JPH04193908A - Production of high strength reinforcing bar excellent in yield elongation - Google Patents
Production of high strength reinforcing bar excellent in yield elongationInfo
- Publication number
- JPH04193908A JPH04193908A JP2322691A JP32269190A JPH04193908A JP H04193908 A JPH04193908 A JP H04193908A JP 2322691 A JP2322691 A JP 2322691A JP 32269190 A JP32269190 A JP 32269190A JP H04193908 A JPH04193908 A JP H04193908A
- Authority
- JP
- Japan
- Prior art keywords
- weight
- yield elongation
- rolling
- elongation
- point
- 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
- 230000003014 reinforcing effect Effects 0.000 title claims abstract description 8
- 238000004519 manufacturing process Methods 0.000 title claims description 10
- 229910000831 Steel Inorganic materials 0.000 claims abstract description 20
- 239000010959 steel Substances 0.000 claims abstract description 20
- 238000001816 cooling Methods 0.000 claims abstract description 13
- 238000005098 hot rolling Methods 0.000 claims abstract description 7
- 239000012535 impurity Substances 0.000 claims abstract description 6
- 229910052720 vanadium Inorganic materials 0.000 claims abstract description 3
- 229910052758 niobium Inorganic materials 0.000 claims abstract 2
- 229910000859 α-Fe Inorganic materials 0.000 claims description 24
- 239000000463 material Substances 0.000 claims description 13
- 229910052802 copper Inorganic materials 0.000 claims 1
- 229910052750 molybdenum Inorganic materials 0.000 claims 1
- 229910052759 nickel Inorganic materials 0.000 claims 1
- 238000005096 rolling process Methods 0.000 abstract description 17
- 239000000203 mixture Substances 0.000 abstract description 5
- 230000001105 regulatory effect Effects 0.000 abstract 1
- 239000013078 crystal Substances 0.000 description 10
- 238000005728 strengthening Methods 0.000 description 10
- 239000006104 solid solution Substances 0.000 description 9
- 230000000694 effects Effects 0.000 description 5
- 238000000034 method Methods 0.000 description 5
- 238000001556 precipitation Methods 0.000 description 5
- ATJFFYVFTNAWJD-UHFFFAOYSA-N Tin Chemical compound [Sn] ATJFFYVFTNAWJD-UHFFFAOYSA-N 0.000 description 3
- 229910001566 austenite Inorganic materials 0.000 description 3
- 229910001563 bainite Inorganic materials 0.000 description 3
- 230000007423 decrease Effects 0.000 description 3
- 238000010438 heat treatment Methods 0.000 description 3
- 239000002244 precipitate Substances 0.000 description 3
- 239000011150 reinforced concrete Substances 0.000 description 3
- 230000009466 transformation Effects 0.000 description 3
- 230000000052 comparative effect Effects 0.000 description 2
- 239000004615 ingredient Substances 0.000 description 2
- 229910001562 pearlite Inorganic materials 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- 238000005496 tempering Methods 0.000 description 2
- 230000002411 adverse Effects 0.000 description 1
- 238000013459 approach Methods 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 238000005336 cracking Methods 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 230000002542 deteriorative effect Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 230000001771 impaired effect Effects 0.000 description 1
- 229910000734 martensite Inorganic materials 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 230000000087 stabilizing effect Effects 0.000 description 1
- 239000002436 steel type Substances 0.000 description 1
- 238000009864 tensile test Methods 0.000 description 1
Classifications
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P10/00—Technologies related to metal processing
- Y02P10/20—Recycling
Abstract
Description
【発明の詳細な説明】
〔産業上の利用分野〕
本発明は下降状点が４０ｋｇｆ／ｍｒｒ？以上の高強度
を有し降伏伸びに優れた鉄筋コンクリート用異形棒鋼の
製造方法に関する。[Detailed Description of the Invention] [Industrial Application Field] The present invention has a descending point of 40 kgf/mrr? The present invention relates to a method for manufacturing a deformed steel bar for reinforced concrete that has high strength and excellent yield elongation.
