JPH0739608B2 - Manufacturing method of steel for steel construction with low elastic modulus decrease at high temperature - Google Patents
Manufacturing method of steel for steel construction with low elastic modulus decrease at high temperatureInfo
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- JPH0739608B2 JPH0739608B2 JP1077614A JP7761489A JPH0739608B2 JP H0739608 B2 JPH0739608 B2 JP H0739608B2 JP 1077614 A JP1077614 A JP 1077614A JP 7761489 A JP7761489 A JP 7761489A JP H0739608 B2 JPH0739608 B2 JP H0739608B2
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Description
【発明の詳細な説明】 （産業上の利用分野） 本発明は鉄骨建築物に用いられる鋼材、特に火災等の罹
災時において鋼材の温度が上昇しても弾性率の低下が少
ない鉄骨建築用鋼材、の製造方法に関する。DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to a steel material used for a steel building, particularly a steel material for a steel building in which the elastic modulus is less likely to decrease even when the temperature of the steel rises during a disaster such as a fire. , A manufacturing method of.
（従来の技術） 例えば、超高層ビルをはじめとする鉄骨建築物が近年益
々増加する傾向にあるが、これは鉄骨が大型の構造物を
造るのに適していること、および柱や梁を小さくするこ
とができるので、居住面積を大きくとることができるこ
となどの利点を有するからである。(Prior Art) For example, steel-framed buildings such as skyscrapers have tended to increase in recent years. This is because steel is suitable for building large structures, and columns and beams are small. This is because it has advantages such as a large living area.
従来、鉄骨建築物用の鋼材には、JIS G3101 SS41、同G3
106 SM50で規定されている鋼材が使用されており、この
ような鋼材は、圧延まま或いは圧延後に焼準処理を施し
て製造されている。また、近年では、圧延後に加速冷却
を施して製造される場合もあり、従来のもの（SM50R、S
M50N）に対してSM50TMCと称されている。Conventionally, JIS G3101 SS41 and G3 are the steel materials for steel frame buildings.
The steel material specified by 106 SM50 is used, and such steel material is manufactured by normalizing treatment as it is after rolling or after rolling. In recent years, it may be manufactured by subjecting it to accelerated cooling after rolling.
M50N) is referred to as SM50TMC.
ところで、このような鉄骨建築物用の鋼材については、
これまで建築基準法により耐火工法が一律に厳しく定め
られていたが、昭和57〜61年の建設省総合技術開発プロ
ジェクト「建築物の防火設計法の開発」の成果により、
火災時の構造安定性が数値シミュレーション及び実験で
確認できれば耐火物の被覆厚さを薄くすること、もしく
は耐火物を被覆することなく使用することが可能とな
り、耐火工法の自由度が大幅に拡大された。By the way, regarding steel materials for such steel structures,
Until now, the fire-resistant construction method has been set strictly by the Building Standards Law uniformly, but due to the results of the Ministry of Construction comprehensive technology development project "Development of fire protection design method for buildings" in 1982-1976,
If the structural stability during a fire can be confirmed by numerical simulations and experiments, it will be possible to reduce the coating thickness of the refractory or use it without coating the refractory, greatly expanding the flexibility of the refractory construction method. It was
しかし、鉄骨建築物用として現在用いられている前記の
鋼材では、火災時に高温にさらされて、例えば鋼材温度
が600℃を超える高温になると強度が著しく低下し、火
災時の構造安定性を保証することができないため、実際
には耐火物を被覆する、例えばロックウールを吹き付け
ることで火災時における鋼材の温度上昇を防いでいる。However, in the above steel materials currently used for steel structures, the strength is remarkably reduced when exposed to high temperatures during a fire, for example, when the steel temperature exceeds 600 ° C, and structural stability during a fire is guaranteed. Therefore, in practice, a refractory is coated, for example, rock wool is sprayed to prevent the temperature of the steel material from rising during a fire.
このロックウールを吹き付ける耐火工法は、安価にでき
る利点があるものの、建築現場では吹き付け時の飛散を
防止するための養生シートをめぐらして被覆作業を施す
必要があり、工期の延長につながるばかりでなく、周囲
の環境を損ねるといった施工上の問題を有していた。Although this fireproof method of spraying rock wool has the advantage of being inexpensive, at the construction site it is necessary to cover the curing sheet to prevent scattering during spraying, and to perform coating work, which not only leads to an extension of the construction period. However, there was a problem in construction such as damaging the surrounding environment.
他方、ロックウールに代えて耐火ボードを用いて鋼材表
面を被覆する方法もあるが、耐火ボードでは鋼材の耐面
が露出するので、耐面を何らかの方法で被覆してやる必
要がある。また、耐火ボードは高価である。On the other hand, there is also a method of coating the surface of the steel material with a refractory board in place of rock wool, but since the refractory surface of the steel material is exposed in the refractory board, it is necessary to coat the surface with some method. Also, refractory boards are expensive.
このようなことから火災時に高温をさらされても強度の
低下しない鋼材、即ち、耐火物の被覆を軽減或いは省略
することができる高温強度に優れた鋼材の開発が望まれ
ている。しかし、単に高温強度に優れたものであっても
鉄骨用建築物の構造用部材として使用するには問題があ
る。鉄骨建築用鋼材は柱や梁にも使用されるので、高温
において柱や梁が座屈しない性能が必要であり、また優
れた溶接性も必須である。For this reason, it is desired to develop a steel material that does not deteriorate in strength even when exposed to high temperatures during a fire, that is, a steel material that is excellent in high-temperature strength and that can reduce or omit coating of refractory material. However, even if it is simply excellent in high temperature strength, there is a problem in using it as a structural member of a steel frame building. Since steel materials for steel construction are also used for columns and beams, it is necessary that the columns and beams do not buckle at high temperatures, and that excellent weldability is also essential.
（発明が解決しようとする課題） 本発明の課題は、耐火物の被覆を軽減或いは省略するこ
とができる高温での強度に優れ、且つ座屈の発生を抑え
るのに有効な高温における弾性率の低下の少なく、さら
に溶接性にも優れた鉄骨建築用鋼材を得ることにある。(Problems to be Solved by the Invention) An object of the present invention is to improve the elasticity at high temperature, which is excellent in strength at high temperature where coating of a refractory can be reduced or omitted and which is effective in suppressing buckling. The purpose of the present invention is to obtain a steel building steel material that is less likely to deteriorate and has excellent weldability.
具体的には、本発明の目的は室温での機械的性質が従来
使用されている鋼材（例えばJIS G3101 SS41、同G3106
SM50で規定する鋼材）と同等の性能を有し、しかも600
℃における機械的性質が室温における目標値の７割以上
であり、弾性率が15000kgf/mm2以上の性能を有する鉄骨
建築用鋼材を製造する方法を提供することにある。Specifically, the object of the present invention is to use steel materials whose mechanical properties at room temperature are conventionally used (for example, JIS G3101 SS41 and G3106).
It has the same performance as steel specified by SM50), and has 600
It is an object of the present invention to provide a method for producing a steel building steel product having mechanical properties at 70 ° C. of 70% or more of a target value at room temperature and an elastic modulus of 15000 kgf / mm 2 or more.
なお、本発明が特に600℃における弾性率が15000kgf/mm
2以上の鋼材の製造を目的とするのは、火災等の罹災時
において鋼材の温度が上昇しても、600℃における弾性
率が15000kgf/mm2以上であれば、鉄骨建築物の柱や梁と
しての使用条件において座屈することがないからであ
る。The present invention has a modulus of elasticity of 15000 kgf / mm especially at 600 ° C.
The purpose of manufacturing steel materials of 2 or more is that, even if the temperature of the steel materials rises in the event of a fire or other disaster, if the elastic modulus at 600 ° C is 15000 kgf / mm 2 or more, the columns and beams of steel building This is because it will not buckle under the conditions of use.
