JP3033459B2 - Manufacturing method of non-heat treated high strength steel - Google Patents
Manufacturing method of non-heat treated high strength steelInfo
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- JP3033459B2 JP3033459B2 JP7002015A JP201595A JP3033459B2 JP 3033459 B2 JP3033459 B2 JP 3033459B2 JP 7002015 A JP7002015 A JP 7002015A JP 201595 A JP201595 A JP 201595A JP 3033459 B2 JP3033459 B2 JP 3033459B2
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- treated high
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Description
【０００１】[0001]
【産業上の利用分野】本発明は、主として建設機械用鋼
材として用いられる非調質高張力鋼の製造方法に関す
る。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing non-heat treated high-strength steel mainly used as steel for construction machinery.
【０００２】[0002]
【従来の技術】近年、使用鋼材の重量軽減を目的とし
て、高強度鋼材が様々な産業界において積極的に利用さ
れるようになってきた。建設機械用鋼材についてもこの
ような傾向が現れ始めており、引張強さが590N/mm2級以
上の高張力鋼板が用いられている。また、近年は製造コ
スト削減のため、非調質化により熱処理コストの削減を
図る方法が既に特開平４−103716号公報および特開平５
−171271号公報等に示されている。2. Description of the Related Art In recent years, high-strength steel materials have been actively used in various industries for the purpose of reducing the weight of steel materials used. And has also begun to appear this tendency, the tensile strength is employed 590N / mm 2 or higher grade of high-tensile steel plate for construction machinery steel materials. In recent years, in order to reduce the production cost, a method for reducing the heat treatment cost by non-tempering has already been disclosed in JP-A-4-103716 and JP-A-5-103716.
No. 171271.
【０００３】特開平４−103716号公報で提案された方法
は、圧延温度 Ar3〜900 ℃での累積圧下率30％以上と、
実質上γ相単相域での熱間圧延であり、この温度域でオ
ーステナイトの微細化による強度向上を図っているもの
である。しかし、目下の目標となっている引張強度780N
/mm2級の性能は得られない。The method proposed in Japanese Patent Application Laid-Open No. 4-103716 discloses that a rolling reduction at a rolling temperature of Ar 3 to 900 ° C. is 30% or more,
This is substantially hot rolling in a single phase region of γ phase, and in this temperature range, strength is improved by miniaturization of austenite. However, the current target tensile strength of 780 N
/ mm Class 2 performance cannot be obtained.
【０００４】また、特開平５−171271号公報に提案され
た方法は、圧延時800 ℃以下の温度での全圧下量を５〜
15mmの範囲に制御し Ar3点以下の温度で圧延を完了する
ことにより、低降伏比の590 〜690 N/mm2 の鋼を得るこ
とを目的とするものであり、用いられているスラブの厚
さが通常200 mmを超えることから、この圧延方法では圧
下量が例えば約８％以下となり、極端にYS、耐力が低く
なることが判明した。また、耐力確保のために低温で圧
延しようとすると鋼板の平坦度が悪くなり矯正のための
コストの増加を招くことが分かった。The method proposed in Japanese Patent Application Laid-Open No. 5-171271 discloses that the total rolling reduction at a temperature of 800 ° C. or less during rolling is 5 to 5.
By completing the rolling at a range in the control and Ar 3 point or less of the temperature of 15 mm, is intended for the purpose of obtaining a low yield ratio of 590 ~690 N / mm 2 of steel, the slab used Since the thickness usually exceeds 200 mm, it was found that the rolling reduction was, for example, about 8% or less in this rolling method, and YS and proof stress were extremely low. In addition, it was found that flatness of the steel sheet deteriorated when rolling was performed at a low temperature in order to secure the proof stress, which led to an increase in cost for straightening.
【０００５】[0005]
【発明が解決しようとする課題】ここに本発明の目的
は、780 N/mm2 級非調質高張力鋼の製造方法を提供する
ものである。より具体的には本発明の目的は、引張強度
780N/mm2以上、降伏強度685N/mm2以上、伸び16％以上、
そしてvE-2047J以上の特性を満足する非調質高張力鋼の
製造方法を提供するものである。An object of the present invention herein INVENTION Problem to be Solved] is to provide a method of manufacturing a 780 N / mm 2 Kyuhi tempered high tensile steel. More specifically, the purpose of the present invention is to determine the tensile strength
780N / mm 2 or more, the yield strength 685N / mm 2 or more, elongation more than 16%,
It is another object of the present invention to provide a method for producing a non-heat-treated high-strength steel satisfying the characteristics of vE -20 47J or more.
