず、かえって固溶Ａｌが
増加し靭性が低下する傾向にある。従って、上限を 0.0
35％とした。Al; Al is an element that refines the muauustenite grains combined with N to improve the toughness. Therefore, 0.005% is required for making the base material finer. On the other hand, in the electron beam welded portion, since the cooling rate after melting is fast, even if a large amount of Al is added, N and Al do not bond, and there is a tendency that the solid solution Al increases and the toughness decreases. Therefore, the upper limit is 0.0
35%.
Ｂ；Ｂは先に述べたように焼入性を向上させ、電子ビー
ム溶接部の靭性を向上させるのに不可欠な元素である。
特に低Ｎ領域でその効果を発揮する。0.0003％未満では
焼入性が低下し、上部ベイナイト組織が生成し、強度、
靭性が低下する。又、0.0010％では、本発明のＮ量範囲
では焼入性向上効果が飽和する。従ってＢの含有量を0.
0003〜0.0010とした。B; B is an element essential for improving the hardenability and improving the toughness of the electron beam welded portion as described above.
Especially, the effect is exhibited in the low N region. If it is less than 0.0003%, the hardenability deteriorates, the upper bainite structure is generated, and the strength,
Toughness decreases. If it is 0.0010%, the effect of improving the hardenability is saturated in the N amount range of the present invention. Therefore, the content of B is 0.
It was set to 0003 to 0.0010.
Ｎ；Ｎは先に述べたように、電子ビーム溶接部において
Ｂに焼入性を十分に発揮するためには、低Ｎ化が有効で
ある。又、Ｎ量が高いと電子ビーム溶接部のビーム先端
部において、溶け込み不良等の溶接欠陥が発生しやすく
なる。これらのことから、Ｎ含有量を0.0050％以下とし
た。N; As described above, N is effective for lowering N in order to fully exert the hardenability on B in the electron beam welded portion. Further, when the N content is high, welding defects such as poor penetration easily occur at the beam tip of the electron beam weld. Therefore, the N content is set to 0.0050% or less.
以上は本発明における鋼の基本成分であるが、更に本発
明は強度及び靭性を一層改善するため以下の成分を選択
添加することができる。The above are the basic components of the steel in the present invention, but in the present invention, the following components can be selectively added in order to further improve the strength and toughness.
Ｃｕ；Ｃｕは靭性を低下させずに強度上昇させると共に
耐蝕性の向上に有効であり、その下限量は 0.1％であ
る。しかし、 1.5％を超えると熱間加工性及び電子ビー
ム溶接部の高温割れを生じるおそれがある。従ってＣｕ
の含有量を 0.1〜1.5 ％とした。Cu; Cu is effective in increasing the strength without lowering the toughness and improving the corrosion resistance, and its lower limit is 0.1%. However, if it exceeds 1.5%, hot workability and hot cracking of electron beam welds may occur. Therefore Cu
Content of 0.1 to 1.5%.
Ｖ；Ｖは焼戻し処理において、炭化物を形成し析出硬化
により母材の強度確保に有効であり、その下限量は 0.0
05％である。しかし、0.10％を超えると電子ビーム溶接
部の靭性が低下する。従ってＶの含有量を 0.005〜0.10
％とした。V: V is effective in securing the strength of the base metal by forming carbides in the tempering treatment and by precipitation hardening, and the lower limit is 0.0
It is 05%. However, if it exceeds 0.10%, the toughness of the electron beam welded portion deteriorates. Therefore, the V content should be 0.005 to 0.10.
%.
Ｎｂ；ＮｂもＶと同様に母材の強度確保と細粒化による
靭性改善のために必要であり、その下限量は 0.005％で
ある。しかし、0.05％を超えると電子ビーム溶接部の靭
性が低下する。従ってＮｂの含有量を 0.005〜0.05％と
した。Similar to V, Nb; Nb is also necessary for securing the strength of the base material and improving the toughness by fine-graining, and the lower limit is 0.005%. However, if it exceeds 0.05%, the toughness of the electron beam welded portion deteriorates. Therefore, the Nb content is set to 0.005 to 0.05%.
