JPS61281815A - Production of high-strength steel products having excellent low temperature toughness - Google Patents
Production of high-strength steel products having excellent low temperature toughnessInfo
- Publication number
- JPS61281815A JPS61281815A JP12341085A JP12341085A JPS61281815A JP S61281815 A JPS61281815 A JP S61281815A JP 12341085 A JP12341085 A JP 12341085A JP 12341085 A JP12341085 A JP 12341085A JP S61281815 A JPS61281815 A JP S61281815A
- Authority
- JP
- Japan
- Prior art keywords
- weight
- rolling
- temperature
- temp
- excellent low
- 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.)
- Pending
Links
- 229910000831 Steel Inorganic materials 0.000 title claims abstract description 20
- 239000010959 steel Substances 0.000 title claims abstract description 20
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 8
- 238000005096 rolling process Methods 0.000 claims abstract description 34
- 238000001816 cooling Methods 0.000 claims abstract description 16
- 229910001563 bainite Inorganic materials 0.000 claims abstract description 6
- 229910000734 martensite Inorganic materials 0.000 claims abstract description 5
- 239000000463 material Substances 0.000 claims description 14
- 230000003014 reinforcing effect Effects 0.000 abstract description 7
- 238000000034 method Methods 0.000 abstract description 6
- 238000005098 hot rolling Methods 0.000 abstract 1
- 239000013078 crystal Substances 0.000 description 8
- 230000009466 transformation Effects 0.000 description 6
- 229910001566 austenite Inorganic materials 0.000 description 3
- 230000000052 comparative effect Effects 0.000 description 3
- 238000007796 conventional method Methods 0.000 description 3
- 238000010438 heat treatment Methods 0.000 description 3
- 229910001562 pearlite Inorganic materials 0.000 description 3
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 3
- 230000000694 effects Effects 0.000 description 2
- 238000002844 melting Methods 0.000 description 2
- 230000008018 melting Effects 0.000 description 2
- 239000000047 product Substances 0.000 description 2
- 230000007704 transition Effects 0.000 description 2
- 230000015572 biosynthetic process Effects 0.000 description 1
- 238000005336 cracking Methods 0.000 description 1
- 238000009863 impact test Methods 0.000 description 1
- 230000001771 impaired effect Effects 0.000 description 1
- 239000002244 precipitate Substances 0.000 description 1
- 238000005496 tempering Methods 0.000 description 1
- 238000009864 tensile test Methods 0.000 description 1
Landscapes
- Heat Treatment Of Steel (AREA)
Abstract
Description
【発明の詳細な説明】
［発明の利用分野］
本発明は低温靭性に優れた高強度鋼材の製造方法に関す
る。DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a method for manufacturing high-strength steel materials with excellent low-temperature toughness.
［発明の背景］
従来鉄筋用の鋼材の製造方法としては、Ｃ：０．０２〜
０．１７ｆｉ量％、Ｓｉ：０．７重量％以下、Ｍｎ：０
．６〜２．０重量％、 Ａ ｌ ： ０．０１〜０．０
７重量％からなる鋼材を、Ａｃ３変態点〜Ａｅ３変態点
上２００℃の温度において圧延を開始し、Ａｎ変態点士
３０℃の温度において仕上圧延後、放冷又は強制冷却す
る方法や、圧延後急冷してベイナイトとパーライト組織
を生じさせないようにしてＡＣＩ変態点以下で焼戻しを
行なう方法が知られている。[Background of the Invention] Conventional methods for manufacturing steel materials for reinforcing bars include C: 0.02~
0.17fi amount%, Si: 0.7% by weight or less, Mn: 0
．． 6-2.0% by weight, Al: 0.01-0.0
A method in which rolling of a steel material consisting of 7% by weight is started at a temperature of 200°C above the Ac3 transformation point to the Ae3 transformation point, finish rolling at a temperature of 30°C above the An transformation point, and then allowed to cool or forced cooling, or after rolling. A method is known in which tempering is performed at a temperature below the ACI transformation point without causing bainite and pearlite structures by rapid cooling.