【０００６】[0006]
【課題を解決するための手段】本発明は、上記問題を解
決するために種々の検討を重ねた結果、化学成分を調整
し、特に圧延時、 (α＋γ) 二相域で累積圧下率16〜30
％となるように熱間圧延することによってフェライト+
オーステナイトの微細化を図ることに着目し、Ni、Nbを
適量添加したスラブをAr3 点以上に加熱した後に、Ar1+
10℃〜Ar3-10℃の (α＋γ) 二相域の温度範囲で16〜30
％の圧下を行い圧延した後(Ar1＋30℃)±20℃の温度で
仕上げた後、空冷したところ、非調質であってもJIS SH
Y685規格を満たす鋼材が得られることを確認して本発明
を完成した。According to the present invention, as a result of various studies to solve the above-mentioned problems, the chemical composition is adjusted, and particularly, during rolling, the cumulative rolling reduction in the (α + γ) two-phase region is 16 to 30
% By hot rolling so that the ferrite +
Noting that miniaturization of austenite, Ni, and suitable amounts slabs of Nb after heating to above 3 points Ar, Ar 1 +
10 ° C. to Ar 3 -10 ° C. the (alpha + gamma) in a temperature range of dual phase region 16-30
% Rolling (Ar 1 + 30 ° C), finishing at a temperature of ± 20 ° C, and then air-cooled.
The present invention was completed after confirming that a steel material meeting the Y685 standard was obtained.
【０００７】よって、本発明の要旨とするところは、重
量％で、 Ｃ：0.10〜0.20％、 Si：0.03〜0.60％、 Mn：0.50〜
2.00％、 Mo：0.10〜0.80％、 Nb：0.008 〜0.100 ％、sol.Al：
0.005 〜0.060 ％、 Ｂ：0.0005〜0.0015％、 残部Feおよび不可避的不純物から成る鋼組成を有する鋼
片を1100〜1250℃の温度範囲に加熱後熱間圧延するに際
して、Ar1+10〜Ar3-10℃ (α＋γ) 二相域温度範囲での
累積圧下率が16〜30％、仕上げ圧延温度(Ar1+30)±20℃
となるように熱間圧延することを特徴とする、引張強度
780N/mm 2 以上、降伏強度685N/mm 2 以上、伸び16％以上、
そしてvE -20 47J以上の特性を満足する非調質高張力鋼の
製造方法である。Therefore, the gist of the present invention is that, in terms of% by weight, C: 0.10 to 0.20%, Si: 0.03 to 0.60%, Mn: 0.50 to
2.00%, Mo: 0.10 ~ 0.80%, Nb: 0.008 ~ 0.100%, sol.Al:
When a steel slab having a steel composition composed of 0.005 to 0.060%, B: 0.0005 to 0.0015%, and the balance of Fe and unavoidable impurities is heated to a temperature range of 1100 to 1250 ° C and then hot-rolled, Ar 1 +10 to Ar 3 -10 ° C (α + γ) Cumulative rolling reduction in the two-phase temperature range is 16-30%, finishing rolling temperature (Ar 1 +30) ± 20 ° C
Tensile strength characterized by hot rolling so that
780N / mm 2 or more, the yield strength 685N / mm 2 or more, elongation more than 16%,
And it is a method for manufacturing a non-heat treated high-strength steel satisfying the characteristics of vE -20 47J or more .
【０００８】本発明の好適態様によれば、前記鋼組成
は、さらに重量で下記成分の少なくとも１種を含むもの
であってもよい。Cu：0.50％以下、Ni：1.50％以下、C
r：1.00％以下、Ｖ0.10％以下、Ti：0.05％以下のうち
１種または２種以上。本発明は、上記成分鋼を上記方法
で熱間圧延し、放冷した後、さらにAc1 点以下の温度に
加熱して焼戻しを行ってもよい。According to a preferred aspect of the present invention, the steel composition may further include at least one of the following components by weight. Cu: 0.50% or less, Ni: 1.50% or less, C
r: 1.00% or less, V0.10% or less, Ti: one or more of 0.05% or less. In the present invention, the component steel may be hot-rolled by the above-described method, allowed to cool, and then tempered by heating to a temperature of 1 point or less of Ac.
