JP2002249845A - Fire-resistant steel having excellent weldability - Google Patents
Fire-resistant steel having excellent weldabilityInfo
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- JP2002249845A JP2002249845A JP2001046881A JP2001046881A JP2002249845A JP 2002249845 A JP2002249845 A JP 2002249845A JP 2001046881 A JP2001046881 A JP 2001046881A JP 2001046881 A JP2001046881 A JP 2001046881A JP 2002249845 A JP2002249845 A JP 2002249845A
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Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、火災等、高温状態
にさらされる可能性のある構造物への利用に適した耐火
鋼材に関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fire resistant steel material suitable for use in a structure which may be exposed to a high temperature condition such as a fire.
【０００２】[0002]
【従来の技術】一般に構造用鋼材は、室温（常温）では
十分な強度が確保できるように設計されているが、５０
０℃以上の高温状態になると大幅に強度が低下すること
が知られている。このため、例えば火災等により高温に
さらされる建築構造物では、建設に用いた鋼材が高温状
態で脆くなって、該構造物が倒壊したり著しく変形する
ことのないよう鋼材に耐火被覆が施される。2. Description of the Related Art Generally, structural steel materials are designed to have sufficient strength at room temperature (normal temperature).
It is known that the strength is significantly reduced when the temperature becomes higher than 0°C. Therefore, for example, in a building structure exposed to a high temperature due to a fire or the like, the steel material used for construction becomes brittle in a high temperature state, and a fireproof coating is applied to the steel material so that the structure does not collapse or deform significantly. It
【０００３】しかしながら、上記耐火被覆工程は建築コ
ストを高め、また工期の長期化を招くことにもなるの
で、この様な耐火対策を施さなくともよい鋼材、または
耐火被覆を薄くすることのできる耐火対策の軽減可能な
鋼材が求められている。この様な要望から、高温時にお
いても高強度を維持することのできる鋼材の開発が進め
られており、これまで、例えば特公平４−５０３６２号
に示されるように、Ｍｏ、Ｎｂ、Ｖ等の元素を添加して
高温強度を高めた耐火鋼材が多く提案されている。しか
しながら、高温強度を高めるこれらの元素は、耐火鋼材
の主要な用途である建築用鋼材にて不可欠とされる溶接
性、特にＨＡＺ靭性を著しく劣化させるという問題があ
る。従って、良好な高温強度および優れた溶接性を同時
に満足して、建築構造物の安全性を高めることのできる
耐火鋼材が期待されている。尚、特公平５−７９７４４
号には、Ｍｏを低減して耐火性に優れた建築用低降伏比
鋼材を得ることが開示されているが、実質的にはＭｏ高
濃度域を対象とするものであり、高温強度と同時に優れ
た溶接性を確保するには、よりＭｏ低濃度域での検討を
要すると考えられる。However, the above-mentioned fireproof coating process raises the construction cost and prolongs the construction period. Therefore, it is not necessary to take such fireproof measures, and the fireproof coating can be thinned. There is a demand for steel materials that can be reduced in measures. From such a demand, the development of steel materials capable of maintaining high strength even at high temperatures has been promoted, and, for example, as shown in Japanese Patent Publication No. 4-50362, Mo, Nb, V, etc. have been developed so far. Many refractory steel materials in which an element is added to enhance high temperature strength have been proposed. However, these elements that increase the high temperature strength have a problem of significantly deteriorating the weldability, particularly HAZ toughness, which is indispensable in steel for construction, which is a main application of fire-resistant steel. Therefore, there is a demand for a fire-resistant steel material capable of enhancing the safety of a building structure while simultaneously satisfying good high-temperature strength and excellent weldability. In addition, Japanese Patent Publication No. 5-79744
Japanese Patent No. 3120 discloses that a low yield ratio steel material for buildings having excellent fire resistance is obtained by reducing Mo, but it is intended for a high Mo concentration region, and at the same time as high temperature strength. In order to secure excellent weldability, it is considered necessary to study in a low Mo concentration range.
