JPH0456721A - Production of steel with low yield ratio for construction use excellent in refractoriness - Google Patents
Production of steel with low yield ratio for construction use excellent in refractorinessInfo
- Publication number
- JPH0456721A JPH0456721A JP2165807A JP16580790A JPH0456721A JP H0456721 A JPH0456721 A JP H0456721A JP 2165807 A JP2165807 A JP 2165807A JP 16580790 A JP16580790 A JP 16580790A JP H0456721 A JPH0456721 A JP H0456721A
- Authority
- JP
- Japan
- Prior art keywords
- steel
- yield ratio
- temperature
- low
- less
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- 229910000831 Steel Inorganic materials 0.000 title claims abstract description 76
- 239000010959 steel Substances 0.000 title claims abstract description 76
- 238000010276 construction Methods 0.000 title claims abstract description 8
- 238000004519 manufacturing process Methods 0.000 title claims description 11
- 229910000859 α-Fe Inorganic materials 0.000 claims abstract description 11
- 238000003303 reheating Methods 0.000 claims abstract description 7
- 239000012535 impurity Substances 0.000 claims abstract description 5
- 238000005098 hot rolling Methods 0.000 claims abstract 3
- 239000000203 mixture Substances 0.000 abstract description 6
- 238000000034 method Methods 0.000 abstract description 5
- 229910052750 molybdenum Inorganic materials 0.000 abstract description 4
- 229910052782 aluminium Inorganic materials 0.000 abstract description 2
- 229910052748 manganese Inorganic materials 0.000 abstract description 2
- 229910052757 nitrogen Inorganic materials 0.000 abstract description 2
- 230000001105 regulatory effect Effects 0.000 abstract 2
- 239000000463 material Substances 0.000 description 17
- 230000000694 effects Effects 0.000 description 15
- 238000005096 rolling process Methods 0.000 description 12
- 230000000052 comparative effect Effects 0.000 description 7
- 239000011248 coating agent Substances 0.000 description 6
- 238000000576 coating method Methods 0.000 description 6
- 230000009970 fire resistant effect Effects 0.000 description 4
- 229910052698 phosphorus Inorganic materials 0.000 description 4
- 238000009749 continuous casting Methods 0.000 description 3
- 238000010438 heat treatment Methods 0.000 description 3
- 229910052751 metal Inorganic materials 0.000 description 3
- 229910000532 Deoxidized steel Inorganic materials 0.000 description 2
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 2
- UCKMPCXJQFINFW-UHFFFAOYSA-N Sulphide Chemical compound [S-2] UCKMPCXJQFINFW-UHFFFAOYSA-N 0.000 description 2
- 229910001563 bainite Inorganic materials 0.000 description 2
- 230000003749 cleanliness Effects 0.000 description 2
- 239000000498 cooling water Substances 0.000 description 2
- 238000005336 cracking Methods 0.000 description 2
- 229910052739 hydrogen Inorganic materials 0.000 description 2
- 239000001257 hydrogen Substances 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- 229910052758 niobium Inorganic materials 0.000 description 2
- 238000007670 refining Methods 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- 229910052719 titanium Inorganic materials 0.000 description 2
- 239000000654 additive Substances 0.000 description 1
- 230000000996 additive effect Effects 0.000 description 1
- 230000002411 adverse Effects 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- 239000010425 asbestos Substances 0.000 description 1
- 239000010953 base metal Substances 0.000 description 1
- 239000004035 construction material Substances 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 239000011491 glass wool Substances 0.000 description 1
- 230000001771 impaired effect Effects 0.000 description 1
- 238000009776 industrial production Methods 0.000 description 1
- 239000004615 ingredient Substances 0.000 description 1
- 239000011810 insulating material Substances 0.000 description 1
- 239000012528 membrane Substances 0.000 description 1
- 239000011490 mineral wool Substances 0.000 description 1
- 239000004570 mortar (masonry) Substances 0.000 description 1
- 230000001376 precipitating effect Effects 0.000 description 1
- 238000001556 precipitation Methods 0.000 description 1
- 229910052895 riebeckite Inorganic materials 0.000 description 1
- 239000006104 solid solution Substances 0.000 description 1
- 238000003892 spreading Methods 0.000 description 1
- 229910001220 stainless steel Inorganic materials 0.000 description 1
- 239000010935 stainless steel Substances 0.000 description 1
- 238000005728 strengthening Methods 0.000 description 1
- 230000003685 thermal hair damage Effects 0.000 description 1
- 229910052720 vanadium Inorganic materials 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
- 238000003466 welding Methods 0.000 description 1
- 229910052726 zirconium Inorganic materials 0.000 description 1
Landscapes
- Heat Treatment Of Steel (AREA)
Abstract
Description
【発明の詳細な説明】
（産業上の利用分野）
本発明は建築、土木及び海洋構造物等の分野における各
種構造物に用いる耐火性の優れた低降伏比鋼の製造方法
に関する。DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for producing low yield ratio steel with excellent fire resistance for use in various structures in the fields of architecture, civil engineering, marine structures, and the like.
