JP2551251B2 - Steel for bolts and nuts with excellent fire resistance - Google Patents
Steel for bolts and nuts with excellent fire resistanceInfo
- Publication number
- JP2551251B2 JP2551251B2 JP3060634A JP6063491A JP2551251B2 JP 2551251 B2 JP2551251 B2 JP 2551251B2 JP 3060634 A JP3060634 A JP 3060634A JP 6063491 A JP6063491 A JP 6063491A JP 2551251 B2 JP2551251 B2 JP 2551251B2
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- strength
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- nuts
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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40kgf/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 a bolt and nut steel used in a building structure. More specifically, it is a high strength hexagon bolt (F10T), hexagon nut (F10) (JIS B 118) at room temperature.
6) Steel for bolts and nuts, which has the same characteristics as steel and high-strength torcia bolt (F10T) (JSS II 09) steel, and has a proof stress of 40 kgf / mm 2 or more at high temperatures, especially at 600 ° C. 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
However, even if a fire occurs in a building, the temperature of these steels will be reduced to 350 ° C.
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 technical development project "Development of fire protection design method for buildings" carried out by the Ministry of Construction from 1976 to 1986, "stability at fire" was confirmed by numerical simulation and experiment. If this is done, it becomes possible to reduce the coating thickness of the refractory material and to use the steel frame without coating, and the degree of freedom in selecting the refractory construction method in steel frame construction has been greatly improved compared to the conventional one. That is, according to this new fireproof design method, it becomes possible to reduce or omit the fireproof coating required by law by using steel materials excellent in high temperature strength, and it is expected to reduce the construction cost and man-hours of steel frame construction. 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とし
ては適用が難しい。However, the well-known heat-resistant steel materials represented by stainless steel and alloy tool steels for hot molds are excellent in high temperature strength, but are too high in room temperature strength and poor in workability.
The price is also very high, so it is difficult to apply as a building structure from the economical aspect.
【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。Under these circumstances, Japanese Patent Laid-Open No. 2-247355 proposes bolts and nuts having excellent high-temperature characteristics and economical manufacturing methods thereof as fastening members based on the new fireproof design method. . However, even the bolts and nuts of the present invention have a proof stress at 600 ° C. of only about 35.8 kgf / mm 2 at most, and it cannot be said that the bolts and nuts for building structures have sufficient high temperature proof stress.
【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
ット鋼よりも遥かに高い、 600℃で40kgf/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。DISCLOSURE OF THE INVENTION An object of the present invention is to improve the high-temperature yield strength of steel for bolts and nuts, and more specifically, to consolidate fire-resistant steel materials for construction based on the new fire-resistant design method. Hexagon bolt (F10T), hexagon nut (F10) steel shows the same room temperature characteristics as steel and high-strength Torsia type bolt (F10T) steel, and its high temperature characteristics during fire are much higher than those of these bolts and nut steels. To provide steel for bolts and nuts with a proof stress of 40 kgf / mm 2 or more.
【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。The present inventor has obtained the following findings as a result of researching the chemical composition and structure of steel in order to achieve the above-mentioned object.
【０００８】1) Mo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 adding an appropriate amount of Mo and then adjusting the amount of C added, a decrease in yield strength at high temperatures can be suppressed.
【０００９】2) NbをCrおよびMoとともに複合添加し、
且つＮ量を適正に調整することにより、高温における耐
力の低下が著しく抑制される。2) Nb is added together with Cr and Mo,
Moreover, by appropriately adjusting the N content, the decrease in yield strength 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 are improved by appropriately adjusting the contained components and then changing the steel structure to a quenched and tempered structure.
【００１１】4) 上記の成分に加えて、Niを適正量添加
すると、高温での耐力の低下が一層抑制される。4) Addition of an appropriate amount of Ni in addition to the above components will further suppress the decrease in yield strength at high temperatures.
