JPH02310313A - Production of weather-resisting steel - Google Patents
Production of weather-resisting steelInfo
- Publication number
- JPH02310313A JPH02310313A JP13359289A JP13359289A JPH02310313A JP H02310313 A JPH02310313 A JP H02310313A JP 13359289 A JP13359289 A JP 13359289A JP 13359289 A JP13359289 A JP 13359289A JP H02310313 A JPH02310313 A JP H02310313A
- Authority
- JP
- Japan
- Prior art keywords
- steel
- rolling
- temperature range
- added
- cooling
- 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 52
- 239000010959 steel Substances 0.000 title claims abstract description 52
- 238000004519 manufacturing process Methods 0.000 title claims description 14
- 238000005096 rolling process Methods 0.000 claims abstract description 30
- 238000001816 cooling Methods 0.000 claims abstract description 27
- 229910052758 niobium Inorganic materials 0.000 claims abstract description 13
- 229910052804 chromium Inorganic materials 0.000 claims abstract description 12
- 229910052802 copper Inorganic materials 0.000 claims abstract description 10
- 229910052719 titanium Inorganic materials 0.000 claims abstract description 10
- 239000012535 impurity Substances 0.000 claims abstract description 5
- 229910052748 manganese Inorganic materials 0.000 claims abstract description 5
- 229910052759 nickel Inorganic materials 0.000 claims abstract description 5
- 238000010438 heat treatment Methods 0.000 claims description 14
- 229910000870 Weathering steel Inorganic materials 0.000 claims description 9
- 229910052742 iron Inorganic materials 0.000 claims description 4
- 239000000203 mixture Substances 0.000 abstract description 5
- 229910052799 carbon Inorganic materials 0.000 abstract description 3
- 229910052720 vanadium Inorganic materials 0.000 abstract 1
- 230000000694 effects Effects 0.000 description 21
- 238000000034 method Methods 0.000 description 13
- 239000000463 material Substances 0.000 description 10
- 229910001566 austenite Inorganic materials 0.000 description 7
- 239000006104 solid solution Substances 0.000 description 7
- 230000001965 increasing effect Effects 0.000 description 6
- 229910020012 Nb—Ti Inorganic materials 0.000 description 5
- 229910000859 α-Fe Inorganic materials 0.000 description 5
- 230000015572 biosynthetic process Effects 0.000 description 4
- 238000012545 processing Methods 0.000 description 3
- 239000000126 substance Substances 0.000 description 3
- 230000009466 transformation Effects 0.000 description 3
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 2
- 229910004688 Ti-V Inorganic materials 0.000 description 2
- 229910010968 Ti—V Inorganic materials 0.000 description 2
- 238000005275 alloying Methods 0.000 description 2
- 229910001563 bainite Inorganic materials 0.000 description 2
- 238000012733 comparative method Methods 0.000 description 2
- 238000002844 melting Methods 0.000 description 2
- 230000008018 melting Effects 0.000 description 2
- 150000004767 nitrides Chemical class 0.000 description 2
- 238000005728 strengthening Methods 0.000 description 2
- 238000012360 testing method Methods 0.000 description 2
- 229910002482 Cu–Ni Inorganic materials 0.000 description 1
- ATJFFYVFTNAWJD-UHFFFAOYSA-N Tin Chemical compound [Sn] ATJFFYVFTNAWJD-UHFFFAOYSA-N 0.000 description 1
- 230000002411 adverse Effects 0.000 description 1
- 238000005266 casting Methods 0.000 description 1
- 239000002131 composite material Substances 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 230000001627 detrimental effect Effects 0.000 description 1
- 229910052733 gallium Inorganic materials 0.000 description 1
- 230000001771 impaired effect Effects 0.000 description 1
- NBJBFKVCPBJQMR-APKOLTMOSA-N nff 1 Chemical compound C([C@H](NC(=O)[C@H](CCC(N)=O)NC(=O)[C@H](CCC(N)=O)NC(=O)[C@@H]1CCCN1C(=O)[C@H](CCCCN)NC(=O)[C@@H]1CCCN1C(=O)CC=1C2=CC=C(C=C2OC(=O)C=1)OC)C(=O)N[C@@H](CC=1C=CC=CC=1)C(=O)NCC(=O)N[C@@H](CC(C)C)C(=O)N[C@@H](CCCCNC=1C(=CC(=CC=1)[N+]([O-])=O)[N+]([O-])=O)C(=O)NCC(O)=O)C1=CC=CC=C1 NBJBFKVCPBJQMR-APKOLTMOSA-N 0.000 description 1
- 230000006911 nucleation Effects 0.000 description 1
- 238000010899 nucleation Methods 0.000 description 1
- 238000001556 precipitation Methods 0.000 description 1
- 230000001737 promoting effect Effects 0.000 description 1
- 238000007670 refining Methods 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 238000010583 slow cooling Methods 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 238000009864 tensile test Methods 0.000 description 1
Abstract
Description
【発明の詳細な説明】
（産業上の利用分野）
本発明は、加速冷却法を適用した耐候性鋼の製造方法に
関し、詳しくは、Ｃｕ、 Ｃｒ、 Ｎｂ、 Ｔｉまたは
Ｃｕ、 Ｎｉ、、Ｃｒ、 Ｎｂ、 Ｔｉを複合添加した
鋼において鋼中のＮ量を制御することにより低い炭素当
量においても、高張力化を可能とする耐候性鋼の製造方
法に関するものである。DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for producing weathering steel using an accelerated cooling method. The present invention relates to a method for manufacturing weathering steel that enables high tensile strength even at low carbon equivalents by controlling the amount of N in steel to which Nb and Ti are added in combination.