Ｔｉ；ＴｉはＡｌと同様にＮと結合し、オーステナイト
粒を細粒化させる元素であり、母材の強度確保と母材靭
性とＨＡＺ（溶接熱影響部）靭性の向上のために添加す
る。 0.005％以下では細粒化効果が小さく、又、0.03％
を超えるとかえって母材靭性及びＨＡＺ靭性を低下させ
る。Ti; Ti is an element that, like Al, combines with N and refines austenite grains, and is added to secure the strength of the base metal and to improve the base metal toughness and HAZ (welding heat affected zone) toughness. If it is less than 0.005%, the grain refining effect is small, and 0.03%
On the contrary, the base material toughness and the HAZ toughness are deteriorated on the contrary.
この鋼を溶製するにあたっては、電気炉、転炉のいずれ
を用いてもよい。鋼板製造にあたっては、鋳造、圧延の
いずれを用いてもよい。又、鋼板の熱処理は、焼入れ焼
戻し処理を行なう。この場合、焼入れ処理を圧延後直接
焼入れ処理で行なってもよい。When melting this steel, either an electric furnace or a converter may be used. In manufacturing the steel sheet, either casting or rolling may be used. The heat treatment of the steel sheet is a quenching and tempering treatment. In this case, the quenching treatment may be carried out by direct quenching treatment after rolling.
（実施例） 第１表に示す化学成分のうち、鋼Ａ〜鋼Ｎは本発明鋼
で、鋼Ｏ〜鋼Ｔは比較鋼である。(Example) Among the chemical components shown in Table 1, steels A to N are steels of the present invention, and steels O to T are comparative steels.
鋼は転炉により溶製し、連続鋳造法及び鋼塊分塊法によ
り鋼片とした後、第１表に示す板鋼25〜100 mmに圧延し
た。The steel was melted by a converter, made into a slab by the continuous casting method and the ingot ingot ingot method, and then rolled into a plate steel of 25 to 100 mm shown in Table 1.
鋼板の熱処理条件は、焼入れ処理 850〜900 ℃の水冷に
続き、役戻し処理 600〜660 ℃の空冷を施した。The heat treatment conditions for the steel sheet were a quenching treatment of 850 to 900 ° C. followed by water cooling, and a cooling treatment of 600 to 660 ° C. in air.
第２表に、これらの鋼板の母材部及び電子ビーム溶接部
の引張試験、シャルピー衝撃試験結果を示す。尚、引張
及び衝撃試験片の採取位置は母材の場合は板鋼中心部で
あり、電子ビーム溶接部の場合は溶着金属部の板鋼中心
部中央である。Table 2 shows the results of the tensile test and the Charpy impact test of the base metal part and the electron beam welded part of these steel plates. The tensile and impact test pieces were sampled at the center of the steel plate in the case of the base metal, and in the center of the steel plate of the weld metal in the case of electron beam welding.
但し電子ビーム溶接条件は次の通りである。However, the electron beam welding conditions are as follows.
本発明鋼Ａ，Ｂ，Ｃ，Ｆ，Ｇ，Ｈ，Ｊ，Ｍは加速電圧 1
50kV、ビーム電流 230mA、溶接速度30cm／min 、鋼Ｉは
加速電圧 150kV、ビーム電流100mA 、溶接速度28cm／mi
n 、鋼Ｄ，Ｅ，Ｋ，Ｌ，Ｎは加速電圧 150kV、ビーム電
流 180mA、溶接速度20cm／min 、又、比較鋼Ｏ，Ｑ，
Ｒ，Ｔは加速電圧 150kV、ビーム電流 230mA、溶接速度
30cm／min 、鋼Ｐ，Ｓは加速電圧 150kV、ビーム電流18
0mA、溶接速度20cm／min である。The invention steels A, B, C, F, G, H, J and M have accelerating voltage 1
50kV, beam current 230mA, welding speed 30cm / min, Steel I acceleration voltage 150kV, beam current 100mA, welding speed 28cm / mi
n, Steels D, E, K, L, N are acceleration voltage 150kV, beam current 180mA, welding speed 20cm / min, and comparative steels O, Q,
R and T are acceleration voltage 150kV, beam current 230mA, welding speed
30 cm / min, steel P, S acceleration voltage 150 kV, beam current 18
0mA, welding speed 20cm / min.