（従来の技術）
周知の通り建築、土木及び海洋構造物等の分野における
各種構造物用構築材として、−殻構造用圧延鋼材（ＪＩ
Ｓ Ｇ ３１０１） 、溶接構造用圧延鋼材（ＪＩＳ
Ｇ ３１０Ｂ） 、溶接構造用耐候性熱間圧延鋼材（Ｊ
ＩＳ Ｇ ３１１４） 、高耐候性圧延鋼材（ＪＩＳ
Ｇ ３４４４）、−膜構造用角形鋼板（ＪＩＳ Ｇ ３
４Ｂｌｉ）等が広（利用されている。(Prior Art) As is well known, rolled steel for shell structures (JI
SG 3101), rolled steel materials for welded structures (JIS
G 310B), weather-resistant hot rolled steel for welded structures (J
IS G 3114), highly weather resistant rolled steel (JIS
G 3444), - square steel plate for membrane structure (JIS G 3
4Bli) etc. are widely used.
これら周知の鋼材は、通常高炉によって得られた溶銑を
脱Ｓ、脱Ｐしたのち転炉精錬を行ない、連続鋳造もしく
は分塊工程において鋼片とし、ついで熱間塑性加工する
ことにより、所望の特性を備えたものとして製品化され
る。These well-known steel materials are usually produced by removing S and P from hot metal obtained in a blast furnace, then refining it in a converter furnace, turning it into billets in a continuous casting or blooming process, and then hot plastic working to achieve the desired properties. It will be commercialized as a product equipped with the following.
ところで、各種建造物のうち、特に生活に密着したビル
や事務所及び住居等の建造物に前記周知鋼材を用いる場
合、火災における安全性を確保するため、十分な耐火被
覆を施すことが義務づけられており、建築関係諸法台で
は、火災時に鋼材温度が３５０℃程度で耐力が常温時の
６０〜７０％になり、建造物の倒壊を引き起こす恐れが
あるため、たとえば、−殻構造用圧延鋼材（ＪＩＳ Ｇ
３１０１）に規定される形鋼を柱材とする構造物の例
では、その表面にスラグウール、ガラスウール、アスベ
スト等を基材とする吹き付は材やフェルトを展着するほ
か、防火モルタルで***する方法及び前記断熱材層の上
に、さらに金属薄板すなわちアルミニウムやステンレス
薄板で保護する方法等、耐火被覆を入念に施し、火災時
における熱的損傷により該鋼材が載荷力を失うことのな
いようにして利用する。By the way, when using the well-known steel materials in buildings such as buildings, offices, and residences that are closely connected to daily life among various buildings, it is mandatory to apply sufficient fireproof coating to ensure safety in the event of a fire. According to various construction-related laws and regulations, in the event of a fire, when the temperature of the steel material is around 350℃, the proof strength will be 60 to 70% of that at room temperature, which may cause the collapse of the structure. (JIS G
3101), the surface of which is sprayed with slag wool, glass wool, asbestos, etc. as a base material, or by spreading felt or fireproof mortar. A fire-resistant coating is carefully applied, such as by encasing the heat insulating material layer or by further protecting it with a thin metal plate, such as aluminum or stainless steel plate, to prevent the steel material from losing its load-bearing capacity due to thermal damage in the event of a fire. Use it like this.
そのため、鋼材費用に比し耐火被覆工費が高額になり、
建築コストが大幅に上昇することを避けることができな
い。As a result, the cost of fireproof coating is high compared to the cost of steel materials,
A significant increase in construction costs cannot be avoided.
そこで、構築材として丸あるいは角鋼管を用い、冷却水
が循環するように構成し、火災時における温度上昇を防
止し載荷力を低下させない技術が提案され、ビルの建築
コストの引き下げと利用空間の拡大が図られている。Therefore, a technology has been proposed that uses round or square steel pipes as construction materials to allow cooling water to circulate, preventing temperature rise in the event of a fire and reducing loading capacity. Expansion is being planned.
たとえば、実公昭５２−１６０２１号公報には、建築物
の上部に水タンクを置き、中空鋼管からなる柱材に冷却
水を供給する耐火構造建造物が開示されている。また、
特願平２−７２５６６号明細書では、定量のＭｏの添加
とＣ／Ｍｎ比の制限及び焼入性の確保により、ミクロ組
織をベイナイトとして、６００℃の高温強度が常温強度
の７０％以上確保できることが示されている。For example, Japanese Utility Model Publication No. 52-16021 discloses a fire-resistant building in which a water tank is placed on the top of the building and cooling water is supplied to pillars made of hollow steel pipes. Also,
In Japanese Patent Application No. 2-72566, by adding a certain amount of Mo, limiting the C/Mn ratio, and ensuring hardenability, the microstructure is made into bainite, and the high-temperature strength at 600°C is ensured to be 70% or more of the room-temperature strength. It has been shown that it can be done.