（従来の技術）
耐候性鋼はＣｕ、 Ｎｉ、 Ｃｒ等の耐候性向上元素を
含有しているため、Ｃｅｑ （炭素当量）が高く、溶接
性が悪いという問題点がある。これを改善するために、
製造工程において圧延仕上）温度の低下、その後の冷却
過程における冷却速度の上昇、冷却停止温度の低下等に
より強度の上昇を図り、この強度上昇に見合う合金元素
を削減し、Ｃｅｑの低減を図る方法が検討されてきた。(Prior Art) Since weathering steel contains weathering improving elements such as Cu, Ni, and Cr, it has a problem of high Ceq (carbon equivalent) and poor weldability. To improve this,
A method in which the strength is increased by lowering the rolling finishing temperature in the manufacturing process, increasing the cooling rate in the subsequent cooling process, lowering the cooling stop temperature, etc., and reducing the amount of alloying elements commensurate with this increase in strength to reduce Ceq. has been considered.
この例として、ＪＩＳ Ｇ３１１４−１９８８溶接構造
用耐候性熱間圧延鋼材があり、ここでは熱加工制御（Ｊ
ＩＳ Ｇ ０２０１鉄鋼熱処理用語 番号１１１２）所
謂制御圧延、制御冷却が綱材の要求品質を確保するため
の一つの方法として規定されている。An example of this is JIS G3114-1988 weather-resistant hot-rolled steel for welded structures, where thermal processing control (J
IS G 0201 Steel Heat Treatment Terminology No. 1112) So-called controlled rolling and controlled cooling are specified as one method to ensure the required quality of the steel rod.
（発明が解決しようとする課題）
しかし、圧延仕上温度を著しく低下させることは、材質
の異方性を増大し、母材靭性を劣化させることになる。(Problems to be Solved by the Invention) However, significantly lowering the finishing rolling temperature increases the anisotropy of the material and deteriorates the toughness of the base material.
また、圧延後の冷却速度の大幅な上昇、冷却停止温度の
低下は鋼材内部の残留応力の増大を招くことになり綱材
本来の特性を損なうという問題がある。Further, a significant increase in the cooling rate after rolling and a decrease in the cooling stop temperature lead to an increase in residual stress inside the steel material, which poses the problem of impairing the original properties of the steel material.
（課題を解決するための手段）
そこで、本発明者らは堰冷却の加速冷却の適用を前提と
し、耐候性網の高張力化を図るべく広範囲な研究を重ね
た結果、耐候性付与元素であるＣｕ、Ｃｒ、 Ｎｂ、
ＴｉまたはＣｕＳＮｉ、 Ｃｒ、 Ｎｂ、 Ｔｉを複合
添加した鋼においては、鋼中のＮ量を制御することによ
って、引張強さを上昇させることが可能であることを見
出して本発明に至ったものである。(Means for Solving the Problems) Therefore, the inventors of the present invention assumed the application of accelerated cooling by weir cooling, and as a result of conducting extensive research in order to increase the tensile strength of weather-resistant nets, we found that Some Cu, Cr, Nb,
The present invention was achieved by discovering that it is possible to increase the tensile strength of steel containing Ti or CuSNi, Cr, Nb, and Ti in combination by controlling the amount of N in the steel. be.
その第１発明は、Ｃ：０．０１〜０．２０％、Ｓｉ：０
．５０％以下、Ｍｎ：０．３〜２．０％、ＡＩ：０．０
１〜０．１０％、Ｃｕ：０．２０〜Ｏ，’５０％、Ｃｒ
：０．３０〜０．７５％、Ｎｂ：０．００５〜０゜０５
０％、Ｔｉ：０．００５〜ｏ、 ０２０％を含み、がっ
、Ｎ：０゜００１〜０．００３％の範囲に制御し、残部
Ｆｅおよび不可避的不純物から成る鋼片を、１０００〜
１２５０℃の温度範囲に加熱した後、７５０〜８５０℃
の温度範囲で圧下率３０％以上の圧下を含む圧延を行い
、７５０〜８５０℃の温度範囲にて圧延を完了し、直ち
に、２〜２０°（： ／ｓｅｃの冷却速度で４００〜６
００ ℃の温度範囲まで冷却する耐候性鋼の製造方法で
ある。The first invention is C: 0.01-0.20%, Si: 0
．． 50% or less, Mn: 0.3-2.0%, AI: 0.0
1~0.10%, Cu:0.20~O,'50%, Cr
:0.30~0.75%, Nb:0.005~0°05
0%, Ti: 0.005 to 0.020%, Ga, N: controlled to a range of 0.001 to 0.003%, and the balance consisting of Fe and unavoidable impurities.