［従来の技術］
近年、建築物は高層化、長大化する傾向にあり、また、
鉄筋コンクリート造が指向されている。このため、それ
に用いる鉄筋も高強度化、高品質化が要求されるように
なり、高強度化にともない安全性の観点から降伏伸びが
大きいことが要求されている。[Conventional technology] In recent years, buildings have tended to become taller and longer.
Reinforced concrete construction is preferred. For this reason, the reinforcing bars used therein are required to have higher strength and higher quality, and with higher strength, higher yield elongation is required from the viewpoint of safety.
一般に高降伏伸びを有するには、特公昭６３−６４４９
４号公報に示されるようにオーステナイト未再結晶域の
圧延を十分行い、微細フェライト−゛パーライト組織を
得る方法や特開昭６１−１２４５２４号公報のように圧
延で得たフェライト−ベイナイト組織をさらに焼き戻し
処理下る方法がとられている。In general, to have high yield elongation,
As shown in Japanese Patent Publication No. 4, the austenite non-recrystallized region is sufficiently rolled to obtain a fine ferrite-pearlite structure, and as in JP-A-61-124524, the ferrite-bainite structure obtained by rolling is further improved. A method of tempering is used.
特公昭６３−６４４９４号公報ではオーステナイト未再
結晶域での圧延を十分行い、中間、仕上圧延を８７５℃
以下で実施することを特徴としているが、８７５℃以下
がＡ ｒ ３変態点以下、つまり、オーストナイト−フ
ェライトの二相域の範囲である場合、処理すると、フェ
ライトが加工され、フェライト粒内での初期可動転位密
度が増加し、降伏伸びは小さくなる。In Japanese Patent Publication No. 63-64494, rolling is carried out sufficiently in the austenite non-recrystallized region, and intermediate and finishing rolling is carried out at 875°C.
The method is characterized in that it is carried out below, but when the temperature is below 875°C, which is below the A r 3 transformation point, that is, in the austonite-ferrite two-phase region, the ferrite is processed and the inside of the ferrite grains are processed. The initial mobile dislocation density increases and the yield elongation decreases.
また、特開昭６１−１２４５２４号公報では圧延後さら
に焼き戻し処理により降伏点伸びを増加させており、生
産性が低くコスト高となる。Furthermore, in JP-A-61-124524, the elongation at yield point is increased by further tempering after rolling, resulting in low productivity and high cost.
本発明は上記問題点に鑑み、降伏点伸びの大きい鉄筋コ
ンクリート用異形棒鋼の製造方法を提供することを目的
とする。In view of the above-mentioned problems, an object of the present invention is to provide a method for manufacturing a deformed steel bar for reinforced concrete with a large elongation at yield point.
本発明者らは、降伏点伸びに及ぼす化学組成、圧延条件
を種々検討した結果、Ａｒ３変態点までは圧延仕上温度
を低（すればする程、降伏伸びは増大し、Ａｒ３変態点
を下回ると、逆に降伏伸びは著しく減少するという知見
を得たことにより本発明を構成した。The present inventors investigated various chemical compositions and rolling conditions that affect the elongation at yield point, and found that the finishing temperature of rolling was lowered until the Ar3 transformation point (the lower the elongation at yield, the higher the elongation at yield; The present invention was constructed based on the finding that, on the contrary, the yield elongation is significantly reduced.