【０００９】[0009]
【作用】以下、本発明の各構成要件をその作用効果とと
もに詳述する。なお、本明細書において成分組成は特に
ことわりがないかぎり「重量％」で示す。The following is a detailed description of each component of the present invention along with its operational effects. In addition, in this specification, a component composition is shown by "weight%" unless there is particular notice.
【００１０】Ｃ：Ｃは添加量が多いと焼入れ性が良くな
り、強度が高くなる一方で溶接性が悪くなる。またＣ量
が少ないと本発明の780N級の強度が得られなくなる。よ
ってＣ添加量が0.10〜0.20％、好ましくは0.12〜0.16％
とした。C: When C is added in a large amount, quenching properties are improved, and strength is increased, but weldability is deteriorated. On the other hand, if the amount of C is small, the 780N class strength of the present invention cannot be obtained. Therefore, the amount of C added is 0.10 to 0.20%, preferably 0.12 to 0.16%.
And
【００１１】Si：Siは脱酸剤であるとともに、Ｃと同
様、鋼板の強度向上に寄与する元素であるが、添加量が
多いと靱性が悪くなり、少ないと強度の向上効果はなく
なる。よってSi添加量は0.03〜0.60％とした。好ましく
は、0.05〜0.35％である。Si: Si is a deoxidizing agent and, like C, is an element that contributes to the improvement of the strength of the steel sheet. However, if the addition amount is large, the toughness is deteriorated, and if it is small, the effect of improving the strength is lost. Therefore, the addition amount of Si is set to 0.03 to 0.60%. Preferably, it is 0.05 to 0.35%.
【００１２】Mn：Mnは添加によって焼入性が良くなり、
強度が高くなるが、添加量が多いと溶接性が悪くなり、
少ないと強度向上効果はなくなる。よってMn添加量は0.
50〜2.00％とした。好ましくは、0.50〜1.5 ％である。Mn: Mn improves hardenability by addition,
Although the strength is high, the weldability is poor if the addition amount is large,
If the amount is small, the effect of improving strength is lost. Therefore, the amount of Mn added is 0.
50 to 2.00%. Preferably, it is 0.50-1.5%.
【００１３】Mo：Moは添加によって焼入性が良くなり強
度が高くなる。さらにオーステナイト再結晶を抑制する
が、添加量が多いとコストの上昇を招くばかりかMn炭化
物が析出することにより靱性が低下する。よってMo添加
量は0.10〜0.80％とした。好ましくは、0.20〜0.50％で
ある。Mo: Mo improves the hardenability and the strength by adding Mo. Further, austenite recrystallization is suppressed. However, if the addition amount is large, not only the cost is increased but also the toughness is reduced due to precipitation of Mn carbide. Therefore, the amount of Mo added was set to 0.10 to 0.80%. Preferably, it is 0.20 to 0.50%.
【００１４】Nb：Nbは制御圧延による結晶粒の微細化作
用効果を奏する元素である。その含有量が0.01％未満で
は上記作用効果を奏することが困難であり、一方0.10％
超では逆に脆化が著しくなり過ぎることとなる。よって
Nb含有量を0.008 〜0.100 ％とした。好ましくは、0.01
0 〜0.035 ％である。Nb: Nb is an element having an effect of making crystal grains fine by controlled rolling. If the content is less than 0.01%, it is difficult to exert the above-mentioned effects, while 0.10%
On the contrary, embrittlement becomes excessively remarkable in the case of exceeding. Therefore
The Nb content was set to 0.008 to 0.100%. Preferably, 0.01
0 to 0.035%.
【００１５】Al：Alは脱酸のために必要な元素であるだ
けでなく窒化物を形成しＮがＢと反応することを防ぐこ
とができるが添加量が少ないと添加効果は得られない。
よってAl添加量は0.005 〜0.060 ％とした。好ましく
は、0.045 〜0.060 ％である。Al: Al is not only an element necessary for deoxidation but also forms a nitride and can prevent N from reacting with B. However, if the addition amount is small, the addition effect cannot be obtained.
Therefore, the addition amount of Al is set to 0.005 to 0.060%. Preferably, it is 0.045 to 0.060%.
