JPH03264645A - High-strength steel sheet having excellent elongation flanging property or the like - Google Patents
High-strength steel sheet having excellent elongation flanging property or the likeInfo
- Publication number
- JPH03264645A JPH03264645A JP2037039A JP3703990A JPH03264645A JP H03264645 A JPH03264645 A JP H03264645A JP 2037039 A JP2037039 A JP 2037039A JP 3703990 A JP3703990 A JP 3703990A JP H03264645 A JPH03264645 A JP H03264645A
- Authority
- JP
- Japan
- Prior art keywords
- martensite
- area ratio
- bainite
- strength steel
- less
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- 229910000831 Steel Inorganic materials 0.000 title claims abstract description 41
- 239000010959 steel Substances 0.000 title claims abstract description 41
- 229910000734 martensite Inorganic materials 0.000 claims abstract description 45
- 229910001563 bainite Inorganic materials 0.000 claims abstract description 28
- 229910001568 polygonal ferrite Inorganic materials 0.000 claims abstract description 11
- 230000001105 regulatory effect Effects 0.000 claims abstract description 7
- 239000012535 impurity Substances 0.000 claims abstract description 6
- 229910052742 iron Inorganic materials 0.000 claims abstract description 6
- 229910052761 rare earth metal Inorganic materials 0.000 claims abstract description 6
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 10
- 239000002131 composite material Substances 0.000 abstract description 10
- 238000000137 annealing Methods 0.000 abstract description 4
- 238000005096 rolling process Methods 0.000 abstract 1
- 230000000694 effects Effects 0.000 description 12
- 239000000463 material Substances 0.000 description 8
- 229910000859 α-Fe Inorganic materials 0.000 description 6
- 238000003466 welding Methods 0.000 description 5
- 238000001816 cooling Methods 0.000 description 3
- 239000000126 substance Substances 0.000 description 3
- 239000000446 fuel Substances 0.000 description 2
- 238000005098 hot rolling Methods 0.000 description 2
- 238000000465 moulding Methods 0.000 description 2
- 238000005728 strengthening Methods 0.000 description 2
- UCKMPCXJQFINFW-UHFFFAOYSA-N Sulphide Chemical compound [S-2] UCKMPCXJQFINFW-UHFFFAOYSA-N 0.000 description 1
- 229910045601 alloy Inorganic materials 0.000 description 1
- 239000000956 alloy Substances 0.000 description 1
- 229910001566 austenite Inorganic materials 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 230000003749 cleanliness Effects 0.000 description 1
- 239000010960 cold rolled steel Substances 0.000 description 1
- 238000005336 cracking Methods 0.000 description 1
- 230000002950 deficient Effects 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 230000009977 dual effect Effects 0.000 description 1
- 238000009661 fatigue test Methods 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- -1 heinite Inorganic materials 0.000 description 1
- 230000001771 impaired effect Effects 0.000 description 1
- 238000011835 investigation Methods 0.000 description 1
- 238000002844 melting Methods 0.000 description 1
- 230000008018 melting Effects 0.000 description 1
- 230000003014 reinforcing effect Effects 0.000 description 1
- 230000000717 retained effect Effects 0.000 description 1
- 239000000523 sample Substances 0.000 description 1
- 229920006395 saturated elastomer Polymers 0.000 description 1
- 239000006104 solid solution Substances 0.000 description 1
- 230000009466 transformation Effects 0.000 description 1
- 230000007704 transition Effects 0.000 description 1
- 238000004804 winding Methods 0.000 description 1
Landscapes
- Heat Treatment Of Steel (AREA)
- Heat Treatment Of Sheet Steel (AREA)
Abstract
Description
【発明の詳細な説明】
本発明は、伸びフランジ性、疲労特性及び抵抗溶接性に
すぐれた高強度鋼板に関する。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a high-strength steel plate with excellent stretch flangeability, fatigue properties, and resistance weldability.
近年、自動車の燃費の節減ために、種々の対策が検討さ
れており、なかでも、車体の軽量化は、そのための最も
効果的な対策であって、この車体軽量化のために、車体
の小型化と、それに平行して、高強度鋼板或いはA7!
