JPH05140652A - Manufacture of low yield ratio cold rolled high tensile strength steel sheet excellent in corrosion resistance - Google Patents
Manufacture of low yield ratio cold rolled high tensile strength steel sheet excellent in corrosion resistanceInfo
- Publication number
- JPH05140652A JPH05140652A JP32950791A JP32950791A JPH05140652A JP H05140652 A JPH05140652 A JP H05140652A JP 32950791 A JP32950791 A JP 32950791A JP 32950791 A JP32950791 A JP 32950791A JP H05140652 A JPH05140652 A JP H05140652A
- Authority
- JP
- Japan
- Prior art keywords
- less
- corrosion resistance
- steel sheet
- rolled
- yield ratio
- 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 50
- 239000010959 steel Substances 0.000 title claims abstract description 50
- 230000007797 corrosion Effects 0.000 title claims abstract description 32
- 238000005260 corrosion Methods 0.000 title claims abstract description 32
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 12
- 238000000137 annealing Methods 0.000 claims abstract description 16
- 229910052802 copper Inorganic materials 0.000 claims abstract description 8
- 229910052748 manganese Inorganic materials 0.000 claims abstract description 8
- 229910052698 phosphorus Inorganic materials 0.000 claims abstract description 8
- 229910052750 molybdenum Inorganic materials 0.000 claims abstract description 6
- 229910052799 carbon Inorganic materials 0.000 claims abstract description 5
- 239000012535 impurity Substances 0.000 claims abstract description 5
- 229910052757 nitrogen Inorganic materials 0.000 claims abstract description 5
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims abstract 6
- 229910052742 iron Inorganic materials 0.000 claims abstract 3
- 238000005096 rolling process Methods 0.000 claims 1
- 238000000034 method Methods 0.000 abstract description 6
- 238000005097 cold rolling Methods 0.000 abstract description 5
- 229910052804 chromium Inorganic materials 0.000 abstract description 4
- 239000010960 cold rolled steel Substances 0.000 abstract description 3
- 238000005098 hot rolling Methods 0.000 abstract description 3
- 229910052759 nickel Inorganic materials 0.000 abstract description 3
- 229910052758 niobium Inorganic materials 0.000 abstract description 3
- 239000002131 composite material Substances 0.000 description 16
- 230000000694 effects Effects 0.000 description 9
- 229910000859 α-Fe Inorganic materials 0.000 description 6
- 238000001816 cooling Methods 0.000 description 5
- 229910000734 martensite Inorganic materials 0.000 description 4
- 229920006395 saturated elastomer Polymers 0.000 description 4
- 238000007792 addition Methods 0.000 description 3
- 150000003839 salts Chemical class 0.000 description 3
- 230000000052 comparative effect Effects 0.000 description 2
- 238000001556 precipitation Methods 0.000 description 2
- 230000008569 process Effects 0.000 description 2
- 239000007921 spray Substances 0.000 description 2
- 238000005728 strengthening Methods 0.000 description 2
- 239000013585 weight reducing agent Substances 0.000 description 2
- 229910018072 Al 2 O 3 Inorganic materials 0.000 description 1
- 229910001209 Low-carbon steel Inorganic materials 0.000 description 1
- 229910006639 Si—Mn Inorganic materials 0.000 description 1
- 238000005275 alloying Methods 0.000 description 1
- 229910001566 austenite Inorganic materials 0.000 description 1
- 238000005452 bending Methods 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 238000005536 corrosion prevention Methods 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 230000003628 erosive effect Effects 0.000 description 1
- 239000012467 final product Substances 0.000 description 1
- 238000007602 hot air drying Methods 0.000 description 1
- JEIPFZHSYJVQDO-UHFFFAOYSA-N iron(III) oxide Inorganic materials O=[Fe]O[Fe]=O JEIPFZHSYJVQDO-UHFFFAOYSA-N 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 238000005554 pickling Methods 0.000 description 1
- 230000001737 promoting effect Effects 0.000 description 1
- 230000003014 reinforcing effect Effects 0.000 description 1
- 239000006104 solid solution Substances 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 230000009466 transformation Effects 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 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
【０００１】[0001]
【産業上の利用分野】本発明は，フエライトとマルテン
サイトからなる複合組織を有する低降伏比，高延性の耐
食性に優れた高張力冷延鋼板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 a high-strength cold-rolled steel sheet having a composite structure composed of ferrite and martensite, having a low yield ratio, high ductility and excellent corrosion resistance.
