JP3003303B2 - Bolt and nut steel with excellent fire resistance - Google Patents
Bolt and nut steel with excellent fire resistanceInfo
- Publication number
- JP3003303B2 JP3003303B2 JP3204083A JP20408391A JP3003303B2 JP 3003303 B2 JP3003303 B2 JP 3003303B2 JP 3204083 A JP3204083 A JP 3204083A JP 20408391 A JP20408391 A JP 20408391A JP 3003303 B2 JP3003303 B2 JP 3003303B2
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- steel
- strength
- bolts
- nuts
- temperature
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Description
【０００１】[0001]
【産業上の利用分野】本発明は、建築構造物に使用され
るボルトおよびナット用鋼であって、詳しくは、常温で
は高力六角ボルト(F10T)、六角ナット(F10) (JIS B 118
6)鋼や高力トルシア形ボルト(F10T) (JSS II 09)鋼と同
等の特性を示し、高温、特に 600℃で45kgf/mm2 以上の
耐力を有する耐火性に優れたボルトおよびナット用鋼に
関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to steel for bolts and nuts used in building structures, and more specifically, to hexagonal bolts (F10T) and hexagonal nuts (F10) (JIS B 118) at room temperature.
6) Steel for bolts and nuts that has the same properties as steel and high-strength torcia-shaped bolts (F10T) (JSS II 09) steel, and has a fire resistance of 45 kgf / mm 2 or more at high temperatures, especially at 600 ° C, and has a resistance to more than 45 kgf / mm It is about.
【０００２】[0002]
【従来の技術】従来、建築構造用鋼材の締結には、JIS
B 1186に定められる高力六角ボルト(F10T)、六角ナット
(F10) やJSS II 09 に定められるトルシア形ボルト(F10
T)などが使用されているが、この種の鋼材は 350℃以上
の高温にさらされると著しく耐力が低下するため、建築
物に火災が発生した場合でもこれらの鋼材の温度が350
℃を超えないように耐火被覆を施すことが法令によって
義務付けられている。2. Description of the Related Art Conventionally, JIS is used for fastening steel materials for building structures.
High-strength hexagon bolt (F10T) and hexagon nut specified in B 1186
(F10) and torcia bolts (F10
T) is used, but when this kind of steel is exposed to a high temperature of 350 ° C or more, its proof strength decreases significantly.
It is required by law to apply fireproof coating not to exceed ℃.
【０００３】一方、昭和51年〜昭和61年に建設省で実施
された総合技術開発プロジェクト「建築物の防火設計法
の開発」の結果、「火災時の安定性」が数値シミュレー
ションおよび実験で確認されれば、耐火物の被覆厚さ
を薄くすること、鉄骨を無被覆で使用すること、が可
能となり、従来よりも鉄骨建築における耐火工法の選択
の自由度が大幅に改善された。即ち、この新耐火設計法
によれば、高温強度に優れた鋼材を使用することによ
り、法令で義務付けられる耐火被覆を削減或いは省略す
ることが可能となり、鉄骨建築の施工コスト、工数の削
減が期待される。On the other hand, as a result of the comprehensive technology development project “Development of a fire prevention design method for buildings” implemented by the Ministry of Construction from 1979 to 1986, “stability in case of fire” was confirmed by numerical simulations and experiments. Then, it becomes possible to make the coating thickness of the refractory thinner and to use the steel frame without coating, and the degree of freedom in selecting the refractory construction method in the steel frame building has been greatly improved as compared with the related art. In other words, according to this new fire-resistant design method, it is possible to reduce or omit the fire-resistant coating required by laws and regulations by using steel materials excellent in high-temperature strength, and it is expected that the construction cost and man-hours of steel-framed buildings will be reduced. Is done.