合金の採用等の材料変更等の多くの試みがなされている
。これらのなかで、車輪の軽量化は、燃費節減に極めて
有効な手段であって、ホイールリムやディスクへの高強
度鋼板の適用が鋭意検討されている。In recent years, various measures have been considered to reduce the fuel consumption of automobiles, and among them, reducing the weight of the car body is the most effective measure. In parallel with this, high-strength steel plate or A7!
Many attempts have been made to change materials such as using alloys. Among these, reducing the weight of wheels is an extremely effective means for reducing fuel consumption, and the application of high-strength steel plates to wheel rims and discs is being actively studied.
このような高強度鋼板として、フェライト及びマルテン
サイトからなる複合組織鋼板、即ち、Dual Pba
se鋼板が提案されている。この複合組織鋼板は、降伏
比が低く、強度に比べて伸びが大きく、成形性、形状凍
結性がすぐれているが、しかし、伸びフランジ性の面で
劣っている。従って、ホイールディスクへの適用に際し
て、ディスク成形時の穴拡げ部からの割れの発生や、ま
た、疲労試験時又は走行試験中の穴拡げ部からの割れの
発生等の問題が解消されないままである。また、ホイー
ルリムへの適用に際しては、フラッシュバット溶接後に
行なわれるロール成形時に割れが発生する問題がある。As such a high-strength steel sheet, a composite structure steel sheet consisting of ferrite and martensite, that is, Dual Pba
SE steel plate has been proposed. This composite structure steel sheet has a low yield ratio, high elongation compared to strength, and excellent formability and shape fixability, but is inferior in stretch flangeability. Therefore, when applied to wheel discs, problems remain unresolved, such as cracks occurring from the hole enlarged portion during disk molding, and cracks occurring from the hole enlarged portion during fatigue tests or running tests. . Furthermore, when applied to wheel rims, there is a problem in that cracks occur during roll forming performed after flash butt welding.
例えば、成形時に熱影響部からの割れ発生率が約50%
にも達するといわれている。For example, the incidence of cracking from the heat affected zone during molding is approximately 50%.
It is said that it can reach up to
本発明者らは、伸びフランジ性を改善すべく、鋼板組織
とこれら特性との関係を詳細に調査研究し、既に、鋼板
組織をポリゴナルフエライトとへイナイトとマルテンサ
イトの3相複合組織とすることが望ましいことを見出し
ている。そこで、本発明者らは、更に、研究を重ねた結
果、上記3相組織において、各組織を面積率にて適正量
に調整したときにも、マルテンサイトの大きさが伸びフ
ランジ性に大きい影響を及ぼすことを見出した。In order to improve stretch flangeability, the present inventors have conducted detailed research into the relationship between the steel plate structure and these properties, and have already determined that the steel plate structure has a three-phase composite structure of polygonal ferrite, heinite, and martensite. We have found that this is desirable. Therefore, as a result of further research, the present inventors found that even when the area ratio of each structure was adjusted to an appropriate amount in the above three-phase structure, the size of martensite had a large effect on stretch flangeability. It was found that
本発明は、かかる知見に基づいてなされたものであって
、ポリゴナルフエライトとベイナイトとマルテンサイト
の3相複合組織からなり、各組織の面積率を特定すると
共に、マルテンサイトの大きさをも特定してなる伸びフ
ランジ性等にすぐれる複合組織高強度鋼板を提供するこ
とを目的とする。The present invention was made based on this knowledge, and consists of a three-phase composite structure of polygonal ferrite, bainite, and martensite, and it specifies the area ratio of each structure and also specifies the size of martensite. The object of the present invention is to provide a composite structure high-strength steel plate with excellent stretch flangeability.