【０００２】[0002]
【従来の技術】自動車産業では車体の防錆化と軽量化を
目的として耐食性と加工性に優れた高張力鋼板が要求さ
れている。一般に鋼は降伏点および引張強さ等の強度が
上昇するに従って伸びや曲げ等の延性が低下する。した
がって，固溶強化，析出強化等を利用して強度を高めた
高張力鋼板では加工用途には不充分となる。2. Description of the Related Art In the automobile industry, high-strength steel sheets having excellent corrosion resistance and workability are required for the purpose of preventing rust and weight of the vehicle body. Generally, steel has lower ductility such as elongation and bending as the strength such as yield point and tensile strength increases. Therefore, high-strength steel sheets, which have been strengthened by utilizing solid solution strengthening, precipitation strengthening, etc., are insufficient for processing applications.
【０００３】このような背景から開発された高張力鋼板
として複合組織冷延高張力鋼板がある。例えば特開昭58
-19441号公報や特開昭58-22332号公報には, Ｃ-Ｓi-Ｍn
系のフエライト＋マルテンサイトの複合組織からなる強
度と伸びを同時に向上させた鋼板が記載されている。As a high-strength steel sheet developed from such a background, there is a composite structure cold-rolled high-strength steel sheet. For example, JP-A-58
-19441 and JP-A-58-22332 describe C-Si-Mn.
A steel sheet having a composite structure of ferrite + martensite and having improved strength and elongation is described.
【０００４】[0004]
【発明が解決しようとする課題】複合組織鋼板の製造技
術は, 特に自動車用高張力鋼板向けにその強度と伸びを
同時に付与するのに開発され，自動車用鋼板の薄肉化す
なわち軽量化を達成しようとするものである。これら鋼
板の採用によって強度面からは鋼板の板厚を薄くするこ
とは可能であるが, 板厚を薄くすると腐食により鋼板の
孔あき腐食が問題となってくる。このため耐食性がこの
鋼板の課題となる。[Problems to be Solved by the Invention] The manufacturing technique of a composite microstructure steel sheet has been developed to impart strength and elongation at the same time especially for high-strength steel sheets for automobiles, and to achieve thinning, that is, weight reduction of automobile steel sheets. It is what Although it is possible to reduce the plate thickness of the steel plate from the viewpoint of strength by adopting these steel plates, perforation corrosion of the steel plate becomes a problem due to corrosion when the plate thickness is reduced. Therefore, corrosion resistance is an issue for this steel sheet.
【０００５】本発明は，上述の事情に鑑み, 複合組織鋼
板の耐食性を改善し，耐食性と加工性を同時に満足しう
る低降伏比冷延高張力熱延板を得ることを目的とする。In view of the above circumstances, it is an object of the present invention to improve the corrosion resistance of a composite structure steel sheet and obtain a low yield ratio cold rolled high tensile strength hot rolled sheet capable of simultaneously satisfying the corrosion resistance and workability.
【０００６】[0006]
【課題を解決するための手段】本発明によれば，重量％
で, Ｃ：0.02〜0.25％, Ｓi：2.0％以下, Ｍn：1.6〜3.
5％, Ｐ：0.03〜0.20％, Ｓ：0.02％以下, Ｃu：0.05〜
2.0％, sol.Ａl：0.005〜0.100％, Ｎ：0.008％以下を
含有し，場合によってはさらにＴi：0.005〜0.06％また
はＮb：0.005〜0.06％の少なくとも一種以上，および／
またはＮi：2.0％以下, Ｍo：3.0％以下またはＣr：3.0
％以下の少なくとも一種以上を含有し，場合によっては
さらにＢ：0.0003〜0.005％を含有したうえ，残部が鉄
および不可避的不純物よりなる鋼のスラブを熱間圧延
し, 酸洗後，目標板厚まで冷間圧延し，ついで連続焼鈍
ラインで720〜950℃の温度で焼鈍することからなる耐食
性に優れた低降伏比冷延高張力鋼板の製造方法を提供す
る。According to the present invention, the weight percent is
C: 0.02 to 0.25%, Si: 2.0% or less, Mn: 1.6 to 3.