【０００４】しかしながら、ステンレス鋼や熱間金型用
の合金工具鋼で代表される周知の耐熱鋼材は、高温強度
に優れるものの常温強度が高すぎて加工性に劣るほか、
価格も非常に高いため経済性の面からも建築構造物の耐
火ボルトおよびナット用鋼としては適用が難しい。ま
た、JIS G 4107に定められている高温用合金鋼ボルト材
は、従来の高力六角ボルト(F10T)、六角ナット(F10) 鋼
や高力トルシア形ボルト(F10T)鋼と同等の常温特性を示
すものの、新耐火設計法を満足できるような高温強度を
有しておらず、同じく建築構造物の耐火ボルトおよびナ
ット用鋼としては適用し難い。[0004] However, known heat-resistant steel materials represented by stainless steel and alloy tool steel for hot dies are excellent in high-temperature strength, but are too low in normal-temperature strength to have poor workability.
Since the price is very high, it is difficult to apply as steel for fire-resistant bolts and nuts of building structures from the viewpoint of economy. In addition, high-temperature alloy steel bolt materials specified in JIS G 4107 have ordinary temperature characteristics equivalent to those of conventional high-strength hexagon bolts (F10T), hexagon nuts (F10) steel, and high-strength torcia bolts (F10T) steel. As shown, it does not have high-temperature strength that satisfies the new refractory design method, and is also difficult to apply as steel for fire-resistant bolts and nuts of building structures.
【０００５】このようなことから、特開平２−247355号
公報に、新耐火設計法に基づく締結部材として、高温特
性に優れたボルトおよびナットと、これらの経済的な製
造方法が提案されている。しかし、この発明のボルトお
よびナットでも 600℃での耐力は高々35.8kgf/mm2 程度
しかなく、建築構造物用耐火ボルトおよびナットとして
は高温耐力が十分にあるとは言い難い。[0005] For these reasons, Japanese Patent Laid-Open No. 247355/1990 proposes bolts and nuts having excellent high-temperature characteristics as a fastening member based on a new refractory design method, and an economical manufacturing method thereof. . However, even the bolts and nuts of the present invention have a proof stress at 600 ° C. of at most about 35.8 kgf / mm 2, and it cannot be said that the fire proof bolts and nuts for building structures have sufficient high-temperature proof strength.
【０００６】[0006]
【発明が解決しようとする課題】本発明の課題は、高温
耐力をより高めたボルトおよびナット用鋼、具体的に
は、新耐火設計法に基づく建築用耐火鋼材の締結にあた
り、従来の高力六角ボルト(F10T)、六角ナット(F10)鋼
や高力トルシア形ボルト(F10T)鋼と同等の常温特性を示
し、火災時における高温特性がこれらのボルトおよびナ
ット鋼よりも遙かに高い、 600℃で45kgf/mm2 以上の耐
力を有するボルトおよびナット用鋼を提供することにあ
る。SUMMARY OF THE INVENTION An object of the present invention is to provide steel for bolts and nuts having a higher high-temperature yield strength, specifically, a conventional high-strength steel for fastening a building fire-resistant steel material based on a new fire-resistant design method. It has the same normal temperature characteristics as hexagon bolt (F10T), hexagon nut (F10) steel and high-strength torcia-type bolt (F10T) steel, and has a much higher high-temperature characteristic in the event of fire than these bolt and nut steels. An object of the present invention is to provide steel for bolts and nuts having a proof stress of not less than 45 kgf / mm 2 at ° C.
【０００７】[0007]
【課題を解決するための手段】本発明者は、上記の課題
を達成するため鋼材の化学組成および組織について研究
を行った結果、下記の知見を得た。Means for Solving the Problems The present inventor has studied the chemical composition and structure of steel materials in order to achieve the above-mentioned objects, and has obtained the following findings.
【０００８】(1) Ｍｏ、Ｖを適正量添加したうえでＣの
添加量を調整することにより、高温における耐力の低下
が抑制される。(1) By adjusting the addition amount of C after adding an appropriate amount of Mo and V, a decrease in proof stress at high temperatures is suppressed.