しかしながら、この方法では、常温の降伏比は低いが、
Ｓ−Ｓカーブは明確な降伏点は見られずラウンド型とな
る。又このタイプの鋼は見かけ上の降伏比は低いが、耐
震性に十分とは言えないことが明らかにされ、問題点を
含んでいた。However, with this method, although the yield ratio at room temperature is low,
The SS curve has a round shape with no clear yield point. Also, although this type of steel has a low apparent yield ratio, it has been found that its seismic resistance is not sufficient, and it has some problems.
第１図（ａ）はミクロ組織がフェライト主体のＳ−Ｓカ
ーブ、第１図（ｂ）はミクロ＃Ｉ織がベイナイト主体の
Ｓ−Ｓカーブを示す。FIG. 1(a) shows an SS curve in which the microstructure is mainly ferrite, and FIG. 1(b) shows an SS curve in which the microstructure #I is mainly bainite.
（発明が解決しようとする課題）
本発明者らは、火災時における鋼材温度について研究の
結果、無被覆使用を目標とした場合、火災時の最高到達
温度が１０００℃であることから、鋼材が該温度で常温
耐力の７０％以上の耐力を備えるためには、やはり高価
な金属元素を多量に添加せねばならず、経済性を失する
ことを知った。(Problem to be Solved by the Invention) As a result of research on the temperature of steel materials during a fire, the present inventors found that when uncoated use is aimed at, the maximum temperature reached during a fire is 1000°C. It has been learned that in order to provide a yield strength of 70% or more of the room temperature yield strength at this temperature, a large amount of expensive metal elements must be added, resulting in a loss of economic efficiency.
つまり、周知の鋼材費とそれに加え耐火被覆を施工する
費用以上に鋼材単価が高くなり、そのような綱材は実際
的に利用することができない。In other words, the unit price of the steel material becomes higher than the cost of the well-known steel material and, in addition, the cost of constructing the fireproof coating, and such a rope material cannot be practically used.
そこで、さらに研究を進めた結果、６００℃での高温耐
力が常温時の７０％以上となる鋼材が最も経済的である
ことをつきとめ、高価な添加元素の量を少なくし、且つ
、耐火被覆を薄くすることが可能で、火災荷重が小さい
場合は、無被覆で使用することができる鋼材の製造方法
を開発した。Therefore, as a result of further research, we found that the most economical steel material had a high-temperature yield strength of 70% or more at 600℃ compared to room temperature, and we decided to reduce the amount of expensive additive elements and add a fire-resistant coating. We have developed a manufacturing method for steel that can be made thin and used without coating if the fire load is small.
（課題を解決するための手段）
本発明は前述の課題を克服し、目的を達成するもので、
重量比で、ＣＯ’、０４〜０．１１％、Ｓｉ０．６％以
下、Ｍｎ０．３〜（１，７％、Ｍｏ０．５〜［１，８％
、ＡｌｌＯｌｌ％以下、Ｎ０．００６％以下、残部がＦ
ｅ及び不可避的不純物を含み、しかも（１）式で与えら
れるＤｉ本値が０，８０未満の成分組成よりなる鋼片を
１１５０〜１３００℃の温度域で再加熱後、熱間圧延を
８００〜１０００℃の温度範囲で終了してミクロ組織を
フェライト主体とする耐火性の優れた建築用低降伏比鋼
の製造方法である。(Means for Solving the Problems) The present invention overcomes the above-mentioned problems and achieves the objects.
In weight ratio, CO', 04~0.11%, Si0.6% or less, Mn0.3~(1,7%, Mo0.5~[1,8%
, AllOll% or less, N0.006% or less, the remainder is F
After reheating a steel piece with a composition containing e and unavoidable impurities and having a Di value given by equation (1) of less than 0.80, it is hot rolled at a temperature of 800 to 800°C. This is a method for producing a low yield ratio steel for architectural use which has excellent fire resistance and has a microstructure mainly composed of ferrite, which is finished in a temperature range of 1000°C.
（１）式
％式％）
更に本発明を重量比でＣ０．０４〜０．１１％、５１０
．６％以下、Ｍｎ０．３〜０．７％、Ｍ ｏ ０ 、５
〜０，８％、Ａ［０，１％以下、Ｎ ０．００６％以下
に加えてＶ ０．００５〜０．０５％、Ｔ ｉ０．００
５〜０．０３％、Ｚｒ０．００５〜０．０３％、Ｃａ０
．０００５〜０．００５％、ＲＥＭＱ、ＱＯｔ〜０．（
１０５％の一種または二種以上を含むことができる。(1) Formula % Formula %) Furthermore, the present invention is C0.04 to 0.11% by weight, 510
．． 6% or less, Mn 0.3-0.7%, M o 0, 5
~0.8%, A [0.1% or less, N 0.006% or less, plus V 0.005-0.05%, Ti 0.00
5-0.03%, Zr0.005-0.03%, Ca0
．． 0005~0.005%, REMQ, QOt~0. (
It can contain 105% of one or more kinds.