【００１６】Ｂ：Ｂは添加によって焼入性が良くなり、
強度および靱性の向上が可能であるが、添加量が少ない
とその効果は得られず、添加量が多いと靱性がかえって
悪くなる。よってＢ添加量は0.0005〜0.0015％とした。
好ましくは、0.0010〜0.0015％である。B: The addition of B improves the hardenability by adding
Although the strength and toughness can be improved, the effect cannot be obtained if the amount is small, and the toughness is rather deteriorated if the amount is large. Therefore, the addition amount of B is set to 0.0005 to 0.0015%.
Preferably, it is 0.0010 to 0.0015%.
【００１７】本発明の鋼組成上さらに強度向上のため
に、下記合金元素の少なくとも１種を添加してもよい。 Cu：Cuは添加量によって固溶強化および析出強化作用に
よる強度向上効果があるが、添加量が多いと靱性が低下
する。よってCu添加量は0.50％以下とした。In order to further improve the strength of the steel composition of the present invention, at least one of the following alloy elements may be added. Cu: Cu has an effect of improving the strength by solid solution strengthening and precipitation strengthening depending on the added amount, but if the added amount is large, the toughness is reduced. Therefore, the added amount of Cu is set to 0.50% or less.
【００１８】Ni：Niは添加によって靱性の向上および焼
入性を良くする。さらに高温でのCuのオーステナイト粒
界への析出による割れ防止としても役に立つ。しかし、
添加量が多いとコストの上昇を伴うので多量に添加する
ことは意味はない。よってNi添加量は1.50％以下とし
た。Ni: Ni enhances toughness and hardenability by adding Ni. Further, it is also useful for preventing cracking due to precipitation of Cu on austenite grain boundaries at high temperatures. But,
It is meaningless to add a large amount because a large amount increases the cost. Therefore, the amount of Ni added is set to 1.50% or less.
【００１９】Cr：Crは添加によって耐食性、強度が高く
なるが、添加量が多いと溶接性の低下を生じる。よって
Cr添加量は1.00％以下とした。Cr: The addition of Cr increases the corrosion resistance and strength, but a large amount of Cr causes a decrease in weldability. Therefore
The Cr content was 1.00% or less.
【００２０】Ｖ：Ｖは析出硬化により強度を向上させる
が、0.1 ％を超えて含有させると靱性が低下する。よっ
てＶ添加量は0.10％以下とした。V: V improves the strength by precipitation hardening, but if it exceeds 0.1%, the toughness decreases. Therefore, the added amount of V is set to 0.10% or less.
【００２１】Ti：Tiは添加によって微細な窒化物を形成
しＮがＢやAlと反応するのを防ぐために必要である。し
かし添加量が多いと靱性を劣化させる。よってTi添加量
は0.05％以下とした。Ti: Ti is necessary in order to form a fine nitride by addition and to prevent N from reacting with B or Al. However, if the addition amount is large, the toughness is deteriorated. Therefore, the addition amount of Ti is set to 0.05% or less.
【００２２】次に、本発明にかかる非調質高張力鋼の製
造方法を説明する。図１は、本発明にかかる非調質高張
力鋼の熱間圧延における熱履歴を、同じく前述の特開平
４−103716号公報および特開平５−171271号公報に開示
の方法の熱履歴と対比して示すグラフである。Next, a method for producing a non-heat treated high-strength steel according to the present invention will be described. FIG. 1 shows the heat history in hot rolling of the non-heat treated high-strength steel according to the present invention in comparison with the heat history of the method disclosed in the above-mentioned JP-A-4-103716 and JP-A-5-171271. FIG.
【００２３】まず、本発明によれば、熱間圧延に先立っ
て鋼片を1100〜1250℃に加熱するが、これは、鋼片の熱
間圧延の加熱温度はNbを固溶させておくことと、後続し
て行われる圧延条件を確保するという観点から1100℃以
上であることが有効であるためである。1100℃より低い
とNbの固溶が不十分となる。しかし、1250℃を超える
と、炉体の損傷が激しくコストアップを伴うため1100℃
以上1250℃以下とした。First, according to the present invention, prior to hot rolling, the slab is heated to 1100 to 1250 ° C. This is because the heating temperature for hot rolling of the slab is such that Nb is dissolved. This is because it is effective that the temperature is 1100 ° C. or more from the viewpoint of securing the rolling conditions to be performed subsequently. If the temperature is lower than 1100 ° C., the solid solution of Nb becomes insufficient. However, if the temperature exceeds 1250 ° C, the furnace body will be severely damaged and the cost will increase.