【０００４】この様な溶接性を劣化させる合金元素に頼
らず、他の元素を添加して高温強度を確保する試みもな
されており、特公平６−１０４８５６号では、常温強度
と高温強度とのバランスを良好なものとする為、Ｍｏ量
を低減してＣｕの析出強化を利用することが提案されて
いる。しかしながら上記公報では、Ｃｕの添加に加え
て、少量添加されたＭｏの高温強度向上効果を有効に発
揮させることについてまで検討されておらず、優れた高
温強度と溶接性の同時達成にはなお改善の余地がある。Attempts have also been made to add high temperature strength by adding other elements without relying on alloying elements that deteriorate the weldability. In Japanese Patent Publication No. 6-104856, room temperature strength and high temperature strength are compared. To improve the balance, it has been proposed to reduce the amount of Mo and utilize the precipitation strengthening of Cu. However, in the above publication, it has not been studied to effectively exhibit the high temperature strength improving effect of Mo added in a small amount in addition to the addition of Cu, and it is still improved to simultaneously achieve excellent high temperature strength and weldability. There is room for
【０００５】[0005]
【発明が解決しようとする課題】本発明はこの様な事情
に鑑みてなされたものであって、その目的は、優れた溶
接性を有し、かつ高温でも高強度を維持することのでき
る優れた耐火性能をも有する耐火用鋼を提供することに
ある。The present invention has been made in view of such circumstances, and an object thereof is excellent weldability and excellent strength capable of maintaining high strength even at high temperature. Another object of the present invention is to provide a refractory steel having excellent fire resistance.
【０００６】[0006]
【０００７】また本発明の耐火鋼材は、Ｃ：０．０３％
を超え０．１５％以下、Ｓｉ：０．０５〜１．０％、Ｍ
ｎ：０．１〜２．０％、Ａｌ：０．０２〜０．１％、Ｃ
ｕ：１．０％を超え２．０％以下、Ｍｏ：０．０５〜
０．４０％未満、Ｔｉ：０．００５〜０．１％、Ｂ：
０．０００３〜０．００３％、Ｃａ：０．００１〜０．
００５％を満たす鋼であって、且つこれらの元素が下記
式（２）を満たすことを要旨とするものでもある。 （５０００×［Ｍｏ］×［Ｂ］）≦２．４ …（２） 〔式中、［Ｍｏ］はＭｏの含有量（質量％）、［Ｂ］は
Ｂの含有量（質量％）を意味する。〕The refractory steel material of the present invention has a C content of 0.03%.
Over 0.15%, Si: 0.05-1.0%, M
n: 0.1-2.0%, Al: 0.02-0.1%, C
u: more than 1.0% and 2.0% or less, Mo: 0.05 to
Less than 0.40%, Ti: 0.005-0.1%, B:
0.0003 to 0.003%, Ca: 0.001 to 0.
It is a steel satisfying 005%, and the gist is that these elements satisfy the following formula (2). (5000×[Mo]×[B])≦2.4 (2) [wherein, [Mo] means Mo content (mass %), and [B] means B content (mass %)) To do. ]
【０００８】前記本発明の耐火用鋼には、必要によっ
て、Ｎｉ：０．０１〜２．０％、Ｎｂ：０．００５〜
０．１％、およびＶ：０．００５〜０．１％よりなる群
から選択される少なくとも１種の元素を含有させること
も有効である。In the refractory steel of the present invention, if necessary, Ni: 0.01-2.0%, Nb: 0.005-
It is also effective to contain at least one element selected from the group consisting of 0.1% and V: 0.005 to 0.1%.
【０００９】[0009]
【発明の実施の形態】本発明者らは、前述した様な状況
の下で、溶接性、特にＨＡＺ靭性を損なうことなく、良
好な高温強度を確保することのできる耐火鋼材の実現を
目指して鋭意研究を進めた。その結果、Ｃｕ添加による
析出強化を十分に活用することで、従来より活用されて
いるＭｏ添加を抑えて溶接性を確保し、更には添加した
Ｍｏの高温強度向上効果を最大限に発揮させるためにＢ
を添加することが有効であることを突き止め、これらの
元素の添加バランスについて追究を重ねた結果、上記本
発明に想到したのである。BEST MODE FOR CARRYING OUT THE INVENTION Under the circumstances as described above, the present inventors aim to realize a refractory steel material capable of ensuring good high-temperature strength without impairing weldability, particularly HAZ toughness. The research was earnestly advanced. As a result, by fully utilizing the precipitation strengthening by the addition of Cu, to suppress the addition of Mo, which has been conventionally used, to secure the weldability, and to maximize the high temperature strength improvement effect of the added Mo. To B
As a result of finding out that the addition of Al is effective and pursuing the addition balance of these elements, the present invention was conceived.