5%, P: 0.03 to 0.20%, S: 0.02% or less, Cu: 0.05 to
2.0%, sol.Al: 0.005 to 0.100%, N: 0.008% or less, and if necessary, at least one or more of Ti: 0.005 to 0.06% or Nb: 0.005 to 0.06%, and /
Or Ni: 2.0% or less, Mo: 3.0% or less or Cr: 3.0
% Or less, and in some cases B: 0.0003 to 0.005%, and the balance is steel and unavoidable impurities, the steel slab is hot-rolled and after pickling, the target thickness Provided is a method for producing a low yield ratio cold rolled high strength steel sheet having excellent corrosion resistance, which comprises cold rolling to a temperature of 720 to 950 ° C in a continuous annealing line.
【０００７】[0007]
【作用】低炭素鋼に焼入れ性を向上させるＭn,Ｎi,Ｃr
等の合金元素を添加して焼鈍状態でフエライト＋マルテ
ンサイトの複合組織とすることができ，さらに, 微量の
Ｔi,Ｎbを含有させると複合組織鋼の延性を改善でき
る。また適量のＣu,Ｐの含有はこの鋼の耐食性を向上さ
せる。高強度化と耐食性を向上させるにはＳi,Ｍnの添
加およびＮi,Ｍo,Ｃrの添加が有効である。これらの複
合的な作用によって加工性と耐食性に優れた自動車用冷
延高張力鋼板を得ることができる。[Operation] Mn, Ni, Cr for improving hardenability in low carbon steel
It is possible to add an alloying element such as, to form a composite structure of ferrite + martensite in the annealed state. Furthermore, if a small amount of Ti, Nb is contained, the ductility of the composite structure steel can be improved. Also, the inclusion of an appropriate amount of Cu, P improves the corrosion resistance of this steel. Addition of Si and Mn and additions of Ni, Mo and Cr are effective for increasing strength and improving corrosion resistance. By these combined actions, it is possible to obtain a cold-rolled high-strength steel sheet for automobiles having excellent workability and corrosion resistance.
【０００８】本発明法に従う鋼板の各種成分の作用およ
びその含有量範囲の限定理由は次のとおりである。The functions of various components of the steel sheet according to the method of the present invention and the reasons for limiting the content range thereof are as follows.
【０００９】Ｃは, フエライトとマルテンサイトからな
る複合組織を得ること，また強度を向上させるに有効な
元素である。目的とする複合組織を得るために，Ｃは0.
02％以上必要であるが，0.25％を超えると延性および溶
接性が悪くなる。このため下限を0.02％, 上限を0.25％
とした。C is an element effective for obtaining a composite structure composed of ferrite and martensite and improving the strength. In order to obtain the target composite structure, C is 0.
02% or more is necessary, but if it exceeds 0.25%, ductility and weldability deteriorate. Therefore, the lower limit is 0.02% and the upper limit is 0.25%.
And
【００１０】Ｓiは，加工性を損なわず鋼の強度を向上
させるに好ましい元素であり，また焼鈍時に高温のオー
ステナイトからの冷却過程においてフエライトの生成が
促進されことを通じて複合組織が得られる効果がある
が，Ｓiが約2.0％を超えるとこの効果が飽和するととも
に硬質となり延性が劣化する。このため上限を2.0％と
した。Si is a preferable element for improving the strength of steel without impairing workability, and it has an effect that a composite structure can be obtained by promoting the formation of ferrite in the cooling process from austenite at high temperature during annealing. However, when Si exceeds about 2.0%, this effect saturates and becomes hard and the ductility deteriorates. Therefore, the upper limit was set to 2.0%.
【００１１】Ｍnは，鋼の焼入れ性を向上させ，複合組
織を得るために有効に作用する元素である。Ｍn量が1.6
％未満では低降伏比特性を有する複合組織が得られず，
一方, 3.5％を超えると加工性および溶接性を低下させ
る。このため下限を1.6％,上限を3.5％とした。Mn is an element that acts effectively to improve the hardenability of steel and obtain a composite structure. Mn amount is 1.6
%, A composite structure having a low yield ratio characteristic cannot be obtained,
On the other hand, if it exceeds 3.5%, the workability and weldability deteriorate. Therefore, the lower limit is 1.6% and the upper limit is 3.5%.