【０００９】(2) ＮｂをＣｒ、ＭｏおよびＶとともに複
合添加することにより、鋼の細粒化が極めて促進され、
高温における耐力の低下が著しく抑制される。(2) By adding Nb in combination with Cr, Mo and V, the grain refinement of steel is greatly promoted,
A decrease in proof stress at high temperatures is significantly suppressed.
【００１０】(3) 含有成分を適正に調整したうえで鋼の
組織を焼入れ焼戻し組織にすることにより、常温強度お
よび高温強度が改善される。(3) The normal temperature strength and the high temperature strength can be improved by appropriately adjusting the contained components and then quenching and tempering the steel structure.
【００１１】(4) 上記の成分に加えてＢ、Ｚｒの１種以
上および／またはＮｉ、Ｃｕの１種以上を適正量添加す
ると、高温での耐力の低下が一段と抑制される。(4) By adding an appropriate amount of one or more of B and Zr and / or one or more of Ni and Cu in addition to the above components, a decrease in proof stress at high temperatures is further suppressed.
【００１２】上記知見に基づく本発明は下記（Ｉ）〜
（IV）に示す化学組成および組織を有するボルトおよび
ナット用鋼を要旨とする。The present invention based on the above findings provides the following (I)
The gist is steel for bolts and nuts having the chemical composition and structure shown in (IV).
【００１３】（I）重量％で、Ｃ：0.30〜0.50％、Ｓ
ｉ： 1.2％以下、Ｍｎ：0.40〜1.50％、Ｃｒ：0.45〜1.
50％、Ｍｏ：0.40〜1.00％、Ｖ：0.01〜0.25％、Ｎｂ：
0.005〜0.15％、Ｔｉ： 0.005〜0.10％、Ａｌ： 0.005
〜0.10％を含有し、残部がＦｅおよび不可避不純物から
なり、焼入れ焼戻し組織を有する耐火性に優れたボルト
およびナット用鋼。(I) By weight%, C: 0.30 to 0.50%, S
i: 1.2% or less, Mn: 0.40 to 1.50%, Cr: 0.45 to 1.
50%, Mo: 0.40 to 1.00%, V: 0.01 to 0.25%, Nb:
0.005 to 0.15%, Ti: 0.005 to 0.10%, Al: 0.005
A steel for bolts and nuts containing about 0.10%, the balance being Fe and inevitable impurities, and having a quenched and tempered structure and excellent fire resistance.
【００１４】（II）上記（Ｉ）に記載の成分に加えて更
に、重量％で、0.0003〜0.0050％のＢおよび0.15％以下
のＺｒのうちの１種以上を含有し、焼入れ焼戻し組織を
有する耐火性に優れたボルトおよびナット用鋼。(II) In addition to the components described in the above (I), the composition further contains, by weight%, at least one of 0.0003 to 0.0050% of B and 0.15% or less of Zr, and has a quenched and tempered structure. Bolt and nut steel with excellent fire resistance.
【００１５】（III)上記（Ｉ）に記載の成分に加えて更
に、重量％で、0.01〜0.60％のＮｉおよび0.05〜 0.60
％のＣｕのうちの１種以上を含有し、焼入れ焼戻し組織
を有する耐火性に優れたボルトおよびナット用鋼。(III) In addition to the components described in the above (I), 0.01 to 0.60% of Ni and 0.05 to 0.60% by weight are further added.
% Of one or more of Cu and having a quenched and tempered structure and excellent fire resistance for bolts and nuts.