【００１０】この様にＭｏの添加を抑制してＣｕを添加
することで、溶接性を低下させることなく優れた高温強
度を確保することができた理由として、ＣｕがＭｏと比
較して、Ｃｕの析出速度が遅く、５００℃以上の高温で
ようやくε−Ｃｕが析出して鋼が析出強化されることが
挙げられる。Ｃｕ添加により良好な高温強度を確保する
には、０．６％以上、好ましくは０．８％以上添加する
必要がある。しかし、Ｃｕを過剰に添加した場合には熱
間加工性が劣化することから、２．０％以下、好ましく
は１．５％以下に抑える。The reason why excellent high temperature strength can be secured without lowering the weldability by adding Cu while suppressing the addition of Mo is that Cu is more The precipitation rate is slow, and ε-Cu finally precipitates at a high temperature of 500° C. or higher to strengthen the steel. In order to secure good high temperature strength by adding Cu, it is necessary to add 0.6% or more, preferably 0.8% or more. However, if Cu is excessively added, the hot workability deteriorates, so 2.0% or less, preferably 1.5% or less is suppressed.
【００１１】本発明者らは、良好な高温強度と溶接性を
同時に確保することを目的に、上述の如く高温強度の確
保に有効なＣｕ、過剰に添加すると溶接性の劣化を引き
起こすＭｏ、およびＭｏとの相互作用により高温強度を
高める効果を有するＢの添加バランスについて検討した
ところ、Ｃｕ含有量が０．６〜１．０％の場合には、下
記式（１）および式（２）を満たすように化学成分を調
整し、Ｃｕ含有量が１．０を超え２．０％以下の場合に
は、下記式（２）を満たすようにすればよいことが分か
った。 １．５≦（［Ｃｕ］＋５０００×［Ｍｏ］×［Ｂ］） …（１） （５０００×［Ｍｏ］×［Ｂ］）≦２．４ …（２） 尚、式中の［Ｃｕ］はＣｕの含有量（質量％）、［Ｍ
ｏ］はＭｏの含有量（質量％）、［Ｂ］はＢの含有量
（質量％）を意味する。The inventors of the present invention aim to secure good high temperature strength and weldability at the same time. As described above, Cu is effective for securing high temperature strength, Mo which causes deterioration of weldability when added in excess, and When the addition balance of B, which has the effect of increasing the high temperature strength by the interaction with Mo, was examined, when the Cu content was 0.6 to 1.0%, the following formula (1) and formula (2) were used. It has been found that the chemical components are adjusted so as to satisfy the above condition, and when the Cu content is more than 1.0 and not more than 2.0%, the following formula (2) should be satisfied. 1.5≦([Cu]+5000×[Mo]×[B]) (1) (5000×[Mo]×[B])≦2.4 (2) Note that [Cu] in the formula is Cu content (mass %), [M
o] means the content of Mo (mass %), and [B] means the content of B (mass %).
【００１２】即ち、Ｃｕ含有量が０．６〜１．０％の場
合、上記式（１）における（［Ｃｕ］＋５０００×［Ｍ
ｏ］×［Ｂ］）の値が１．５以上となるようＣｕ量に応
じて適宜ＭｏおよびＢの添加量を調整すれば、所望の高
温強度を確保できることが分かった。尚、上記（［Ｃ
ｕ］＋５０００×［Ｍｏ］×［Ｂ］）の値は好ましくは
２．０以上である。That is, when the Cu content is 0.6 to 1.0%, ([Cu]+5000×[M
It has been found that a desired high temperature strength can be secured by appropriately adjusting the addition amounts of Mo and B according to the Cu amount so that the value of (o]×[B]) becomes 1.5 or more. In addition, the above ([C
The value of u]+5000×[Mo]×[B]) is preferably 2.0 or more.
【００１３】また優れた溶接性を確保するには、Ｃｕ含
有量が０．６〜１．０％の場合および１．０％を超えて
２．０％以下の場合のいずれにおいても、上記式（２）
における（５０００×［Ｍｏ］×［Ｂ］）の値が２．４
以下となるようＭｏおよびＢの添加量を調整すればよい
ことが分かった。尚、上記（５０００×［Ｍｏ］×
［Ｂ］）の値は、好ましくは２．２以下である。Further, in order to secure excellent weldability, the above formula is satisfied when the Cu content is 0.6 to 1.0% and when the Cu content exceeds 1.0% and is 2.0% or less. (2)
The value of (5000×[Mo]×[B]) in 2.4 is 2.4.
It was found that the addition amounts of Mo and B should be adjusted so as to be as follows. In addition, the above (5000×[Mo]×
The value of [B]) is preferably 2.2 or less.
