JP2669220B2 - Steel for bolts and nuts with excellent fire resistance - Google Patents
Steel for bolts and nuts with excellent fire resistanceInfo
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- JP2669220B2 JP2669220B2 JP25813391A JP25813391A JP2669220B2 JP 2669220 B2 JP2669220 B2 JP 2669220B2 JP 25813391 A JP25813391 A JP 25813391A JP 25813391 A JP25813391 A JP 25813391A JP 2669220 B2 JP2669220 B2 JP 2669220B2
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Description
【発明の詳細な説明】DETAILED DESCRIPTION OF THE INVENTION
【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 steel materials will increase 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。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.
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, the high temperature alloy steel bolt material specified in JIS G 4107 has the same room temperature characteristics as conventional high strength hexagon bolt (F10T), hexagon nut (F10) steel and high strength torcia type bolt (F10T) steel. Although it is shown, it does not have high temperature strength that can satisfy the new fireproof design method, and it is also difficult to apply it as a steel for fireproof 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。Under these circumstances, Japanese Patent Application 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
ット鋼よりも遙かに高い、 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. It has room temperature characteristics equivalent to those of hexagon bolts (F10T), hexagon nut (F10) steel, and high-strength torcia type bolt (F10T) steel, and its high-temperature characteristics during fire are much higher than those of these bolts and nut steels. An object of the present invention is to provide steel for bolts and nuts having a proof stress of 40 kgf / mm 2 or more 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およびＷ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) After adding appropriate amounts of Mo and W, C
The decrease in yield strength at high temperature is suppressed by adjusting the addition amount of.
【０００９】2) NbをCr、Mo、ＷおよびＢ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) By adding Nb together with Cr, Mo, W and B and adjusting the N content appropriately, the decrease in yield strength at high temperature 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、ＶおよびNi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層
抑制される。4) In addition to the above components, one of V and Ni
Addition of an appropriate amount of seeds or more further suppresses 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 has a gist for bolt and nut steel having the following chemical composition and structure.
【００１３】（Ｉ）重量％で、Ｃ：0.18〜0.33％、Si：
0.10〜0.50％、Mn：0.40〜1.30％、Cr：0.45〜1.50％、
Mo：0.25〜0.65％、Ｗ：0.05〜0.80％、Nb： 0.005〜0.
15％、Al： 0.005〜0.10％、Ｂ：0.0003〜0.0050％を含
有し、更に、Ｎを下記 (1)式で表されるＮ* として 0.0
05〜0.030 ％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) C: 0.18 to 0.33% by weight, Si:
0.10 to 0.50%, Mn: 0.40 to 1.30%, Cr: 0.45 to 1.50%,
Mo: 0.25 to 0.65%, W: 0.05 to 0.80%, Nb: 0.005 to 0.
15%, Al: 0.005 to 0.10%, B: 0.0003 to 0.0050%, and N is 0.0 as N * represented by the following formula (1).
A steel for bolts and nuts containing 0.05 to 0.030%, with the balance being Fe and inevitable impurities and having a quenched and tempered structure and excellent fire resistance.
【００１４】 Ｎ* ＝Ｎ(%) −｛Ｂ(%)/ 0.78 ｝ ・・・ (1) （II）上記（Ｉ）に記載の成分に加えて、更に、重量％
で、0.01〜0.15％のＶおよび0.10〜0.60％のNi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。N * = N (%)-{B (%) / 0.78} (1) (II) In addition to the components described in (I) above, further% by weight
A steel for bolts and nuts, which contains one or more of 0.01 to 0.15% V and 0.10 to 0.60% Ni and has a quenched and tempered structure and excellent 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（なお、
「％」は「重量％」を意味する）。The reasons for limiting the chemical composition and structure of the steel according to the present invention as described above will be described below.
"%" Means "% by weight").
【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0.18％未満では添加効果に乏しく、一方、Moお
よびＷとの共存下でＣ含有量が0.33％を超えるとかえっ
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0.18〜0.33％とした。A) Chemical composition of steel C: C is added to secure the desired strength, but if the content is less than 0.18%, the effect of addition is poor, while on the other hand, in the coexistence of Mo and W, C is contained. If the amount exceeds 0.33%, the proof stress at high temperatures is rather reduced, so the content was set to 0.18 to 0.33%.