【００１２】上記知見に基づく本発明は下記の化学組成
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 is summarized by bolt and nut steels having the following chemical compositions and structures.
【００１３】(I)重量％で、Ｃ：0.20％を超え0.30％未
満、Si：0.20％を超え0.50％まで、Mn：0.40〜1.30％、
Cr：0.45〜1.50％、Mo：0.30％を超え0.65％まで、Nb：
0.005〜0.15％、Al：0.005 〜0.10％、Ｎ：0.005 〜
0.030％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: more than 0.20% and less than 0.30%, Si: more than 0.20% and up to 0.50%, Mn: 0.40 to 1.30%,
Cr: 0.45 to 1.50%, Mo: over 0.30% to 0.65%, Nb:
0.005-0.15%, Al: 0.005-0.10%, N: 0.005-
Steel for bolts and nuts that contains 0.030%, the balance consisting of Fe and unavoidable impurities, and has a quenched and tempered structure with excellent fire resistance.
【００１４】(II) 上記(I) に記載の成分に加えて更
に、0.10〜0.60重量％のNi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) A steel for bolts and nuts which, in addition to the components described in (I) above, further contains 0.10 to 0.60% by weight of Ni and has a quenched and tempered structure and which is excellent in fire resistance.
【００１５】[0015]
【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 reason for limiting the chemical composition and structure of steel in the present invention as described above will be explained below.
【００１６】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0.20％以下では添加効果に乏しく、一方、Moの共存
下でＣ含有量が0.30％以上になるとかえって高温での耐
力が低下することになるので、その含有量を0.20％を超
え0.30％未満とした。A) Chemical composition of steel C: C is added to secure the desired strength, but if the content of C is 0.20% or less, the effect of addition is poor, while the content of C in the presence of Mo is 0.30. %, The yield strength at high temperature will rather decrease, so the content was made more than 0.20% and less than 0.30%.
【００１７】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
が、その含有量が0.20％以下では所望の効果が得られ
ず、0.50％を超えると靭性が劣化するのみならず、冷間
加工性も劣化するようになるので、その含有量を0.20％
を超え0.50％までとした。Si: Si is an element effective for deoxidizing steel and increasing strength, but if its content is 0.20% or less, the desired effect cannot be obtained, and if it exceeds 0.50%, the toughness only deteriorates. Not only that, cold workability also deteriorates, so its content is 0.20%.
Over 0.50%.
【００１８】Mn： Mnは脱酸のほか強度および靭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、1.30％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0.40〜1.30％とした。Mn: Mn is an element effective for securing strength and toughness in addition to deoxidation. However, if the content is less than 0.40%, the desired strength cannot be obtained, and if it exceeds 1.30%, the effect of improving the strength and toughness is saturated, and only the cost increases, so the content is 0.40 to 1.30. %.
【００１９】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およびNb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 room temperature strength and high temperature strength.
In particular, the combined addition of Mo and Nb remarkably improves the high temperature strength, but if the content is less than 0.45% the desired effect is not obtained, and if it exceeds 1.50% the cold workability deteriorates. , Its content was 0.45 to 1.50%.
【００２０】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およびNbとの複合添加でその効果が著しい。しかし、
その含有量が0.30％以下では所望の高温強度が得られ
ず、0.65％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0.30％を超え0.
65％までとした。Mo: Mo is an element that is extremely effective in improving high temperature strength.
The effect is remarkable when combined with Cr and Nb. But,
When the content is 0.30% or less, the desired high temperature strength cannot be obtained, and when it exceeds 0.65%, the above effect is saturated, which is economically disadvantageous, so the content exceeds 0.30% and 0.
Up to 65%.
【００２１】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
温強度を向上させる。Nb: Nb is an important element in the present invention, and its addition at a trace amount improves the high temperature strength.