【００１６】（IV）上記（Ｉ）に記載の成分に加えて更
に、重量％で、0.0003〜0.0050％のＢおよび0.15％以下
のＺｒのうちの１種以上と、0.01〜0.60％のＮｉおよび
0.05〜0.60％のＣｕのうちの１種以上を含有し、焼入れ
焼戻し組織を有する耐火性に優れたボルトおよびナット
用鋼。(IV) In addition to the components described in (I) above, one or more of 0.0003 to 0.0050% of B and 0.15% or less of Zr, and 0.01 to 0.60% of Ni and
A steel for bolts and nuts containing 0.05 to 0.60% of Cu and having a quenched and tempered structure and excellent fire resistance.
【００１７】[0017]
【作用】以下に、本発明における鋼の化学組成および組
織を上記のように限定する理由を説明する。The reasons for limiting the chemical composition and structure of steel in the present invention as described above will be described below.
【００１８】Ａ）鋼の化学組成 Ｃ：Ｃは所望の強度を確保するために添加するが、その
含有量が0.30％未満では添加効果に乏しく、一方、Ｍｏ
およびＶとの共存下でＣ含有量が0.50％を超えるとかえ
って高温での耐力が低下することになり、また、焼入れ
時の割れ感受性が増大することになるので、その含有量
を0.30〜0.50％とした。A) Chemical composition of steel C: C is added in order to secure a desired strength, but if its content is less than 0.30%, the effect of addition is poor.
If the C content exceeds 0.50% in the coexistence of V and V, the proof stress at high temperatures is rather reduced, and the susceptibility to cracking during quenching is increased. %.
【００１９】Ｓｉ：Ｓｉは鋼の脱酸および強度増加のた
めに有効な元素である。しかし、 1.2％を超えて含有す
ると靱性および冷間加工性が劣化するのみならず、脱炭
を生じやすくなるので、その含有量を 1.2％以下とし
た。Si: Si is an effective element for deoxidizing steel and increasing strength. However, if the content exceeds 1.2%, not only is the toughness and cold workability deteriorated, but decarburization tends to occur, so the content was set to 1.2% or less.
【００２０】Ｍｎ：Ｍｎは脱酸のほか強度および靱性を
確保するのに有効な元素である。しかし、その含有量が
0.40％未満では所望の強度が得られず、1.50％を超える
と強度および靱性の向上効果が飽和し、コストのみが上
昇することになるので、その含有量を0.40〜1.50％とし
た。Mn: Mn is an element effective for securing strength and toughness in addition to deoxidation. However, its content
If it is less than 0.40%, the desired strength cannot be obtained, and if it exceeds 1.50%, the effect of improving the strength and toughness is saturated, and only the cost rises. Therefore, the content was made 0.40 to 1.50%.
【００２１】Ｃｒ：Ｃｒは常温強度および高温強度を向
上させる作用がある。特に、Ｍｏ、ＮｂおよびＶとの複
合添加で著しく高温強度を向上させるが、その含有量が
0.45％未満では所望の効果が得られず、1.50％を超える
と冷間加工性が劣化するようになるので、その含有量を
0.45〜1.50％とした。Cr: Cr has the effect of improving the room temperature strength and the high temperature strength. In particular, the high-temperature strength is remarkably improved by the complex addition with Mo, Nb and V.
If the content is less than 0.45%, the desired effect cannot be obtained, and if it exceeds 1.50%, the cold workability deteriorates.
0.45 to 1.50%.
【００２２】Ｍｏ：Ｍｏは高温強度の向上に極めて有効
な元素であり、特に、Ｃｒ、ＮｂおよびＶとの複合添加
でその効果が著しい。しかし、その含有量が0.40％未満
では所望の高温強度が得られず、1.00％を超えると前記
の効果が飽和し、経済的に不利を招くことになるので、
その含有量を0.40〜1.00％とした。Mo: Mo is an extremely effective element for improving the high-temperature strength, and its effect is particularly remarkable when added in combination with Cr, Nb and V. However, if the content is less than 0.40%, the desired high-temperature strength cannot be obtained, and if the content exceeds 1.00%, the above-mentioned effect is saturated, which disadvantageously causes economic disadvantage.
The content was set to 0.40 to 1.00%.