（課題を解決するための手段） 本発明者は、上記目的を達成するために鋼材の組成およ
び製造プロセスを含む全般について、詳細に検討を行っ
た結果、下記の知見を得た。即ち、 （ａ）高温における強度および弾性率を上昇させるに
は、CrおよびMoを添加するのが有効である。また、Ｖ、
Cu、Ni、Ti、Ｂも強度および弾性率の一方又は両方を上
昇させる効果がある。(Means for Solving the Problems) The present inventor has obtained the following findings as a result of detailed examination of the overall composition including the composition and manufacturing process of the steel material in order to achieve the above object. That is, (a) it is effective to add Cr and Mo to increase the strength and elastic modulus at high temperature. Also, V,
Cu, Ni, Ti and B also have the effect of increasing one or both of strength and elastic modulus.
（ｂ）しかし、これらの元素の多量添加は高温における
強度および弾性率を上昇させても、室温の強度を著しく
上昇させるため、現行のSS41あるいはSM50で規定する強
度範囲の上限を超えてしまう。また、これら元素の多量
添加は、炭素当量を著しく高めて溶接割れ感受性を高め
る。従って、これらの元素は適正な範囲内で添加する必
要がある。(B) However, addition of a large amount of these elements significantly increases the strength at room temperature even if the strength and elastic modulus at high temperatures are increased, and thus exceeds the upper limit of the strength range specified by the current SS41 or SM50. Also, the addition of a large amount of these elements significantly increases the carbon equivalent and increases the susceptibility to welding cracks. Therefore, it is necessary to add these elements within an appropriate range.
（ｃ）室温における機械的性質を満たし、かつ高温にお
ける所望の特性を得るには、合金添加元素の調整だけで
は不足で、熱間圧延条件をも含めた熱処理条件の最適化
が必要である。(C) In order to satisfy the mechanical properties at room temperature and obtain the desired properties at high temperature, it is not enough to adjust the alloying additive element, and it is necessary to optimize the heat treatment conditions including the hot rolling conditions.
本発明は、上記の知見により完成したものであって、そ
の要旨は下記Ｉの素材鋼をIIのプロセスで製造する方法
にある。The present invention has been completed based on the above findings, and its gist resides in a method for producing the following raw material steel I by the process II.
Ｉ素材鋼 Ｉ−１（素材鋼１） 重量％で、C :0.03〜0.15％、Si:0.05〜0.90％、 Mn:0.30〜2.00％、P :0.005〜0.050％、 Cr:0.10〜2.00％、Mo:0.25〜0.70％、 Sol.Al:0.005〜0.10％、 を含有し、残部はFe及び不可避不純物からなり、かつ下
記式で示すPCMが0.30％以下の鋼。I material steel I-1 (material steel 1)% by weight, C: 0.03-0.15%, Si: 0.05-0.90%, Mn: 0.30-2.00%, P: 0.005-0.050%, Cr: 0.10-2.00%, Steel containing Mo: 0.25 to 0.70%, Sol.Al: 0.005 to 0.10%, the balance Fe and unavoidable impurities, and P CM shown by the following formula: 0.30% or less.
PCM（％）＝Ｃ＋（1/30）Si＋（1/20）Mn ＋（1/20）Cu＋（1/60）Ni＋（1/20）Cr ＋（1/15）Mo＋（１＋10）Ｖ＋5B・・・・
・ ここで、中の元素記号はその元素の含有量（重量％）
を表す。P CM (%) = C + (1/30) Si + (1/20) Mn + (1/20) Cu + (1/60) Ni + (1/20) Cr + (1/15) Mo + (1 + 10) V + 5B ・...
・ Here, the symbol of the element is the content of the element (% by weight)
Represents
Ｉ−２（素材鋼２） 重量％で、C :0.03〜0.15％、Si:0.05〜0.90％、 Mn:0.30〜2.00％、P :0.005〜0.050％、 Cr:0.10〜2.00％、Mo:0.25〜0.70％、 Sol.Al:0.005〜0.10％、 ならびに0.005〜0.15％のＶ、0.10〜0.50％のCu、0.10
〜0.50％のNi、0.005〜0.06％のTiおよび0.00015〜0.00
30％のＢの中から選ばれた１種以上を含有し、残部はFe
及び不可避不純物からなり、かつ前記式で示すPCMが
0.30％以下の鋼。I-2 (material steel 2)% by weight, C: 0.03 to 0.15%, Si: 0.05 to 0.90%, Mn: 0.30 to 2.00%, P: 0.005 to 0.050%, Cr: 0.10 to 2.00%, Mo: 0.25 ~ 0.70%, Sol.Al: 0.005 to 0.10%, and 0.005 to 0.15% V, 0.10 to 0.50% Cu, 0.10
~ 0.50% Ni, 0.005-0.06% Ti and 0.00015-0.00
Contains at least one selected from 30% B, with the balance being Fe
And the inevitable impurities, and P CM shown in the above formula
Steel less than 0.30%.
IIプロセス II−１（焼準−焼戻し） 1000℃以上1250℃以下の温度域で加熱後熱間加工し、次
いでAc3変態点以上1000℃以下の温度域に加熱後空冷し
て焼準し、600℃以上Ac1変態点以下の温度域で焼き戻
す。II Process II-1 (normalizing - tempering) 1000 and processed between heated after heat in a temperature range of ° C. or higher 1250 ° C. or less, then normalizing by heating after air cooling to Ac 3 transformation point or higher 1000 ° C. or less of the temperature range, Tempering is performed in the temperature range of 600 ° C or higher and Ac 1 transformation point or lower.
II−２（直接冷却−焼戻し） 1000℃以上1250℃以下の温度域で加熱後、下記式で示
すAr3変態点以上の温度域で熱間加工を終了し、熱間加
工後直ちに600℃以下の温度まで水冷以上の冷却速度で
冷却し、600℃以上Ac1変態点以下の温度域で焼き戻す。II-2 (Direct cooling-tempering) After heating in the temperature range of 1000 ℃ or more and 1250 ℃ or less, finish the hot working in the temperature range of Ar 3 transformation point or more shown by the following formula, and immediately after hot working 600 ℃ or less At a cooling rate of at least water, and tempering in the temperature range of 600 ° C or higher and Ac 1 transformation point or lower.
Ar3（℃）＝910−310C−80Mn−20Cu−55Ni ＋0.35（ｔ−８） ・・・・ この式中の元素記号はその元素の含有量（重量％）を
表し、ｔは板厚（mm）を表す。Ar 3 (° C) = 910-310C-80Mn-20Cu-55Ni +0.35 (t-8) ································· In this formula, the symbol represents the content (% by weight) of the element, t is the plate thickness (Mm)
II−３（熱間加工−高温巻取） 1000℃以上1250℃以下の温度域で加熱後、上記式で示
すAr3変態点以上の温度域で熱間加工を終了し、熱間加
工後直ちに600℃以上の温度からコイルに巻取る。II-3 (Hot working-high temperature winding) After heating in the temperature range of 1000 ° C or higher and 1250 ° C or lower, the hot working is finished in the temperature range of the Ar 3 transformation point or higher shown by the above formula, and immediately after the hot working. Wind the coil from a temperature of 600 ° C or higher.
本発明方法は、上記素材鋼１または２を、それぞれプロ
セスII−１〜II−３のいずれかで処理するものである。According to the method of the present invention, the raw steel 1 or 2 is treated by any one of processes II-1 to II-3.
（作用） 以下、本発明の鉄骨建築用鋼材の製造方法における素材
鋼の組成および加工プロセスの各条件につき詳細に説明
する。(Operation) The composition of the raw material steel and each condition of the working process in the method for manufacturing a steel material for steel construction of the present invention will be described in detail below.
まず、素材鋼の組成、PCMを前記のように限定する理由
を作用効果とともに説明する。なお、成分含有量の
「％」は全て「重量％」である。First, the reason for limiting the composition of the raw material steel and P CM as described above will be explained together with the action and effect. In addition, all "%" of component content is "weight%."