【００１４】即ち、所望の高温強度および優れた溶接性
を確保するには、Ｃｕが０．６〜１．０％の場合には、
上記式（１）および式（２）のどちらも満足するようＣ
ｕ、ＭｏおよびＢの添加量を調整すればよく、またＣｕ
が１．０％を超えて２．０％以下の場合には、Ｍｏ量お
よびＢ量が少なくても十分に高温強度を確保することが
できることから、上記式（２）のみを満足するようＭｏ
量およびＢ量を調整すればよいことが分かった。That is, in order to secure the desired high temperature strength and excellent weldability, when Cu is 0.6 to 1.0%,
C so that both equations (1) and (2) are satisfied
It suffices to adjust the amounts of u, Mo and B added, and Cu
Is more than 1.0% and not more than 2.0%, sufficient high temperature strength can be ensured even with a small amount of Mo and B, so Mo should be satisfied so that only the above formula (2) is satisfied.
It was found that the amount and the amount of B should be adjusted.
【００１５】Ｍｏは、上述の如く高温強度を確保する上
で有効な元素であることから、０．０５％以上、好まし
くは０．１％以上添加するが、過剰の添加はＨＡＺ靭性
を劣化させるので、０．４０％未満、好ましくは０．３
１％未満、より好ましくは０．３０％以下、最も好まし
くは０．２０％未満に抑えることとする。Since Mo is an element effective in securing high temperature strength as described above, it is added in an amount of 0.05% or more, preferably 0.1% or more, but excessive addition deteriorates the HAZ toughness. Therefore, less than 0.40%, preferably 0.3
The amount is less than 1%, more preferably 0.30% or less, and most preferably less than 0.20%.
【００１６】また本発明は、Ｂを添加することによっ
て、添加したＭｏの高温強度向上効果を最大限に引き出
すというＢとＭｏの複合添加効果を図ったものであり、
この様にＭｏとの相互作用により高温強度を上昇させる
には、Ｂを０．０００３％以上、好ましくは０．０００
５％以上添加する必要がある。しかし過剰の添加は、Ｆ
ｅ23（ＣＢ）6等の化合物が粗大に析出して靭性劣化を
招くこととなるので、０．００３％以下、好ましくは
０．００２％以下に抑えることとする。Further, the present invention is intended to achieve the combined effect of B and Mo by maximizing the high temperature strength improving effect of the added Mo by adding B.
Thus, in order to increase the high temperature strength by the interaction with Mo, B is 0.0003% or more, preferably 0.000%.
It is necessary to add 5% or more. However, excessive addition of F
Since a compound such as e 23 (CB) 6 coarsely precipitates and causes deterioration of toughness, the content is controlled to 0.003% or less, preferably 0.002% or less.
【００１７】本発明で、その他の化学成分を規定した理
由について詳述する。The reason why the other chemical components are defined in the present invention will be described in detail.
【００１８】Ｃ：０．０３％を超え０．１５％以下 Ｃは、鋼の強度確保に必須の元素であるので、その含有
量が０．０３％を超えるようにする必要があり、好まし
い含有量は０．０４％以上である。しかし過剰に含有さ
れているとＨＡＺ靭性の確保が困難となるので、０．１
５％以下、好ましくは０．１２％以下に抑える必要があ
る。C: more than 0.03% and not more than 0.15% C is an element essential for securing the strength of steel, so it is necessary to make its content exceed 0.03%. The amount is 0.04% or more. However, if it is contained excessively, it becomes difficult to secure the HAZ toughness.
It is necessary to suppress it to 5% or less, preferably 0.12% or less.
【００１９】Ｓｉ：０．０５〜１．０％ Ｓｉは、製鋼時の脱酸に必要な元素であり、また固溶強
化により鋼材の強度を高めるのにも必要な元素であるの
で、０．０５％以上、好ましくは０．１％以上添加する
必要がある。しかしながら多量に添加すると、Martensi
te−AusteniteConstituent（ＭＡ）が生成されてＨＡＺ
靭性を劣化させることとなるので、１．０％以下、好ま
しくは０．８％以下に抑えることとする。Si: 0.05 to 1.0% Si is an element necessary for deoxidation at the time of steel making, and is also an element necessary for increasing the strength of steel by solid solution strengthening. It is necessary to add at least 05%, preferably at least 0.1%. However, when added in large amounts, Martensi
te-Austenite Constituent (MA) is generated and HAZ
Since the toughness is deteriorated, the content is controlled to 1.0% or less, preferably 0.8% or less.
【００２０】Ｍｎ：０．１〜２．０％ Ｍｎは、強度および靭性を確保する上で重要な元素であ
るので、０．１％以上、好ましくは０．５％以上添加す
る。しかしながら、過剰に添加すると必要以上に強度が
高まり、溶接性の劣化を招くことにもなるので、２．０
％以下、好ましくは１．８％以下に抑える。Mn: 0.1 to 2.0% Since Mn is an important element for ensuring strength and toughness, 0.1% or more, preferably 0.5% or more is added. However, if added excessively, the strength will be increased more than necessary and the weldability will be deteriorated.