【００２３】Ｖ：Ｖは鋼の常温強度および高温強度を向
上させる作用を有している。その作用は特に、Ｃｒ、Ｍ
ｏおよびＮｂとの複合添加で大きく発揮される。しか
し、その含有量が0.01％未満では所望の効果が得られ
ず、0.25％を超えるとその効果が飽和するばかりかかえ
って高温強度の低下をきたし、また、靱性の劣化を招く
ようになるので、その含有量を0.01〜0.25％とした。V: V has the effect of improving the room-temperature strength and high-temperature strength of steel. Its action is particularly Cr, M
It is greatly exerted by complex addition with o and Nb. However, if the content is less than 0.01%, the desired effect cannot be obtained. If the content exceeds 0.25%, not only the effect is saturated, but also the high-temperature strength is reduced, and the toughness is deteriorated. The content was set to 0.01 to 0.25%.
【００２４】Ｎｂ：Ｎｂは本発明において重要な元素で
あり、微量の添加で高温強度が向上する。Nb: Nb is an important element in the present invention, and high-temperature strength is improved by adding a small amount.
【００２５】特に、Ｃｒ、ＭｏおよびＶとの複合添加で
高温強度が著しく向上する。その効果を確保するために
は、 0.005％以上の含有量を必要とするが、0.15％を超
えて含有してもその効果が飽和するのみならず、熱間加
工性および冷間加工性が劣化するようになるので、その
含有量を 0.005〜 0.15％とした。In particular, the high temperature strength is remarkably improved by the complex addition with Cr, Mo and V. To ensure the effect, a content of 0.005% or more is required, but if the content exceeds 0.15%, not only the effect is saturated, but also hot workability and cold workability deteriorate. Therefore, its content was made 0.005 to 0.15%.
【００２６】Ｔｉ：Ｔｉは常温強度および高温強度を向
上させる作用がある。しかし、その含有量が 0.005％未
満では所望の効果が得られず、0.10％を超えると鋼の靱
性が劣化し、また、被削性の低下をも招くことになるの
で、その含有量を 0.005〜0.10％とした。Ti: Ti has the effect of improving the room temperature strength and the high temperature strength. However, if the content is less than 0.005%, the desired effect cannot be obtained, and if it exceeds 0.10%, the toughness of the steel deteriorates, and the machinability also decreases. -0.10%.
【００２７】Ａｌ：Ａｌは鋼の脱酸の安定化および均質
化を図るのに有効な元素である。しかし、その含有量が
0.005％未満では所望の効果を得ることができず、0.10
％を超えるとその効果は飽和してしまい、逆に介在物の
増大により疵が発生し、靱性を劣化させることになるの
で、その含有量を 0.005〜0.10％とした。Al: Al is an element effective for stabilizing and homogenizing steel deoxidation. However, its content
If it is less than 0.005%, the desired effect cannot be obtained.
%, The effect is saturated, and conversely, an increase in inclusions causes flaws and deteriorates toughness. Therefore, the content was made 0.005 to 0.10%.
【００２８】本発明のボルトおよびナット用鋼には、上
記の成分に加えて更にＢ、Ｚｒの１種以上および／また
はＮｉ、Ｃｕの１種以上を含んでいてもよい。これらの
合金元素の作用効果と望ましい含有量は下記の通りであ
る。The steel for bolts and nuts of the present invention may further contain one or more of B and Zr and / or one or more of Ni and Cu in addition to the above components. The effects and desirable contents of these alloy elements are as follows.