本発明による伸びフランジ性、疲労特性及び抵抗溶接性
にすぐれた高強度鋼板は、重量%にて(a)C 0
.01〜0.2%、
Mn 0.6〜2.5%、
Si0.02〜1.5%
を含み、更に、
(b) Cr 0.1〜1.5%、
Cu 0.1〜0.6%、及び
B 0.0005〜0.1 %
よりなる群から選ばれる少なくとも1種の元素を含み、
残部鉄及び不可避的不純物よりなり、Sを0.02%以
下に規制した鋼であって、その組織がポリゴナルフエラ
イト、ベイナイト及びマルテンサイトの3相からなり、
ベイナイト面積率4〜45%、マルテンサイト面積率1
〜15%であると共に、マルテンサイト面積率がベイナ
イト面積率よりも小さく、且つ、マルテンサイ1〜の平
均直径が6μ以下であることを特徴とする。The high-strength steel plate with excellent stretch flangeability, fatigue properties, and resistance weldability according to the present invention has (a) C 0
.. (b) Cr 0.1-1.5%, Cu 0.1-0. 6%, and at least one element selected from the group consisting of B 0.0005 to 0.1%,
The balance is iron and unavoidable impurities, the S content is regulated to 0.02% or less, the structure is composed of three phases of polygonal ferrite, bainite and martensite,
Bainite area ratio 4-45%, martensite area ratio 1
~15%, the martensite area ratio is smaller than the bainite area ratio, and the average diameter of martensite 1~ is 6μ or less.
本発明において、ベイナイトとは、炭化物を内包するベ
イナイトのみならず、ベイナイテイックフエライト及び
所謂アシキュラーフェライトをも含む。また、マルテン
サイトとは、一部、残留オーステナイトをも含む。In the present invention, bainite includes not only bainite containing carbide but also bainitic ferrite and so-called acicular ferrite. Furthermore, martensite also includes some retained austenite.
本発明による高強度鋼板においては、特に、伸びフラン
ジ性の観点から、ベイナイト面積率は4〜45%の範囲
とされる。In the high-strength steel plate according to the present invention, the bainite area ratio is in the range of 4 to 45%, particularly from the viewpoint of stretch flangeability.
ポリゴナルフエライト、ベイナイト及びマルテンサイト
からなる3相複合組織鋼板は、降伏比については、フェ
ライト及びマルテンサイトからなるDual Phas
e 1iiI板のそれと近似する低降伏比を有し、強度
−伸びバランスは、フェライト及びベイナイトからなる
複合組織鋼板と近イ以する良好な値を有するという特徴
を備えているが、伸びフランジ性について調査した結果
、良好な伸びフランジ性、即ち、穴拡げ率を示すベイナ
イト面積率4〜45%の範囲内においても、特に、すぐ
れた値を有するものが見出された。A three-phase composite steel sheet consisting of polygonal ferrite, bainite and martensite has a yield ratio of 3-phase composite steel sheet consisting of ferrite and martensite.
It has a low yield ratio similar to that of e1iii plate, and has a good strength-elongation balance that is close to that of a composite steel sheet consisting of ferrite and bainite, but it has poor stretch flangeability. As a result of the investigation, it was found that a material having a particularly excellent value even within the range of bainite area ratio of 4 to 45%, which indicates good stretch flangeability, ie, hole expansion rate, was found.
そこで、この原因を明らかにすべく、上記範囲の鋼板に
ついて、マルテンサイトの大きさの差異に着目し、マル
テンサイトの平均直径と穴拡げ率との関係を調べた結果
、マルテンサイトの平均直径が6μm以下、特に、5μ
m以下のとき、すくれた穴拡げ率、即ち、伸びフランジ
性を有することが明らかとなった。従って、本発明によ
る3相複合組織鋼板においては、マルテンサイトは、そ
の平均直径が6μm以下、好ましくは、5μm以下に規
制される。Therefore, in order to clarify the cause of this, we focused on the difference in the size of martensite for steel plates in the above range and investigated the relationship between the average diameter of martensite and the hole expansion rate. As a result, the average diameter of martensite was 6μm or less, especially 5μm
It has become clear that when the diameter is less than m, the hole has a low expansion rate, that is, it has stretch flangeability. Therefore, in the three-phase composite steel sheet according to the present invention, the average diameter of martensite is limited to 6 μm or less, preferably 5 μm or less.
次に、マルテンサイト面積率は、1〜15%の範囲であ
る。マルテンサイト面積率が15%を越えるときは、降
伏比が上昇し、他方、1%よりも少ないときは、マルテ
ンサイトの導入効果が少ない。特に、マルテンサイト面
積率は、1〜10%の範囲が好ましく、また、ベイナイ
ト面積率は、11〜35%の範囲が好ましい。更に、マ
ルテンサイト面積率は、ベイナイト面積率より小さいこ
とが望ましい。Next, the martensite area ratio is in the range of 1 to 15%. When the martensite area ratio exceeds 15%, the yield ratio increases, while when it is less than 1%, the effect of introducing martensite is small. In particular, the martensite area ratio is preferably in the range of 1 to 10%, and the bainite area ratio is preferably in the range of 11 to 35%. Furthermore, it is desirable that the martensite area ratio is smaller than the bainite area ratio.