C:0.03〜0.15％ Ｃは強度を得るために必要な元素であり、そのためには
0.03％以上含有させる必要がある。しかし、必要以上の
含有は接触硬化性、溶接割れ感受性を高めるので0.15％
以下に抑えるべきである。C: 0.03 to 0.15% C is an element necessary for obtaining strength, and for that purpose,
It is necessary to contain 0.03% or more. However, if the content exceeds the necessary level, it increases contact hardening and weld cracking susceptibility, so 0.15%
Should be kept below.
Si:0.05〜0.90％ Siは製鋼時の脱酸剤として使用されるだけでなく、常温
および高温における強度を確保するのに有効な元素であ
る。このような効果を得るには0.05％以上含有させる必
要があるが、0.90％を超えて含有されると靱性が大幅に
低下するので、0.05〜0.90％の含有量とした。Si: 0.05 to 0.90% Si is an element effective not only as a deoxidizer during steel making but also for ensuring strength at room temperature and high temperature. To obtain such an effect, it is necessary to contain 0.05% or more. However, if the content exceeds 0.90%, the toughness is significantly reduced, so the content was made 0.05 to 0.90%.
Mn:0.30〜2.00％ Mnは強度および靱性を高めるために有効な元素であり、
そのためには0.30％以上含有させる必要がある。しか
し、2.00％を超えて含有されると強度および靱性の向上
効果が飽和するほか、溶接割れ感受性が著しく高くなる
ので、0.30〜2.00％の含有量とした。Mn: 0.30-2.00% Mn is an element effective for increasing strength and toughness,
Therefore, it is necessary to contain 0.30% or more. However, if the content exceeds 2.00%, the effect of improving strength and toughness saturates, and the weld cracking susceptibility becomes remarkably high, so the content was made 0.30 to 2.00%.
P:0.005〜0.050％ Ｐは不可避的不純物として鋼中に含まれる元素である
が、歪時効硬化特性を有するため高温域での強度を上昇
させる効果がある。この効果を得るには0.005％以上含
有させる必要があるが、0.050％を超えて含有されると
溶接割れ感受性が高くなるので、0.005〜0.050％の含有
量とした。P: 0.005 to 0.050% P is an element contained in steel as an unavoidable impurity, but since it has strain age hardening characteristics, it has the effect of increasing the strength at high temperatures. In order to obtain this effect, it is necessary to contain 0.005% or more, but if the content exceeds 0.050%, the weld cracking sensitivity becomes high, so the content was made 0.005 to 0.050%.
Cr:0.10〜2.00％ Crは高温における強度および弾性率を高めるのに有効な
元素である。そのためには、0.10％以上含有させる必要
があるが、2.00％を超えて含有させても効果が飽和する
とともに製造コストも上昇するので、その含有量を0.10
〜2.00％とした。Cr: 0.10 to 2.00% Cr is an element effective in increasing strength and elastic modulus at high temperatures. For that purpose, it is necessary to contain 0.10% or more, but if the content exceeds 2.00%, the effect will be saturated and the manufacturing cost will increase, so the content should be 0.10%.
~ 2.00%.
Mo:0.25〜0.70％ MoはCrと同じく高温における強度および弾性率を高める
効果がある。しかし、0.25％未満では前記の効果が小さ
く、0.70％を超えて含有されると室温における強度が必
要以上のレベルとなり、高温での焼き戻し処理を施す必
要が生じ、製造コストが上昇するので、0.05〜0.70％の
含有量とした。Mo: 0.25 to 0.70% Mo has the effect of increasing strength and elastic modulus at high temperatures, similar to Cr. However, if the content is less than 0.25%, the above effect is small, and if it is contained in excess of 0.70%, the strength at room temperature becomes an unnecessarily high level, and it becomes necessary to perform a tempering treatment at a high temperature, which increases the manufacturing cost. The content was set to 0.05 to 0.70%.
Sol.Al:0.005〜0.10％ Alは製鋼時に脱酸剤として使用されるとともに組織の細
粒化を通じて靱性を改善する効果がある。しかし、0.00
5％未満の含有量では前記効果が得られず、0.10％を超
えて含有されてもその効果は飽和し、且つ経済的に不利
を招くことになるので、Sol.Al含有量で0.005％〜0.10
％とした。Sol.Al: 0.005 to 0.10% Al is used as a deoxidizer during steel making and has the effect of improving toughness through grain refinement of the structure. But 0.00
If the content is less than 5%, the above effect cannot be obtained, and even if the content is more than 0.10%, the effect is saturated, and economically disadvantageous. 0.10
%.
素材鋼１は、上記成分の外、残部はFeおよび不可避不純
物からなる。不純物は、例えば、Ｓ、Sn、Sb等である。
これらはできるだけ低いことが望ましい。なお、Ｎ（窒
素）は、通常0.002〜0.005％程度、不純物として混入す
る。Raw material steel 1 is composed of Fe and inevitable impurities in the balance in addition to the above components. The impurities are, for example, S, Sn, Sb and the like.
It is desirable that these are as low as possible. In addition, N (nitrogen) is usually mixed as an impurity in an amount of about 0.002 to 0.005%.
PCM:0.30％以下 PCMは溶接割れ感受性を示す指数であり、この値が低い
ほど溶接予熱温度を低くして割れを生じることなく溶接
を行うことができる。このPCMは次式で表される。P CM : 0.30% or less P CM is an index showing the susceptibility to welding cracks. The lower this value is, the lower the preheating temperature of welding and the more welding can be performed without cracking. This P CM is expressed by the following equation.
PCM（％）＝Ｃ＋（1/30）Si＋（1/20）Mn ＋（1/20）Cu＋（1/60）Ni＋（1/20）Cr ＋（1/15）Mo＋（1/10）Ｖ＋5B・・・・ 前述のとおり、この式中の元素記号はその元素の含有量
（重量％）を表す。P CM (%) = C + (1/30) Si + (1/20) Mn + (1/20) Cu + (1/60) Ni + (1/20) Cr + (1/15) Mo + (1/10) V + 5B ... As mentioned above, the symbol of the element in this formula represents the content (% by weight) of the element.
一般に、鉄骨建築構造物の現場での溶接による組立に
は、溶接時に予熱処理を行うことは実際上不可能であ
る。前記PCMを0.30％以下に抑えておけば予熱なしでも
溶接割れを生じさせることなく溶接することができる。In general, it is practically impossible to perform a preheat treatment during welding for assembling a steel building structure by welding in the field. If the P CM is kept to 0.30% or less, welding can be performed without causing weld cracking without preheating.
素材鋼の２は、前記成分の外に、更にＶ、Cu、Ni、Tiお
よびＢの中から選ばれた１種以上の元素含み、式のP
CMが0.30％以下の鋼である。これらの元素を含む鋼材
は、さらに高靱性或いは高強度を要求される場合に有利
である。2 of the material steel further contains one or more elements selected from V, Cu, Ni, Ti and B in addition to the above components, and P of the formula
CM is steel with 0.30% or less. Steel materials containing these elements are advantageous when high toughness or high strength is required.
これら元素の具体的な作用効果は下記の通りである。Specific actions and effects of these elements are as follows.
V:0.005〜0.15％ Ｖは、鋼中で400℃を超える温度域にさらされると炭窒
化物を形成し、高温における強度と弾性率を上昇させる
作用がある。そのためには0.005％以上含有させるのが
よいが、0.15％を超えて含有させてもその効果は飽和
し、製造コストの上昇を招くだけであるから、Ｖを含有
させる場合は、その範囲は0.005〜0.15％とするのがよ
い。V: 0.005-0.15% V forms a carbonitride when exposed to a temperature range exceeding 400 ° C in steel, and has the effect of increasing the strength and elastic modulus at high temperatures. For that purpose, it is preferable to contain 0.005% or more, but even if the content exceeds 0.15%, the effect is saturated and the production cost is only increased. Therefore, when V is contained, the range is 0.005%. It is recommended to be ~ 0.15%.