【００２９】ＢおよびＺｒ：ＢおよびＺｒには鋼の焼入
れ性を一段と向上させる作用があるので、特に製品寸法
が大きい場合に高強度を確保する目的で１種以上を添加
してもよい。しかし、Ｂの場合には0.0003％未満の含有
量では所望の効果が得られず、0.0050％を超えて含有す
ると鋼の靱性および高温強度が劣化するようになる。一
方、Ｚｒの場合には0.15％を超えて含有すると前記の作
用が飽和するばかりか、鋼の靱性および被削性が劣化す
るようになる。従って、これらの合金元素を１種以上添
加する場合は、Ｂ：0.0003〜0.0050％、Ｚｒ：0.15％以
下の含有量とするのがよい。B and Zr: Since B and Zr have an effect of further improving the hardenability of steel, one or more of them may be added for the purpose of ensuring high strength especially when the product size is large. However, in the case of B, if the content is less than 0.0003%, the desired effect cannot be obtained. If the content exceeds 0.0050%, the toughness and high-temperature strength of the steel deteriorate. On the other hand, in the case of Zr, if the content exceeds 0.15%, not only the above-mentioned action is saturated, but also the toughness and machinability of the steel deteriorate. Therefore, when one or more of these alloying elements are added, the content of B is preferably 0.0003 to 0.0050% and the content of Zr is 0.15% or less.
【００３０】ＮｉおよびＣｕ：ＮｉおよびＣｕには強度
と靱性を向上させる作用があるので、より以上の高強度
や靱性を求められる場合は、必要に応じて１種以上添加
してもよい。しかし、Ｎｉの場合には0.01％未満の含有
量では所望の効果が得られず、 0.60％を超えて含有す
ると冷間加工性の劣化をきたす。一方、Ｃｕの場合には
0.05％未満の含有量では所望の効果が得られず、0.60
％を超えて含有すると熱間加工性の劣化をきたす。従っ
て、これらの合金元素を１種以上添加する場合は、Ｎ
ｉ：0.01〜0.60％、Ｃｕ：0.05〜0.60％の含有量とする
のがよい。なお、ＮｉおよびＣｕは必要に応じて１種以
上添加することができるが、ＮｉにはＣｕによる熱間加
工性の劣化を防止する作用もあるので、Ｃｕを添加する
場合にはＮｉも同時に添加するほうが望ましい。Ni and Cu: Since Ni and Cu have the effect of improving strength and toughness, if higher strength and toughness are required, one or more of them may be added as necessary. However, in the case of Ni, if the content is less than 0.01%, the desired effect cannot be obtained. If the content exceeds 0.60%, the cold workability is deteriorated. On the other hand, in the case of Cu
If the content is less than 0.05%, the desired effect cannot be obtained,
%, The hot workability deteriorates. Therefore, when one or more of these alloy elements are added, N
i: 0.01 to 0.60%, Cu: 0.05 to 0.60%. One or more of Ni and Cu can be added as necessary. However, since Ni also has an effect of preventing deterioration of hot workability due to Cu, when Cu is added, Ni is also added at the same time. It is better to do it.
【００３１】Ｂ）鋼の組織 上記の化学組成を有する鋼であっても、その組織がフェ
ライト、パーライト、高温ベイナイトといったいわゆる
高温変態生成物からなるものでは目的とする常温強度お
よび高温強度が得られない。常温強度が従来のボルトお
よびナット用鋼と同等以上で、高温強度、特に 600℃で
の耐力が45kgf/mm2 以上のものとするためには、焼入れ
および焼戻し処理して、鋼の組織を焼入れ焼戻し組織と
する必要がある。鋼の組織を焼入れ焼戻し組織とする際
の焼入れ処理は、熱間加工後の高温の鋼を直ちに急冷し
て焼入れするいわゆる直接焼入れ法によって行ってもよ
く、熱間加工後の高温の鋼を一旦室温まで冷却した後、
再加熱して焼入れする方法によって行ってもよい。B) Structure of Steel Even if the steel has the above-mentioned chemical composition, if the structure is composed of so-called high-temperature transformation products such as ferrite, pearlite, and high-temperature bainite, the desired ordinary-temperature strength and high-temperature strength can be obtained. Absent. At room temperature strength is equal to or more than the conventional bolts and steel nuts, high temperature strength, in order to particularly yield strength at 600 ° C. and 45 kgf / mm 2 or more things, and quenching and tempering treatment, quenching the steel structure It is necessary to have a tempered structure. The quenching treatment when the structure of the steel is quenched and tempered may be performed by a so-called direct quenching method in which the high-temperature steel after hot working is immediately quenched and quenched. After cooling to room temperature,
It may be performed by a method of reheating and quenching.