しかし、従来のこの種の方法により製造した鋼材には低
温靭性に劣るという欠点がある。特に、鋼材を鉄筋とし
て用いる場合、近時鉄筋は寒冷部においても多用される
ようになっているので、鉄筋にも低温靭性の特性が要求
されるようになっているが、従来の方法により製造した
鉄筋ではかかる要求に対応できない。However, steel materials manufactured by this type of conventional method have a drawback of poor low-temperature toughness. In particular, when steel materials are used as reinforcing bars, recently reinforcing bars have come to be used frequently even in cold areas, so the reinforcing bars are also required to have low-temperature toughness characteristics, but they cannot be manufactured using conventional methods. Reinforced steel bars cannot meet such requirements.
［発明の目的］
本発明は低温靭性に優れ、かつ、高強度の鋼材を製造す
る方法を提供することを目的とする。[Object of the Invention] An object of the present invention is to provide a method for manufacturing a steel material having excellent low-temperature toughness and high strength.
［発明の概要１ 上記目的は。[Summary of the invention 1 The above purpose is.
Ｃ： ０．０２〜０．１０重量％。C: 0.02 to 0.10% by weight.
Ｓｉ：０．０５〜０．５重量％。Si: 0.05-0.5% by weight.
Ｍｎ ＝ １．８０〜３．００重量％。Mn = 1.80 to 3.00% by weight.
ＡＪｌ：０．０２０〜０．０７０重量％。AJl: 0.020 to 0.070% by weight.
Ｎ ： ０．０１０ ＮＯ，０３０重量％。N: 0.010 NO, 030% by weight.
Ｆｅ： 残部
からなる素材を圧延開始温度８５０℃〜１０５０℃、仕
上げ圧延温度７８０℃〜６８０℃、仕上圧延率ｌパスあ
たり１５％以上で圧延をした後、５００℃以下までは１
０℃／秒以上の冷却速度で冷却してマルテンサイトとベ
イナイト組織にしたことを特徴とする低温の靭性が優れ
た高強度鋼材の製造方法によって達成される。Fe: After rolling the material consisting of the remainder at a rolling start temperature of 850°C to 1050°C, a finish rolling temperature of 780°C to 680°C, and a finishing rolling rate of 15% or more per 1 pass, 1
This is achieved by a method for producing a high-strength steel material with excellent low-temperature toughness, which is characterized by cooling at a cooling rate of 0° C./second or higher to form a martensite and bainite structure.
Ｃは０．０２〜０．１０重量％である。 ０．０２重量
％以上としたのは、高強度にするためである。 ０．１
０重量％以下としたのは、０．１０重量％を越えると低
温靭性が急激に劣化するためである。すなわち本発明で
は、Ｃを０．１０重量％以下にして低温惰性を良くして
いる点に１つの特徴がある。C is 0.02 to 0.10% by weight. The reason why the content is 0.02% by weight or more is to obtain high strength. 0.1
The reason for setting the content to be 0% by weight or less is because if it exceeds 0.10% by weight, the low temperature toughness will deteriorate rapidly. That is, one feature of the present invention is that the C content is set to 0.10% by weight or less to improve low-temperature inertia.
Ｓｉは０．０５〜０．５重量％である。 ０．０５重量
％以上としたのは、溶製時に脱酸を十分に行なうためで
あり、また１強度を改善するためである。Si is 0.05 to 0.5% by weight. The reason why the content is 0.05% by weight or more is to ensure sufficient deoxidation during melting and to improve the strength.
０．５重量％以下としたのは、０．５重量％を越えると
溶製時の脱酸生成物が非金属介在物として残存し、靭性
を害するためである。The reason why the content is set at 0.5% by weight or less is that if it exceeds 0.5% by weight, deoxidized products during melting will remain as nonmetallic inclusions, impairing toughness.