Cu:0.10〜0.50％ Cuは高温強度を向上させるのに有効な元素であり、0.10
％以上含有させるのがよい。しかし、過度に添加すると
表面割れを生じて溶接割れを助長する傾向を招くので、
上限は0.50％にとどめるのがよい。従って、Cuを添加し
て高温強度向上を図る場合には、0.10〜0.50％の範囲で
含有させるのがよい。Cu: 0.10 to 0.50% Cu is an element effective in improving the high temperature strength.
% Or more is preferable. However, if added excessively, it will cause surface cracks and tend to promote welding cracks.
The upper limit should be 0.50%. Therefore, when Cu is added to improve the high temperature strength, it is preferable to contain Cu in the range of 0.10 to 0.50%.
Ni:0.10〜0.50％ NiもCuと同様に高温強度を向上させるのに有効な元素で
ある。このような効果を発揮させるには0.10％以上含ま
せるのがよいが、0.50％を超えて含有させてもその効果
が飽和し、製造コストの上昇を招くだけであるので、Ni
を添加する場合は0.10〜0.50％の範囲で含ませるのがよ
い。Ni: 0.10 to 0.50% Like Ni, Ni is also an effective element for improving high temperature strength. In order to exert such an effect, it is preferable to contain 0.10% or more, but even if it exceeds 0.50%, the effect is saturated and the production cost is only increased.
When added, it is preferable to add it in the range of 0.10 to 0.50%.
Ti:0.005〜0.06％ TiはフリーＮをTiNとして捕らえることにより次にに述
べる固溶ＢのBNとしての損失を防ぎ、Ｂ添加鋼の焼入性
を向上させる効果があるので、適用板厚が厚くなった時
の強度補償に有効な元素である。そのためには、0.005
％以上含ませるのがよいが、0.006％を超えて含有させ
ると母材の靱性が著しく損なわれるので、添加する場合
は0.005〜0.06％の範囲で含ませるのがよい。Ti: 0.005 to 0.06% Ti captures free N as TiN to prevent the loss of solute B as described below as BN and has the effect of improving the hardenability of B-added steel. It is an effective element for strength compensation when it becomes thick. For that, 0.005
%, But if it is added in excess of 0.006%, the toughness of the base material is significantly impaired. Therefore, when it is added, it is recommended to be added in the range of 0.005 to 0.06%.
B:0.00015〜0.0030％ Ｂは溶接性を大きく劣化させることなく強度を上昇させ
る効果がある。B: 0.00015-0.0030% B has the effect of increasing the strength without significantly deteriorating the weldability.
適用板厚が厚い場合には必要強度を満足させようとすれ
ば、前記のCuやMo等の合金元素を多量に添加すればよい
が、CuやMo等の多量添加は溶接性を阻害する。Ｂはこの
ような不利を招くことなく強度を高める効果があるの
で、添加する場合は0.00015％以上含有させるのがよ
い。しかし、0.0030％を超えて含有させると炭硼化物が
形成されて靭性が低下する。特に熱影響部の靱性の低下
が著しくなるので、上限は0.0030％とするのがよい。When the applicable plate thickness is large, in order to satisfy the required strength, a large amount of the above-mentioned alloy elements such as Cu and Mo may be added, but the large addition of Cu and Mo hinders weldability. B has the effect of increasing the strength without incurring such disadvantages, so when it is added, it is preferable to contain 0.00015% or more. However, if the content exceeds 0.0030%, carbon boride is formed and the toughness decreases. In particular, the toughness of the heat-affected zone significantly decreases, so the upper limit is preferably 0.0030%.
次にIIの加工プロセスについて説明する。Next, the processing process of II will be described.
II−１のプロセス 前記素材鋼１または２を、1000℃以上1250℃以下の温度
域で加熱後熱間加工し、次いで、Ac3変態点以上1000℃
以下の温度域に加熱後空冷して焼準し、600℃以上Ac1変
態点以下の温度域で焼き戻す方法である。Process of II-1 The material steel 1 or 2 is heated in a temperature range of 1000 ° C or higher and 1250 ° C or lower and then hot-worked, and then Ac 3 transformation point or higher and 1000 ° C or higher.
It is a method of heating in the following temperature range, air-cooling, normalizing, and tempering in the temperature range of 600 ° C. or higher and Ac 1 transformation point or lower.
熱間加工および熱処理条件を上記のように限定する理由
は下記の通りである。The reasons for limiting the hot working and heat treatment conditions as described above are as follows.
〔加熱温度:1000℃以上1250℃以下〕 素材鋼（例えばスラブ）を1000℃以上1250以下の温度域
で加熱する。加熱温度が1000℃未満では、Ｖを含む成分
系の鋼の場合にはＶの炭窒化物の固溶が図れないため、
これらの析出強化を利用することができなくなる。ま
た、Ｖなどの合金成分を含まない成分系の鋼でも1000℃
以上の温度域に加熱しておかないとCr、Mo等の合金成分
の均一固溶がはかれない。一方、1250℃を超える温度で
加熱すると圧延初期γ粒の粗大化につながり圧延材の靱
性を損なうことになる。[Heating temperature: 1000 ° C or more and 1250 ° C or less] Material steel (for example, slab) is heated in a temperature range of 1000 ° C or more and 1250 or less. If the heating temperature is less than 1000 ° C., the carbonitride of V cannot be formed as a solid solution in the case of a component steel containing V.
It becomes impossible to utilize these precipitation strengthening. In addition, even for component steels that do not contain alloy components such as V, 1000 ° C
If it is not heated in the above temperature range, a uniform solid solution of alloy components such as Cr and Mo cannot be obtained. On the other hand, heating at a temperature higher than 1250 ° C. leads to coarsening of γ grains in the initial stage of rolling, which impairs the toughness of the rolled material.
熱間加工は、加熱後の鋼を所定の板厚、形状まで加工し
て厚鋼板、ホットコイル、ロールＨ型鋼等にするもので
ある。In the hot working, the steel after heating is worked into a predetermined plate thickness and shape into a thick steel plate, a hot coil, a roll H-shaped steel and the like.
この製造方法のように熱間加工後、焼準および焼き戻し
の両工程をとる場合は、熱間加工は通常の条件でよい
が、後述する焼準処理を必要としない方法で厚鋼板、ロ
ールＨ型鋼もしくはホットコイル等を製造する場合は、
熱間圧延をAr3変態点以上で終了する必要がある。When both normalizing and tempering steps are performed after hot working as in this manufacturing method, hot working may be performed under normal conditions, but a thick steel plate and a roll may be manufactured by a method that does not require normalizing treatment described below. When manufacturing H-section steel or hot coils,
It is necessary to finish hot rolling at the Ar 3 transformation point or higher.
〔焼準温度：Ac3変態点以上1000℃以下〕 高温における強度あるいは弾性率を向上させるために
は、焼準処理を施して鋼中のCr、Mo、Ｖ等の元素を一旦
固溶させ、次の焼き戻し処理において微細な析出物とし
て析出させることが重要である。これら微細な析出物
は、高温での変形時に転位の移動を止めることを通じ
て、強度あるいは弾性率を上昇させる。[Normalizing temperature: Ac 3 transformation point or more and 1000 ° C. or less] In order to improve strength or elastic modulus at high temperature, normalizing treatment is performed to temporarily dissolve elements such as Cr, Mo and V in steel, It is important to precipitate as fine precipitates in the subsequent tempering treatment. These fine precipitates increase the strength or elastic modulus by stopping the movement of dislocations during deformation at high temperature.
そのためには、焼準はAc3変態点以上1000℃以下の温度
域にて加熱後空冷する条件で行う必要がある。焼準温度
がAc3変態点未満では、Cr、Mo、Ｖ等が充分に固溶しな
いので、強度あるいは弾性率を高めることができない。
一方、1000℃を超える温度で加熱すればオーステナイト
粒が粗大化して靱性が低下する。For that purpose, the normalization needs to be performed under the condition of heating in the temperature range of Ac 3 transformation point or more and 1000 ° C. or less and then air cooling. If the normalizing temperature is lower than the Ac 3 transformation point, Cr, Mo, V, etc. do not sufficiently form a solid solution, so that the strength or elastic modulus cannot be increased.