以上のような組織の調整は、後述する化学成分を考慮し
たうえで、熱間圧延及びその後の冷却条件を調節するこ
と、或いは熱間圧延、冷間圧延板にその後の焼鈍条件(
連続焼鈍、バッチ焼鈍)を調節することによって得るこ
とができる。Adjustment of the structure as described above can be achieved by adjusting the hot rolling and subsequent cooling conditions in consideration of the chemical components described below, or by adjusting the subsequent annealing conditions (
It can be obtained by adjusting continuous annealing, batch annealing).
次に、本発明による高強度鋼板における化学成分につい
て説明する。Next, the chemical components of the high-strength steel plate according to the present invention will be explained.
Cは、必要な強度維持と共に、ベイナイト及びマルテン
サイトからなる低温変態生成物を形成させるために必須
の元素であるが、0.2%を越えるときは、延性の劣化
が著しく、溶接性を害する。C is an essential element for maintaining the necessary strength and forming a low-temperature transformation product consisting of bainite and martensite, but when it exceeds 0.2%, the ductility deteriorates significantly and weldability is impaired. .
0
尚、成形性を特に要求される場合は、C量は、0゜09
%以下とすることが望ましい。Cの下限量は、強化及び
焼入れ性向上効果を有効に発揮させるために、0.01
%とする。0 If moldability is particularly required, the amount of C should be 0°09
% or less. The lower limit amount of C is 0.01 in order to effectively exhibit the effect of strengthening and improving hardenability.
%.
Mnは、焼入れ性を増し、所望の組織を得るために必須
の元素である。これらの効果を有効に得るためには、0
.6%以上を必要とするが、しかし、2.5%を越える
ときは、溶接上、困難を生じると共に、延性や溶接性を
害し、更に、鋼板の価格を高くする。Mn is an essential element for increasing hardenability and obtaining a desired structure. In order to effectively obtain these effects, 0
.. A content of 6% or more is required, but if it exceeds 2.5%, it causes difficulties in welding, impairs ductility and weldability, and further increases the price of the steel plate.
Siは、溶鋼の脱酸に必要な元素であり、また、置換型
固溶元素として、最も有効な元素であって、高強度且つ
高延性の鋼板を得るために、必要不可欠の元素である。Si is an element necessary for deoxidizing molten steel, and is the most effective element as a substitutional solid solution element, and is an essential element in order to obtain a steel plate with high strength and high ductility.
更に、Siは、清浄なポリゴナルフエライト形成を有利
にする作用をも有している。このような効果をを効に得
るために、0.02%を下限として、溶接部の脆化(遷
移温度の上昇)を防止し、他方、表面スケール状態の悪
化を防くために、上限を1.5%とする。Furthermore, Si also has the effect of favoring the formation of clean polygonal ferrite. In order to effectively obtain this effect, the lower limit is set at 0.02% to prevent embrittlement of the weld (increase in transition temperature), and on the other hand, the upper limit is set to prevent deterioration of the surface scale condition. It shall be 1.5%.
Sは、成形性、特に、伸びフランジ性の改善のために、
0.020%以下とし、厳しい伸びフランジ性が要求さ
れるときは、0.OO9%以下が望ましい。S is for improving formability, especially stretch flangeability,
0.020% or less, and when strict stretch flangeability is required, 0.020% or less. OO9% or less is desirable.
Cr −、Cu及びBは、いずれも、鋼の強化に寄与す
る元素であって、特に、焼入れ性を向上させ、所望の組
織を得るうえで有用な元素である。これらの元素の添加
量は、下限は、その効果を有効に発揮させ得る量から、
また、上限は2.その効果が飽和する経済的な見地から
決定される。従って、添加量は、Cr 0.1〜1.5
%、Cu 0.1〜0.6%、Bo、0005〜0.1
%の範囲である。Cr −, Cu, and B are all elements that contribute to strengthening steel, and are particularly useful elements for improving hardenability and obtaining a desired structure. The lower limit of the amount of these elements to be added is from the amount that can effectively exhibit their effects,
Also, the upper limit is 2. It is determined from an economic point of view that the effect is saturated. Therefore, the addition amount is Cr 0.1-1.5
%, Cu 0.1-0.6%, Bo, 0005-0.1
% range.