% Or less, preferably 1.8% or less.
【００２１】Ａｌ：０．０２〜０．１％ Ａｌは、Ｓｉと同様、脱酸剤として用いる元素であり、
０．０２％以上、好ましくは０．０３％以上添加する。
しかしながら、過剰の添加はＨＡＺ靭性を劣化させるこ
ととなるので、０．１％以下、好ましくは０．０８％以
下に抑えるようにする。Al: 0.02 to 0.1% Al, like Si, is an element used as a deoxidizer,
Add 0.02% or more, preferably 0.03% or more.
However, excessive addition deteriorates the HAZ toughness, so the content is controlled to 0.1% or less, preferably 0.08% or less.
【００２２】Ｔｉ：０．００５〜０．１％ Ｔｉは、炭窒化物を形成してＨＡＺ組織を微細化し、靭
性改善に寄与する効果を有する。この様な効果を有効に
発揮させるには、０．００５％以上、好ましくは０．０
０７％以上の添加を要する。一方、過剰の添加は、微細
炭化物の析出量を増加させ、却って靭性を劣化させるこ
ととなるので、０．１％以下、好ましくは０．０８％以
下に抑える。Ti: 0.005 to 0.1% Ti has the effect of forming carbonitrides to refine the HAZ structure and contributing to improving toughness. In order to exert such effects effectively, 0.005% or more, preferably 0.0
Addition of at least 07% is required. On the other hand, excessive addition increases the precipitation amount of fine carbides and rather deteriorates the toughness, so the content is suppressed to 0.1% or less, preferably 0.08% or less.
【００２３】Ｃａ：０．００１〜０．００５％ Ｃａは、硫化物の形態を制御して靭性の改善に寄与する
元素である。この様な効果を有効に発揮させるには０．
００１％以上添加すればよく、０．００２％以上の添加
が好ましい。しかし過剰の添加は、Ｃａの酸化物に起因
する靭性低下を招くこととなるので、０．００５％以
下、好ましくは０．００４％以下に抑える。Ca: 0.001 to 0.005% Ca is an element that controls the form of sulfides and contributes to the improvement of toughness. In order to effectively exhibit such an effect, it is 0.
It is sufficient to add 001% or more, preferably 0.002% or more. However, excessive addition causes a decrease in toughness due to the oxide of Ca, so is suppressed to 0.005% or less, preferably 0.004% or less.
【００２４】本発明における基本的な化学成分組成は以
上の通りであるが、必要によってはＮｉ、ＮｂおよびＶ
よりなる群から選択される少なくとも１種の元素を含有
させて、次の様な改善効果を得ることも有効である。The basic chemical composition of the present invention is as described above, but if necessary, Ni, Nb and V are used.
It is also effective to incorporate at least one element selected from the group consisting of to obtain the following improvement effects.
【００２５】Ｎｉ：０．０１〜２．０％ Ｎｉは靭性の改善に有効な元素であるので、０．０１％
以上添加することが好ましく、より好ましくは０．１％
以上である。しかし過剰に添加しても、効果が飽和して
高コストとなるだけであるので、２．０％以下に抑える
ことが好ましく、より好ましくは１．５％以下である。Ni: 0.01-2.0% Since Ni is an element effective in improving the toughness, 0.01%.
It is preferable to add the above, more preferably 0.1%
That is all. However, even if added excessively, the effect is saturated and the cost becomes high. Therefore, it is preferable to suppress it to 2.0% or less, and more preferably 1.5% or less.
【００２６】Ｎｂ：０．００５〜０．１％ Ｎｂは、常温時および高温時において良好な強度を確保
するのに有効な元素であり、この様な効果を有効に発揮
させるには、Ｎｂを０．００５％以上添加することが好
ましく、より好ましくは０．０１％以上である。しかし
過剰に添加すると、炭化物が形成されてＨＡＺ靭性を劣
化させることとなるので、０．１％以下に抑えることが
好ましく、より好ましくは０．０８％以下である。Nb: 0.005 to 0.1% Nb is an element effective for ensuring good strength at normal temperature and high temperature, and in order to exert such effects effectively, Nb is used. It is preferable to add 0.005% or more, and more preferably 0.01% or more. However, if added excessively, carbides will be formed and the HAZ toughness will be deteriorated, so it is preferable to suppress it to 0.1% or less, and more preferably 0.08% or less.