On the other hand, heating at a temperature higher than 1000 ° C. causes the austenite grains to become coarse and the toughness to decrease.
〔焼戻し温度:600℃以上Ac1変態点以下〕 600℃の温度における強度および弾性率を保証するため
には、600℃にさらされても上述した微細な析出物は安
定して微細なままの状態で存在していなければならな
い。そのためには、あらかじめ600℃以上の温度で焼き
戻し処理を行い、焼準で固溶させたCr、Mo、Ｖ等を微細
な析出物として析出させておく必要がある。また、更に
火災に遭遇して鋼材の温度が上昇しても、その温度が焼
戻し温度を超えなければ、高温強度の向上に効果のある
微細な析出物は安定に微細なままであるから、被災後も
再利用が可能である。しかし、Ac1変態点を超える温度
で焼き戻し処理するとα−γ変態を生じ、新しく形成さ
れたγ相中に前記の微細な析出物が再固溶し、高温域で
の強度あるいは弾性率を上昇させる効果が消失する。従
って、焼戻しは、600℃以上Ac1変態点以下の温度域で行
う必要がある。[Tempering temperature: 600 ° C or higher and Ac 1 transformation point or lower] In order to guarantee the strength and elastic modulus at a temperature of 600 ° C, the above-mentioned fine precipitates remain stable and fine even when exposed to 600 ° C. Must exist in a state. For that purpose, it is necessary to perform a tempering treatment in advance at a temperature of 600 ° C. or higher to deposit Cr, Mo, V, etc., which are solid-solved in the normalization, as fine precipitates. Moreover, even if the temperature of the steel material rises due to a further fire, if the temperature does not exceed the tempering temperature, the fine precipitates that are effective in improving the high temperature strength will remain stable and fine. It can be reused afterwards. However, when tempered at a temperature above the Ac 1 transformation point, α-γ transformation occurs, the fine precipitates described above are re-dissolved in the newly formed γ phase, and strength or elastic modulus at high temperature is The increasing effect disappears. Therefore, tempering needs to be performed in a temperature range of 600 ° C. or higher and Ac 1 transformation point or lower.
以上の製造方法は、熱間加工後に焼準および焼戻しの両
工程を採用したものである。この方法による場合は、熱
間加工後の冷却条件や巻取り温度などには特に制約はな
い。The above manufacturing method employs both normalizing and tempering steps after hot working. In the case of this method, there are no particular restrictions on the cooling conditions and the winding temperature after hot working.
II−２のプロセス 焼準および焼戻しの両工程を採用する上記の方法に代え
て、下記に述べる方法でも同様の鋼材を製造することが
できる。II-2 Process In place of the above method employing both normalizing and tempering steps, a similar steel material can be manufactured by the method described below.
即ち、素材鋼を前記と同じ温度域で加熱後、前記式で
示すAr3変態点以上の温度域で熱間加工を終了し、熱間
加工後直ちに600℃以下の温度まで水冷以上の冷却速度
で冷却し、前記と同じ条件で焼き戻しする方法である。That is, after heating the material steel in the same temperature range as above, finish the hot working in a temperature range of Ar 3 transformation point or higher shown in the above formula, and immediately after hot working, cooling rate of water cooling or higher to a temperature of 600 ° C or lower. It is a method of cooling with, and tempering under the same conditions as described above.
この製造方法において、熱間加工および冷却の各条件を
前記のように限定する理由は、次の通りである。In this manufacturing method, the reasons for limiting the conditions of hot working and cooling as described above are as follows.
〔熱間仕上温度：Ar3変態点以上〕 熱間圧延をAr3変態点未満の温度域で行うということ
は、フェライトが生成した温度域でも圧延することを意
味している。このような場合は、圧延集合組織が形成さ
れ圧延異方性が著しくなり、圧延方向と圧延方向に直角
な方向の機械的性質に差を生じる。更に、圧延材の板面
に並行にフェライトの脆化面である（100）面が形成さ
れることになり、板面に垂直方向の機械的性質も劣化す
ることになる。建築用の構造部材として使用される場
合、単に圧延方向のみが機械的性質に優れていれば良い
のではなく、機械的性質に異方性のないものが好まし
い。[Hot Finishing Temperature: Above Ar 3 Transformation Point] Performing hot rolling in a temperature range below the Ar 3 transformation point means rolling even in a temperature range in which ferrite is formed. In such a case, a rolling texture is formed and rolling anisotropy becomes remarkable, which causes a difference in mechanical properties between the rolling direction and the direction perpendicular to the rolling direction. Further, the (100) plane, which is the embrittlement surface of ferrite, is formed in parallel with the plate surface of the rolled material, and the mechanical properties in the direction perpendicular to the plate surface are also deteriorated. When used as a structural member for construction, it is not necessary that only the rolling direction has excellent mechanical properties, and it is preferable that the mechanical properties have no anisotropy.
熱間圧延を前記式で示すAr3変態点以上の温度域で終
えれば、上記のような問題が生じないので、仕上温度を
Ar3変態点以上とした。If the hot rolling is completed in the temperature range of the Ar 3 transformation point or higher shown by the above formula, the above problems do not occur, so the finishing temperature is
Ar 3 and above.
〔圧延後の冷却条件：水冷以上の冷却速度で600℃以下
まで冷却〕 これは、コイル巻取らない鋼材（厚鋼板、ロールＨ型
鋼）を製造する場合の条件である。[Cooling condition after rolling: cooling to 600 ° C or lower at a cooling rate of water cooling or higher] This is a condition for manufacturing a steel material (thick steel plate, roll H-shaped steel) that is not coiled.
圧延後の冷却速度及び冷却停止温度の制御は、得られる
組織の細粒化や高温における強度、弾性率の向上に寄与
する元素の固溶量の確保に重要な影響を及ぼすので、冷
却速度及び冷却停止温度は重要な意味をもつ。Control of the cooling rate and the cooling stop temperature after rolling has an important influence on securing the solid solution amount of elements contributing to the refinement of the obtained structure, the strength at high temperature, and the improvement of the elastic modulus. The cooling stop temperature has an important meaning.
即ち、水冷以上の冷却速度でかつ600℃以下まで強制的
に冷却しなければ、得られる組織の細粒化は達成できず
靱性の低下は避けられない。また、高温における強度お
よび弾性率を向上させるCr、Mo、Ｖの固溶量を確保する
ことができず、引き続いて行う600℃以上Ac1変態点以下
の温度での焼き戻し処理時に微細な析出物を形成するこ
とができないため、高温域の強度および弾性率を向上さ
せることができない。That is, unless the water is cooled at a cooling rate higher than or equal to 600 ° C., the grain refinement of the obtained structure cannot be achieved, and a decrease in toughness cannot be avoided. In addition, it is not possible to secure the solid solution amounts of Cr, Mo, and V that improve the strength and elastic modulus at high temperatures, and fine precipitation occurs during the subsequent tempering treatment at a temperature of 600 ° C. or higher and Ac 1 transformation point or lower. Since a substance cannot be formed, the strength and elastic modulus in the high temperature region cannot be improved.
なお、この冷却は圧延ラインでの水冷で行うのがよい。
この処理の後は、先に述べた600℃以上Ac1変態点以下の
温度域で焼き戻しを行う。Note that this cooling is preferably performed by water cooling in the rolling line.
After this treatment, tempering is performed in the above-mentioned temperature range of 600 ° C. or higher and Ac 1 transformation point or lower.
II−３のプロセス この方法は、II−２のプロセスと同じく前記式で示す
Ar3変態点以上の温度域で熱間加工を終了し、熱間加工
後直ちに600℃以上の温度からコイルに巻取る方法であ
る。巻取り温度を前記のように定めた理由は下記のとお
りである。II-3 process This method is similar to the process of II-2 and is represented by the above formula.