Ｍｎは１．８０〜３．００重量％である。 １．８０
重量％以上としたのは、冷却中のパーライト変態を抑制
し、ベイナイトあるいはマルテンサイト変態を促進する
ためである。つまり、焼入性を改善し。Mn is 1.80 to 3.00% by weight. 1.80
The reason for setting the content to be at least % by weight is to suppress pearlite transformation during cooling and promote bainite or martensitic transformation. In other words, it improves hardenability.
高強度化を図るためである。すなわち、本発明ではＭｎ
を高くして焼入性を高くすることにより強度を高めてい
る点に１つの特徴がある。一方、３．００重量％以下と
したのは、 ３．００を量％を越すと靭性を害するため
である。This is to increase the strength. That is, in the present invention, Mn
One of the characteristics is that the strength is increased by increasing the hardenability by increasing the hardenability. On the other hand, the reason why the content is 3.00% by weight or less is that if the content exceeds 3.00% by weight, the toughness will be impaired.
入車は０．０２０〜０．０７０重量％である。Ａｌは脱
酸と結晶粒を微細にするために必要な成分であり、脱酸
だけならば０．０１重量でもよいが。The content is 0.020-0.070% by weight. Al is a necessary component for deoxidizing and making crystal grains fine, and 0.01 weight may be enough for just deoxidizing.
０．０２０重量％以上としたのは、結晶粒を微細化して
低温靭性を高めるためである。 ０．０７０重量％以下
としたのは、 ０．０７０９量％を越えると圧延中に割
れが発生するためである。The reason why the content is 0.020% by weight or more is to refine the crystal grains and improve low-temperature toughness. The reason why it is set at 0.070% by weight or less is that if it exceeds 0.0709% by weight, cracks will occur during rolling.
Ｎはｏ、ｏｔｏ〜０．０３０重量％である。Ｎも結晶粒
を微細にするために必要な成分であり、圧延中の再結晶
粒を極微細にするにはＡＩＮを多量に作る必要があり、
そのためにはｏ、ｏｔｏ重量％を必要とする。ただ、
０．０３０重量％を越えると圧延割れのおそれがある。N is o, oto to 0.030% by weight. N is also a necessary component to make the crystal grains fine, and in order to make the recrystallized grains extremely fine during rolling, it is necessary to make a large amount of AIN.
For this purpose, o, oto weight % is required. just,
If it exceeds 0.030% by weight, there is a risk of rolling cracking.
圧延開始温度（素材の加熱温度）は８５０”０〜１０５
０℃である。加熱温度はオーステナイト結晶粒の粗大化
を防ぐために低温にすることが望ましく、１０５０℃を
越えるとオーステナイト結晶粒の粗大化を招く、ただ、
８５０℃未満では、ＡｆＬＮを多く含むため圧延割れを
生ずるおそれがある。Rolling start temperature (heating temperature of material) is 850" 0 to 105
It is 0°C. It is desirable that the heating temperature be low in order to prevent coarsening of austenite crystal grains, and if it exceeds 1050°C, coarsening of austenite crystal grains will occur.However,
If the temperature is lower than 850°C, rolling cracks may occur due to the high content of AfLN.
仕上圧延は７８０℃〜６８０℃において行なう、結晶粒
の微細化のためには仕上圧延は低温で行なうほど効果的
であるので７８０℃以下とする。しかし、圧延中の表面
割れの発生を防止するために６８０℃以上にする。Finish rolling is carried out at a temperature of 780°C to 680°C. Since finishing rolling is more effective at a lower temperature for grain refinement, the temperature is set at 780°C or lower. However, in order to prevent surface cracks from occurring during rolling, the temperature is set at 680°C or higher.
また、仕上圧延は、圧延率１５％以上で行なう、圧延率
を１５％以上としたのは、圧延中に再結晶化する結晶粒
を微細にするためであり、これ未満では結晶粒は粗大粒
になってしまう。In addition, finish rolling is performed at a rolling rate of 15% or more.The purpose of setting the rolling rate to be 15% or more is to make the crystal grains that recrystallize during rolling fine.If the rolling rate is less than this, the crystal grains become coarse grains. Become.