［課題を解決するための手段］
上記課題を解決するための本発明の技術手段は次の通り
である。すなわち、
Ｃ：０．０１〜０．０９重量％
Ｓｉ：０．０４〜１．００重量％
Ｍｎ ： ０．１０〜０．８０重量％
Ａｆ２： ０．０１０〜０．１００重量％Ｎ・０．０１
００重量％以下を含み、
さらに、
Ｔｉ：０．００５〜０．３００重量％
Ｎ、ｂ：０．００５〜０．３００重量％Ｖ ： ０．０
０５〜０．４００重量％のうち、１種または２種以上含
有し残部Ｆｅ及び不可避的不純物からなる鋼素材を９５
０℃以上に加熱し、Ａ 、ｒ ３点直上の温度で圧下率
１０％以上で仕上圧延する熱間圧延を施したのち空冷し
、フェライト組織の体積率が８０％以上を有するように
したことを特徴とする降伏伸びに優れた高強度鉄筋の製
造方法である。また、上記と同じ組成を有する鋼素材を
、９５０℃以上に加熱し、Ａｒ３点直上の温度で圧下率
１０％以上で仕上圧延する熱間圧延を施したのち、５℃
／ｓ以上の強制冷却を施し、４００℃以上で冷却を停止
し、フェライト組織の体積率が８０％以上を有するよう
にしてもよい。[Means for Solving the Problems] The technical means of the present invention for solving the above problems are as follows. That is, C: 0.01-0.09% by weight Si: 0.04-1.00% by weight Mn: 0.10-0.80% by weight Af2: 0.010-0.100% by weight N.0. 01
Furthermore, Ti: 0.005 to 0.300 wt% N, b: 0.005 to 0.300 wt% V: 0.0
A steel material containing one or more of 05 to 0.400% by weight, with the remainder being Fe and unavoidable impurities.
After being heated to 0°C or higher and finish-rolled at a temperature just above 3 points A and r with a reduction rate of 10% or more, it is air cooled so that the volume fraction of the ferrite structure is 80% or more. This is a method for manufacturing high-strength reinforcing bars with excellent yield elongation. In addition, a steel material having the same composition as above is heated to 950°C or higher, finish-rolled at a temperature just above the Ar3 point with a reduction rate of 10% or more, and then 5°C
Forced cooling may be performed at a rate of /s or more, and the cooling may be stopped at a temperature of 400° C. or more, so that the volume fraction of the ferrite structure is 80% or more.
鋼素材が、上記組成にさらに、
Ｃｒ ： ０．０５〜１．２０重量％
Ｍｏ ： ０．０５〜１．００重量％
Ｃｕ：０１０５〜１．５０重量％
Ｎｉ：０．０５〜１．５０重量％
Ｂ ：０．０００５〜０．００５０重量％のうち、１種
又は２種以上を含有し、残部Ｆｅ及び不可避的不純物か
らなる鋼素材であって、９５０℃以上に加熱し、Ａｒ３
点直上の温度で圧下率１０％以上で仕上圧延する熱間圧
延を施したのち空冷し、フェライト組織の体積率が８０
％以上を有するようにするか、又は９５０℃以上に加熱
し、Ａｒ３点直上の温度で圧下率１０％以上で仕上圧延
する熱間圧延を施したのち、５℃／ｓ以上の強制冷却を
施し、４００℃以上で冷却を停止し、フェライト組織の
体積率が８０％以上を有するようにしたことを特徴とす
る降伏伸びに優れた高強度鉄筋の製造方法である。The steel material further has the above composition: Cr: 0.05-1.20% by weight Mo: 0.05-1.00% by weight Cu: 0105-1.50% by weight Ni: 0.05-1.50% by weight %B: A steel material containing one or more of 0.0005 to 0.0050% by weight, with the balance consisting of Fe and unavoidable impurities, heated to 950°C or higher, Ar3
After finishing hot rolling at a temperature just above the point and with a reduction rate of 10% or more, air cooling is performed, and the volume fraction of the ferrite structure is 80.
% or more, or after hot rolling by heating to 950°C or more and finish rolling at a temperature just above the Ar3 point with a reduction rate of 10% or more, forced cooling at 5°C/s or more. , a method for producing high-strength reinforcing bars with excellent yield elongation, characterized in that cooling is stopped at 400° C. or higher, and the volume fraction of the ferrite structure is 80% or higher.
降伏伸びとは、第１図に示すような応力歪曲線において
、弾性領域εａから塑性領域に変化するりューダース帯
の伝播部分εｂをいう。The yield elongation refers to the propagation portion εb of the Luders band that changes from the elastic region εa to the plastic region in a stress strain curve as shown in FIG.
［作用１
鋼材を引張った場合にリューダース帯の形成される前の
最高応力が上降伏点であり、リューダース帯の伝播に必
要な応力が下降伏点である。[Action 1] When a steel material is stretched, the highest stress before the Lüders band is formed is the upper yield point, and the stress required for the propagation of the Lüders band is the lower yield point.