After heating to a temperature range of 1250℃, 750-850℃
Rolling including reduction with a reduction rate of 30% or more is carried out in a temperature range of 2 to 20 degrees (: 400 to 6
This is a method for producing weathering steel that is cooled to a temperature range of 0.000C.
第２発明は、Ｃ：０．０１〜０．２０％、Ｓｉ：０．５
０％以下、Ｍｎ：０．３〜２．０ ％、八ｌ：０．０
１ 〜０．１０％、Ｃｕ：０．２０〜０．５０％、Ｎｉ
：０．３０％以下、Ｃｒ：０．３０〜０．７５％、Ｎｂ
：０．００５〜０．０５０％、Ｔ ｉ ： ０ 、００
５〜０．０２０％を含み、かつ、Ｎ：０．００Ｌ〜０．
００３％の範囲に制御し、残部Ｆｅおよび不可避的不純
物から成る鋼片を、１０００〜１２５０℃の温度範囲に
加熱した後、７５０〜８５０℃の温度範囲で圧下率３０
％以上の圧下を含む圧延を行い、７５０〜８５０℃の温
度範囲にて圧延を完了し、直ちに、２〜２０℃：、 ／
ｓｅｃの冷却速度で４００〜６００℃の温度範囲まで冷
却する耐候性鋼の製造方法である。The second invention is C: 0.01 to 0.20%, Si: 0.5
0% or less, Mn: 0.3-2.0%, 8l: 0.0
1 - 0.10%, Cu: 0.20 - 0.50%, Ni
: 0.30% or less, Cr: 0.30-0.75%, Nb
: 0.005-0.050%, Ti: 0,00
5-0.020%, and N: 0.00L-0.
After heating a steel piece consisting of Fe and unavoidable impurities to a temperature range of 1000 to 1250°C, a rolling reduction rate of 30% was applied in a temperature range of 750 to 850°C.
% or more, complete the rolling in a temperature range of 750 to 850°C, and immediately reduce the rolling to 2 to 20°C:, /
This is a method for manufacturing weathering steel in which the steel is cooled to a temperature range of 400 to 600° C. at a cooling rate of sec.
ある。be.
第３発明は、Ｖ：０．０１〜０．１０％、Ｂ：Ｏ，００
０５〜０゜００３５％の内から選んだ１種または２種を
含む請求項（１）または請求項（２）の製造方法である
。The third invention is V: 0.01 to 0.10%, B: O, 00
The method of claim (1) or claim (2) includes one or two selected from 0.05 to 0.0035%.
（作用） 以下、本発明の作用について詳述していくことにする。(effect) Hereinafter, the effects of the present invention will be explained in detail.
先ずは、本発明の骨子について説明する。First, the gist of the present invention will be explained.
従来、鋼中のＮは、その含有量の増大に伴ってその固溶
強化あるいは鋼中に窒化物生成元素がある場合には、窒
化物の生成による析出強化によって強度を上昇させるこ
とが知られている。Conventionally, it has been known that N in steel increases its strength by solid solution strengthening as its content increases, or by precipitation strengthening due to the formation of nitrides if the steel contains nitride-forming elements. ing.
しかし、本発明者らは、ＣｕＳＣｒ、 Ｎｂ、、Ｔｉま
たはＣｕ、 Ｎｉ、 Ｃｒ、 Ｎｂ、 Ｔｉを複合添加
した鋼を制御圧延および加速冷却して鋼材にする場合、
鋼中のＮｌを低減させることによって、上記制御圧延お
よび加速冷却の条件を一定にしたままで、鋼材強度を大
幅に上昇させることができると言う新しい知見を得てい
る。However, the present inventors found that when a steel containing CuSCr, Nb, Ti or a composite of Cu, Ni, Cr, Nb, and Ti is subjected to controlled rolling and accelerated cooling to produce a steel material,
We have obtained new knowledge that by reducing Nl in steel, the strength of the steel material can be significantly increased while keeping the conditions of controlled rolling and accelerated cooling constant.
第１図は、Ｃｕ−Ｃｒ−Ｎｂ−Ｔｉ系およびＣｕ−Ｎｉ
−Ｎｂ−Ｔｉ系鋼について、引張強さに及ぼすＮ’ｒＪ
の影ツを示したものである。同図から明らかなように、
Ｎｆｆ１の低減が強度上昇に太き（寄与することがわか
る。これらの現象についてさらに詳しく説明する。Figure 1 shows Cu-Cr-Nb-Ti system and Cu-Ni system.