（作 用）
さて、本発明の特徴は、中Ｃ−中Ｍｎ鋼に一定量のＭｏ
を添加した組成の鋼片を高温で再加熱したのち、比較的
高温で圧延を終了することにあり、本発明法によって製
造した鋼及び鋼材（以下鋼）は、適当な常温耐力と明確
な降伏現象（降伏点が明瞭に認められる）を伴った低い
降伏強度を有するとともに、高温耐力か高い特性を備え
ている。(Function) Now, the feature of the present invention is that a certain amount of Mo is added to medium C-medium Mn steel.
The steel and steel materials (hereinafter referred to as steel) produced by the method of the present invention have appropriate room temperature yield strength and clear yield strength. It has a low yield strength with a clear phenomenon (yield point is clearly recognized) and has high high temperature yield strength.
つまり、常温耐力に対し６００℃の温度における耐力の
割合が大きい。この理由は中Ｃのベース成分に相当量の
Ｍｏを添加した鋼で、フェライト組織（フェライト面積
率６０％以上）としているためである。In other words, the ratio of the proof stress at a temperature of 600° C. to the room temperature proof stress is large. The reason for this is that the steel has a medium C base component with a considerable amount of Mo added, and has a ferrite structure (ferrite area ratio of 60% or more).
つぎに、本発明にかかる特徴的な成分元素とその添加量
について説明する。Next, characteristic component elements according to the present invention and their addition amounts will be explained.
Ｍｏは微細な炭窒化物を形成し、さらに、固溶体強化に
よって高温強度を増加させるか、ミクロ組織がフェライ
トでＮｂを添加しない本発明鋼の場合、その添加量は比
較的多く必要である。そのため、ＭＯ添加量の下限は０
．５％である。しかしながら、Ｍｏ量が多すぎると、溶
接性が悪くなり、さらに、溶接熱影響部（ＨＡＺ）の靭
性か劣化するので、Ｍｏｍの上限は０．８％とする必要
がある。Mo forms fine carbonitrides, and in the case of the steel of the present invention, which increases high-temperature strength by solid solution strengthening or has a ferrite microstructure and does not contain Nb, a relatively large amount of Mo is required. Therefore, the lower limit of the amount of MO added is 0.
．． It is 5%. However, if the amount of Mo is too large, weldability deteriorates and furthermore, the toughness of the weld heat affected zone (HAZ) deteriorates, so the upper limit of Mo needs to be 0.8%.
さて、常温において、溶接構造周圧鋼材（ＪＩＳＧ ３
１０６）に規定する性能を満足し、且つ、６００℃の高
温において高い耐力を維持せしめるためには、鋼成分と
共に鋼の再加熱及び圧延にかかる条件が重要である。Now, at room temperature, welded structure circumferential steel (JISG 3
In order to satisfy the performance specified in 106) and maintain high yield strength at a high temperature of 600°C, the conditions for reheating and rolling the steel are important as well as the steel composition.
前述のＭｏ添加による高温強度の増大を図るには、Ｍｏ
を再加熱時に十分に溶体化させる必要があり、このため
再加熱温度の下限を１１５０℃とする。In order to increase the high-temperature strength by adding Mo as described above, it is necessary to add Mo.
It is necessary to sufficiently dissolve the material during reheating, and therefore the lower limit of the reheating temperature is set at 1150°C.
また、再加熱温度が高すぎると結晶粒が大きくなって低
温靭性が劣化するので、その上限は１３００℃にせねば
ならない。Furthermore, if the reheating temperature is too high, the crystal grains will become large and the low temperature toughness will deteriorate, so the upper limit must be set at 1300°C.
さらに、圧延終了温度を８００℃以上とする理由は、圧
延中にＭｏの炭窒化物を析出させないためである。周知
の低温圧延（制御圧延）はラインパイプ等低温靭性が必
要な鋼材では必須要件であるが、本発明鋼のように低温
靭性について、高い要求がなく、常温強度と６００℃の
強度及びそのバランスが重要な場合には、ミクロ組織を
比較的粗粒のフェライト主体とするため、圧延を高温で
終了せねばならない。また、本発明において、圧延終了
温度の上限を１０００℃としたのは、建築用鋼としての
靭性を確保するためである。Furthermore, the reason why the rolling end temperature is set to 800° C. or higher is to prevent Mo carbonitride from precipitating during rolling. Well-known low-temperature rolling (controlled rolling) is an essential requirement for steel materials that require low-temperature toughness such as line pipes, but there is no high requirement for low-temperature toughness like the steel of the present invention, and the strength at room temperature and 600°C and the balance thereof are required. If this is important, the rolling must be completed at a high temperature in order to make the microstructure mainly composed of relatively coarse grained ferrite. Further, in the present invention, the upper limit of the rolling end temperature is set to 1000° C. in order to ensure toughness as a construction steel.