【００１２】ＰおよびＣuは，本発明における特徴的な
元素であり,これらの元素の複合添加によって耐食性が
著しく改善される。耐食性の改善のためにＰは0.03％以
上,Ｃuは0.05％以上必要である。一方Ｐは0.20％を, Ｃ
uは2.0％を超えて添加しても耐食性改善効果が飽和し，
延性が劣化する。このためＰは0.03〜0.20％, Ｃuは0.0
5〜2.0％とする。P and Cu are characteristic elements in the present invention, and the corrosion resistance is remarkably improved by the combined addition of these elements. To improve the corrosion resistance, P must be 0.03% or more and Cu must be 0.05% or more. On the other hand, P is 0.20%, C
Even if u exceeds 2.0%, the effect of improving corrosion resistance saturates,
Ductility deteriorates. Therefore, P is 0.03 to 0.20%, Cu is 0.0
5 to 2.0%.
【００１３】Ｓは，鋼にとって本質的に有害な元素であ
り, 少ないほど望ましいが0.02％までは許容できるので
0.02％以下とする。S is an element that is essentially harmful to steel. The smaller the amount, the more desirable, but 0.02% is acceptable.
0.02% or less.
【００１４】Ａlは，脱酸剤としての役割を果たすため
に0.005％以上必要であるが，0.10％を超えるとＡl2Ｏ3
などの介在物が増加し，加工性および表面品質を劣化さ
せるので，下限を0.005％, 上限を0.10％とした。Al needs to be 0.005% or more in order to function as a deoxidizer, but if it exceeds 0.10%, Al 2 O 3
Increasing inclusions such as these deteriorate workability and surface quality, so the lower limit was made 0.005% and the upper limit was made 0.10%.
【００１５】Ｎは，本発明鋼の場合には本質的に有害な
元素であり少ないほど望ましいが,0.008％までは許容で
きるので0.008％以下とする。In the case of the steel of the present invention, N is an essentially harmful element, and the smaller the amount, the better. However, N is 0.008% or less, so 0.008% or less is acceptable.
【００１６】また，本発明においては，2.0％までのＮ
i, 3.0％までのＭo, 3.0％までのＣrの一種もしくは二
種以上含有させると鋼板の強度と耐食性を改善すること
ができる。Further, in the present invention, N up to 2.0%
If one or more of i, Mo up to 3.0% and Cr up to 3.0% are contained, the strength and corrosion resistance of the steel sheet can be improved.
【００１７】Ｎiは，Ｃuによる熱間脆性の防止と耐食性
の改善に有効に作用するが，2.0％を超えるとその効果
は飽和するとともに製造コストが高価となる。このため
上限を2.0％とする。Ni effectively acts to prevent hot brittleness and improve corrosion resistance due to Cu, but if it exceeds 2.0%, the effect is saturated and the manufacturing cost becomes expensive. Therefore, the upper limit is 2.0%.
【００１８】Ｍoは，鋼板の強度上昇と耐食性の改善に
有効に作用するが，3.0％を超えるとその効果は飽和す
るとともに製造コストが高価となるので上限を3.0％と
する。Mo effectively acts to increase the strength of the steel sheet and improve the corrosion resistance, but if it exceeds 3.0%, the effect is saturated and the manufacturing cost becomes high, so the upper limit is made 3.0%.
【００１９】Ｃrは，耐孔あき腐食性の改善に有効に作
用するが3.0％を超えると製造コスト高となるので，上
限を3.0％とする。Cr is effective in improving the resistance to pitting corrosion, but if it exceeds 3.0%, the manufacturing cost becomes high, so the upper limit is made 3.0%.
【００２０】Ｂは，焼入れ性を向上させるとともに粒界
を強化する元素である。このような効果を得るには0.00
03％以上の添加が必要であるが,0.005％を超えて添加し
てもその効果は飽和する。このため下限を0.0003％, 上
限を0.005％とする。B is an element that improves hardenability and strengthens grain boundaries. 0.00 for this effect
It is necessary to add more than 03%, but even if added over 0.005%, the effect is saturated. Therefore, the lower limit is 0.0003% and the upper limit is 0.005%.