【００２７】Ｖ：０．００５〜０．１％ ＶはＮｂと同様の効果を持つ元素であり、高温時の良好
な強度確保に有効であるので、好ましくは０．００５％
以上、より好ましくは０．０１％以上添加する。しかし
０．１％を超えて添加すると、Ｎｂ添加の場合と同様に
炭化物を形成してＨＡＺ靭性の劣化を招くこととなるの
で、０．１％以下とすることが好ましく、より好ましく
は０．０８％以下である。V: 0.005 to 0.1% V is an element having the same effect as Nb and is effective for ensuring good strength at high temperatures, so 0.005% is preferable.
Or more, more preferably 0.01% or more. However, if added in excess of 0.1%, carbides will be formed and the HAZ toughness will be deteriorated as in the case of adding Nb, so the content is preferably set to 0.1% or less, more preferably 0.1%. It is at most 08%.
【００２８】Ｃｒは、高温強度の改善に寄与しないだけ
でなく、ＨＡＺ靭性の低下も招く元素であるので、その
含有量を０．１０％以下（０％を含む）に抑えることが
望ましい。[0028] Cr is an element that not only contributes to the improvement of high temperature strength but also causes a drop in HAZ toughness, so it is desirable to keep its content to 0.10% or less (including 0%).
【００２９】本発明に係る耐火鋼材は、残部成分を実質
的にＦｅとするものであるが、その他、微量の不可避不
純物の含有が許容されるのは勿論のこと、前記本発明の
作用に悪影響を与えない範囲で、更に他の元素を積極的
に含有させることも可能である。積極添加が許容される
他の元素の例として、Ｔｉと同様の効果を有するＺｒ等
が挙げられる。The refractory steel material according to the present invention has a balance of substantially Fe, but in addition to the inclusion of a trace amount of unavoidable impurities, it adversely affects the operation of the present invention. It is also possible to positively contain other elements within the range that does not give. Examples of other elements that can be positively added include Zr, which has the same effect as Ti.
【００３０】[0030]
【実施例】以下、実施例を挙げて本発明をより具体的に
説明するが、本発明はもとより下記実施例によって制限
を受けるものではなく、前・後記の趣旨に適合し得る範
囲で適当に変更を加えて実施することも可能であり、そ
れらはいずれも本発明の技術的範囲に含まれる。即ち、
下記実施例においては、本発明の鋼材を用いて熱間圧延
を行っているが、本発明は、最終製品の形状や製造方法
等を特定するものではなく、種々の条件で製造されたも
のも本発明の技術的範囲に含まれる。EXAMPLES The present invention will be described in more detail with reference to the following examples. However, the present invention is not limited by the following examples, and may be appropriately applied within the scope of the above and the following points. Modifications can be made and implemented, all of which are included in the technical scope of the present invention. That is,
In the following examples, hot rolling is performed using the steel material of the present invention, but the present invention does not specify the shape or manufacturing method of the final product, and those manufactured under various conditions may also be used. It is included in the technical scope of the present invention.
【００３１】表１に示す化学成分組成の鋼材を用いて熱
間圧延を行い、得られた圧延材から試験材を採取して、
常温引張試験、高温引張試験、熱サイクル試験およびシ
ャルピー衝撃試験を実施した。高温強度については、６
００℃での耐力（ＹＳ）が常温耐力（ＹＳ）に対して７
０％以上確保できているものを合格とし、溶接性につい
ては、８００℃から５００℃の温度域の冷却速度が４０
℃／secである熱サイクルを施した試験片［入熱５ｋＪ
／ｍｍで溶接した際の熱影響部（ＨＡＺ部）に相当す
る］を用いてシャルピー衝撃試験を行い、−１０℃での
シャルピー衝撃吸収エネルギーが４７Ｊ以上のものを合
格とした。これらの試験結果を一括して表２に示す。Hot rolling was performed using steel materials having the chemical composition shown in Table 1, and test materials were taken from the obtained rolled materials,
A normal temperature tensile test, a high temperature tensile test, a heat cycle test and a Charpy impact test were carried out. For high temperature strength, see 6
Proof strength (YS) at 00℃ is 7 against room temperature yield strength (YS)
If 0% or more is secured, the result is acceptable, and the weldability is 40% in the temperature range of 800°C to 500°C.
Test piece subjected to thermal cycle of ℃/sec [heat input 5kJ
Corresponding to the heat affected zone (HAZ section) when welded at 1/mm], a Charpy impact test was carried out, and a Charpy impact absorbed energy at −10° C. of 47 J or more was passed. The test results are collectively shown in Table 2.