さて、高温強度を上昇せしめるため、Ｍｏを利用するこ
とは、従来のボイラー用鋼管等に利用されている鋼では
知られているが、この鋼は基本的な特性を得るため、圧
延／造管後調質熱処理を施しており、本発明鋼とは製造
プロセスが異なる。Now, the use of Mo in order to increase high-temperature strength is known in steel used for conventional boiler steel pipes, etc., but this steel has been rolled/pipe-formed in order to obtain the basic properties. It is subjected to post-refining heat treatment, and the manufacturing process is different from that of the steel of the present invention.
また、建築用に用いる耐火鋼材として先に本出願人が出
願している特願昭６３−１４３７４０号明細書がある。In addition, there is Japanese Patent Application No. 143740/1988, which was previously filed by the present applicant as a fire-resistant steel material for use in construction.
この鋼は微量のＭｏとＮｂを添加し、高温加熱−高温圧
延により製造するプロセスである。This steel is manufactured by adding trace amounts of Mo and Nb and by high-temperature heating and high-temperature rolling.
この製造法は本発明鋼と同じであるが、高温強度を得る
ため、ＭｏとＮｂの複合添加を必須としており、本発明
のＭＯ単独添加とは異なる。さらに、Ｎｂ添加鋼は一般
的に低降伏比化は難しいことが知られており、その理由
は、フェライト粒径を細粒にする効果や圧延中にＮｂか
析出するためと考えられている。This manufacturing method is the same as that for the steel of the present invention, but in order to obtain high-temperature strength, the combined addition of Mo and Nb is essential, which is different from the sole addition of MO in the present invention. Furthermore, it is generally known that it is difficult to reduce the yield ratio of Nb-added steel, and the reason for this is believed to be the effect of reducing the ferrite grain size and the precipitation of Nb during rolling.
このため、比較的薄い鋼板では、圧下比が大きいことや
圧延温度が低下しやすいため、上記の理由から常温の降
伏比が増加しやすい。この発明鋼では、常温の降伏比が
７５％以下で製造できることが明らかにされているか、
薄手の低降伏比鋼板を工業的に製造することは難しいと
考えられる。For this reason, in a relatively thin steel sheet, the rolling reduction ratio is large and the rolling temperature tends to decrease, so the yield ratio at room temperature tends to increase for the above-mentioned reasons. Has it been clarified that this invented steel can be manufactured with a yield ratio of 75% or less at room temperature?
It is considered difficult to industrially produce thin, low yield ratio steel sheets.
本発明鋼は常温では低降伏比で６００℃では、常温の７
０％以上の降伏強度を有する板厚４０ｍｍ以下の鋼板の
製造に適しており、工業的な生産に適している。The steel of the present invention has a low yield ratio at room temperature, and at 600°C, it has a yield ratio of 7
It is suitable for manufacturing steel plates with a thickness of 40 mm or less and has a yield strength of 0% or more, and is suitable for industrial production.
つぎに、本発明における前記Ｍｏ以外の成分限定理由に
ついて詳細に説明する。Next, the reason for limiting components other than Mo in the present invention will be explained in detail.
Ｃは母材及び溶接部の強度確保ならびにＭｏの添加効果
を発揮させるために必要であり、０．０４％未満では効
果が薄れるので下限は０．０４％とする。C is necessary to ensure the strength of the base metal and the welded part and to exhibit the effect of adding Mo. If it is less than 0.04%, the effect will be weakened, so the lower limit is set to 0.04%.
また、Ｃ量が多すぎると常温の降伏比が上昇し、さらに
、ＨＡＺの低温靭性に悪影響を及ぼすので、０．１１％
が上限となる。In addition, if the amount of C is too large, the yield ratio at room temperature will increase, and it will also have a negative effect on the low temperature toughness of the HAZ, so 0.11%
is the upper limit.
Ｓｔは脱酸上鋼に含まれる元素で、Ｓｉ量が多くなると
溶接性、ＨＡＺ靭性が劣化するため、その上限を０．６
％とした。St is an element contained in deoxidized steel, and as the amount of Si increases, weldability and HAZ toughness deteriorate, so the upper limit is set to 0.6.
%.