【００２１】ＴiおよびＮbはフエライト結晶粒を微細化
し，延性を向上させる元素である。このような効果を得
るには, いずれの元素も0.005％以上の添加が必要であ
る。しか0.06％を超えて添加すると微細なＴiＣやＮbＣ
の析出量が多くなり逆に延性を劣化させる。このためこ
れらの元素はいずれも下限を0.005％, 上限を0.06％と
した。Ti and Nb are elements for making the ferrite crystal grains fine and improving the ductility. In order to obtain such effects, it is necessary to add 0.005% or more of each element. If added over 0.06%, fine TiC and NbC
However, the amount of precipitation increases and the ductility deteriorates. Therefore, the lower limit of these elements is 0.005% and the upper limit is 0.06%.
【００２２】本発明においては, かかる成分を含有する
鋼を熱間圧延工程および冷間圧延工程を経て連続焼鈍を
行なう。熱間圧延工程での仕上げ温度はＡr3変態点以上
とするのが加工性向上のうえから好ましく, またその巻
取り温度は500〜750℃の範囲内で行えばよい。冷間圧延
工程における冷延率は50〜95％の範囲とするのがよい。In the present invention, steel containing such components is subjected to continuous annealing through a hot rolling step and a cold rolling step. It is preferable that the finishing temperature in the hot rolling step is not less than the Ar 3 transformation point in order to improve workability, and the winding temperature may be in the range of 500 to 750 ° C. The cold rolling rate in the cold rolling step is preferably in the range of 50 to 95%.
【００２３】連続焼鈍ラインにおける焼鈍は720〜950℃
の温度範囲で行なう。必要に応じてこの焼鈍材に軽度の
スキンパスを施して最終板厚の製品鋼板を得る。焼鈍温
度の下限を720℃とするのは，複合組織を得るために必
要な最低温度として720℃は要するからである。上限を9
50℃とするのは，この温度を超えても加工性の向上効果
が飽和すると共に，連続焼鈍ラインにおいて表面疵が発
生し易くなるためである。Annealing in the continuous annealing line is 720 to 950 ° C.
Perform within the temperature range. If necessary, this annealed material is lightly skin-passed to obtain a final product steel plate. The lower limit of the annealing temperature is 720 ° C because 720 ° C is required as the minimum temperature required to obtain the composite structure. Up to 9
The reason for setting the temperature to 50 ° C is that the workability improving effect is saturated even if this temperature is exceeded, and surface defects easily occur in the continuous annealing line.
【００２４】連続焼鈍ラインにおける焼鈍後の冷却過程
での冷却速度が遅いと複合組織が得にくく，そのため焼
入れ性向上元素の添加を多く必要とする。このため冷却
速度は速い方が望ましいが，焼鈍温度から約450℃まで
の平均冷却速度が３℃/sec以上であれば問題はない。If the cooling rate in the cooling process after annealing in the continuous annealing line is slow, it is difficult to obtain a composite structure, and therefore it is necessary to add many hardenability improving elements. Therefore, it is desirable that the cooling rate is high, but there is no problem if the average cooling rate from the annealing temperature to about 450 ° C is 3 ° C / sec or more.
【００２５】[0025]
【実施例】表１に示す化学成分値の鋼を，表２に示す条
件のもとで，熱間圧延によって板厚2.5mmの熱延板とし
たうえ，酸洗後，冷間圧延によって板厚0.8mmの冷延板
を製造した。この冷延板を表２に示す温度で連続焼鈍
し, その後伸び率0.3％のスキンパス圧延を行った。得
られた鋼板から試験片を採取して各種の特性を調べた。
その結果を表２に示した。[Examples] Steels having the chemical composition values shown in Table 1 were hot-rolled under the conditions shown in Table 2 into hot-rolled sheets with a thickness of 2.5 mm, and after being pickled, cold-rolled A cold rolled sheet having a thickness of 0.8 mm was manufactured. The cold-rolled sheet was continuously annealed at the temperature shown in Table 2 and then skin-pass rolled with an elongation of 0.3%. Test pieces were taken from the obtained steel sheet and various characteristics were examined.
The results are shown in Table 2.