The temperature was set to 1250 ° C or lower.
【００２４】図１から分かるように、圧延に際してはま
ずAr3 点以上の温度で圧下を加える。これは鋼板に大き
な加工歪を生じ、冷却工程で析出するフェライトの結晶
粒を微細化にするためである。As can be seen from FIG. 1, during rolling, a reduction is first applied at a temperature not lower than the Ar 3 point. This is because a large work strain is generated in the steel sheet, and crystal grains of ferrite precipitated in the cooling step are made fine.
【００２５】次に本発明では、Ar1+10℃〜Ar3-10℃の
(α＋γ) 二相域温度範囲の累積圧下率を16〜30％とす
る圧延を行い、さらに(Ar3＋30℃) ±20℃で圧延を完了
させる。これによって析出フェライトが加工を受けて降
伏比を上昇させ、JIS SHY685規格を満たす値が得られ
る。この時Ar1 点以下で圧下を行ったりすると鋼板の平
坦度が悪くなり矯正に伴うコストの増加を招く。Next, in the present invention, Ar 1 + 10 ° C. to Ar 3 -10 ° C.
(α + γ) Rolling is performed so that the cumulative draft in the two-phase region temperature range is 16 to 30%, and the rolling is completed at (Ar 3 + 30 ° C.) ± 20 ° C. As a result, the precipitated ferrite is processed to increase the yield ratio, and a value satisfying the JIS SHY685 standard is obtained. At this time or perform pressure below Ar 1 point causes an increase in cost due to the flatness is poor becomes straightening of the steel sheet.
【００２６】熱間圧延完了後は、そのまま放冷 (空冷)
し圧延ままで、または圧延後Ac1 点以下の温度に加熱し
て焼戻しを行い土木建築用に供する。本発明によれば加
速冷却などを行うことなく圧延のままでJIS SHY685規格
を満たすに十分な強度、靱性が実現され、非調質材とし
て安価な材料が得られる。After the completion of hot rolling, it is allowed to cool as it is (air cooling)
As-rolled, or after rolling, it is heated to a temperature of 1 point or less of Ac and tempered to be used for civil engineering construction. According to the present invention, strength and toughness sufficient to satisfy the JIS SHY685 standard can be realized as rolled without performing accelerated cooling or the like, and an inexpensive material can be obtained as a non-heat treated material.
【００２７】この点、例えば特開平４−103716号公報に
開示する方法では、γ相単相域での圧延であり、低降伏
比を得るためＣ、Ｂ含有量も比較的低く抑えており、し
たがって、得られるYS、TSもそのような規格を十分満足
するとはいえない。In this respect, for example, in the method disclosed in Japanese Patent Application Laid-Open No. 4-103716, rolling is performed in a single phase region of γ phase, and the C and B contents are relatively low to obtain a low yield ratio. Therefore, the obtained YS and TS do not fully satisfy such standards.
【００２８】さらに特開平５−171271号公報に開示する
方法では、確かに本発明と同様に (α＋γ) ２相域Alを
行っているが、その圧下量は約８％以下とかなり低く、
軽圧下によって低降伏比高張力鋼を実現しようとするも
のであるが、この点、本発明では、Ｂを積極的に配合
し、Mnを比較的低く抑えることで２相域での高圧下を実
現し、上記従来法では実現できない高いYS、TSを実現で
きる。次に実施例によって本発明の作用効果をさらに具
体的に示す。Further, in the method disclosed in Japanese Patent Application Laid-Open No. 5-171271, (α + γ) two-phase region Al is carried out in the same manner as in the present invention, but the rolling reduction is as low as about 8% or less.
Attempts to realize a high yield strength steel with a low yield ratio by light pressure reduction, but in this regard, in the present invention, B is positively blended and Mn is kept relatively low to reduce the high pressure in the two-phase region. High YS and TS that cannot be realized by the above conventional methods can be realized. Next, the working effects of the present invention will be more specifically described with reference to examples.