本発明においては、上記の元素に加えて、鋼板は、次の
ような元素を含んでいてもよい。In the present invention, in addition to the above elements, the steel plate may contain the following elements.
希土類元素(REM)及びCaは、硫化物形態制御を通
じて、延性、特に、伸びフランジ性を改善する効果を有
する。これら元素の添加量も、下限は、その効果を有効
に発揮させ得る必要最小限の量から、また、上限は、そ
の効果が飽和する経済的な見地と共に、逆に清浄度を悪
化させる量から決定される。従って、添加量は、REM
0.o01
2
5〜0.2%、Ca0.005〜0.1%の範囲である
ことが望ましい。Rare earth elements (REM) and Ca have the effect of improving ductility, particularly stretch flangeability, through sulfide morphology control. The lower limit of the amount of these elements to be added is the minimum necessary amount to effectively exhibit their effects, and the upper limit is from an economic standpoint that saturates the effect, and on the other hand, from an amount that worsens cleanliness. It is determined. Therefore, the amount added is REM
0. It is desirable that the content is in the range of o01 2 5 to 0.2% and Ca 0.005 to 0.1%.
A6は、脱酸剤として、0.005〜0.06%の範囲
で含存される場合がある。また、Pは、粒界脆化しない
範囲、即ち、0.1%以下の範囲で添加することができ
る。Pは、強化作用が強く、且つ、Siと同様に、フェ
ライトを純化する作用を有し、伸び等の改善に役立つ。A6 may be contained as a deoxidizing agent in a range of 0.005 to 0.06%. Furthermore, P can be added within a range that does not cause grain boundary embrittlement, that is, within a range of 0.1% or less. P has a strong reinforcing effect and, like Si, has an effect of purifying ferrite, and is useful for improving elongation and the like.
以下に実施例を挙げて本発明を説明するが、本発明はこ
れら実施例により何ら限定されるものではない。The present invention will be explained below with reference to Examples, but the present invention is not limited to these Examples in any way.
実施例
第1表に示す化学成分を有する供試材を真空溶解炉にて
溶製し、粗圧延した3Q*m厚さスラブを3パスにて厚
さ4nの熱延板とした。また、一部の熱延板は、冷間圧
延(75%)した。EXAMPLES Test materials having the chemical components shown in Table 1 were melted in a vacuum melting furnace and roughly rolled into 3Q*m thick slabs, which were made into 4n thick hot-rolled plates by 3 passes. In addition, some of the hot rolled sheets were cold rolled (75%).
これら熱延鋼板及び冷延鋼板について、780〜950
°Cの各温度にて5〜1o分間加熱し、その後、種々の
冷却速度にて冷却して、Mi織の異なる供試材を作製し
た。これら供試材の熱処理条件3
を第2表に示す。また、得られた鋼板の機械的性質及び
顕微鏡組織観察結果を第3表に示す。For these hot rolled steel sheets and cold rolled steel sheets, 780 to 950
It was heated for 5 to 10 minutes at each temperature of °C, and then cooled at various cooling rates to produce test materials with different Mi weaves. Heat treatment conditions 3 for these test materials are shown in Table 2. Furthermore, Table 3 shows the mechanical properties and microscopic structure observation results of the obtained steel plate.
第3表から明らかなように、本発明による供試材は、い
ずれも、ポリゴナルフエライト、ベイナイト及びマルテ
ンサイトの適切なバランスを有し、且つ、マルテンサイ
トの平均直径が6μm以下であって、高強度、低降伏比
であって、強度−伸びバランス及び伸びフランジ性にす
ぐれている。As is clear from Table 3, all of the test materials according to the present invention have an appropriate balance of polygonal ferrite, bainite, and martensite, and the average diameter of martensite is 6 μm or less, It has high strength, low yield ratio, and excellent strength-elongation balance and stretch flangeability.