リューダース帯が形成される条件とは隣接結晶にすべり
を伝えるよりは、同一結晶内に一様なすべりを誘起した
方が容易な場合である。The conditions under which Lüders bands are formed are those where it is easier to induce uniform slip within the same crystal than to transmit slip to adjacent crystals.
結晶粒が小さい方が、リューダース帯つまり同一結晶内
にすべりを誘起しやすい。その時の応力は一般に下記の
ように示される。Smaller crystal grains are more likely to induce Lüders bands, or slip within the same crystal. The stress at that time is generally expressed as follows.
＋ ｋ ｙｄ ”２ ・・・（１）σ：上
降伏点、
Ｃ１：単結晶の降伏強さ
（結晶粒の大きさによらない）
△Ｃ１：変形速度を１０倍にしたときの変形応力の増大
Ｎ：変形結晶粒数
ｄ：結晶粒直径
ｋｙ：結晶粒の大きさによる係数
上記（１）式により、結晶粒が粗大な程Ｎｄ３は１に近
似し、そのとき、リューダース帯は形成されず、降伏点
における応力降下は０に等しい。+ k yd "2... (1) σ: Upper yield point, C1: Yield strength of single crystal (irrespective of crystal grain size) △C1: Deformation stress when the deformation rate is increased by 10 times Increase N: Number of deformed grains d: Grain diameter ky: Coefficient depending on grain size According to equation (1) above, the coarser the crystal grains, the closer Nd3 approaches 1, and at that time, Lüders bands are formed. First, the stress drop at the yield point is equal to zero.
つまり、
Ｃ＝σｉ＋ｋｙｄ ・・・（２）と
なり、下降伏点応力を示す値となる。In other words, C=σi+kyd (2), which is a value indicating the lower yield point stress.
また、同一結晶粒径でも加工され、初期可動転位密度が
高い場合、Ｃ，Ｎなどにトラップされている転位が少な
いので、明瞭な降伏点が出現しにくい。同様にベイナイ
トパーライト組織の方が、フェライト組織より、降伏点
が出現しにくい。Further, when the same crystal grain size is processed and the initial mobile dislocation density is high, there are few dislocations trapped by C, N, etc., so a clear yield point is difficult to appear. Similarly, a yield point is less likely to appear in a bainitic pearlite structure than in a ferrite structure.
以上の観点より降伏伸びの大きな鋼材を製造するには、
下記条件を満足させなければならないことがわかる。From the above points of view, in order to manufacture steel materials with large yield elongation,
It can be seen that the following conditions must be satisfied.
（１）結晶粒径は小さければ小さいほどよい。(1) The smaller the crystal grain size, the better.
（２）無加工な結晶であること。(2) It must be an unprocessed crystal.
（３）フェライト組織を多く含むこと。(3) Contains a large amount of ferrite structure.
これらを満足させるための成分、圧延条件の理由を下記
に示す。The reasons for the ingredients and rolling conditions to satisfy these requirements are shown below.
Ｃ：フェライト組織を８０％以上有するようにするため
、０．０９重量％Ｃを上限とする。また、０．０１重量
％より少ないと強度が確保できないのでこれを下限とす
る。C: In order to have a ferrite structure of 80% or more, the upper limit is 0.09% by weight C. Further, if it is less than 0.01% by weight, strength cannot be ensured, so this is set as the lower limit.
Ｓｉ：Ｓｉはフェライト相安定化元素であり、かつ固溶
硬化としての作用をもつ。１．００重量％を越えると靭
性に悪影響を及ぼす。また、製鋼時脱酸の役目を果たす
ため、０．０４重量％以上必要である。Si: Si is a ferrite phase stabilizing element and has a solid solution hardening effect. If it exceeds 1.00% by weight, toughness will be adversely affected. Further, in order to fulfill the role of deoxidizing during steel manufacturing, 0.04% by weight or more is required.