【００２９】[0029]
【実施例】表１に示す組成の各鋼片(220mm厚さ) を表２
の条件で加熱後圧延して12mm厚さの熱間圧延ままの鋼板
および圧延後焼戻し処理を施した鋼板を作成した。ま
た、表２には熱間圧延後、鋼板より試験片を採取した引
張試験およびシャルピー衝撃試験の結果を示す。EXAMPLE Each steel slab (220 mm thick) having the composition shown in Table 1 was used.
Rolled after heating under the conditions described above, a 12 mm thick hot-rolled steel sheet and a steel sheet subjected to tempering after rolling were prepared. Table 2 shows the results of a tensile test and a Charpy impact test in which a test piece was sampled from a steel sheet after hot rolling.
【００３０】表２の製造条件は、No.1〜９は本発明例で
あり、No.10 〜13は成分が条件を外れた場合、No.14 〜
17は圧延条件が外れた場合の例である。本発明法で製造
したNo.1〜９は機械特性、靱性とも表２に示すJIS SHY6
85規格の目標特性をすべて満たすが、比較例であるNo.1
0 はMnが少ないため0.2 ％YS、TSが不足し、No.11 はMo
が多いためTSが規格値を上回っている。The production conditions in Table 2 are as follows: Nos. 1 to 9 are examples of the present invention, and Nos. 10 to 13 are Nos. 14 to
17 is an example when the rolling conditions are out of order. Nos. 1 to 9 manufactured by the method of the present invention are JIS SHY6 shown in Table 2 in both mechanical properties and toughness.
It satisfies all of the target characteristics of the 85 standard, but is a comparative example No. 1
0 is low in Mn, so 0.2% YS and TS are insufficient.
Due to the large number, TS exceeds the standard value.
【００３１】また、No.12 はＣ、Nbが少ないために0.2
％YS、TSが低く、No.13 はＣ、Moが多いためTSが高くな
っている。一方、製造条件No.14 〜17では、成分値は条
件を満たしているもののNo.14 は圧下率の不足、No.15
は仕上げ温度の上限外れにより共に0.2 ％YSが不足して
おり、No.16 においては圧下率が高くかつ仕上げ温度が
低くなったため鋼板の平坦度が悪くなり試験片の採取が
できない。なお、No.17 では焼戻し温度が上限を外れた
ために0.2 ％YS、TSが低い。No. 12 has a small content of C and Nb, and thus has a content of 0.2%.
% YS and TS are low, and No.13 has a high TS due to the large amount of C and Mo. On the other hand, in manufacturing conditions Nos. 14 to 17, although the component values satisfy the conditions, No. 14 has insufficient rolling reduction and No. 15
In both cases, 0.2% YS was insufficient due to exceeding the upper limit of the finishing temperature. In No.16, the specimen was not sampled because the flatness of the steel sheet deteriorated because the rolling reduction was high and the finishing temperature was low. Note that in No. 17, the 0.2% YS and TS were low because the tempering temperature exceeded the upper limit.
【００３２】[0032]
【表１】 [Table 1]
【００３３】[0033]
【表２】 [Table 2]
【００３４】[0034]
【発明の効果】本発明により規定した成分を添加し、11
00〜1250℃に加熱後熱間圧延するに際して、Ar1+10℃〜
Ar3-10℃の温度範囲での累積圧下率が16〜30％、仕上げ
圧延を(Ar1＋30℃) ±20℃となるように熱間圧延するこ
とにより780N/mm2級の高張力鋼でも非調質化が可能とな
った。これにより従来行われている焼入れおよび焼戻
し、または焼入れのみ熱処理コストが削減できるにもか
かわらず性能は従来と変わらぬ鋼板を得られた意義は大
きいといえる。The components defined by the present invention are added, and 11
When hot rolling after heating to 00 to 1250 ° C, Ar 1 + 10 ° C
Ar 3 -10 cumulative rolling reduction is 16-30% in the temperature range ° C., the finish rolling (Ar 1 + 30 ℃) ± 20 ℃ become so hot rolled 780N / mm 2 class high strength steel by However, non-tempering is now possible. Thus, although it is possible to reduce the heat treatment cost only for the conventional quenching and tempering or quenching, it can be said that the significance of obtaining a steel sheet having the same performance as the conventional steel plate is significant.
【図１】本発明にかかる方法の熱履歴を従来のそれと比
較して示すグラフである。FIG. 1 is a graph showing the thermal history of a method according to the present invention in comparison with that of a conventional method.