【００３２】[0032]
【実施例】表１に示す化学組成の鋼を通常の方法によっ
て溶製した。表１において、鋼Ａ〜Ｋは本発明鋼、鋼Ｌ
〜Ｐは成分のいずれかが本発明で規定する含有量の範囲
から外れた比較鋼である。EXAMPLES Steel having the chemical composition shown in Table 1 was melted by an ordinary method. In Table 1, steels A to K are steels of the present invention and steel L
-P is a comparative steel in which any of the components is out of the range of the content specified in the present invention.
【００３３】次いで、これらの本発明鋼および比較鋼を
連続鋳造法或いは造塊−分塊法によって鋼片となした
後、1200〜1250℃の温度に加熱してから、25mm径の丸棒
に熱間圧延し、一部のものは熱間圧延後、 920〜1020℃
の温度から直ちに焼入れを行った。他のものは熱間圧延
後、一旦室温まで冷却し、880 〜 950℃の温度に再加熱
して焼入れを行った。しかるのち、全ての丸棒に 420〜
680℃の温度で焼戻しを施し、その組織が焼入れ焼戻し
組織になるように調整した。Next, the steel of the present invention and the comparative steel were formed into steel slabs by a continuous casting method or an ingot-bulking method, and then heated to a temperature of 1200 to 1250 ° C., and then formed into a round bar having a diameter of 25 mm. Hot rolling, some after hot rolling, 920 ~ 2020 ℃
The quenching was performed immediately from the temperature. Others, after hot rolling, were once cooled to room temperature and reheated to a temperature of 880 to 950 ° C. for quenching. After a while, 420 ~
Tempering was performed at a temperature of 680 ° C., and the structure was adjusted so as to be a quenched and tempered structure.
【００３４】こうして得られた焼入れ焼戻し後の丸棒か
ら試験片を切り出し、常温および600℃における引張特
性を調査した。その結果を焼入れおよび焼戻し温度とと
もに表２に示す。Test pieces were cut out from the thus obtained quenched and tempered round bars, and the tensile properties at room temperature and 600 ° C. were examined. The results are shown in Table 2 together with the quenching and tempering temperatures.
【００３５】表２から本発明鋼は常温強度および高温強
度ともに良好な特性値を有しており、新耐火設計法に基
づく締結部材（ボルト、ナット）用鋼として優れた鋼で
あることがわかる。これに対して比較鋼は常温強度は本
発明鋼とほぼ同等であるが、高温強度が著しく低い。From Table 2, it can be seen that the steel of the present invention has good characteristic values at both ordinary temperature strength and high temperature strength, and is an excellent steel as a steel for fastening members (bolts and nuts) based on the new refractory design method. . On the other hand, the comparative steel has a normal temperature strength substantially equal to that of the steel of the present invention, but has a remarkably low high-temperature strength.
【００３６】[0036]
【表１】 [Table 1]
【００３７】[0037]
【表２】 [Table 2]
【００３８】[0038]
【発明の効果】以上説明したように、本発明鋼は高温特
性が著しく改善されている上に、常温強度も高いから、
新耐火設計法に基づく建築用耐火鋼材の締結のためのボ
ルトおよびナット用鋼として利用することができる。As described above, the steel of the present invention has remarkably improved high-temperature characteristics and high strength at normal temperature.
It can be used as bolt and nut steel for fastening building fire-resistant steel materials based on the new fire-resistant design method.