-N'rJ effect on tensile strength for Nb-Ti steel
This shows the shadow of As is clear from the figure,
It can be seen that the reduction in Nff1 greatly contributes to the increase in strength. These phenomena will be explained in more detail.
本発明においては、Ｃｕ、 Ｃｒ、 Ｎｂを必須元素と
して含有している。これらの元素は、固溶状態において
はオーステナイト粒界に偏析して、粒界でのフェライト
核生成の駆動力を低減し、フェライト変態を抑制すると
ともに、ベイナイト変態を促進する作用をし、Ｃｕ、
Ｃｒ、 Ｎｂの共存状態において、この効果が一層高め
られると考えられる。なかでもＮｂは、鋼の焼入れ性を
最も向上させる作用をしているものとみられるので、圧
延の完了時に固溶状態にて存在するＮｂ量によって、鋼
の焼入れ性がほぼ決定されるとみられる。In the present invention, Cu, Cr, and Nb are contained as essential elements. In a solid solution state, these elements segregate at austenite grain boundaries, reduce the driving force for ferrite nucleation at grain boundaries, suppress ferrite transformation, and promote bainite transformation.
It is thought that this effect is further enhanced when Cr and Nb coexist. Among them, Nb seems to have the effect of most improving the hardenability of steel, so it seems that the hardenability of steel is almost determined by the amount of Nb present in solid solution at the completion of rolling.
−ＩＩＱに、固溶状態で存在する元素量は化合物の生成
の難易によって大きく影響されることは良く知られてい
るが、本発明の方法においては、上記Ｎｂは溶解度積か
らみて、窒化物を形成しやすい元素であるので、圧延完
了時に固溶状態にて存在するＮｂ量は鋼中のＮ量によっ
て大きく影響され、その結果、鋼の焼入れ性、ひいては
鋼の強度が鋼中のＮｉによって決定されるのであろう。It is well known that the amount of elements present in solid solution in -IIQ is greatly influenced by the difficulty of forming the compound, but in the method of the present invention, the above Nb is Since it is an element that is easily formed, the amount of Nb present in solid solution at the completion of rolling is greatly influenced by the amount of N in the steel, and as a result, the hardenability of steel and, ultimately, the strength of steel are determined by Ni in steel. It will probably be done.
つぎに、本発明の方法における個々の化学成分の限定理
由について説明する。Next, the reasons for limiting the individual chemical components in the method of the present invention will be explained.
Ｃは、鋼の強度を確保するために必要な元素であって、
０．０３％より少ないときはこの効果に乏しい。しかし
、０．２０％を超えて過多に添加するときは低温靭性お
よび溶接性を劣化させる。このため、その添、加重は０
．０３〜０．２０％とする。C is an element necessary to ensure the strength of steel,
When it is less than 0.03%, this effect is poor. However, when added in excess of 0.20%, low temperature toughness and weldability deteriorate. Therefore, its index and weight are 0
．． 03 to 0.20%.
Ｓｔは、鋼の溶製時の脱酸のために添加される。St is added for deoxidation during melting of steel.
しかし、０．５０％を超えて添加すると靭性にを害な影
響を及ぼす、このため、その添加量は０．５０％以下と
する。However, adding more than 0.50% will have a detrimental effect on toughness, so the amount added should be 0.50% or less.
Ｍｎは、鋼の強度の確保のために、少な（とも０゜３％
を添加する必要がある。しかし、２．０％を超えて添加
すると靭性を損なうため、その添加量は０．３〜２．０
％とする。In order to ensure the strength of the steel, Mn must be contained in a small amount (0.3%).
need to be added. However, adding more than 2.0% will impair toughness, so the amount added should be 0.3 to 2.0%.
%.
＾ｌは、鋼の脱酸剤として不可欠であるとともに、鋼中
の固溶ＮをＡＩＮとして固定し、鋼の靭性の向上に効果
を有する。さらに、ＡＩＮは、鋼片の加熱時のオーステ
ナイト粒の粗大化を抑制し、鋼の靭性を高める効果を有
する。かかる効果を有効に得るためには、０．０１％以
上の添加を必要とするが、０．１０％を超えて多量に添
加するときは、酸化物系介在物を形成して、かえって靭
性を劣化させる。従って、その添加量は０．０１〜０．
１０％とする。^l is essential as a deoxidizing agent for steel, and also fixes solid solution N in steel as AIN, which is effective in improving the toughness of steel. Furthermore, AIN has the effect of suppressing coarsening of austenite grains during heating of the steel billet and improving the toughness of the steel. In order to effectively obtain this effect, it is necessary to add 0.01% or more, but when adding in a large amount exceeding 0.10%, oxide inclusions may be formed and the toughness may be adversely affected. deteriorate. Therefore, the amount added is 0.01 to 0.
10%.