Ｍｎ：固溶強化元素であり、強度上０．１０重量％以上
必要である。また、０．８０重量％より多く添加すると
変態強化であるベイナイトが生成し、フェライト体積率
が８０％を下回り、降伏伸びが下がる。Mn: A solid solution strengthening element, 0.10% by weight or more is required for strength. Furthermore, if more than 0.80% by weight is added, bainite, which is transformation strengthening, is generated, the ferrite volume fraction becomes less than 80%, and the yield elongation decreases.
Ａｌ：脱酸剤として０．１００重量％以下添加する。Al: Added as a deoxidizing agent in an amount of 0.100% by weight or less.
Ｔｉ：フェライト相での析出強化を目的とし、０．００
５重量％以上添加する必要があり、０、３００重量％を
越えると粗大なＴｉＮを作り、靭性を阻害する。Ti: 0.00 for the purpose of precipitation strengthening in the ferrite phase
It is necessary to add 5% by weight or more, and if it exceeds 0.300% by weight, coarse TiN is formed and the toughness is impaired.
Ｎｂ：析出強化を目的とし、最！０．００５重量％以上
必要とし、０．３００重量％を越えても比例的に強度は
増加しない。Nb: For the purpose of precipitation strengthening, the highest! 0.005% by weight or more is required, and even if it exceeds 0.300% by weight, the strength will not increase proportionally.
Ｖ：Ｔｉと同様にフェライト相での析出強化を目的とし
、最低０．００５重量％以上必要とし、０．４００重量
％を越えると粗大なＶＮを形成し、延・靭性を阻害する
。V: Like Ti, it aims at precipitation strengthening in the ferrite phase, and requires at least 0.005% by weight. If it exceeds 0.400% by weight, coarse VN is formed, which impedes elongation and toughness.
Ｎ：ＴｉＮ、ＶｐＪなどの析出物による強度確保を目的
とし、０．０１００重量％より多く含有されると、粗大
なＴｉＮ、ＶＮ又はＡｆｆＮを析出し、さらにフリー固
溶Ｎの増加により、延性、靭性が著しく低下する。N: The purpose is to ensure strength by precipitates such as TiN and VpJ. If the content exceeds 0.0100% by weight, coarse TiN, VN or AffN will precipitate, and the increase in free solid solution N will reduce ductility and Toughness is significantly reduced.
Ｃｒ：固溶強化元素であり、靭性を低下されることな（
強度増加ができ、この効力を発揮するため０．０５重量
％以上必要で１．２０重量％以上添加すると、熱間加工
性が阻害される。Cr: Solid solution strengthening element that does not reduce toughness (
It is possible to increase strength, and in order to exhibit this effect, 0.05% by weight or more is required, and if 1.20% by weight or more is added, hot workability is inhibited.
Ｍｏ二固溶強化による強度増加に有効な元素で１．０重
量％を越えると、靭性が低下し、さらにコストも高くな
る。Mo2 is an element effective in increasing strength through solid solution strengthening, and if it exceeds 1.0% by weight, the toughness decreases and the cost also increases.
Ｃｕ：固溶強化による強度増加に有効な元素で１．５重
量％以上含有すると、熱間圧延中、表面割れが生じる。Cu: An element effective in increasing strength through solid solution strengthening, and if it is contained in an amount of 1.5% by weight or more, surface cracks will occur during hot rolling.
Ｎ１：靭性を改善するのに有効な元素であり、かつＣｕ
と同時に添加することにより、Ｃｕ添加時の熱間圧延で
の割れを防止する作用がある。N1: An element effective in improving toughness, and Cu
Adding Cu at the same time has the effect of preventing cracking during hot rolling when Cu is added.
多量に添加しても上記効果は比較的に望めないので、上
限を１．５重量％とした。Even if a large amount is added, the above effect cannot be expected, so the upper limit was set at 1.5% by weight.
Ｂ：固溶強化及びＢＮによる析出強化を目的として添加
し、０．００５重量％を越えると、γ粒界に偏析する固
溶Ｂ又はＢＮが増加し、フェライト生成成長の妨げとな
る。B: Added for the purpose of solid solution strengthening and precipitation strengthening by BN, and if it exceeds 0.005% by weight, solid solution B or BN segregated at the γ grain boundaries increases, which hinders ferrite formation and growth.