仕上圧延後は、５００℃以下まではｌＯ℃／秒以上の冷
却速度で４却する。仕上圧延後は、結晶粒は粒度Ｎｏ、
で１０以上の極細粒になっているためすぐ成長しやすい
、従って、仕上圧延後はすぐに急冷し、パーライト組織
が形成しないように、５００℃以下まではｌＯ℃／秒以
上の冷却速度で冷却する。After finish rolling, the steel is cooled to 500°C or less at a cooling rate of 10°C/second or more. After finish rolling, the grain size is No.
Because it has ultrafine grains of 10 or more, it is easy to grow.Therefore, it is rapidly cooled immediately after finish rolling, and cooled at a cooling rate of 10°C/sec or more until it reaches 500°C or below to prevent the formation of pearlite structure. do.
低温の惰性を高めるとともに強度を高くするためには圧
延中のオーステナイト結晶粒を細粒にしてそれが成長す
る以前にマルテンサイトとベイナイト変態させることが
必要であるが、本発明の上記構成によりそれが達成され
る。In order to increase the low-temperature inertia and increase the strength, it is necessary to make the austenite crystal grains fine during rolling and transform them into martensite and bainite before they grow. is achieved.
なお、素材成分として、Ｎｉ：０．１〜０．５重量％と
、Ｎｂ又は／及びＭｏをＮ ｂ ： ０．０１−０．０
５重量％、 Ｍ ｏ ： ０．０７〜０．３０重量％と
を選択的に含んでもよい、この場合には、強度が一層向
上する。In addition, as material components, Ni: 0.1 to 0.5% by weight, Nb or/and Mo, Nb: 0.01 to 0.0
5% by weight and Mo: 0.07 to 0.30% by weight. In this case, the strength is further improved.
この場合において、Ｎ［は、０．１重量％以上で低温靭
性をより一層改善するが、０．５重量％を越えるとその
効果が少なくなる。Ｗｂは０．０１重量％以上で強度と
低温靭性をより一層向上せしめるが、０．０５重量％を
越えると析出物のため靭性が劣化してくる。Ｍｏは０．
０７重量％以上で強度をより一層向上せしめるが、０．
３０重量％を越えると靭性が悪くなる。In this case, when N[ is 0.1% by weight or more, the low-temperature toughness is further improved, but when it exceeds 0.5% by weight, the effect is reduced. When Wb is 0.01% by weight or more, it further improves the strength and low-temperature toughness, but when it exceeds 0.05% by weight, the toughness deteriorates due to precipitates. Mo is 0.
If the content is 0.07% by weight or more, the strength will be further improved.
If it exceeds 30% by weight, toughness will deteriorate.
本発明により製造した鋼材は、低温靭性１強度に優れ、
たとえば低温で使用される鉄筋、ＬＰＧ容器、冷凍庫用
容器等に用いることができる。The steel produced according to the present invention has excellent low temperature toughness and strength.
For example, it can be used for reinforcing bars used at low temperatures, LPG containers, freezer containers, etc.
［発明の実施例］
第１表に示す成分の鋼を溶製し、鋼片に分塊後、第２表
中の加熱温度に加熱して、圧延をした。圧延の中間水冷
によって仕上げ温度のコントロールをした。仕上げ圧延
率は２０％であり、仕上げは直径２５ｍｍの棒である。[Examples of the Invention] Steels having the components shown in Table 1 were melted, and after blooming into steel slabs, they were heated to the heating temperatures shown in Table 2 and rolled. Finishing temperature was controlled by water cooling during rolling. The finish rolling rate is 20%, and the finish is a bar with a diameter of 25 mm.