【００２２】特に、CrおよびMoとの複合添加で高温強度
を著しく向上させる。その効果を確保するためには 0.0
05％以上の含有量を必要とする。しかし、0.15％を超え
て含有してもその効果は飽和するのみならず、熱間加工
性および冷間加工性を劣化させることになるので、その
含有量を 0.005〜0.15％とした。In particular, the combined addition of Cr and Mo significantly improves the high temperature strength. 0.0 to secure the effect
A content of 05% or more is required. However, if the content exceeds 0.15%, not only the effect is saturated, but also the hot workability and cold workability are deteriorated, so the content was made 0.005 to 0.15%.
【００２３】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％を超えて含有しても
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、靭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 in stabilizing and homogenizing deoxidation of steel. However, if the content is less than 0.005%, the desired effect cannot be obtained, and if it exceeds 0.10%, the effect is saturated, and conversely, the increase in inclusions causes flaws and toughness. Therefore, its content was set to 0.005 to 0.10%.
【００２４】Ｎ： Ｎは本発明鋼の成分系では高温強度の向上に寄与する有
効な元素であるが、その含有量が 0.005％未満では所望
の効果が得られないので、下限を0.005 ％とした。一
方、低合金鋼において 0.030％を超えるＮ量を含有させ
ることは難しいので、上限を 0.030％とした。N: N is an effective element that contributes to the improvement of high temperature strength in the component system of the steel of the present invention, but if its content is less than 0.005%, the desired effect cannot be obtained, so the lower limit is made 0.005%. did. On the other hand, it is difficult to make the low alloy steel contain N in excess of 0.030%, so the upper limit was made 0.030%.
【００２５】Ni： Niには強度と靱性を向上させる作用があるので、より以
上の高強度や靭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、0.10％未満ではその効
果に乏しく、0.60％を超えると冷間加工性の劣化をきた
すようになるので、Niを添加する場合は0.10〜0.60％の
含有量とするのがよい。Ni: Ni has the effect of improving strength and toughness, so if higher strength and toughness are required, 1
You may add 1 or more types. However, if it is less than 0.10%, its effect is poor, and if it exceeds 0.60%, cold workability is deteriorated. Therefore, when Ni is added, the content is preferably 0.10 to 0.60%.
【００２６】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40kgf/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。B) Steel Microstructure Even if the steel has the above chemical composition, if the microstructure consists of so-called high temperature transformation products such as ferrite, pearlite and high temperature bainite, the desired room temperature strength and high temperature strength can be obtained. Absent. In order to have room temperature strength equal to or higher than that of conventional bolt and nut steels, and high temperature strength, especially proof stress at 600 ° C of 40kgf / mm 2 or more, quench and temper the steel structure to quench. A tempered structure is required.
【００２７】なお、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。The quenching treatment for making the structure of the steel into a quenched and tempered structure may be carried out by a so-called direct quenching method in which the high temperature steel after hot working is immediately quenched and quenched. Alternatively, the high temperature steel may be once cooled to room temperature, then reheated and quenched.
【００２８】[0028]
【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〜Ｆは本発明鋼、鋼Ｇ
〜Ｋ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。EXAMPLE Steels having the chemical compositions shown in Table 1 were melted by a usual method. In Table 1, steels A to F are steels of the present invention and steels G
K is a comparative steel in which any of the components is out of the range of the content specified in the present invention.
【００２９】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、 850〜930 ℃の温度に再加熱して焼入
れを行った。しかるのち、全ての丸棒を 420〜 680℃の
温度で焼戻しを行い、その組織が焼入れ焼戻し組織にな
るように調整した。Next, these invented steels and comparative steels were made into billets by a continuous casting method or an ingot making method, and then 1200
After heating to a temperature of 11250 ° C., it was hot-rolled into a round bar having a diameter of 25 mm. Others, after hot rolling, were once cooled to room temperature and then reheated to a temperature of 850 to 930 ° C. for quenching. After that, all the round bars were tempered at a temperature of 420 to 680 ° C. and adjusted so that the structure became a quenched and tempered structure.