Ｃｕは、耐候性を確保するために必要であり、０゜２０
％より少ないときはこの効果に乏しい。しかし、０．５
０％を超えて過多に添加すると溶接性を劣化させる。こ
のため、その添加量はＯ４？０〜０．５０％とする。Cu is necessary to ensure weather resistance and is 0°20
%, this effect is poor. However, 0.5
When added in excess of more than 0%, weldability deteriorates. Therefore, the amount of O4 added is 0 to 0.50%.
Ｎｉは、靭性の向上、に有効な元素であるとともに、Ｃ
ｕ、 Ｃｒとの複合添加によって耐候性を向上させる元
素であり、要求される特性に応して添加れる。しかし、
経済性の観点から添加量の上限を０．３０％とする。Ni is an element that is effective in improving toughness, and is also effective in improving toughness.
It is an element that improves weather resistance when added in combination with u and Cr, and is added depending on the required characteristics. but,
From the viewpoint of economy, the upper limit of the amount added is set at 0.30%.
Ｃｒは、耐候性を確保するために必要な元素であり、０
．３０％より少ないときはこの効果に乏しい。Cr is an element necessary to ensure weather resistance, and 0
．． When the amount is less than 30%, this effect is poor.
しかし、０．７５％を超えて過多に添加するときは溶接
性を劣化させる。このため、その添加量は０，３０〜０
．７５％とする。However, when added in excess of 0.75%, weldability deteriorates. Therefore, the amount added is 0.30~0
．． It shall be 75%.
Ｎｂは、固溶状態で鋼の焼入れ性を著しく高めることが
できる元素であり、フェライト生成温度の低下によるフ
ェライト粒の微細化およびベイナイト変態の促進を通じ
て、靭性の向上に有効に作用する。かかる効果を有効に
得るには、本発明においては、Ｎｂを０．００５％以上
を添加する必要がある。しかし、過多に添加するときは
溶接性の劣化等を招くので、その添加量はｏ、ｏｏｓ〜
０．０５０％とする。Nb is an element that can significantly improve the hardenability of steel in a solid solution state, and effectively works to improve toughness by reducing the ferrite formation temperature to refine ferrite grains and promote bainite transformation. In order to effectively obtain such an effect, in the present invention, it is necessary to add Nb in an amount of 0.005% or more. However, if too much is added, it will cause deterioration of weldability, so the amount of addition should be o, oos ~
It shall be 0.050%.
Ｔｉは、ＴｉＮの形成を通して、鋼片の加熱時のオース
テナイト粒粗大化の抑制およびフェライト）亥生成の促
進の効果を有する。これらの効果を十分に発揮させるに
は、その添加量はｏ、ｏｏｓ〜０．０２０％とする。Through the formation of TiN, Ti has the effect of suppressing coarsening of austenite grains during heating of a steel billet and promoting the formation of ferrite. In order to fully exhibit these effects, the amount added should be from o,oos to 0.020%.
Ｎは、上記のＡＩおよびＴｉとともに、窒化物を形成し
て組織の微細化を促進し、靭性を改善する効果を有する
。しかし、過多に添加すると低Ｎ化による十分な強度上
昇効果が得られなくなる。従って、本発明においてはそ
の添加量は０．００１〜０．００３％とする。N, together with the above-mentioned AI and Ti, forms nitrides, promotes microstructural refinement, and has the effect of improving toughness. However, if it is added in excess, a sufficient strength-increasing effect due to the low N content cannot be obtained. Therefore, in the present invention, the amount added is 0.001 to 0.003%.
上記の元素の他に、強度上昇の点から下記の元素を１種
または２種を添加しても本発明の効果は損なわれるもの
ではない。In addition to the above-mentioned elements, the effects of the present invention will not be impaired even if one or two of the following elements are added in order to increase the strength.
Ｖは、強度上昇効果を有する元素であり、そのためには
少な（とも０．０１％を添加する必要がある。しかし、
ｏ、 ｉｏ％を超えて過多に添加すると溶接性を劣化さ
せる。このため、その添加量は０．０１〜０．１０％と
する。V is an element that has the effect of increasing strength, and for that purpose it is necessary to add a small amount (0.01%. However,
If added in excess of more than 0.0% or io%, weldability will deteriorate. Therefore, the amount added is 0.01 to 0.10%.
Ｂは、微量の添加によって焼入れ性を向上させるが、そ
の添加量が０．０００５％よりも少ないときは、その効
果が乏しく、一方、０．００３５％を超えて過多に添加
するとかえって焼入れ性が低下する。このため、その添
加量は０．０００５〜０．００３５％とする。B improves hardenability when added in a trace amount, but when the amount added is less than 0.0005%, the effect is poor; on the other hand, when added in excess of 0.0035%, the hardenability is improved. descend. Therefore, the amount added is 0.0005 to 0.0035%.