【００３２】[0032]
【表１】 [Table 1]
【００３３】[0033]
【表２】 [Table 2]
【００３４】表１および表２より、Ｎｏ．１〜２２は、
本発明の規定を満たすものであり、高温においても常温
での高強度をほぼ維持することができ、かつ良好なＨＡ
Ｚ靭性も確保できていることが分かる。これに対してＮ
ｏ．２３〜３０では、本発明の要件の何れかを満たさ
ず、高温強度またはＨＡＺ靭性が劣化する結果となっ
た。From Table 1 and Table 2, No. 1-22 are
It satisfies the requirements of the present invention, can maintain high strength at room temperature even at high temperatures, and has good HA.
It can be seen that Z toughness is also secured. On the other hand, N
o. Nos. 23 to 30 did not satisfy any of the requirements of the present invention, resulting in deterioration of high temperature strength or HAZ toughness.
【００３５】即ち、Ｎｏ．２３，２７および３０では、
ＨＡＺ靭性が劣化する結果となったが、これは、Ｎｏ．
２３ではＣ含有量が高すぎたこと、Ｎｏ．２７ではＭｏ
含有量が本発明で規定する範囲を超えたこと、Ｎｏ．３
０ではＢ含有量が多すぎて式（２）を満足しなかったこ
とが理由として挙げられる。尚、Ｎｏ．２９より、良好
なＨＡＺ靭性を得るには、Ｃｒ含有量を抑えることが望
ましいことが分かる。また、Ｎｏ．２４，２６および２
８では、いずれも式（１）における（［Ｃｕ］＋５００
０×［Ｍｏ］×［Ｂ］）が１．５を下回る値となったた
め、高温時の強度が低下する結果となった。That is, No. At 23, 27 and 30,
The result was that the HAZ toughness deteriorated.
In No. 23, the C content was too high. 27 is Mo
When the content exceeds the range specified in the present invention, No. Three
The reason for 0 is that the content of B was too large to satisfy the formula (2). Incidentally, No. From 29, it can be seen that it is desirable to suppress the Cr content in order to obtain good HAZ toughness. In addition, No. 24, 26 and 2
In the case of No. 8, all of ([Cu]+500 in the formula (1) are used.
Since 0×[Mo]×[B]) was less than 1.5, the strength at high temperature decreased.
【００３６】Ｎｏ．２５は、Ｃｕ含有量が規定範囲を超
えたものであり、熱間圧延中に割れが生じたため、以後
の測定は行わなかった。No. In No. 25, the Cu content exceeded the specified range, and cracking occurred during hot rolling, so that the subsequent measurement was not performed.
【００３７】[0037]
【発明の効果】本発明は以上のように構成されており、
上述の如く化学成分組成を適切に制御することによっ
て、良好な溶接性を確保したまま、高温時においても高
強度を維持することができたのである。そして、この様
な高温強度および溶接性に優れた耐火鋼材の実現によっ
て、建築構造物等に用いる鋼材の耐火対策を軽減するこ
とができることとなった。またこの様な耐火対策を講じ
なくても、火災等で高温にさらされた場合に、高強度を
維持して倒壊または著しく変形することのない建築用鋼
材を供給できることとなったのである。The present invention is configured as described above,
By properly controlling the chemical composition as described above, it was possible to maintain high strength even at high temperature while maintaining good weldability. By realizing such a fire-resistant steel material excellent in high-temperature strength and weldability, it is possible to reduce fire-resistant measures for steel materials used for building structures and the like. Further, even if such fire resistance measures are not taken, it is possible to supply a structural steel material that does not collapse or is not significantly deformed while maintaining high strength when exposed to a high temperature such as a fire.