つぎに、Ｍｎは強度、靭性を確保する上で不可欠の元素
であり、その下限は０．３％である。しかし、Ｍｎ量が
多すぎると焼入性が増加して溶接性、ＨＡＺ靭性が劣化
するため、Ｍｎの上限を０．７％とした。Next, Mn is an essential element for ensuring strength and toughness, and its lower limit is 0.3%. However, if the amount of Mn is too large, hardenability increases and weldability and HAZ toughness deteriorate, so the upper limit of Mn was set at 0.7%.
Ａ、７７は一般に脱酸上鋼に含まれる元素であるか、Ｓ
ｌ及びＴ１によっても脱酸は行なわれるので、本発明鋼
については下限は限定しない。しかしＡｇ量が多くなる
と鋼の清浄度が悪くなり、溶接部の靭性が劣化するので
上限を０．１％とした。A, 77 is an element generally included in deoxidized steel, or S
Since deoxidation is also carried out by l and T1, there is no lower limit for the steel of the present invention. However, if the amount of Ag increases, the cleanliness of the steel will deteriorate and the toughness of the weld will deteriorate, so the upper limit was set at 0.1%.
Ｎは一般に不可避的不純物として鋼中に含まれるもので
あるが、Ｎ量が多くなるとＨＡＺ靭性の劣化や連続鋳造
スラブの表面キズの発生等を助長するので、その上限を
ｏ、ｏｏｅ％とした。N is generally contained in steel as an unavoidable impurity, but if the amount of N increases, it promotes the deterioration of HAZ toughness and the occurrence of surface scratches on continuous casting slabs, so the upper limit was set as o, ooe%. .
なお、本発明鋼は、不可避的不純物としてＰ及びＳを含
有する。Ｐ、Ｓは高温強度に与える影響は小さいので、
その量について特に限定しないが、一般に靭性、板厚方
向強度等に関する鋼の特性は、これらＰ、Ｓ元素の量が
少ないほど向上する。望ましいｐ、ｓ量はそれぞれ０．
０２％、 ０．００５％以下である。Note that the steel of the present invention contains P and S as inevitable impurities. Since P and S have little effect on high temperature strength,
Although there is no particular limitation on the amount, generally the properties of steel regarding toughness, strength in the thickness direction, etc. are improved as the amount of these P and S elements is smaller. Desirable amounts of p and s are each 0.
0.02%, 0.005% or less.
基本的な特性を得るための成分は以上のとおりであるが
、本発明鋼は用途が厳しい条件（溶接部の水素割れ性が
要求されたり、大入熱の溶接か適用される）での適用を
考慮しており、以下に述べる元素即ちＶ、Ｔｉ 、Ｚｒ
、Ｃａ、ＲＥＭを選択的に添加することにより特性の向
上を図っている。The ingredients for obtaining the basic properties are as described above, but the steel of the present invention can be used under severe conditions (hydrogen cracking resistance is required in the weld, or high heat input welding is applied). The elements mentioned below, namely V, Ti, Zr
, Ca, and REM are selectively added to improve the characteristics.
ＶはＮと結合してＶＮを形成し、高温強度を向上させる
。しかし、０．００５％未満では、その効果が薄く、０
．０５％超では、溶接部の靭性を害するため、０．００
５〜０，０５％に限定する。V combines with N to form VN and improves high temperature strength. However, if it is less than 0.005%, the effect is weak and 0.
．． If it exceeds 0.05%, the toughness of the welded part will be impaired;
Limited to 5-0.05%.
Ｔ１は炭窒化物を形成してＨＡＺ靭性を向上させる。Ａ
ｇ量が少ない場合、ＴＩの酸化物を形成しＨＡＺ靭性を
向上させるが、０．００５％未満では効果がなく、０．
０３％を超えるとＨＡＺ靭性に好ましくない影響がある
ため、０．００５〜０．０３％に限定する。T1 forms carbonitrides and improves HAZ toughness. A
When the amount is small, TI oxides are formed and the HAZ toughness is improved, but when it is less than 0.005%, there is no effect, and when the amount is less than 0.005%, there is no effect.
If it exceeds 0.03%, it will have an unfavorable effect on HAZ toughness, so it is limited to 0.005 to 0.03%.
ＺｒはＴｉとほぼ同じ効果をもつが、その効果が有効な
範囲は０．００５〜０．０３％である。Zr has almost the same effect as Ti, but the effective range is 0.005 to 0.03%.
（ｌ、ＲＥＭは硫化物（ＭｎＳ）の形態を制御し、溶接
部のラメラ−テアの改善や耐水素有機割れ性の改善に効
果を発揮するほか、シャルピー吸収エネルギーを増加さ
せ、低温靭性を向上させる効果がある。(l, REM controls the morphology of sulfide (MnS) and is effective in improving lamellar tear and hydrogen organic cracking resistance in welds, as well as increasing Charpy absorbed energy and improving low-temperature toughness. It has the effect of
しかし、Ｃａ量は０．０００５％未満では実用上効果が
なく、また、０．００５％を超えると、Ｃａｂ。However, if the amount of Ca is less than 0.0005%, it has no practical effect, and if it exceeds 0.005%, it becomes Cab.