つぎに、製造条件の限定理由について説明する加熱温度
の上限を１２５０℃とした理由は、これ以上の温度では
加熱時のオーステナイト粒が粗大化し、その後の圧延で
の細粒化効果が十分得られず製品の靭性を劣化させるた
めである。また、加熱温度の下限を１ｏｏｏ’ｃとした
理由は、１０００℃未満ではオーステナイト粒への加工
歪みの付与に必要な固）容Ｎｂが得られないためである
。従って、加熱温度は１０００〜１２５０℃の範囲とす
る。Next, we will explain the reason for limiting the manufacturing conditions.The reason why the upper limit of the heating temperature was set at 1250°C is that at temperatures higher than this, the austenite grains during heating will become coarse, and the subsequent rolling will not be able to obtain a sufficient grain refining effect. This is because it deteriorates the toughness of the product. Further, the reason why the lower limit of the heating temperature is set to 100'C is that if it is less than 1000C, the solid volume Nb necessary for imparting processing strain to the austenite grains cannot be obtained. Therefore, the heating temperature is in the range of 1000 to 1250°C.
オーステナイト粒への加工歪みの付与には、オーステナ
イト低温域での圧延が有効でり、そのためには、７５０
〜８５０℃の温度範囲で少なくとも３０％以上の圧下が
必要である。従って、圧下は７５０〜８５０℃の温度範
囲で３０％以上と規定する。Rolling in the austenite low temperature range is effective for imparting processing strain to austenite grains, and for this purpose rolling at 750
A pressure reduction of at least 30% or more is required at a temperature range of ~850°C. Therefore, the reduction is defined as 30% or more in the temperature range of 750 to 850°C.
圧延完了温度は、７５０℃未満では材質の異方性が増大
し靭性も劣化し、また、８５０℃を超えても靭性が劣化
する。このため、圧延完了温度は７５０〜８５０℃の温
度範囲とする。If the rolling completion temperature is less than 750°C, the anisotropy of the material will increase and the toughness will deteriorate, and if it exceeds 850°C, the toughness will deteriorate. Therefore, the rolling completion temperature is in the temperature range of 750 to 850°C.
冷却速度は２℃／ｓｅｃ未満では加速冷却による十分な
強度上昇効果がなく、また、２０℃／ｓｅｃを超えると
鋼材内部の残留応力が増大する。このため、冷却速度は
２〜２０℃／ｓｅｃの範囲とする。If the cooling rate is less than 2°C/sec, accelerated cooling will not have a sufficient strength increasing effect, and if it exceeds 20°C/sec, residual stress inside the steel material will increase. Therefore, the cooling rate is set in a range of 2 to 20°C/sec.
冷却停止温度は４００℃未満では鋼材内部の残留応力が
増大し、６００″Ｃを超えると加速冷却による十分な強
度上昇効果が得られない。このため、冷却停止温度は４
００〜６００℃の温度範囲とする。If the cooling stop temperature is less than 400°C, the residual stress inside the steel material will increase, and if it exceeds 600"C, a sufficient strength increase effect cannot be obtained by accelerated cooling. Therefore, the cooling stop temperature is 4
The temperature range is 00 to 600°C.
（実施例）
本発明の構成は上記の通りであるが、以下に実施例につ
いて説明する。(Example) Although the configuration of the present invention is as described above, an example will be described below.
供試鋼板は第１表に示す化学成分を有する鋼を常法によ
り溶製、鋳造し、得られた鋼片を第２表に示す加熱、圧
延条件および冷却条件にしたがい、所定の厚さにしたも
のである。The test steel plates were made by melting and casting steel having the chemical composition shown in Table 1 using conventional methods, and rolling the obtained steel slabs to the specified thickness according to the heating, rolling and cooling conditions shown in Table 2. This is what I did.
これらの鋼板から試験片を採取し、引張試験を行った。Test pieces were taken from these steel plates and subjected to a tensile test.
その結果を第２表に併記する。The results are also listed in Table 2.
第１表には本発明法および比較法の化学成分、Ｃｅｑを
、第２表には加熱温度、圧延条件、冷却条件および引張
特性をそれぞれ示す。Table 1 shows the chemical components and Ceq of the method of the present invention and the comparative method, and Table 2 shows the heating temperature, rolling conditions, cooling conditions, and tensile properties, respectively.
”（以下余白）
第２表の線番号１〜３はＣｕ−Ｃｒ−Ｎｂ−Ｔｉ系、線
番号４〜６はＣｕ−Ｎｉ−Ｃｒ−Ｎｂ−Ｔｉ系、線番号
７．８はＣｕ−Ｎ１−Ｃｒ−Ｎｂ−Ｔｉ−Ｂ系、線番号
９．１０はＣｕ−Ｃｒ−Ｎｂ−Ｔｉ−Ｖ系、線番号１１
．１２はＣｕ−Ｎ１−Ｃｒ−Ｎｂ−Ｔｉ−Ｖ系、線番号
１３．１４はＣｕ−Ｃｒ−Ｎｂ−Ｔｉ−Ｂ系においてＮ
ｉのみを変化させたものである。ただし、加熱温度、圧
延条件、冷却条件は各成分系で一定である。(Left below) Wire numbers 1 to 3 in Table 2 are Cu-Cr-Nb-Ti system, wire numbers 4 to 6 are Cu-Ni-Cr-Nb-Ti system, and wire number 7.8 is Cu-N1. -Cr-Nb-Ti-B system, wire number 9.10 is Cu-Cr-Nb-Ti-V system, wire number 11
．． 12 is Cu-N1-Cr-Nb-Ti-V system, and wire number 13.14 is Cu-Cr-Nb-Ti-B system.