仕上げロールを出た後に水冷をすることによって５００
℃までの平均冷却速度を５０℃／秒にした。水冷を行な
わない場合は平均３℃／秒の冷却速度である。圧延棒鋼
の引張試験と２ｍｍＶノツチシャルピー衝撃試験による
結果を第１表に示す。500 by water cooling after exiting the finishing roll.
The average cooling rate to °C was 50 °C/sec. When water cooling is not performed, the average cooling rate is 3° C./sec. Table 1 shows the results of the tensile test and 2 mm V notch Charpy impact test of the rolled steel bar.
比較例に比べ本実施例に係るものは、いづれも引張強さ
が高く、また、破面遷移温度マＴｒｓも低い、さらに−
１００℃におけるエネルギー遷移温度マＥ−□。、は比
較例に比べ１０倍以上も高い、すなわち、本実施例にお
いては、低温靭性１強度の両者ともに比較例に比べ優れ
ている。Compared to the comparative example, the specimens of this example all have higher tensile strength, lower fracture surface transition temperature Trs, and -
Energy transition temperature MaE-□ at 100°C. is more than 10 times higher than that of the comparative example. That is, in this example, both low-temperature toughness and strength are superior to the comparative example.
［発明の効果］
本発明は以上のように構成したので、従来品に比べ靭性
１強度ともに優れてた鋼材が得られる。[Effects of the Invention] Since the present invention is configured as described above, a steel material superior in both toughness and strength compared to conventional products can be obtained.
Claims (1)
上げ圧延温度７８０℃〜６８０℃、仕上圧延率１パスあ
たり１５％以上で圧延をした後、５００℃以下までは１
０℃／秒以上の冷却速度で冷却してマルテンサイトとベ
イナイト組織にしたことを特徴とする低温の靭性が優れ
た高強度鋼材の製造方法。 ２ Ｎｉ：０．１〜０．５重量％と Ｎｂ又は／及びＭｏを Ｎｂ：０．０１〜０．０５重量％、 Ｍｏ：０．０７〜０．３０重量％ で含む特許請求の範囲第１項記載の低温靭性に優れた高
強度鋼材の製造方法。[Claims] 1 C: 0.02-0.10% by weight, Si: 0.05-0.5% by weight, Mn: 1.80-3.00% by weight, Al: 0.020-0. .070% by weight, N: 0.010-0.030% by weight, Fe: The remaining material was rolled at a starting temperature of 850°C to 1050°C, a finishing rolling temperature of 780°C to 680°C, and a finishing rolling rate of 15% per pass. After rolling at above temperature, 1
A method for producing a high-strength steel material with excellent low-temperature toughness, characterized by cooling at a cooling rate of 0° C./second or more to form a martensite and bainite structure. 2 Claim 1 containing Ni: 0.1 to 0.5% by weight and Nb or/and Mo in the following proportions: Nb: 0.01 to 0.05% by weight, Mo: 0.07 to 0.30% by weight A method for producing a high-strength steel material with excellent low-temperature toughness as described in Section 1.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP12341085A JPS61281815A (en) | 1985-06-06 | 1985-06-06 | Production of high-strength steel products having excellent low temperature toughness |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP12341085A JPS61281815A (en) | 1985-06-06 | 1985-06-06 | Production of high-strength steel products having excellent low temperature toughness |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPS61281815A true JPS61281815A (en) | 1986-12-12 |
Family
ID=14859864
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP12341085A Pending JPS61281815A (en) | 1985-06-06 | 1985-06-06 | Production of high-strength steel products having excellent low temperature toughness |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS61281815A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS62164823A (en) * | 1986-01-16 | 1987-07-21 | Nippon Steel Corp | Production of reinforcing steel bar having excellent low temperature toughness |
-
1985
- 1985-06-06 JP JP12341085A patent/JPS61281815A/en active Pending
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS62164823A (en) * | 1986-01-16 | 1987-07-21 | Nippon Steel Corp | Production of reinforcing steel bar having excellent low temperature toughness |
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