圧延における加熱温度は少なくともＴｉＣ１ＮｂＣ１Ｖ
Ｃが固溶される温度に加熱する必要があり、９５０℃以
上とした。The heating temperature during rolling is at least TiC1NbC1V
It was necessary to heat to a temperature at which C was dissolved as a solid solution, and the temperature was set at 950°C or higher.
仕上圧延はオーステナイト粒を微細にし、かつ、加工フ
ェライトとならないためにＡｒ３直上で１０％以上の圧
下率と定めた。また高強度・高靭化の必要がある場合、
圧延後さらに強制冷却を行い、および粗大防止のため５
℃／ｓ以上で冷却する。冷却停止温度が４００”Ｃを下
回ると、組織において、下部ベイナイト島状マルテンサ
イトの混在が著しくなり、延性、靭性を著しく劣化させ
る。In order to make the austenite grains fine and to prevent processed ferrite from forming in the finish rolling, a reduction rate of 10% or more was set immediately above Ar3. In addition, if high strength and toughness are required,
After rolling, forced cooling is further performed, and 5
Cool at ℃/s or more. When the cooling stop temperature is lower than 400''C, the presence of lower bainite island martensite becomes significant in the structure, significantly deteriorating ductility and toughness.
フェライト組織は大きな降伏伸び値を得るための必須組
織であり、体Ｐｌ！率８０％以上であると、明瞭な降伏
機及び降伏伸びを有し、建築設計上の要求を確実に満足
する。８０％より少ないと、降伏伸びが明確に現われな
い。The ferrite structure is an essential structure for obtaining a large yield elongation value, and the body Pl! When the ratio is 80% or more, the yield strength and yield elongation are clear, and architectural design requirements are certainly satisfied. If it is less than 80%, yield elongation will not clearly appear.
［実施例］ 第１表に実施例及び比較例の化学成分を示す。[Example] Table 1 shows the chemical components of Examples and Comparative Examples.
第１表中■〜［株］が実施例であり、■〜０は比較例で
ある。In Table 1, ■ to [stock] are examples, and ■ to 0 are comparative examples.
第２表は各々の鋼種における圧延条件を示すもので、加
熱は９５０℃以上で行い、仕上温度はＡｒｇ付近、仕上
圧延速度はおよそ８ ｍ ／ ｓ〜１２ｍ／ｓで実施し
た。断面１５０ｘ １５０ｍｍの正方形ビレットから公
称径２５ｍｍの異形棒鋼を製造した。Table 2 shows the rolling conditions for each steel type; heating was performed at 950° C. or higher, the finishing temperature was around Arg, and the finishing rolling speed was approximately 8 m/s to 12 m/s. A deformed steel bar with a nominal diameter of 25 mm was produced from a square billet with a cross section of 150 x 150 mm.
第３表に機械的特性値と（降伏伸びＥ、ｂ ） ／（弾
性伸びεａ）値及びフェライト体積率を示す。引張試験
はＪＩＳＧ３１１２に従って、評価した。Table 3 shows the mechanical property values, (yield elongation E,b)/(elastic elongation εa) values, and ferrite volume fraction. The tensile test was evaluated according to JISG3112.
本発明鋼及び本発明圧延条件を実施すればＹＳ≧４０
（ＳＤ４０クラス以上）ｋｇｆ／ｍｍ’でがつ（降伏伸
び）／（弾性伸び）の大きい（１０，０％以上）の異形
棒鋼を得ることが明らかである。If the steel of the present invention and the rolling conditions of the present invention are implemented, YS≧40
It is clear that a deformed steel bar with a large (yield elongation)/(elastic elongation) (10.0% or more) in kgf/mm' (SD40 class or higher) can be obtained.
Ｃ量を０．０７重量％レベルにした成分でＴｉｃ、Ｎｂ
ＣまたはＶＣの析出を利用した材料では（微細フェライ
ト）＋（析出物）の組織となり、第２図に示すように、
降伏伸びの絶対値が１２．０〜１４．０と大きい特性が
得られ、また、Ａｒ３を下回る温度で仕上圧延を実施し
た場合（■−Ｃ）、Ａｒ３直上の場合（■−Ｂ）と比べ
、半分以下の降伏伸びとなっている。これはフェライト
体積がたとえ８０％以上となっていても加工フエライト
となっているからである。Ingredients with C content at the level of 0.07% by weight, Tic, Nb
Materials using precipitation of C or VC have a structure of (fine ferrite) + (precipitates), as shown in Figure 2.