本発明鋼Ａ〜Ｇは降伏強度60kgｆ／mm2級鋼、鋼Ｈ〜Ｎ
は降伏強度80kgｆ／mm2で、Ｃ，Ｐ，Ａｌ，ＢとＮ量を
適切に入れることにより、良好な電子ビーム溶接部の強
度及び靭性を有している。又、母材特性も良好である。 The present invention steels A to G are yield strength 60 kgf / mm 2 grade steels, steels H to N.
Has a yield strength of 80 kgf / mm 2 , and has good strength and toughness of an electron beam welded portion by appropriately adding C, P, Al, B and N amounts. The base material characteristics are also good.
これに対し、比較鋼Ｏ，Ｐ，Ｑは降伏強度60kgｆ／mm2
級鋼で、鋼Ｏは〔Ｂ〕が添加されておらず、電子ビーム
溶接部は上部ベイナイト組織となり靭性が低い、鋼Ｐは
〔Ｃ〕と〔Ｐ〕が高く、電子ビーム溶接部はマルテンサ
イト一層組織となり靭性が低い。鋼Ｑは〔Ａｌ〕と
〔Ｎ〕が高く、電子ビーム溶接部の靭性は低い。更に、
比較鋼Ｒ，Ｓ，Ｔは降伏強度80kgｆ／mm2級鋼で、鋼Ｒ
は〔Ｂ〕が添加されておらず、電子ビーム溶接部は上部
ベイナイト組織となり強度、靭性が低い。鋼Ｓは〔Ｎ〕
が高く、又、〔Ｂ〕が0.0001％と無添加に近く、電子ビ
ーム溶接部は上部ベイナイト組織となり強度、靭性共低
い。鋼Ｔは〔Ｃ〕，〔Ｂ〕が高く、電子ビーム溶接部は
マルテンサイト組織となり、更にＡｌが高いことも相俟
って靭性が低い。On the other hand, the comparative steels O, P and Q have a yield strength of 60 kgf / mm 2
It is a grade-grade steel, steel [B] is not added, the electron beam welded part has an upper bainite structure and low toughness, steel P has high [C] and [P], and electron beam welded part is martensite. It has an even more structured structure and low toughness. Steel Q has a high [Al] and [N], and the toughness of the electron beam weld is low. Furthermore,
Comparative steels R, S and T are yield strength 80kgf / mm 2 grade steels, steel R
[B] is not added, and the electron beam welded portion has an upper bainite structure and has low strength and toughness. Steel S is [N]
Is high, and [B] is 0.0001%, which is almost non-additive, and the electron beam welded portion has an upper bainite structure, and both strength and toughness are low. Steel T has a high [C] and [B], the electron beam welded portion has a martensitic structure, and the high Al content also contributes to low toughness.
（発明の効果） 以上述べたように本発明の成分範囲により、電子ビーム
溶接部は、下部ベイナイトあるいはマルテンサイト＋下
部ベイナイトの混合組織となり、強度及び靭性を向上さ
せることが可能となり、産業上多大な効果を奏するもの
である。(Effects of the Invention) As described above, according to the composition range of the present invention, the electron beam welded portion has a lower bainite or a mixed structure of martensite + lower bainite, which makes it possible to improve strength and toughness, which is industrially significant. It has a great effect.
第１図は電子ビーム溶接部の降伏強度及びシャルピー遷
移温度に及ぼすＢ量とＮ量の影響について示す図表、第
２図は電子ビーム溶接部のシャルピー遷移温度に及ぼす
Ｐ量とミクロ組織差の影響について示した図表、第３図
は電子ビーム溶接部のシャルピー遷移温度に及ぼすＡｌ
量の影響について示す図表である。Fig. 1 is a chart showing the effects of B content and N content on the yield strength and Charpy transition temperature of electron beam welds, and Fig. 2 is the effect of P content and microstructure difference on the Charpy transition temperature of electron beam welds. Fig. 3 shows the effect of Al on the Charpy transition temperature of electron beam welds.