【００２６】引張特性についてはJIS Z 2201の５号試験
片を用いて行った。耐食試験は70×150 mmの試験片を切
りだし複合腐食試験を行った。複合腐食試験はJIS Z 23
71の塩水噴霧試験に準じ, 塩水濃度が５％の塩水噴霧試
験を２時間→60℃の熱風乾燥を４時間→湿潤試験を２時
間の計８時間を１サイクルとして，240サイクル後の腐
食による最大侵食深さを測定することによって評価し
た。The tensile properties were measured using JIS Z 2201 No. 5 test piece. For the corrosion resistance test, a 70 × 150 mm test piece was cut out and a complex corrosion test was performed. Compound corrosion test is JIS Z 23
According to 71 salt spray test, salt spray test with salt water concentration of 5% for 2 hours → hot air drying at 60 ° C for 4 hours → wet test for 2 hours as a cycle for a total of 8 hours, resulting in corrosion after 240 cycles It was evaluated by measuring the maximum erosion depth.
【００２７】[0027]
【表１】 [Table 1]
【００２８】[0028]
【表２】 [Table 2]
【００２９】表２の結果に見られるように，Ｍn,Ｐが本
発明で規定するより低く且つＣu無添加の比較鋼No.1を
用いて製造した鋼板は，降伏比 (ＹＲ）が高くて低降伏
比の複合組織鋼板が得られていないし，伸び（Ｅｌ）も
低い。そして耐食性が劣っている。No.2の比較鋼を用い
て製造した鋼板は，Ｍnの増量によって複合組織が得ら
れており，降伏比（ＹＲ）が低く伸び（Ｅｌ）が向上し
ている。しかしＰが低く且つＣu無添加である。このた
めに耐食性が劣っている。As can be seen from the results of Table 2, the steel sheet manufactured using Comparative Steel No. 1 in which Mn and P were lower than those specified in the present invention and Cu was not added had a high yield ratio (YR). No composite steel sheet with a low yield ratio has been obtained, and the elongation (El) is low. And the corrosion resistance is inferior. The steel sheet manufactured by using the No. 2 comparative steel has a composite structure by increasing the amount of Mn, and has a low yield ratio (YR) and an improved elongation (El). However, P is low and Cu is not added. Therefore, the corrosion resistance is poor.
【００３０】これに対して本発明法に従うNo.4〜15鋼の
鋼板は，降伏比（ＹＲ）が低く，伸び（Ｅｌ）が良好で
あり, しかも耐食性に優れている。On the other hand, the steel sheets No. 4 to 15 according to the method of the present invention have a low yield ratio (YR), a good elongation (El), and excellent corrosion resistance.
【００３１】[0031]
【発明の効果】以上のように本発明によれば，低降伏
比, 高延性を維持しながら強度と耐食性が共に優れた冷
延高張力鋼板を製造することができる。この鋼板は自動
車の車体特に補強部材等の軽量化と腐食防止に大きく寄
与することができる。As described above, according to the present invention, it is possible to manufacture a cold-rolled high-strength steel sheet which is excellent in strength and corrosion resistance while maintaining a low yield ratio and high ductility. This steel sheet can greatly contribute to the weight reduction and corrosion prevention of the car body, especially the reinforcing member.
Claims (3)
％以下, Ｍn：1.6〜3.5％, Ｐ：0.03〜0.20％, Ｓ：0.0
2％以下, Ｃu：0.05〜2.0％, sol.Ａl：0.005〜0.100
％, Ｎ：0.008％以下を含有し，残部が鉄および不可避
的不純物よりなる鋼のスラブを熱間圧延し, 酸洗後，目
標板厚まで冷間圧延し, ついで連続焼鈍ラインで720〜9
50℃の温度で焼鈍することからなる耐食性に優れた低降
伏比冷延高張力鋼板の製造方法。1. By weight%, C: 0.02-0.25%, Si: 2.0
% Or less, Mn: 1.6 to 3.5%, P: 0.03 to 0.20%, S: 0.0
2% or less, Cu: 0.05 to 2.0%, sol.Al: 0.005 to 0.100
%, N: 0.008% or less, the balance being steel and the balance being steel and unavoidable impurities, hot-rolled a slab of steel, pickled, cold-rolled to the target thickness, and then continuously annealing at 720-9
A method for producing a low-yield ratio cold-rolled high-strength steel sheet excellent in corrosion resistance, which comprises annealing at a temperature of 50 ° C.