ＣａＳが多量に生成して大形介在物となり、鋼の靭性の
みならず清浄度も害し、さらに、溶接性、耐ラメラ−テ
ア性にも悪影響を与えるので、Ｃａ添加量の範囲を０．
０００５〜０．００５％とする。A large amount of CaS is generated and becomes large inclusions, which impairs not only the toughness but also the cleanliness of the steel, and also has an adverse effect on weldability and lamellar tear resistance.
0005 to 0.005%.
また、ＲＥＭについてもＣａと同様な効果があり、添加
量を多くするとＣａと同様な問題を生じ、さらに経済性
も悪くなるので、ＲＥＭｆｆｉの下限を０．００１％、
上限を０．００５％とした。In addition, REM has the same effect as Ca, and increasing the amount added causes the same problems as Ca, and is also less economical, so the lower limit of REMffi is set at 0.001%.
The upper limit was set at 0.005%.
（実 施 例）
周知の転炉、連続鋳造、厚板工程によって鋼板を製造し
、常温と６００℃の強度を調査した。(Example) A steel plate was manufactured using a well-known converter, continuous casting, and thick plate process, and its strength at room temperature and 600°C was investigated.
第１表のＮｏ、ｌ 〜Ｎｏ、１０に本発明鋼を、Ｎｏ、
１１〜Ｎｏ、 １６に比較鋼の化学成分を示す。In Table 1, No. l to No. 10 are the steels of the present invention, No.
Nos. 11 to 16 show the chemical compositions of comparative steels.
続いて、第２表に本発明鋼と比較鋼の加熱、圧延等の製
造条件とその強度特性を示す。Next, Table 2 shows the manufacturing conditions such as heating and rolling of the steel of the present invention and the comparative steel, as well as their strength characteristics.
第２表の本発明鋼Ｎ０２１〜Ｎｏ、 １０の例では、ミ
クロ組織のフェライト分率が６０％超で、常温の降伏比
（降伏強度／引張強度）が７０％以下と低く、６００℃
の降伏強度が常温の７０％以上を有している。In the examples of the invention steels No. 021 to No. 10 in Table 2, the ferrite fraction in the microstructure is over 60%, the yield ratio (yield strength/tensile strength) at room temperature is as low as 70% or less, and the yield ratio at 600 ° C.
Its yield strength is 70% or more of that at room temperature.
これに対し、比較鋼Ｎｏ、 ｌ ｌでは、Ｍｎが低いた
め、常温、６００℃の強度とも低く、常温の降伏強度に
対する６００℃の降伏強度の割合が７０％に達しないレ
ベルであった。また、比較鋼Ｎｏ、１２では、Ｍｎが高
すぎるため、６００℃の降伏強度は十分であるが、常温
の降伏比が高すぎ７７％にも達した。比較鋼Ｎｏ。On the other hand, comparative steels No. 1 and 11 had low strength at room temperature and 600° C. due to their low Mn content, and the ratio of the yield strength at 600° C. to the yield strength at room temperature did not reach 70%. Furthermore, in Comparative Steel No. 12, since the Mn content was too high, the yield strength at 600° C. was sufficient, but the yield ratio at room temperature was too high, reaching 77%. Comparative steel No.
１３では、Ｍｏが低いため、常温と６００℃の降伏強度
か低く、常温の降伏強度に対する６００℃の降伏強度の
割合が７０％に達しないレベルであった。これと逆に、
比較鋼Ｎｏ、 １４では、ＭＯか高すぎ、６００℃の降
伏強度は十分であるか、常温の降伏比か高すぎ、８１％
にも達した。比較鋼Ｎｏ、 １５では、Ｃか低いため、
常温と６００℃の降伏強度か低く、常温の降伏強度に対
する６００℃の降伏強度の割合か７０％に達しないレベ
ルであった。さらに、比較鋼Ｎｏ、 １６では、Ｃか高
すぎるため、６００℃の降伏強度は十分であるか、常温
の降伏比か高すぎ、７８００にも達した。In No. 13, since the Mo content was low, the yield strength at room temperature and 600° C. was low, and the ratio of the yield strength at 600° C. to the yield strength at room temperature did not reach 70%. On the contrary,
For comparative steel No. 14, the MO is too high, the yield strength at 600°C is sufficient, and the yield ratio at room temperature is too high, 81%.
It also reached Comparative steel No. 15 has a low C, so
The yield strength at room temperature and at 600°C was low, and the ratio of the yield strength at 600°C to the yield strength at room temperature was less than 70%. Furthermore, in comparison steel No. 16, the C content was too high, so the yield strength at 600°C was not sufficient, or the yield ratio at room temperature was too high, reaching 7800.