This is a method in which hot working is completed in a temperature range of the Ar 3 transformation point or higher, and the coil is wound from a temperature of 600 ° C. or higher immediately after hot working. The reason for setting the winding temperature as described above is as follows.
〔巻取り温度:600℃以上〕 Ac3変態点以上の温度域で熱間加工を終えた後、ホット
コイルに巻取る場合には600℃以上の温度で巻き取って
徐冷することが重要である。[Coiling temperature: 600 ° C or higher] After finishing hot working in the temperature range of Ac 3 transformation point or higher, it is important to wind at 600 ° C or higher and slowly cool when winding in a hot coil. is there.
600℃以上の温度で巻き取れば、鋼板はコイル状態で徐
冷させることになり、高温域における強度、弾性率向上
に効果をもつCr、Mo、Ｖの微細な析出物の形成が促進さ
れる。600℃未満の温度で巻取って徐冷しても微細な析
出物は形成されるが、600℃未満の温度で形成された析
出物は600℃以上の温度域にさらされると粗大化する傾
向が強く、この温度域での転移の移動を止めることがで
きないので、強度上昇あるいは弾性率の向上効果が得ら
れない。そのために巻取り温度は600℃以上とした。If rolled up at a temperature of 600 ° C or higher, the steel sheet will be gradually cooled in a coiled state, and the formation of fine precipitates of Cr, Mo, and V that have the effect of improving strength and elastic modulus in the high temperature range will be promoted. . Fine precipitates are formed even if wound at a temperature lower than 600 ° C and gradually cooled, but precipitates formed at a temperature lower than 600 ° C tend to coarsen when exposed to a temperature range of 600 ° C or higher. Is too strong to stop the movement of the transition in this temperature range, so that the effect of increasing the strength or improving the elastic modulus cannot be obtained. Therefore, the winding temperature was set to 600 ° C or higher.
巻取りの後は、特に焼き戻しを行う必要はない。After winding, it is not necessary to temper.
以下、実施例により本発明を更に説明する。The present invention will be further described below with reference to examples.
（実施例） 第１表に示す化学組成の鋼を溶製し、300mm厚の鋳片と
した後、第２表に示す条件で熱間加工および熱処理を行
い、厚鋼板もしくはホットコイルを製造した。(Example) A steel having the chemical composition shown in Table 1 was melted into a slab having a thickness of 300 mm, and then hot working and heat treatment were performed under the conditions shown in Table 2 to produce a thick steel plate or a hot coil. .
このようにして製造した厚鋼板およびホットコイルから
試験片を採取し、室温および600℃での強度（YS、T
S）、靱性（ｖE0）、弾性率（Ｅ）を調査した。さら
に、溶接性を調べるためＹ開先拘束割れ試験を実施し
た。これらの結果を同じく第２表に示す。Test pieces were taken from the thick steel plate and hot coil manufactured in this way, and the strength (YS, T
S), toughness (vE 0 ) and elastic modulus (E) were investigated. Furthermore, a Y-groove restraint cracking test was carried out to examine the weldability. The results are also shown in Table 2.
弾性率は熱間共振型弾性率測定装置を用いて測定した。
これは試験片を振動させ、固有振動数を求めて次式から
弾性率を測定するものである。The elastic modulus was measured using a hot resonance type elastic modulus measuring device.
In this method, the test piece is vibrated, the natural frequency is obtained, and the elastic modulus is measured from the following equation.
ｆ＝（1/2）×1/a・E/ρ ここで、ａ＝試験片長さ（cm）、ρ＝試験片見かけ密
度、ｆ＝固有振動数（S-1）、Ｅ＝弾性率（kgf/mm2）、
を意味する。f = (1/2) × 1 / a · E / ρ where a = length of test piece (cm), ρ = apparent density of test piece, f = natural frequency (S −1 ), E = elastic modulus ( kgf / mm 2 ),
Means
Ｙ開先拘束割れ試験は、各鋼板から斜めＹ開先拘束割れ
試験片（板厚25mm）を採取し、入熱量:17KJ/cmで手溶接
（電流170A、電圧25V、速度15cm/mim.）し、「表面割
れ」および「ルート割れ」の有無を調べた。このときの
判定基準は、予熱無しでもこのような割れが発生しなか
ったものを○、予熱温度を100℃以上としなければ割れ
発生を抑えることができなかったものを×とした。In the Y-groove restraint cracking test, diagonal Y-groove restraint cracking test pieces (plate thickness 25 mm) were taken from each steel plate and manually welded with a heat input of 17 KJ / cm (current 170 A, voltage 25 V, speed 15 cm / mim.). Then, the presence or absence of “surface crack” and “root crack” was examined. The criteria for judgment at this time were as follows: no cracking occurred even without preheating, and no cracking could be suppressed unless the preheating temperature was 100 ° C or higher.
なお、試験片の板厚については実施例の値と異なるが溶
接時の割れ性を評価する場合、鋼の成分で概ね評価する
ことができるため、本検討では板厚を25mmに揃えて実施
した。Although the plate thickness of the test piece is different from the value of the example, when evaluating the cracking property at the time of welding, it can be roughly evaluated by the composition of the steel, so in this study, the plate thickness was adjusted to 25 mm. .
第１表中に「本発明鋼」と記したのは、素材鋼の組成が
本発明で定める範囲内であって、適切な製造条件により
600℃での弾性率が15000kgf/mm2以上となり得るもので
ある。In Table 1, "inventive steel" means that the composition of the raw material steel is within the range defined by the present invention and
The elastic modulus at 600 ° C can be 15000 kgf / mm 2 or more.
第２表において、試験番号１〜３および試験番号12〜16
は本発明例である。本発明例のものは低温および600℃
での機械的性質はともに本発明が目標とする性能を満た
し、且つ溶接割れも発生していない。 In Table 2, test numbers 1 to 3 and test numbers 12 to 16
Is an example of the present invention. The examples of the present invention are at low temperature and 600 ° C
The mechanical properties of both satisfy the target performance of the present invention, and no weld cracking occurs.
これに対して、比較例の試験番号４〜６および試験番号
21〜24は、製造条件が本発明で規定する範囲外のもので
あり、試験番号７〜10および試験番号17〜20は、素材の
鋼が本発明で規定する範囲外のものである。この場合、
室温における機械的性質、600℃における機械的性質お
よび弾性率の少なくとも一つが、本発明で目標とする性
能を満たしていない。さらに、試験番号７および試験番
号９のものは、溶接時に100℃以上の温度に予熱しない
と割れを防止することができない。On the other hand, test numbers 4 to 6 and test numbers of Comparative Examples
21 to 24 are those whose manufacturing conditions are outside the range specified by the present invention, and test numbers 7 to 10 and test numbers 17 to 20 are those whose raw material steel is outside the range specified by the present invention. in this case,
At least one of the mechanical properties at room temperature, the mechanical properties at 600 ° C., and the elastic modulus does not satisfy the performance targeted in the present invention. Further, the test Nos. 7 and 9 cannot prevent cracking unless they are preheated to a temperature of 100 ° C. or higher during welding.
試験番号11および試験番号25は、従来鋼（SS41、SM50）
を用いて従来の方法で製造したものである。常温におけ
る特性には問題がないが、600℃における機械的性質お
よび弾性率のいずれもが、本発明で目標とする性能を満
たしていない。Test No. 11 and Test No. 25 are conventional steel (SS41, SM50)
Is manufactured by a conventional method using. There is no problem with the properties at room temperature, but neither the mechanical properties nor the elastic modulus at 600 ° C. satisfy the performance targeted by the present invention.