A property with a large absolute value of yield elongation of 12.0 to 14.0 was obtained, and when finish rolling was performed at a temperature below Ar3 (■-C), compared to the case just above Ar3 (■-B). , the yield elongation is less than half. This is because even if the ferrite volume is 80% or more, it is processed ferrite.
［発明の効果］
本発明は低Ｃ量（０，０１〜０．０９重量％）で、Ａ
ｒ ３直上付近間で加工を加えることにより、微細なフ
ェライトが得られ、降伏伸びが大きい材料が製造可能な
ことを見出した。[Effect of the invention] The present invention has a low C content (0.01 to 0.09% by weight), and A
It has been found that fine ferrite can be obtained and a material with a large yield elongation can be manufactured by applying processing to the area just above r3.
第１図は本発明鋼において仕上温度とεｂ／εａの関係
を示すグラフ、第２図は降伏伸びを評価するための弾性
領域をεａと降伏伸びεｂの定義を示す応力歪曲線図で
ある。FIG. 1 is a graph showing the relationship between finishing temperature and εb/εa for the steel of the present invention, and FIG. 2 is a stress strain curve diagram showing the definition of the elastic region εa and yield elongation εb for evaluating yield elongation.
Claims (1)
的不純物からなる鋼素材を９５０℃以上に加熱し、Ａｒ
＿３点直上の温度で圧下率１０％以上で仕上圧延する熱
間圧延を施したのち空冷し、フェライト組織の体積率が
８０％以上を有することを特徴とする降伏伸びに優れた
高強度鉄筋の製造方法。 ２ Ｃ：０．０１〜０．０９重量％ Ｓｉ：０．０４〜１．００重量％ Ｍｎ：０．１０〜０．８０重量％ Ａｌ：０．０１０〜０．１００重量％ Ｎ：０．０１００重量％以下を含み、 さらに、 Ｔｉ：０．００５〜０．３００重量％ Ｎｂ：０．００５〜０．３００重量％ Ｖ：０．００５〜０．４００重量％ のうち、１種または２種以上を含有し残部Ｆｅ及び不可
避的不純物からなる鋼素材を９５０℃以上に加熱し、Ａ
ｒ＿３点直上の温度で圧下率１０％以上で仕上圧延する
熱間圧延を施したのち、５℃／ｓ以上の強制冷却を施し
、４００℃以上で冷却を停止し、フェライト組織の体積
率が８０％以上を有することを特徴とする降伏伸びに優
れた高強度鉄筋の製造方法。 ３ 鋼素材が、 Ｃ：０．０１〜０．０９重量％ Ｓｉ：０．０４〜１．００重量％ Ｍｎ：０．１０〜０．８０重量％ Ａｌ：０．０１０〜０．１００重量％ Ｎ：０．０１００重量％以下を含み、 さらに、 Ｔｉ：０．００５〜０．３００重量％ Ｎｂ：０．００５〜０．３００重量％ Ｖ：０．００５〜０．４００重量％ のうち、１種または２種以上、および Ｃｒ：０．０５〜１．２０重量％ Ｍｏ：０．０５〜１．００重量％ Ｃｕ：０．０５〜１．５０重量％ Ｎｉ：０．０５〜１．５０重量％ Ｂ：０．０００５〜０．００５０重量％ のうち、１種又は２種以上を含有し、残部Ｆｅ及び不可
避的不純物からなる鋼素材である請求項１または２記載
の降伏伸びに優れた高強度鉄筋の製造方法。[Claims] 1 C: 0.01-0.09% by weight Si: 0.04-1.00% by weight Mn: 0.10-0.80% by weight Al: 0.010-0.100% by weight %N: 0.0100% by weight or less, furthermore, Ti: 0.005-0.300% by weight, Nb: 0.005-0.300% by weight, V: 0.005-0.400% by weight, A steel material containing one or more types and the remainder being Fe and unavoidable impurities is heated to 950°C or higher and Ar
A high-strength reinforcing bar with excellent yield elongation characterized by having a volume fraction of ferrite structure of 80% or more after being hot-rolled at a temperature just above the 3 point and with a reduction rate of 10% or more and then air-cooled. Production method. 2 C: 0.01-0.09% by weight Si: 0.04-1.00% by weight Mn: 0.10-0.80% by weight Al: 0.010-0.100% by weight N: 0.0100 and one or more of Ti: 0.005 to 0.300 weight %, Nb: 0.005 to 0.300 weight %, and V: 0.005 to 0.400 weight %. A steel material containing Fe and unavoidable impurities is heated to 950°C or higher, and A