マt、−1一部の熱延鋼板について、フラッシュ八ツH
8接の結果、疲労特性及びホイールディスク成形試験(
r+−25)結果を第3表に示す。Mat, -1 For some hot rolled steel sheets, Flash Yatsu H
8 contact results, fatigue properties and wheel disc forming test (
r+-25) The results are shown in Table 3.
尚、フラッシュバット溶接の条件は、以下のとおりであ
る。The conditions for flash butt welding are as follows.
フラッシュ化 3ta
フラッシュ時間 3秒
アップセット化 3■
アップセット時間 2/60秒
アップセット速度 150鶴/秒
素板形状 3.2龍厚X 3 Q mm幅×75龍長5
処理条件
第
2
表
(続き)
次に、供試材1の相当成分にCe 0.02%を添加し
た供試材について、第4表に示す熱延、冷却及び巻取条
件にて熱延鋼板を製造した。Flashing 3ta Flash time 3 seconds Upset 3■ Upset time 2/60 seconds Upset speed 150 cranes/second Plain plate shape 3.2 Dragon thickness x 3 Q mm width x 75 Dragon length 5 Processing conditions Table 2 ( (continued) Next, a hot rolled steel plate was manufactured using a test material in which 0.02% of Ce was added to the corresponding components of test material 1 under the hot rolling, cooling and winding conditions shown in Table 4.
この熱延鋼板の機械的性質及び顕微鏡組織観察結果を第
5表に示す。更に、この熱延鋼板のフラッシュハツト溶
接の結果、疲労特性及びホイールディスク成形試験(n
−25)結果を第5表に示特開平3
264645 (7)
Q−j是 龜: 石
275
0
1ミ p
特開平3
264645 (9)
ず。尚、フラッシュハツト溶接の条件は、前述と同じで
ある。Table 5 shows the mechanical properties and microscopic structure observation results of this hot rolled steel sheet. Furthermore, the results of flash hat welding of this hot rolled steel sheet, fatigue properties and wheel disc forming test (n
-25) The results are shown in Table 5. Note that the conditions for flash hat welding are the same as described above.
第5表から明らかなように、本発明による供試材2−2
から2−4は、前述した諸性質に加えて、フラッシュハ
ツト溶接性及び疲労強度にすぐれており、ホイールディ
スクに成形した場合においても、不良率が極めて小さい
という特性を有している。As is clear from Table 5, sample material 2-2 according to the present invention
In addition to the above-mentioned properties, No. 2-4 has excellent flash hat weldability and fatigue strength, and has an extremely low defective rate even when molded into a wheel disk.
Claims (4)
残部鉄及び不可避的不純物よりなり、Sを0.02%以
下に規制した鋼であつて、その組織がポリゴナルフエラ
イト、ベイナイト及びマルテンサイトの3相からなり、
ベイナイト面積率4〜45%、マルテンサイト面積率1
〜15%であると共に、マルテンサイト面積率がベイナ
イト面積率よりも小さく、且つ、マルテンサイトの平均
直径が6μ以下であることを特徴とする伸びフランジ性
、疲労特性、抵抗溶接性にすぐれた高強度鋼板。(1) Contains (a) 0.01 to 0.2% of C, 0.6 to 2.5% of Mn, and 0.02 to 1.5% of Si in weight%, and further contains (b) 0.1 to 1.5% of Cr. 5%, Cu0.1-0.6%, and B0.0005-0.1%,
A steel whose balance consists of iron and unavoidable impurities, and whose S content is regulated to 0.02% or less, whose structure consists of three phases of polygonal ferrite, bainite and martensite,
Bainite area ratio 4-45%, martensite area ratio 1
~15%, the martensite area ratio is smaller than the bainite area ratio, and the average diameter of martensite is 6μ or less.It has excellent stretch flangeability, fatigue properties, and resistance weldability. Strength steel plate.
005〜0.01% よりなる群から選ばれる少なくとも1種の元素とを含み
、残部鉄及び不可避的不純物よりなり、Sを0.02%
以下に規制した鋼であつて、その組織がポリゴナルフエ
ライト、ベイナイト及びマルテンサイトの3相からなり
、ベイナイト面積率4〜45%、マルテンサイト面積率
1〜15%であると共に、マルテンサイト面積率がベイ
ナイト面積率よりも小さく、且つ、マルテンサイトの平
均直径が6μ以下であることを特徴とする伸びフランジ
性、疲労特性、抵抗溶接性にすぐれた高強度鋼板。(2) Contains (a) 0.01 to 0.2% of C, 0.6 to 2.5% of Mn, and 0.02 to 1.5% of Si, and further contains (b) 0.1 to 1.5% of Cr by weight. 5%, Cu0.1-0.6%, and B0.0005-0.1%; (c) rare earth element 0.005-0.2%; and Ca0. ..