（発明の効果） 以上詳述したように、本発明方法で製造された鉄骨建築
用鋼材は、火災時において鋼材の温度が上昇しても、強
度および弾性率の低下が少ない。従って、耐火物の被覆
を軽減もしくは省略して使用することができる。また、
本発明方法によれば、このような鋼材を安定して製造す
ることができる。(Effects of the Invention) As described in detail above, the steel material for steel frame construction manufactured by the method of the present invention has little decrease in strength and elastic modulus even if the temperature of the steel material rises during a fire. Therefore, the refractory coating can be reduced or omitted before use. Also,
According to the method of the present invention, such a steel material can be stably manufactured.
Claims (6)
記式で示すPCMが0.30％以下である鋼を、1000℃以上1
250℃以下の温度域で加熱後熱間加工し、次いでAc3変態
点以上1000℃以下の温度域に加熱後空冷して焼準し、60
0℃以上Ac1変態点以下の温度域で焼き戻すことを特徴と
する高温での弾性率低下の少ない鉄骨建築用鋼材の製造
方法。 PCM（％）＝Ｃ＋（1/30）Si＋（1/20）Mn ＋（1/20）Cu＋（1/60）Ni＋（1/20）Cr ＋（1/15）Mo＋（１＋10）Ｖ＋5B・・・・
・ ここで、式中の元素記号はその元素の含有量（重量％）
を表す。1. By weight%, C: 0.03-0.15%, Si: 0.05-0.90%, Mn: 0.30-2.00%, P: 0.005-0.050%, Cr: 0.10-2.00%, Mo: 0.25-0.70% , Sol.Al: 0.005 to 0.10%, the balance consisting of Fe and unavoidable impurities, and the P CM expressed by the formula below is 0.30% or less.
After heating in the temperature range of 250 ℃ or less, hot working, then heating in the temperature range of Ac 3 transformation point or more and 1000 ℃ or less, air cooling and normalizing, 60
A method for manufacturing a steel building steel material with a small decrease in elastic modulus at high temperatures, characterized by tempering in a temperature range of 0 ° C or more and Ac 1 transformation point or less. P CM (%) = C + (1/30) Si + (1/20) Mn + (1/20) Cu + (1/60) Ni + (1/20) Cr + (1/15) Mo + (1 + 10) V + 5B ・...
-Here, the element symbol in the formula is the content (% by weight) of the element
Represents
〜0.50％のNi、0.005〜0.06％のTiおよび0.00015〜0.00
30％のＢの中から選ばれた１種以上を含有し、残部はFe
及び不可避不純物からなり、かつ下記式で示すPCMが
0.30％以下である鋼を、1000℃以上1250℃以下の温度域
で加熱後熱間加工し、次いでAc3変態点以上1000℃以下
の温度域に加熱後空冷して焼準し、600℃以上Ac1変態点
以下の温度域で焼き戻すことを特徴とする高温での弾性
率低下の少ない鉄骨建築用鋼材の製造方法。 PCM（％）＝Ｃ＋（1/30）Si＋（1/20）Mn ＋（1/20）Cu＋（1/60）Ni＋（1/20）Cr ＋（1/15）Mo＋（1/10）Ｖ＋5B・・・・・
ここで、式中の元素記号はその元素の含有量（重量％）
を表す。2. By weight%, C: 0.03-0.15%, Si: 0.05-0.90%, Mn: 0.30-2.00%, P: 0.005-0.050%, Cr: 0.10-2.00%, Mo: 0.25-0.70% , Sol.Al: 0.005-0.10%, as well as 0.005-0.15% V, 0.10-0.50% Cu, 0.10
~ 0.50% Ni, 0.005-0.06% Ti and 0.00015-0.00
Contains at least one selected from 30% B, with the balance being Fe
And the inevitable impurities, and P CM shown by the following formula
Steel that is 0.30% or less is heated in a temperature range of 1000 ° C or more and 1250 ° C or less and then hot-worked, and then heated to a temperature range of Ac 3 transformation point or more and 1000 ° C or less, air-cooled and normalized, and 600 ° C or more A method for manufacturing a steel building steel material with a small decrease in elastic modulus at high temperatures, characterized by tempering in a temperature range below the Ac 1 transformation point. P CM (%) = C + (1/30) Si + (1/20) Mn + (1/20) Cu + (1/60) Ni + (1/20) Cr + (1/15) Mo + (1/10) V + 5B ...
Here, the element symbol in the formula is the content (% by weight) of the element
Represents
記式で示すPCMが0.30％以下である鋼を、1000℃以上1
250℃以下の温度域で加熱後、下記式で示すAr3変態点
以上の温度域で熱間加工を終了し、熱間加工後直ちに、
600℃以下の温度まで水冷以上の冷却速度で冷却し、600
℃以上Ac1変態点以下の温度域で焼き戻すことを特徴と
する高温での弾性率低下の少ない鉄骨建築用鋼材の製造
方法。 PCM（％）＝Ｃ＋（1/30）Si＋（1/20）Mn ＋（1/20）Cu＋（1/60）Ni＋（1/20）Cr ＋（1/15）Mo＋（1/10）Ｖ＋5B・・・・ Ar3（℃）＝910−310C−80Mn−20Cu−55Ni ＋0.35（ｔ−８） ・・・・ ここで、および式中の元素記号はその元素の含有量
（重量％）を表し、式のｔは板厚（mm）を表す。3. By weight%, C: 0.03-0.15%, Si: 0.05-0.90%, Mn: 0.30-2.00%, P: 0.005-0.050%, Cr: 0.10-2.00%, Mo: 0.25-0.70% , Sol.Al: 0.005 to 0.10%, the balance consisting of Fe and unavoidable impurities, and the P CM expressed by the formula below is 0.30% or less.
After heating in a temperature range of 250 ° C. or lower, hot working is completed in a temperature range of Ar 3 transformation point or higher shown by the following formula, and immediately after hot working,
Cool to a temperature of 600 ° C or lower at a cooling rate of water cooling or higher, and
A method for producing a steel building steel material with a small decrease in elastic modulus at high temperatures, characterized by tempering in a temperature range of ℃ to Ac 1 transformation point. P CM (%) = C + (1/30) Si + (1/20) Mn + (1/20) Cu + (1/60) Ni + (1/20) Cr + (1/15) Mo + (1/10) V + 5B ... ・ Ar 3 (° C.) = 910−310C−80Mn−20Cu−55Ni +0.35 (t−8) ・ ・ ・ ・ where the element symbol in the formula is the content of the element (% by weight). ), And t in the formula represents the plate thickness (mm).
〜0.50％のNi、0.005〜0.06％のTiおよび0.00015〜0.00
30％のＢの中から選ばれた１種以上を含有し、残部はFe
及び不可避不純物からなり、かつ下記式で示すPCMが
0.30％以下である鋼を、1000℃以上1250℃以下の温度域
で加熱後、下記式で示すAr3変態点以上の温度域で熱
間加工を終了し、熱間加工後直ちに600℃以下の温度ま
で水冷以上の冷却速度で冷却し、600℃以上Ac1変態点以
下の温度域で焼き戻すことを特徴とする高温での弾性率
低下の少ない鉄骨建築用鋼材の製造方法。 PCM（％）＝Ｃ＋（1/30）Si＋（1/20）Mn ＋（1/20）Cu＋（1/60）Ni＋（1/20）Cr ＋（1/15）Mo＋（1/10）Ｖ＋5B・・・・ Ar3（℃）＝910−310C−80Mn−20Cu−55Ni ＋0.35（ｔ−８） ・・・・ ここで、および式中の元素記号はその元素の含有量
（重量％）を表し、式のｔは板厚（mm）を表す。4. By weight%, C: 0.03-0.15%, Si: 0.05-0.90%, Mn: 0.30-2.00%, P: 0.005-0.050%, Cr: 0.10-2.00%, Mo: 0.25-0.70% , Sol.Al: 0.005-0.10%, as well as 0.005-0.15% V, 0.10-0.50% Cu, 0.10
~ 0.50% Ni, 0.005-0.06% Ti and 0.00015-0.00
Contains at least one selected from 30% B, with the balance being Fe
And the inevitable impurities, and P CM shown by the following formula
Steel that is 0.30% or less is heated in the temperature range of 1000 ° C or more and 1250 ° C or less, then hot working is finished in the temperature range of Ar 3 transformation point or more shown by the following formula, and 600 ° C or less immediately after hot working. A method for producing a steel building steel material with a small decrease in elastic modulus at high temperature, which comprises cooling to a temperature at a cooling rate of water cooling or more and tempering in a temperature range of 600 ° C. or more and Ac 1 transformation point or less. P CM (%) = C + (1/30) Si + (1/20) Mn + (1/20) Cu + (1/60) Ni + (1/20) Cr + (1/15) Mo + (1/10) V + 5B ... ・ Ar 3 (° C.) = 910−310C−80Mn−20Cu−55Ni +0.35 (t−8) ・ ・ ・ ・ where the element symbol in the formula is the content of the element (% by weight). ), And t in the formula represents the plate thickness (mm).