【００３０】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。A test piece was cut out from the round bar after quenching and tempering thus obtained, and the tensile properties at room temperature and 600 ° C. were investigated. The results are shown in Table 2 together with the quenching and tempering temperatures.
【００３１】[0031]
【表１】 [Table 1]
【００３２】[0032]
【表２】 [Table 2]
【００３３】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 in both room temperature strength and high temperature strength, and is an excellent steel for fastening members (bolts, nuts) based on the new fireproof design method. Recognize. On the other hand, the comparative steel has almost the same room temperature strength as the steel of the present invention, but the high temperature strength is extremely low.
【００３４】[0034]
【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.
Claims (2)
Si：0.20％を超え0.50％まで、Mn：0.40〜1.30％、Cr：
0.45〜1.50％、Mo：0.30％を超え0.65％まで、Nb：0.00
5 〜0.15％、Al：0.005 〜0.10％、Ｎ：0.005 〜 0.030
％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。1. C: more than 0.20% and less than 0.30% by weight,
Si: over 0.20% to 0.50%, Mn: 0.40 to 1.30%, Cr:
0.45 to 1.50%, Mo: 0.30% to 0.65%, Nb: 0.00
5 to 0.15%, Al: 0.005 to 0.10%, N: 0.005 to 0.030
%, The balance is Fe and unavoidable impurities, and a steel for bolts and nuts with a hardened and tempered structure and excellent fire resistance.
〜0.60重量％のNi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. In addition to the components of claim 1, 0.10
Steel for bolts and nuts containing ~ 0.60% by weight of Ni and having a quenched and tempered structure and excellent fire resistance.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3060634A JP2551251B2 (en) | 1991-03-26 | 1991-03-26 | Steel for bolts and nuts with excellent fire resistance |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3060634A JP2551251B2 (en) | 1991-03-26 | 1991-03-26 | Steel for bolts and nuts with excellent fire resistance |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0551698A JPH0551698A (en) | 1993-03-02 |
| JP2551251B2 true JP2551251B2 (en) | 1996-11-06 |
Family
ID=13147944
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP3060634A Expired - Fee Related JP2551251B2 (en) | 1991-03-26 | 1991-03-26 | Steel for bolts and nuts with excellent fire resistance |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2551251B2 (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0585889U (en) * | 1993-03-23 | 1993-11-19 | 金井 宏之 | Interior material |
| KR102117401B1 (en) * | 2018-08-21 | 2020-06-01 | 주식회사 포스코 | High-strength wire rod with excellent hydrogen brittleness resistance, steel for volt using the same, and methods for manufacturing thereof |
| CN116024499B (en) * | 2022-12-28 | 2024-06-25 | 燕山大学 | Steel for 10.9-grade bolt resistant to hydrogen-induced delayed fracture and preparation method of 10.9-grade bolt |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS59107063A (en) * | 1982-12-10 | 1984-06-21 | Daido Steel Co Ltd | Wire rod for bolt and its production |
| JPS6164815A (en) * | 1984-09-03 | 1986-04-03 | Sumitomo Metal Ind Ltd | Manufacture of high strength steel excellent in delay breakdown resistance |
| JPS6293343A (en) * | 1985-10-17 | 1987-04-28 | Daido Steel Co Ltd | Non-heattreated steel wire |
| JPS63161117A (en) * | 1986-12-24 | 1988-07-04 | Kobe Steel Ltd | Production of hot rolled steel products having high strength and high toughness |
| JPH02217437A (en) * | 1989-02-20 | 1990-08-30 | Sumitomo Metal Ind Ltd | Steel for cold working |
-
1991
- 1991-03-26 JP JP3060634A patent/JP2551251B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0551698A (en) | 1993-03-02 |
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|---|---|---|---|
| LAPS | Cancellation because of no payment of annual fees |