【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0.10％未満では所望
の効果が得られず、0.50％を超えると靱性が劣化するの
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0.10〜0.50％とした。Si: Si is an element effective for deoxidizing steel and increasing strength, but if its content is less than 0.10%, the desired effect cannot be obtained, and if it exceeds 0.50%, the toughness only deteriorates. However, the cold workability also deteriorates, so the content was set to 0.10 to 0.50%.
【００１８】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、1.30％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, its content is 0.40
If it is less than 1.0%, 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 is increased, so the content was made 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、Nb、ＷおよびＢ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 an effect of improving room temperature strength and high temperature strength. In particular, the addition of Mo, Nb, W, and B significantly improves the high-temperature strength.
%, The desired effect cannot be obtained, and if it exceeds 1.50%, the cold workability deteriorates.
It was set 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、Nb、ＷおよびＢとの複合添加でそ
の効果が著しい。しかし、その含有量が0.25％未満では
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0.25〜0.65％とした。Mo: Mo is an element extremely effective in improving the high-temperature strength, and its effect is particularly remarkable when added in combination with Cr, Nb, W and B. However, if the content is less than 0.25%, the desired high temperature strength cannot be obtained, and if it exceeds 0.65%, the above effect is saturated, which is economically disadvantageous, so the content should be 0.25 to 0.65%. And
【００２１】Ｗ：Ｗは高温強度を向上させるのに有効な
元素であり、特に、Cr、Mo、NbおよびＢとの複合添加で
その効果が著しい。しかし、その含有量が0.05％未満で
は所望の高温強度が得られず、0.80％を超えると前記の
効果が飽和する上に冷間加工性が劣化し、経済的に不利
となるので、その含有量を0.05〜0.80％とした。W: W is an element effective for improving high temperature strength, and its effect is particularly remarkable when it is added in combination with Cr, Mo, Nb and B. However, if the content is less than 0.05%, the desired high-temperature strength cannot be obtained, and if it exceeds 0.80%, the above effects are saturated and the cold workability deteriorates, which is economically disadvantageous. The amount was 0.05-0.80%.
【００２２】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 improves the high-temperature strength by adding a small amount.
【００２３】特に、Cr、Mo、ＷおよびＢ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 0.005％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 high-temperature strength is remarkably improved by adding Cr, Mo, W and B in combination. To secure the effect, a content of 0.005% or more is required. But 0.15
% Does not only saturate the effect,
Since the hot workability and the cold workability are deteriorated, the content is set to 0.005 to 0.15%.
【００２４】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 0.0
05％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、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 is 0.0
If it is less than 05%, the desired effect cannot be obtained, and if it exceeds 0.10%, the effect is saturated, and on the contrary, the increase of inclusions causes flaws and deteriorates the toughness. Therefore, its content was made 0.005 to 0.10%.
【００２５】Ｂ：Ｂ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、Cr、Mo、Ｗ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0.00
03％未満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
るので、その含有量を0.0003〜0.0050％とした。B: B has the function of improving the room temperature strength and the high temperature strength. In particular, the addition of Cr, Mo, W and Nb significantly enhances the high-temperature strength.
If the content is less than 03%, the desired effect cannot be obtained. If the content exceeds 0.0050%, the toughness and high-temperature strength of the steel deteriorate, so the content was made 0.0003 to 0.0050%.
【００２６】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、Ｂとの結合力が強
い。Ｂと化合物を形成した残りのＮであるＮ* は下記
(1)式で表されるが、このＮ* としての含有量が 0.005
％未満では所望の効果が得られず、一方、低合金鋼にお
いて、Ｎ* として 0.030％を超えるＮ量を含有させるこ
とは難しい。そのため、本発明では、Ｎの含有量はＮ*
として 0.005〜0.030 ％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 has a strong binding force with B. The remaining N that formed the compound with B, N *, is
(1), the content as N * is 0.005
%, The desired effect cannot be obtained. On the other hand, it is difficult for low alloy steel to contain an N content exceeding 0.030% as N * . Therefore, in the present invention, the content of N is N *
As 0.005 to 0.030%.
【００２７】 Ｎ* ＝Ｎ(%) −｛Ｂ(%)/ 0.78 ｝ ・・・ (1) ＶおよびNi：Ｖには常温強度および高温強度を向上させ
る作用があり、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、Ｖの場
合には0.01％未満では所望の効果が得られず、0.15％を
超えるとその効果が飽和し、コストの上昇を招くのみな
らず、靭性の劣化をきたすので、Ｖを添加する場合は0.