記式で示すPCMが0.30％以下である鋼を、1000℃以上1
250℃以下の温度域で加熱後、下記式で示すAr3変態点
以上の温度域で熱間加工を終了し、熱間加工後直ちに60
0℃以上の温度からコイルに巻取ることを特徴とする高
温での弾性率低下の少ない鉄骨建築用鋼材の製造方法。 PCM（％）＝Ｃ＋（1/30）Si＋（1/20）Mn ＋（1/20）Cu＋（1/60）Ni＋（1/20）Cr ＋（1/15）Mo＋（1/10）Ｖ＋5B・・・・ Ar3（℃）＝910−310C−80Mn−20Cu−55Ni ＋0.35（ｔ−８） ・・・・ ここで、および式中の元素記号はその元素の含有量
（重量％）を表し、式のｔは板厚（mm）を表す。5. By weight%, C: 0.03-0.15%, Si: 0.05-0.90%, Mn: 0.30-2.00%, P: 0.005-0.050%, Cr: 0.10-2.00%, Mo: 0.25-0.70% , Sol.Al: 0.005 to 0.10%, the balance consisting of Fe and unavoidable impurities, and the P CM expressed by the formula below is 0.30% or less.
After heating in the temperature range of 250 ℃ or less, finish the hot working in the temperature range of Ar 3 transformation point or higher shown by the following formula, and immediately after hot working 60
A method for manufacturing a steel material for steel construction, which is characterized in that a coil is wound from a temperature of 0 ° C. or higher and a decrease in elastic modulus at a high temperature is small. P CM (%) = C + (1/30) Si + (1/20) Mn + (1/20) Cu + (1/60) Ni + (1/20) Cr + (1/15) Mo + (1/10) V + 5B ... ・ Ar 3 (° C.) = 910−310C−80Mn−20Cu−55Ni +0.35 (t−8) ・ ・ ・ ・ where the element symbol in the formula is the content of the element (% by weight). ), And t in the formula represents the plate thickness (mm).
〜0.50％のNi、0.005〜0.06％のTiおよび0.00015〜0.00
30％のＢの中から選ばれた１種以上を含有し、残部はFe
及び不可避不純物からなり、かつ下記式で示すPCMが
0.30％以下である鋼を、1000℃以上1250℃以下の温度域
で加熱後、下記式で示すAr3変態点以上の温度域で熱
間加工を終了し、熱間加工後直ちに600℃以上の温度か
らコイルに巻取ることを特徴とする高温での弾性率低下
の少ない鉄骨建築用鋼材の製造方法。 PCM（％）＝Ｃ＋（1/30）Si＋（1/20）Mn ＋（1/20）Cu＋（1/60）Ni＋（1/20）Cr ＋（1/15）Mo＋（1/10）Ｖ＋5B・・・・ Ar3（℃）＝910−310C−80Mn−20Cu−55Ni ＋0.35（ｔ−８） ・・・・・ ここで、および式中の元素記号はその元素の含有量
（重量％）を表し、式のｔは板厚（mm）を表す。6. By weight%, C: 0.03-0.15%, Si: 0.05-0.90%, Mn: 0.30-2.00%, P: 0.005-0.050%, Cr: 0.10-2.00%, Mo: 0.25-0.70% , Sol.Al: 0.005-0.10%, as well as 0.005-0.15% V, 0.10-0.50% Cu, 0.10
~ 0.50% Ni, 0.005-0.06% Ti and 0.00015-0.00
Contains at least one selected from 30% B, with the balance being Fe
And the inevitable impurities, and P CM shown by the following formula
Steel that is 0.30% or less is heated in the temperature range of 1000 ℃ or more and 1250 ℃ or less, then hot working is finished in the temperature range of Ar 3 transformation point or more shown by the following formula, and immediately after hot working, A method for manufacturing a steel material for steel construction, which is characterized in that it is wound into a coil from a temperature and the elastic modulus is not lowered at a high temperature. P CM (%) = C + (1/30) Si + (1/20) Mn + (1/20) Cu + (1/60) Ni + (1/20) Cr + (1/15) Mo + (1/10) V + 5B ・ ・ ・ ・ Ar 3 (° C.) = 910−310C−80Mn−20Cu−55Ni +0.35 (t−8) ・ ・ ・ Here, and the element symbol in the formula is the content (weight) of the element. %), And t in the formula represents the plate thickness (mm).
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1077614A JPH0739608B2 (en) | 1989-03-28 | 1989-03-28 | Manufacturing method of steel for steel construction with low elastic modulus decrease at high temperature |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1077614A JPH0739608B2 (en) | 1989-03-28 | 1989-03-28 | Manufacturing method of steel for steel construction with low elastic modulus decrease at high temperature |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH02254133A JPH02254133A (en) | 1990-10-12 |
| JPH0739608B2 true JPH0739608B2 (en) | 1995-05-01 |
Family
ID=13638792
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP1077614A Expired - Fee Related JPH0739608B2 (en) | 1989-03-28 | 1989-03-28 | Manufacturing method of steel for steel construction with low elastic modulus decrease at high temperature |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0739608B2 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103938104A (en) * | 2014-05-12 | 2014-07-23 | 武汉钢铁(集团)公司 | Offshore drilling platform steel with fatigue strength of at least 560MPa and production method thereof |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH036322A (en) * | 1989-06-02 | 1991-01-11 | Nippon Steel Corp | Production of low yield ratio steel products for building having excellent fire resistivity and steel material for building formed by using these steel products |
| JPH05112822A (en) * | 1991-10-18 | 1993-05-07 | Kobe Steel Ltd | Manufacture of 400n/mm2 class fire resistant steel for building construction having low yield ratio |
| JP3524790B2 (en) * | 1998-09-30 | 2004-05-10 | 株式会社神戸製鋼所 | Coating steel excellent in coating film durability and method for producing the same |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5814849B2 (en) * | 1979-07-31 | 1983-03-22 | 新日本製鐵株式会社 | Manufacturing method for high Young's modulus steel |
| JPS61104056A (en) * | 1984-10-25 | 1986-05-22 | Kobe Steel Ltd | High-strength and high-toughness low-carbon cr-mo steel plate having excellent creep-resisting property as well as superior resistance to weld crack and erosion |
| JPH0832945B2 (en) * | 1988-12-16 | 1996-03-29 | 新日本製鐵株式会社 | Steel material for building structure having excellent fire resistance and its manufacturing method |
| JPH0788554B2 (en) * | 1988-12-23 | 1995-09-27 | 日本鋼管株式会社 | Fireproof steel for construction |
-
1989
- 1989-03-28 JP JP1077614A patent/JPH0739608B2/en not_active Expired - Fee Related
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103938104A (en) * | 2014-05-12 | 2014-07-23 | 武汉钢铁(集团)公司 | Offshore drilling platform steel with fatigue strength of at least 560MPa and production method thereof |
| CN103938104B (en) * | 2014-05-12 | 2016-08-17 | 武汉钢铁(集团)公司 | The marine drilling platform steel of fatigue strength >=560MPa and production method |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH02254133A (en) | 1990-10-12 |
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