Only i is changed. However, the heating temperature, rolling conditions, and cooling conditions are constant for each component system.
本発明法の線番号１．４．７．９．１１．１３は成分系
はそれぞれ異なっているが、いずれの場合も、引張強さ
、降伏強さは鋼中のＮ量の低下により増大していること
が明らかである。一方、比較法の線番号２．３．５．６
．８．１０．１２．１４は、Ｎ量が本発明の規定値より
も多いため、引張強さ、降伏強さとも本発明法のそれら
よりも低下している。The wire numbers 1.4.7.9.11.13 of the present invention have different compositions, but in all cases, the tensile strength and yield strength increase due to the decrease in the amount of N in the steel. It is clear that On the other hand, line number 2.3.5.6 of the comparative method
．． In No. 8.10.12.14, since the amount of N was higher than the specified value of the present invention, both the tensile strength and yield strength were lower than those of the method of the present invention.
以上の実施例からも明らかなように、本発明に係わる耐
候性鋼の製造方法は、Ｎｉを０．００３％以下にするこ
とにより、大幅な強度上昇効果を得ることができる。As is clear from the above examples, the method for manufacturing weathering steel according to the present invention can significantly increase strength by reducing Ni to 0.003% or less.
なお、上記実施例は厚鋼板の製造方法についてのもので
あるが、本発明は他の鋼製品、例えば条鋼、形鋼の製造
にも適応し得ることはいうまでもない。It should be noted that although the above-mentioned embodiment relates to a method for manufacturing thick steel plates, it goes without saying that the present invention can also be applied to the manufacturing of other steel products, such as long steel and shaped steel.
（発明の効果）
以上説明したように、本発明に係わる耐候性鋼の製造方
法は、上記の構成であるから、鋼中のＮ量を低減するこ
とにより、大きな強度上昇効果を得ることができるため
、強度上昇に見合う合金元素が低減でき、Ｃｅｑも低く
することが可能で、ひいては、大幅に溶接性を向上させ
ることができ、また緩冷却のため鋼材内部の残留応力を
低下させるという優れた効果を有するものである。(Effects of the Invention) As explained above, since the method for manufacturing weathering steel according to the present invention has the above configuration, it is possible to obtain a large strength increasing effect by reducing the amount of N in the steel. Therefore, the amount of alloying elements commensurate with the increase in strength can be reduced, Ceq can also be lowered, and weldability can be significantly improved.Also, due to slow cooling, residual stress inside the steel material can be reduced. It is effective.
第１図はＣｕ−Ｃｒ−Ｎｂ−Ｔｉ系およびＣｕ−Ｎｉ−
Ｃｒ−Ｎｂ４ｉ系鋼についてのＮｉと引張強さとの関係
を示すグラフである。Figure 1 shows Cu-Cr-Nb-Ti and Cu-Ni-
It is a graph showing the relationship between Ni and tensile strength for Cr-Nb4i steel.
Claims (3)
下、Ｍｎ：０．３〜２．０％、Ａｌ：０．０１〜０．１
０％、Ｃｕ：０．２０〜０．５０％、Ｃｒ：０．３０〜
０．７５％、Ｎｂ：０．００５〜０．０５０％、Ｔｉ：
０．００５〜０．０２０％を含み、かつ、Ｎ：０．００
１〜０．００３％の範囲に制御し、残部Ｆｅおよび不可
避的不純物から成る鋼片を、１０００〜１２５０℃の温
度範囲に加熱した後、７５０〜８５０℃の温度範囲で圧
下率３０％以上の圧下を含む圧延を行い、７５０〜８５
０℃の温度範囲にて圧延を完了し、直ちに、２〜２０℃
／ｓｅｃの冷却速度で４００〜６００℃の温度範囲まで
冷却することを特徴とする耐候性鋼の製造方法。(1) C: 0.01-0.20%, Si: 0.50% or less, Mn: 0.3-2.0%, Al: 0.01-0.1
0%, Cu: 0.20~0.50%, Cr: 0.30~
0.75%, Nb: 0.005-0.050%, Ti:
Contains 0.005 to 0.020%, and N: 0.00
After heating a steel piece consisting of Fe and unavoidable impurities to a temperature range of 1000 to 1250°C, with a reduction rate of 30% or more in a temperature range of 750 to 850°C. Rolling including reduction is carried out to 750-85
Rolling is completed in the temperature range of 0°C, and immediately the temperature is reduced to 2 to 20°C.