───────────────────────────────────────────────────── フロントページの続き (58)調査した分野(Int.Cl.7，ＤＢ名) C21D 8/02 ──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. 7 , DB name) C21D 8/02
Claims (5)
〜0.60％、Mn:0.50 〜2.00％、 Mo: 0.10〜0.80％、 Nb:0.008 〜0.100 ％、sol.Al: 0.
005 〜0.060 ％、 Ｂ: 0.0005〜0.0015％、残部Feおよび不可避不純物から
なる鋼組成を有する鋼片を1100〜1250℃の温度範囲に加
熱後、圧延するに際して、Ar1 ＋10℃〜Ar3 −10℃の温
度範囲で累積圧下率が16〜30％、仕上げ温度(Ar1＋30
℃) ±20℃となるように熱間圧延することを特徴とす
る、引張強度780N/mm2以上、降伏強度685N/mm2以上、伸
び16％以上、そしてvE-2047J以上の特性を満足する非調
質高張力鋼の製造方法。C .: 0.10 to 0.20% by weight, Si: 0.03% by weight
0.60%, Mn: 0.50 to 2.00%, Mo: 0.10 to 0.80%, Nb: 0.008 to 0.100%, sol.Al: 0.
005 to 0.060%, B: 0.0005 to 0.0015%, a steel slab having a steel composition consisting of the balance of Fe and unavoidable impurities is heated to a temperature range of 1100 to 1250 ° C., and then rolled, when rolling, Ar 1 + 10 ° C. to Ar 3 -10. cumulative rolling reduction is 16-30% in the temperature range of ° C., finishing temperature (Ar 1 +30
° C.) characterized by hot rolling such that the ± 20 ° C., a tensile strength of 780N / mm 2 or more, the yield strength 685N / mm 2 or more, elongation more than 16%, and satisfies vE -20 47J or more properties To manufacture non-heat treated high strength steel.
求項１記載の非調質高張力鋼の製造方法。2. The method according to claim 1, wherein the steel composition is C: 0.12 to 0.20%.
求項１または２記載の非調質高張力鋼の製造方法。3. The method for producing a non-heat-treated high-strength steel according to claim 1, wherein the steel composition is Mn: 0.50 to 1.50%.
0.10％以下、Ti:0.05％以下のうち１種または２種以上
を含むことを特徴とする請求項１ないし３のいずれかに
記載の非調質高張力鋼の製造方法。4. The steel composition further includes, by weight%, Cu: 0.50% or less, Ni: 1.50% or less, Cr: 1.00% or less, V:
The method for producing a non-heat-treated high-strength steel according to any one of claims 1 to 3, comprising one or more of 0.10% or less and Ti: 0.05% or less.
を行うことを特徴とする請求項１ないし４のいずれかに
記載の非調質高張力鋼の製造方法。5. The method for producing a non-heat treated high-strength steel according to claim 1 , wherein after the hot rolling, tempering is further performed at an Ac point or less.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP7002015A JP3033459B2 (en) | 1995-01-10 | 1995-01-10 | Manufacturing method of non-heat treated high strength steel |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP7002015A JP3033459B2 (en) | 1995-01-10 | 1995-01-10 | Manufacturing method of non-heat treated high strength steel |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH08188823A JPH08188823A (en) | 1996-07-23 |
| JP3033459B2 true JP3033459B2 (en) | 2000-04-17 |
Family
ID=11517533
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP7002015A Expired - Fee Related JP3033459B2 (en) | 1995-01-10 | 1995-01-10 | Manufacturing method of non-heat treated high strength steel |
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| Country | Link |
|---|---|
| JP (1) | JP3033459B2 (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP4358898B1 (en) | 2008-04-01 | 2009-11-04 | 新日本製鐵株式会社 | Method for producing high-tensile thick steel plate having a tensile strength of 780 MPa or more, excellent in weldability and joint low-temperature toughness |
| KR101252996B1 (en) | 2008-10-23 | 2013-04-15 | 신닛테츠스미킨 카부시키카이샤 | High tensile strength steel thick plate having excellent weldability and tensile strength of 780mpa or above, and process for manufacturing same |
-
1995
- 1995-01-10 JP JP7002015A patent/JP3033459B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH08188823A (en) | 1996-07-23 |
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