01〜0.15％の含有量とするのがよい。一方、Niの場合に
も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。N * = N (%) − {B (%) / 0.78} (1) V and Ni: V has an effect of improving ordinary-temperature strength and high-temperature strength, and Ni has strength and toughness. If higher strength and toughness are required,
One or more may be added as necessary. However, in the case of V, if the content is less than 0.01%, the desired effect cannot be obtained, and if it exceeds 0.15%, the effect is saturated and not only the cost is increased, but also the toughness is deteriorated, so V is added. 0 in case.
The content is preferably from 01 to 0.15%. On the other hand, when Ni is less than 0.10%, its effect is poor, and when it exceeds 0.60, cold workability is deteriorated. Therefore, when Ni is added, the content should be 0.10 to 0.60%. Is good.
【００２８】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、
すなわち焼戻しマルテンサイト、焼戻しベイナイト（但
し、高温ベイナイトは除く）、またはこれらの混合組織
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. Tempered structure,
That is, it is necessary to use tempered martensite, tempered bainite (excluding high temperature bainite), or a mixed structure thereof.
【００２９】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 when the structure of the steel is changed to a quenched and tempered structure may be performed by a so-called direct quenching method in which the hot steel immediately after hot working is immediately cooled and quenched. It may be performed by a method of once cooling the high-temperature steel to room temperature, then reheating and quenching.
【００３０】[0030]
【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〜Ｇは本発明鋼、鋼Ｈ
〜Ｍ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 G are steels of the present invention and steels H
ＭM is a comparative steel in which one of the components is out of the range of the content specified in the present invention.
【００３１】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。Then, the steel of the present invention and the comparative steel were formed into a billet by a continuous casting method or an ingot-making method.
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.
【００３２】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.
【００３３】[0033]
【表１】 [Table 1]
【００３４】[0034]
【表２】 [Table 2]
【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 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 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]
【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.
【００３７】[0037]
Claims (2)
0.50％、Mn：0.40〜1.30％、Cr：0.45〜1.50％、Mo：0.
25〜0.65％、Ｗ：0.05〜0.80％、Nb： 0.005〜0.15％、
Al： 0.005〜0.10％、Ｂ：0.0003〜0.0050％を含有し、
更に、Ｎを下記 (1)式で表されるＮ* として 0.005〜0.
030 ％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。 Ｎ* ＝Ｎ(%) −｛Ｂ(%)/ 0.78 ｝ ・・・ (1)1. By weight%, C: 0.18-0.33%, Si: 0.10-
0.50%, Mn: 0.40-1.30%, Cr: 0.45-1.50%, Mo: 0.
25-0.65%, W: 0.05-0.80%, Nb: 0.005-0.15%,
Al: 0.005-0.10%, B: 0.0003-0.0050%,
Furthermore, N is 0.005 to 0, where N * is expressed by the following equation (1).
030%, with the balance being Fe and unavoidable impurities,
Steel for bolts and nuts with a hardened and tempered structure and excellent fire resistance. N * = N (%)-{B (%) / 0.78} ... (1)
％で、0.01〜0.15％のＶおよび0.10〜0.60％のNi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, containing, in addition to the components described in claim 1, one or more of 0.01 to 0.15% V and 0.10 to 0.60% Ni by weight. Steel for bolts and nuts with excellent properties.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP25813391A JP2669220B2 (en) | 1991-10-04 | 1991-10-04 | Steel for bolts and nuts with excellent fire resistance |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP25813391A JP2669220B2 (en) | 1991-10-04 | 1991-10-04 | Steel for bolts and nuts with excellent fire resistance |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0598389A JPH0598389A (en) | 1993-04-20 |
| JP2669220B2 true JP2669220B2 (en) | 1997-10-27 |
Family
ID=17315976
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP25813391A Expired - Fee Related JP2669220B2 (en) | 1991-10-04 | 1991-10-04 | Steel for bolts and nuts with excellent fire resistance |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2669220B2 (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE19942641A1 (en) * | 1999-08-30 | 2001-03-22 | Mannesmann Ag | Use of a steel alloy for the production of high-strength seamless steel pipes |
-
1991
- 1991-10-04 JP JP25813391A patent/JP2669220B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0598389A (en) | 1993-04-20 |
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