A method for producing weathering steel, characterized by cooling to a temperature range of 400 to 600°C at a cooling rate of /sec.
下、Ｍｎ：０．３〜２．０％、Ａｌ：０．０１〜０．１
０％、Ｃｕ：０．２０〜０．５０％、Ｎｉ：０．３０％
以下、Ｃｒ：０．３０〜０．７５％、Ｎｂ：０．００５
〜０．０５０％、Ｔｉ：０．００５〜０．０２０％を含
み、かつ、Ｎ：０．００１〜０．００３％の範囲に制御
し、残部Ｆｅおよび不可避的不純物から成る鋼片を、１
０００〜１２５０℃の温度範囲に加熱した後、７５０〜
８５０℃の温度範囲で圧下率３０％以上の圧下を含む圧
延を行い、７５０〜８５０℃の温度範囲にて圧延を完了
し、直ちに、２〜２０℃／ｓｅｃの冷却速度で４００〜
６００℃の温度範囲まで冷却することを特徴とする耐候
性鋼の製造方法。(2) C: 0.01-0.20%, Si: 0.50% or less, Mn: 0.3-2.0%, Al: 0.01-0.1
0%, Cu: 0.20-0.50%, Ni: 0.30%
Below, Cr: 0.30-0.75%, Nb: 0.005
~0.050%, Ti: 0.005~0.020%, N: controlled within the range of 0.001~0.003%, and the balance consisting of Fe and unavoidable impurities.
After heating to a temperature range of 000~1250℃, 750~
Rolling including reduction with a rolling reduction rate of 30% or more is performed in a temperature range of 850°C, and rolling is completed in a temperature range of 750 to 850°C. Immediately, rolling is performed at a cooling rate of 2 to 20°C/sec.
A method for producing weathering steel, characterized by cooling to a temperature range of 600°C.
０．００３５％の内から選んだ１種または２種を含む請
求項（１）または請求項（２）の製造方法。(3) V: 0.01~0.10%, B: 0.0005~
The manufacturing method according to claim (1) or claim (2), containing one or two selected from 0.0035%.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP13359289A JPH02310313A (en) | 1989-05-25 | 1989-05-25 | Production of weather-resisting steel |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP13359289A JPH02310313A (en) | 1989-05-25 | 1989-05-25 | Production of weather-resisting steel |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH02310313A true JPH02310313A (en) | 1990-12-26 |
Family
ID=15108414
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP13359289A Pending JPH02310313A (en) | 1989-05-25 | 1989-05-25 | Production of weather-resisting steel |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH02310313A (en) |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2000043561A1 (en) * | 1999-01-20 | 2000-07-27 | Bethlehem Steel Corporation | Method of making an as-rolled multi-purpose weathering steel plate and product therefrom |
| KR100435428B1 (en) * | 1999-06-17 | 2004-06-10 | 주식회사 포스코 | Method of making an As-rolled multi-purpose weathering steel plate and product therefrom |
| KR100554756B1 (en) * | 2001-12-27 | 2006-02-24 | 주식회사 포스코 | A Method of Manufacturing the Fine-Grained Ferrite High-Strength Steel |
| CN106191672A (en) * | 2016-07-12 | 2016-12-07 | 山东钢铁股份有限公司 | The weathering steel of a kind of electric power tunnel use and manufacture method thereof |
| CN108251737A (en) * | 2018-02-23 | 2018-07-06 | 柳州钢铁股份有限公司 | A kind of manufacturing method of yield strength 550MPa grade high-strength weathering steels |
-
1989
- 1989-05-25 JP JP13359289A patent/JPH02310313A/en active Pending
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2000043561A1 (en) * | 1999-01-20 | 2000-07-27 | Bethlehem Steel Corporation | Method of making an as-rolled multi-purpose weathering steel plate and product therefrom |
| AU772626B2 (en) * | 1999-01-20 | 2004-05-06 | Isg Technologies | Method of making an as-rolled multi-purpose weathering steel plate and product therefrom |
| KR100435428B1 (en) * | 1999-06-17 | 2004-06-10 | 주식회사 포스코 | Method of making an As-rolled multi-purpose weathering steel plate and product therefrom |
| KR100554756B1 (en) * | 2001-12-27 | 2006-02-24 | 주식회사 포스코 | A Method of Manufacturing the Fine-Grained Ferrite High-Strength Steel |
| CN106191672A (en) * | 2016-07-12 | 2016-12-07 | 山东钢铁股份有限公司 | The weathering steel of a kind of electric power tunnel use and manufacture method thereof |
| CN108251737A (en) * | 2018-02-23 | 2018-07-06 | 柳州钢铁股份有限公司 | A kind of manufacturing method of yield strength 550MPa grade high-strength weathering steels |
| CN108251737B (en) * | 2018-02-23 | 2019-12-17 | 柳州钢铁股份有限公司 | Manufacturing method of high-strength weathering steel with yield strength of 550MPa |
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