After finishing hot rolling at a temperature just above the r_3 point with a reduction rate of 10% or more, forced cooling is performed at a rate of 5°C/s or more, cooling is stopped at 400°C or more, and the volume fraction of the ferrite structure is 80%. % or more, a method for producing high-strength reinforcing bars with excellent yield elongation. 3 The steel material is: C: 0.01-0.09% by weight Si: 0.04-1.00% by weight Mn: 0.10-0.80% by weight Al: 0.010-0.100% by weight N : 0.0100% by weight or less, and further one of Ti: 0.005-0.300% by weight, Nb: 0.005-0.300% by weight, V: 0.005-0.400% by weight. or two or more, and Cr: 0.05-1.20 wt% Mo: 0.05-1.00 wt% Cu: 0.05-1.50 wt% Ni: 0.05-1.50 wt% The high strength steel material with excellent yield elongation according to claim 1 or 2, which is a steel material containing one or more of B: 0.0005 to 0.0050% by weight, with the balance being Fe and unavoidable impurities. Method of manufacturing reinforcing bars.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP32269190A JP3031485B2 (en) | 1990-11-28 | 1990-11-28 | Method for manufacturing high-strength rebar with excellent yield elongation |
| CA002056348A CA2056348C (en) | 1990-11-28 | 1991-11-27 | Toner for developing electrostatic image and fixing method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP32269190A JP3031485B2 (en) | 1990-11-28 | 1990-11-28 | Method for manufacturing high-strength rebar with excellent yield elongation |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH04193908A true JPH04193908A (en) | 1992-07-14 |
| JP3031485B2 JP3031485B2 (en) | 2000-04-10 |
Family
ID=18146544
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP32269190A Expired - Fee Related JP3031485B2 (en) | 1990-11-28 | 1990-11-28 | Method for manufacturing high-strength rebar with excellent yield elongation |
Country Status (2)
| Country | Link |
|---|---|
| JP (1) | JP3031485B2 (en) |
| CA (1) | CA2056348C (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5716464A (en) * | 1995-06-15 | 1998-02-10 | Sollac | Process for producing a strip of hot rolled steel sheet having a very high yield point and the steel sheet obtained |
| JP2014009367A (en) * | 2012-06-28 | 2014-01-20 | Kyoei Steel Ltd | Bar steel for reinforcement used for stud welding |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR102317641B1 (en) * | 2019-11-29 | 2021-10-26 | 덴버코리아이엔씨(주) | Monitor apparatus for grouting |
-
1990
- 1990-11-28 JP JP32269190A patent/JP3031485B2/en not_active Expired - Fee Related
-
1991
- 1991-11-27 CA CA002056348A patent/CA2056348C/en not_active Expired - Lifetime
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5716464A (en) * | 1995-06-15 | 1998-02-10 | Sollac | Process for producing a strip of hot rolled steel sheet having a very high yield point and the steel sheet obtained |
| JP2014009367A (en) * | 2012-06-28 | 2014-01-20 | Kyoei Steel Ltd | Bar steel for reinforcement used for stud welding |
Also Published As
| Publication number | Publication date |
|---|---|
| CA2056348C (en) | 1999-10-19 |
| JP3031485B2 (en) | 2000-04-10 |
| CA2056348A1 (en) | 1992-05-30 |
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