It is a chart showing the influence of quantity.
Claims (2)
って溶接された部分が下部ベイナイト組織あるいはマル
テンサイト＋下部ベイナイトとの混合組織を形成するこ
とを特徴とする電子ビーム溶接性の優れた降伏強度60kg
f/mm2級以上の高靭性高張力鋼。1. By weight% C: 0.02 to 0.10% Si; 0.02 to 0.50% Mn; 0.5 to 1.5% P; 0.005% or less S; 0.010% or less Ni; 0.2 to 4.5% Cr; 0.2 to 1.0% Mo; 0.1-0.8% Al; 0.005-0.035% B; 0.0003-0.0010% N; 0.0050% or less The balance is iron and inevitable impurities, and the part welded by electron beam is a lower bainite structure or mixed with martensite + lower bainite Yield strength 60 kg with excellent electron beam weldability characterized by forming a structure
High-toughness, high-strength steel with f / mm 2 grade or higher.
る請求項１記載の電子ビーム溶接性の優れた降伏強度60
kgf/mm2級以上の高靭性高張力鋼。2. A strength-improving element group comprising one or more of Cu; 0.1 to 1.5% V; 0.005 to 0.10% Nb; 0.005 to 0.05% Ti; 0.005 to 0.03% by weight. Yield strength 60 with excellent electron beam weldability according to 1.
High toughness and high strength steel of kgf / mm 2 grade or higher.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1097480A JPH0625392B2 (en) | 1989-04-21 | 1989-04-21 | High-toughness and high-strength steel with a yield strength of 60 kgf / ▲ mm2 ▼ and above with excellent electron beam weldability |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1097480A JPH0625392B2 (en) | 1989-04-21 | 1989-04-21 | High-toughness and high-strength steel with a yield strength of 60 kgf / ▲ mm2 ▼ and above with excellent electron beam weldability |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH02282446A JPH02282446A (en) | 1990-11-20 |
| JPH0625392B2 true JPH0625392B2 (en) | 1994-04-06 |
Family
ID=14193449
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP1097480A Expired - Lifetime JPH0625392B2 (en) | 1989-04-21 | 1989-04-21 | High-toughness and high-strength steel with a yield strength of 60 kgf / ▲ mm2 ▼ and above with excellent electron beam weldability |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0625392B2 (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP1104816A4 (en) * | 1999-06-04 | 2005-01-26 | Jfe Steel Corp | High-tension steel material with excellent suitability for welding with high-energy-density heat source and welded structure thereof |
| JP4719118B2 (en) * | 2006-10-02 | 2011-07-06 | 新日本製鐵株式会社 | Electron beam welded joint with excellent brittle fracture resistance |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5419412A (en) * | 1977-07-13 | 1979-02-14 | Nippon Steel Corp | High tensilie strength steel excelent in toughness of welded zone |
| JPS61117245A (en) * | 1984-11-12 | 1986-06-04 | Nippon Steel Corp | Steel for welding having toughness at low temperature |
| JPS6314843A (en) * | 1986-07-07 | 1988-01-22 | Kawasaki Steel Corp | Steel for high heat input welding with more than 70kj/cm heat input |
| JPS6415321A (en) * | 1987-07-08 | 1989-01-19 | Nippon Steel Corp | Production of steel for electron beam welding having excellent low-temperature toughness |
| JPS6434598A (en) * | 1987-07-31 | 1989-02-06 | Nippon Steel Corp | Steel for marine structure with 40-60kg class tensile strength |
| JPS6434599A (en) * | 1987-07-31 | 1989-02-06 | Nippon Steel Corp | Steel for pressure vessel with 40-60kg class tensile strength |
-
1989
- 1989-04-21 JP JP1097480A patent/JPH0625392B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPH02282446A (en) | 1990-11-20 |
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