At least one element selected from the group consisting of 0.005 to 0.01%, the balance consisting of iron and unavoidable impurities, and 0.02% of S.
A steel regulated as below, whose structure consists of three phases of polygonal ferrite, bainite, and martensite, with a bainite area ratio of 4 to 45%, a martensite area ratio of 1 to 15%, and a martensite area ratio of 4 to 45%. A high-strength steel plate with excellent stretch flangeability, fatigue properties, and resistance weldability, characterized in that the area ratio of martensite is smaller than the area ratio of bainite, and the average diameter of martensite is 6μ or less.
残部鉄及び不可避的不純物よりなり、Sを0.02%以
下に規制した鋼であつて、その組織がポリゴナルフエラ
イト、ベイナイト及びマルテンサイトの3相からなり、
ベイナイト面積率4〜45%、マルテンサイト面積率1
〜15%であると共に、マルテンサイト面積率がベイナ
イト面積率よりも小さく、且つ、マルテンサイトの平均
直径が6μ以下であることを特徴とする伸びフランジ性
、疲労特性、抵抗溶接性にすぐれた高強度鋼板。(3) Contains (a) C0.01-0.2%, Mn0.6-2.5%, Si0.02-1.5%, Al0.005-0.06% in weight%, and further, (b) Contains at least one element selected from the group consisting of Cr0.1-1.5%, Cu0.1-0.6%, and B0.0005-0.1%,
A steel whose balance consists of iron and unavoidable impurities, and whose S content is regulated to 0.02% or less, whose structure consists of three phases of polygonal ferrite, bainite and martensite,
Bainite area ratio 4-45%, martensite area ratio 1
~15%, the martensite area ratio is smaller than the bainite area ratio, and the average diameter of martensite is 6μ or less.It has excellent stretch flangeability, fatigue properties, and resistance weldability. Strength steel plate.
005〜0.01% よりなる群から選ばれる少なくとも1種の元素とを含み
、残部鉄及び不可避的不純物よりなり、Sを0.02%
以下に規制した鋼であつて、その組織がポリゴナルフエ
ライト、ベイナイト及びマルテンサイトの3相からなり
、ベイナイト面積率4〜45%、マルテンサイト面積率
1〜15%であると共に、マルテンサイト面積率がベイ
ナイト面積率よりも小さく、且つ、マルテンサイトの平
均直径が6μ以下であることを特徴とする伸びフランジ
性、疲労特性、抵抗溶接性にすぐれた高強度鋼板。(4) Contains (a) C0.01-0.2%, Mn0.6-2.5%, Si0.02-1.5%, Al0.005-0.06% in weight%, and further, (b) at least one element selected from the group consisting of 0.1% to 1.5% Cr, 0.1% to 0.6% Cu, and 0.0005% to 0.1% B; and (c) 0.0% rare earth element. 005-0.2%, and Ca0.
At least one element selected from the group consisting of 0.005 to 0.01%, the balance consisting of iron and unavoidable impurities, and 0.02% of S.