％以下, Ｍn：1.6〜3.5％, Ｐ：0.03〜0.20％, Ｓ：0.0
2％以下, Ｃu：0.05〜2.0％, sol.Ａl：0.005〜0.100
％, Ｎ：0.008％以下を含有したうえ，さらに，Ｔi：0.
005〜0.06％またはＮb：0.005〜0.06％の少なくとも一
種以上，および／またはＮi：2.0％以下, Ｍo：3.0％以
下またはＣr：3.0％以下の少なくとも一種以上を含有
し，残部が鉄および不可避的不純物よりなる鋼のスラブ
を熱間圧延し, 酸洗後，目標板厚まで冷間圧延し，つい
で連続焼鈍ラインで720〜950℃の温度で焼鈍することか
らなる耐食性に優れた低降伏比冷延高張力鋼板の製造方
法。2. By weight%, C: 0.02 to 0.25%, Si: 2.0
% Or less, Mn: 1.6 to 3.5%, P: 0.03 to 0.20%, S: 0.0
2% or less, Cu: 0.05 to 2.0%, sol.Al: 0.005 to 0.100
%, N: 0.008% or less, and Ti: 0.
005 to 0.06% or Nb: 0.005 to 0.06% at least one or more, and / or Ni: 2.0% or less, Mo: 3.0% or less or Cr: 3.0% or less at least one or more, and the balance is iron and unavoidable A steel slab made of impurities is hot-rolled, pickled, cold-rolled to a target plate thickness, and then annealed at a temperature of 720 to 950 ° C in a continuous annealing line. Manufacturing method of rolled high strength steel sheet.
％以下, Ｍn：1.6〜3.5％, Ｐ：0.03〜0.20％, Ｓ：0.0
2％以下, Ｃu：0.05〜2.0％, sol.Ａl：0.005〜0.100
％, Ｎ：0.008％以下，Ｂ：0.0003〜0.005％を含有した
うえ，さらに，Ｔi：0.005〜0.06％またはＮb：0.005〜
0.06％の少なくとも一種以上，および／またはＮi：2.0
％以下, Ｍo：3.0％以下またはＣr：3.0％以下の少なく
とも一種以上を含有し，残部が鉄および不可避的不純物
よりなる鋼のスラブを熱間圧延し, 酸洗後，目標板厚ま
で冷間圧延し，ついで連続焼鈍ラインで720〜950℃の温
度で焼鈍することからなる耐食性に優れた低降伏比冷延
高張力鋼板の製造方法。3. By weight%, C: 0.02-0.25%, Si: 2.0
% Or less, Mn: 1.6 to 3.5%, P: 0.03 to 0.20%, S: 0.0
2% or less, Cu: 0.05 to 2.0%, sol.Al: 0.005 to 0.100
%, N: 0.008% or less, B: 0.0003 to 0.005%, Ti: 0.005 to 0.06% or Nb: 0.005 to
0.06% of at least one and / or Ni: 2.0
% Or less, Mo: 3.0% or less or Cr: 3.0% or less, at least one of which is steel and the balance is iron and unavoidable impurities, hot-rolled, pickled, and then cold-rolled to the target thickness. A method for producing a low yield ratio cold rolled high strength steel sheet with excellent corrosion resistance, which comprises rolling and then annealing at a temperature of 720 to 950 ° C in a continuous annealing line.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP32950791A JP3347151B2 (en) | 1991-11-18 | 1991-11-18 | Manufacturing method of low yield ratio cold rolled high strength steel sheet with excellent corrosion resistance |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP32950791A JP3347151B2 (en) | 1991-11-18 | 1991-11-18 | Manufacturing method of low yield ratio cold rolled high strength steel sheet with excellent corrosion resistance |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH05140652A true JPH05140652A (en) | 1993-06-08 |
| JP3347151B2 JP3347151B2 (en) | 2002-11-20 |
Family
ID=18222150
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP32950791A Expired - Fee Related JP3347151B2 (en) | 1991-11-18 | 1991-11-18 | Manufacturing method of low yield ratio cold rolled high strength steel sheet with excellent corrosion resistance |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3347151B2 (en) |
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