───────────────────────────────────────────────────── フロントページの続き (72)発明者 畠 英雄 神戸市西区高塚台１丁目５番５号 株式会 社神戸製鋼所神戸総合技術研究所内 (72)発明者 槙井 浩一 神戸市西区高塚台１丁目５番５号 株式会 社神戸製鋼所神戸総合技術研究所内 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Hideo Hatake, 1-5-5 Takatsukadai, Nishi-ku, Kobe-shi, Kobe Steel Research Institute, Kobe Steel, Ltd. 5th-5th Stock Company Kobe Steel Works Kobe Research Institute
Claims (4)
３％を超え０．１５％以下、Ｓｉ：０．０５〜１．０
％、Ｍｎ：０．１〜２．０％、Ａｌ：０．０２〜０．１
％、Ｃｕ：０．６〜１．０％、Ｍｏ：０．０５〜０．４
０％未満、Ｔｉ：０．００５〜０．１％、Ｂ ：０．０
００３〜０．００３％、Ｃａ：０．００１〜０．００５
％を満たす鋼であって、且つこれらの元素が下記式
（１）および式（２）を満たすことを特徴とする溶接性
に優れた耐火鋼材。 １．５≦（［Ｃｕ］＋５０００×［Ｍｏ］×［Ｂ］） …（１） （５０００×［Ｍｏ］×［Ｂ］）≦２．４ …（２） 〔式中、［Ｃｕ］はＣｕの含有量（質量％）、［Ｍｏ］
はＭｏの含有量（質量％）、［Ｂ］はＢの含有量（質量
％）を意味する。〕1. In mass% (hereinafter the same), C: 0.0
More than 3% and 0.15% or less, Si: 0.05 to 1.0
%, Mn: 0.1 to 2.0%, Al: 0.02 to 0.1
%, Cu: 0.6 to 1.0%, Mo: 0.05 to 0.4
Less than 0%, Ti: 0.005 to 0.1%, B: 0.0
003 to 0.003%, Ca: 0.001 to 0.005
%, and these elements satisfy the following formulas (1) and (2), a refractory steel material excellent in weldability. 1.5≦([Cu]+5000×[Mo]×[B]) (1) (5000×[Mo]×[B])≦2.4 (2) [wherein [Cu] is Cu Content (mass %), [Mo]
Means the content of Mo (mass %), and [B] means the content of B (mass %). ]
２．０％、Ｎｂ：０．００５〜０．１％、Ｖ ：０．０
０５〜０．１％よりなる群から選択される少なくとも１
種の元素を含むものである請求項１に記載の溶接性に優
れた耐火鋼材。2. As another element, Ni: 0.01-
2.0%, Nb: 0.005 to 0.1%, V: 0.0
At least 1 selected from the group consisting of 05-0.1%
The refractory steel material having excellent weldability according to claim 1, wherein the refractory steel material contains different elements.
Ｓｉ：０．０５〜１．０％、Ｍｎ：０．１〜２．０％、
Ａｌ：０．０２〜０．１％、Ｃｕ：１．０％を超え２．
０％以下、Ｍｏ：０．０５〜０．４０％未満、Ｔｉ：
０．００５〜０．１％、Ｂ ：０．０００３〜０．００
３％、Ｃａ：０．００１〜０．００５％を満たす鋼であ
って、且つこれらの元素が下記式（２）を満たすことを
特徴とする溶接性に優れた耐火鋼材。 （５０００×［Ｍｏ］×［Ｂ］）≦２．４ …（２） 〔式中、［Ｍｏ］はＭｏの含有量（質量％）、［Ｂ］は
Ｂの含有量（質量％）を意味する。〕3. C: more than 0.03% and 0.15% or less,
Si: 0.05 to 1.0%, Mn: 0.1 to 2.0%,
Al: 0.02-0.1%, Cu: over 1.0% 2.
0% or less, Mo: 0.05 to less than 0.40%, Ti:
0.005-0.1%, B: 0.0003-0.00
A fire-resistant steel material having excellent weldability, which is steel satisfying 3% and Ca: 0.001 to 0.005%, and these elements satisfy the following formula (2). (5000×[Mo]×[B])≦2.4 (2) [wherein, [Mo] means Mo content (mass %), and [B] means B content (mass %)) To do. ]
２．０％、Ｎｂ：０．００５〜０．１％、Ｖ ：０．０
０５〜０．１％よりなる群から選択される少なくとも１
種の元素を含むものである請求項３に記載の溶接性に優
れた耐火鋼材。4. Ni: 0.01-
2.0%, Nb: 0.005 to 0.1%, V: 0.0
At least 1 selected from the group consisting of 05-0.1%
The refractory steel material having excellent weldability according to claim 3, which contains different elements.
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|---|---|---|---|
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2007191747A (en) * | 2006-01-18 | 2007-08-02 | Kobe Steel Ltd | Low-yield-ratio fire-resistant steel material |
-
2001
- 2001-02-22 JP JP2001046881A patent/JP3718637B2/en not_active Expired - Fee Related
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2007191747A (en) * | 2006-01-18 | 2007-08-02 | Kobe Steel Ltd | Low-yield-ratio fire-resistant steel material |
| JP4656417B2 (en) * | 2006-01-18 | 2011-03-23 | 株式会社神戸製鋼所 | Low yield ratio refractory steel |
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| Publication number | Publication date |
|---|---|
| JP3718637B2 (en) | 2005-11-24 |
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