A steel regulated as below, whose structure consists of three phases of polygonal ferrite, bainite, and martensite, with a bainite area ratio of 4 to 45%, a martensite area ratio of 1 to 15%, and a martensite area ratio of 4 to 45%. A high-strength steel plate with excellent stretch flangeability, fatigue properties, and resistance weldability, characterized in that the area ratio of martensite is smaller than the area ratio of bainite, and the average diameter of martensite is 6μ or less.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2037039A JPH03264645A (en) | 1982-03-29 | 1990-02-16 | High-strength steel sheet having excellent elongation flanging property or the like |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP5190782A JPS58167750A (en) | 1982-03-29 | 1982-03-29 | High strength steel plate excellent in elongation flange property |
JP2037039A JPH03264645A (en) | 1982-03-29 | 1990-02-16 | High-strength steel sheet having excellent elongation flanging property or the like |
Related Parent Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP5190782A Division JPS58167750A (en) | 1982-03-29 | 1982-03-29 | High strength steel plate excellent in elongation flange property |
Publications (2)
Publication Number | Publication Date |
---|---|
JPH03264645A true JPH03264645A (en) | 1991-11-25 |
JPH0572460B2 JPH0572460B2 (en) | 1993-10-12 |
Family
ID=26376140
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP2037039A Granted JPH03264645A (en) | 1982-03-29 | 1990-02-16 | High-strength steel sheet having excellent elongation flanging property or the like |
Country Status (1)
Country | Link |
---|---|
JP (1) | JPH03264645A (en) |
Cited By (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH0657376A (en) * | 1992-08-11 | 1994-03-01 | Kobe Steel Ltd | High strength hot-rolled steel plate good in workability and having 730n/mm2 or higher strength and its production |
WO1995004838A1 (en) * | 1993-08-04 | 1995-02-16 | Nippon Steel Corporation | High tensile strength steel having superior fatigue strength and weldability at welds and method for manufacturing the same |
US5634988A (en) * | 1993-03-25 | 1997-06-03 | Nippon Steel Corporation | High tensile steel having excellent fatigue strength at its weld and weldability and process for producing the same |
JP2003505604A (en) * | 1999-07-31 | 2003-02-12 | ティッセンクルップ シュタール アクチェンゲゼルシャフト | High-strength steel strip or steel sheet and method for producing the same |
US7780799B2 (en) | 2003-05-21 | 2010-08-24 | Nippon Steel Corporation | Cold-rolled steel sheet having a tensile strength of 780 MPA or more, an excellent local formability and a suppressed increase in weld hardness |
US20120241057A1 (en) * | 2009-09-30 | 2012-09-27 | Jfe Steel Corporation | Low yield ratio, high strength and high toughness steel plate and method for manufacturing the same |
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Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP4894863B2 (en) | 2008-02-08 | 2012-03-14 | Jfeスチール株式会社 | High-strength hot-dip galvanized steel sheet excellent in workability and manufacturing method thereof |
JP6119923B1 (en) * | 2015-05-26 | 2017-04-26 | 新日鐵住金株式会社 | Steel sheet and manufacturing method thereof |
-
1990
- 1990-02-16 JP JP2037039A patent/JPH03264645A/en active Granted
Cited By (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH0657376A (en) * | 1992-08-11 | 1994-03-01 | Kobe Steel Ltd | High strength hot-rolled steel plate good in workability and having 730n/mm2 or higher strength and its production |
US5634988A (en) * | 1993-03-25 | 1997-06-03 | Nippon Steel Corporation | High tensile steel having excellent fatigue strength at its weld and weldability and process for producing the same |
WO1995004838A1 (en) * | 1993-08-04 | 1995-02-16 | Nippon Steel Corporation | High tensile strength steel having superior fatigue strength and weldability at welds and method for manufacturing the same |
CN1040555C (en) * | 1993-08-04 | 1998-11-04 | 新日本制铁株式会社 | High tensile strength steel having superior fatigue strength and weldability at welds and method for manufacturing the same |
JP2003505604A (en) * | 1999-07-31 | 2003-02-12 | ティッセンクルップ シュタール アクチェンゲゼルシャフト | High-strength steel strip or steel sheet and method for producing the same |
JP4745572B2 (en) * | 1999-07-31 | 2011-08-10 | ティッセンクルップ スチール アクチェンゲゼルシャフト | High-strength steel strip or steel plate and method for producing the same |
US7780799B2 (en) | 2003-05-21 | 2010-08-24 | Nippon Steel Corporation | Cold-rolled steel sheet having a tensile strength of 780 MPA or more, an excellent local formability and a suppressed increase in weld hardness |
US20120241057A1 (en) * | 2009-09-30 | 2012-09-27 | Jfe Steel Corporation | Low yield ratio, high strength and high toughness steel plate and method for manufacturing the same |
US8778096B2 (en) * | 2009-09-30 | 2014-07-15 | Jfe Steel Corporation | Low yield ratio, high strength and high toughness steel plate and method for manufacturing the same |
Also Published As
Publication number | Publication date |
---|---|
JPH0572460B2 (en) | 1993-10-12 |
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