／
／
（発明の効果）
本発明の化学成分及び製造法で製造した鋼材は６００℃
の降伏強度が高く且つ、６００℃の降伏強度が常温降伏
強度の７０％以上で、常温の降伏比も７０％以下と低く
、耐火性及び耐震性の優れた全く新しい鋼である。/ / (Effect of the invention) The steel material manufactured using the chemical composition and manufacturing method of the present invention has a temperature of 600°C.
It is a completely new steel that has a high yield strength, the yield strength at 600°C is 70% or more of the yield strength at room temperature, and the yield ratio at room temperature is as low as 70% or less, and has excellent fire resistance and earthquake resistance.
第１図（ａ） 、 （ｂ）は応カー歪の図表である。 代 理 人 弁理士 茶野木 立 夫Ｃｂ） 手続補正書（方式） FIGS. 1(a) and 1(b) are graphs of Kerr distortion. Representative Patent Attorney Tatsuo Chanoki Cb) Procedural amendment (formality)
Claims (1)
で与えられるＤｉ＾＊値が０．８０未満の成分組成より
なる鋼片を１１５０〜１３００℃の温度域で再加熱後、
熱間圧延を８００〜１０００℃の温度範囲で終了してミ
クロ組織をフェライト主体とすることを特徴とする耐火
性の優れた建築用低降伏比鋼の製造方法。 （１）式 Ｄｉ＾＊＝０．３１６√Ｃ（１＋０．７Ｓｉ）（４．１
Ｍｎ＋０．３５）（１＋３Ｍｏ）（成分単位：重量％）
２、ｗｔ％で Ｖ０．００５〜０．０５％、 Ｔｉ０．００５〜０．０３％、 Ｚｒ０．００５〜０．０３％、 Ｃａ０．０００５〜０．００５％、 ＲＥＭ０．００１〜０．００５％ の一種または二種以上を含む請求項１記載の耐火性の優
れた建築用低降伏比鋼の製造方法。[Claims] 1. In wt%, C0.04-0.11%, Si0.6% or less, Mn0.3-0.7%, Mo0.5-0.8%, Al0.1% or less, Reheating a steel billet in a temperature range of 1150 to 1300°C, with the remainder containing Fe and unavoidable impurities of N0.006% or less, and the Di^* value given by equation (1) being less than 0.80. rear,
A method for producing a low yield ratio steel for construction with excellent fire resistance, characterized in that hot rolling is completed in a temperature range of 800 to 1000° C. so that the microstructure is mainly ferrite. (1) Formula Di^*=0.316√C(1+0.7Si)(4.1
Mn+0.35) (1+3Mo) (component unit: weight%)
2, wt% V0.005-0.05%, Ti0.005-0.03%, Zr0.005-0.03%, Ca0.0005-0.005%, REM0.001-0.005% The method for producing a low yield ratio steel for construction with excellent fire resistance according to claim 1, which contains one or more kinds.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2165807A JPH0456721A (en) | 1990-06-26 | 1990-06-26 | Production of steel with low yield ratio for construction use excellent in refractoriness |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2165807A JPH0456721A (en) | 1990-06-26 | 1990-06-26 | Production of steel with low yield ratio for construction use excellent in refractoriness |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0456721A true JPH0456721A (en) | 1992-02-24 |
| JPH0545646B2 JPH0545646B2 (en) | 1993-07-09 |
Family
ID=15819371
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2165807A Granted JPH0456721A (en) | 1990-06-26 | 1990-06-26 | Production of steel with low yield ratio for construction use excellent in refractoriness |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0456721A (en) |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS61272319A (en) * | 1985-05-28 | 1986-12-02 | Sumitomo Metal Ind Ltd | Manufacture of steel plate superior in carburizing characteristic |
| JPH0277523A (en) * | 1988-06-13 | 1990-03-16 | Nippon Steel Corp | Production of building low yield ratio steel having excellent fire resistance and building steel material using same steel |
| JPH03107420A (en) * | 1989-09-22 | 1991-05-07 | Nippon Steel Corp | Production of structural steel stock excellent in fire resisting strength |
-
1990
- 1990-06-26 JP JP2165807A patent/JPH0456721A/en active Granted
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS61272319A (en) * | 1985-05-28 | 1986-12-02 | Sumitomo Metal Ind Ltd | Manufacture of steel plate superior in carburizing characteristic |
| JPH0277523A (en) * | 1988-06-13 | 1990-03-16 | Nippon Steel Corp | Production of building low yield ratio steel having excellent fire resistance and building steel material using same steel |
| JPH03107420A (en) * | 1989-09-22 | 1991-05-07 | Nippon Steel Corp | Production of structural steel stock excellent in fire resisting strength |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0545646B2 (en) | 1993-07-09 |
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