───────────────────────────────────────────────────── フロントページの続き (56)参考文献 特開 平５−51698（ＪＰ，Ａ) 特開 平２−170943（ＪＰ，Ａ) 特開 平２−163341（ＪＰ，Ａ) 特開 平２−217437（ＪＰ，Ａ) (58)調査した分野(Int.Cl.7，ＤＢ名) C22C 38/00 - 38/60 ──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-5-51698 (JP, A) JP-A-2-170943 (JP, A) JP-A-2-163341 (JP, A) JP-A-2-163 217437 (JP, A) (58) Fields investigated (Int. Cl. 7 , DB name) C22C 38/00-38/60
Claims (4)
％以下、Ｍｎ：0.40〜1.50％、Ｃｒ：0.45〜1.50％、Ｍ
ｏ：0.40〜1.00％、Ｖ：0.01〜0.25％、Ｎｂ： 0.005〜
0.15％、Ｔｉ： 0.005〜0.10％、Ａｌ： 0.005〜0.10％
を含有し、残部がＦｅおよび不可避不純物からなり、焼
入れ焼戻し組織を有する耐火性に優れたボルトおよびナ
ット用鋼。C .: 0.30 to 0.50% by weight, Si: 1.2% by weight
%, Mn: 0.40 to 1.50%, Cr: 0.45 to 1.50%, M
o: 0.40 to 1.00%, V: 0.01 to 0.25%, Nb: 0.005 to
0.15%, Ti: 0.005-0.10%, Al: 0.005-0.10%
And a balance of Fe and unavoidable impurities, and has a quenched and tempered structure and excellent fire resistance for bolts and nuts.
％で、0.0003〜0.0050％のＢおよび0.15％以下のＺｒの
うちの１種以上を含有し、焼入れ焼戻し組織を有する耐
火性に優れたボルトおよびナット用鋼。2. A refractory material having a quenched and tempered structure further comprising, in addition to the components of claim 1, at least one of 0.0003 to 0.0050% of B and 0.15% or less of Zr by weight. Excellent steel for bolts and nuts.
％で、0.01〜0.60％のＮｉおよび0.05〜0.60％のＣｕの
うちの１種以上を含有し、焼入れ焼戻し組織を有する耐
火性に優れたボルトおよびナット用鋼。3. A refractory having a quenched and tempered structure further comprising, in addition to the components of claim 1, at least one of 0.01 to 0.60% Ni and 0.05 to 0.60% Cu by weight. Steel for bolts and nuts with excellent properties.
％で、0.0003〜0.0050％のＢおよび0.15％以下のＺｒの
うちの１種以上と、0.01〜0.60％のＮｉおよび0.05〜0.
60％のＣｕのうちの１種以上を含有し、焼入れ焼戻し組
織を有する耐火性に優れたボルトおよびナット用鋼。4. The composition according to claim 1, further comprising at least one of 0.0003 to 0.0050% of B and 0.15% or less of Zr, 0.01 to 0.60% of Ni and 0.05 to 0.005% by weight. 0.
A steel for bolts and nuts containing one or more of 60% Cu and having a quenched and tempered structure and excellent in fire resistance.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3204083A JP3003303B2 (en) | 1991-08-14 | 1991-08-14 | Bolt and nut steel with excellent fire resistance |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3204083A JP3003303B2 (en) | 1991-08-14 | 1991-08-14 | Bolt and nut steel with excellent fire resistance |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0543981A JPH0543981A (en) | 1993-02-23 |
| JP3003303B2 true JP3003303B2 (en) | 2000-01-24 |
Family
ID=16484505
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP3204083A Expired - Lifetime JP3003303B2 (en) | 1991-08-14 | 1991-08-14 | Bolt and nut steel with excellent fire resistance |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3003303B2 (en) |
-
1991
- 1991-08-14 JP JP3204083A patent/JP3003303B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0543981A (en) | 1993-02-23 |
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