JPH0413419B2 - - Google Patents
Info
- Publication number
- JPH0413419B2 JPH0413419B2 JP59182582A JP18258284A JPH0413419B2 JP H0413419 B2 JPH0413419 B2 JP H0413419B2 JP 59182582 A JP59182582 A JP 59182582A JP 18258284 A JP18258284 A JP 18258284A JP H0413419 B2 JPH0413419 B2 JP H0413419B2
- Authority
- JP
- Japan
- Prior art keywords
- steel
- plating
- amount
- hot
- 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.)
- Expired - Lifetime
Links
- 229910000831 Steel Inorganic materials 0.000 claims description 78
- 239000010959 steel Substances 0.000 claims description 78
- 238000007747 plating Methods 0.000 claims description 76
- 229910001335 Galvanized steel Inorganic materials 0.000 claims description 21
- 239000008397 galvanized steel Substances 0.000 claims description 21
- KFZAUHNPPZCSCR-UHFFFAOYSA-N iron zinc Chemical compound [Fe].[Zn] KFZAUHNPPZCSCR-UHFFFAOYSA-N 0.000 claims description 16
- 229910001297 Zn alloy Inorganic materials 0.000 claims description 14
- 229910052758 niobium Inorganic materials 0.000 claims description 11
- 238000005246 galvanizing Methods 0.000 claims description 9
- 239000007787 solid Substances 0.000 claims description 7
- 229910052757 nitrogen Inorganic materials 0.000 claims description 5
- 229910052698 phosphorus Inorganic materials 0.000 claims description 5
- 239000000758 substrate Substances 0.000 claims description 3
- 239000012535 impurity Substances 0.000 claims description 2
- 229910052717 sulfur Inorganic materials 0.000 claims description 2
- 229910000905 alloy phase Inorganic materials 0.000 description 13
- 230000000694 effects Effects 0.000 description 13
- 238000000034 method Methods 0.000 description 10
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 9
- 239000000463 material Substances 0.000 description 9
- 229910052799 carbon Inorganic materials 0.000 description 8
- 238000005275 alloying Methods 0.000 description 7
- 238000000137 annealing Methods 0.000 description 7
- 238000006243 chemical reaction Methods 0.000 description 7
- 238000012545 processing Methods 0.000 description 7
- 230000007423 decrease Effects 0.000 description 6
- 230000007547 defect Effects 0.000 description 6
- 238000001953 recrystallisation Methods 0.000 description 5
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 4
- HCHKCACWOHOZIP-UHFFFAOYSA-N Zinc Chemical compound [Zn] HCHKCACWOHOZIP-UHFFFAOYSA-N 0.000 description 4
- 238000007792 addition Methods 0.000 description 4
- 230000015572 biosynthetic process Effects 0.000 description 4
- 230000000052 comparative effect Effects 0.000 description 4
- 239000002436 steel type Substances 0.000 description 4
- 238000009628 steelmaking Methods 0.000 description 4
- 239000011701 zinc Substances 0.000 description 4
- 229910052725 zinc Inorganic materials 0.000 description 4
- 230000006866 deterioration Effects 0.000 description 3
- 238000011161 development Methods 0.000 description 3
- 230000018109 developmental process Effects 0.000 description 3
- 238000005516 engineering process Methods 0.000 description 3
- 238000005098 hot rolling Methods 0.000 description 3
- 229910052742 iron Inorganic materials 0.000 description 3
- 229910052748 manganese Inorganic materials 0.000 description 3
- 238000004519 manufacturing process Methods 0.000 description 3
- 239000000203 mixture Substances 0.000 description 3
- 239000002244 precipitate Substances 0.000 description 3
- 239000006104 solid solution Substances 0.000 description 3
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 2
- 229910000655 Killed steel Inorganic materials 0.000 description 2
- 230000002159 abnormal effect Effects 0.000 description 2
- 230000032683 aging Effects 0.000 description 2
- 238000005452 bending Methods 0.000 description 2
- 239000010960 cold rolled steel Substances 0.000 description 2
- 238000007872 degassing Methods 0.000 description 2
- 238000009792 diffusion process Methods 0.000 description 2
- 238000009863 impact test Methods 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- 229910052751 metal Inorganic materials 0.000 description 2
- 150000004767 nitrides Chemical class 0.000 description 2
- 239000000047 product Substances 0.000 description 2
- 238000012360 testing method Methods 0.000 description 2
- 229910000851 Alloy steel Inorganic materials 0.000 description 1
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- 238000003723 Smelting Methods 0.000 description 1
- 238000004140 cleaning Methods 0.000 description 1
- 238000011109 contamination Methods 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 230000001419 dependent effect Effects 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 238000006477 desulfuration reaction Methods 0.000 description 1
- 230000023556 desulfurization Effects 0.000 description 1
- 238000004134 energy conservation Methods 0.000 description 1
- 230000002349 favourable effect Effects 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 229910052739 hydrogen Inorganic materials 0.000 description 1
- 239000011810 insulating material Substances 0.000 description 1
- 229910052745 lead Inorganic materials 0.000 description 1
- 238000002844 melting Methods 0.000 description 1
- 230000008018 melting Effects 0.000 description 1
- 238000001000 micrograph Methods 0.000 description 1
- 238000007639 printing Methods 0.000 description 1
- 238000003672 processing method Methods 0.000 description 1
- 239000011819 refractory material Substances 0.000 description 1
- 238000005096 rolling process Methods 0.000 description 1
- 150000003839 salts Chemical class 0.000 description 1
- 238000001878 scanning electron micrograph Methods 0.000 description 1
- 238000005507 spraying Methods 0.000 description 1
- 238000004804 winding Methods 0.000 description 1
Landscapes
- Coating With Molten Metal (AREA)
- Heat Treatment Of Sheet Steel (AREA)
Description
［産業上の利用分野］
本発明は、メツキ密着性の優れた深絞り用溶融
亜鉛メツキ鋼板に関するものである。
［従来の技術］
近年、省資源、省エネルギーに対する社会的要
求から溶融亜鉛メツキ鋼板の用途が拡大し、それ
と同時に品質に対する要求も高まりつつある。自
動車用溶融亜鉛メツキ鋼板もその一つで、寒冷地
域における塩害対策のために従来冷延鋼板が使用
されていた部材に亜鉛メツキ鋼板が使われるよう
になり、その結果高度の加工性が要求されるよう
になつてきた。亜鉛メツキ鋼板がプレス成形等の
加工を受けると、加工度の高い部分ではメツキ層
に割れが発生したり、場合によつてはメツキ層が
鋼板から剥離する現象が起こる。この場合、剥離
したメツキ小片がプレス型等にビルドアツプし製
品表面にキズを作つたり、また、剥離によつて鉄
地が露出するために、メツキ鋼板の加工後の耐食
性も低下する。このようなメツキ密着性不良につ
いては従来からシリコンキルド鋼や他の高強度溶
融亜鉛メツキ鋼板に関して研究されており、それ
らの原因は鋼中に含まれるSiやAl等、Feより酸
化され易い元素が、連続溶融亜鉛メツキライン
（以下CGLという）内の焼鈍炉内で選択的に酸化
され、それらがメツキ後もメツキ層鉄地界面に残
るための考えられている（日戸ら：日本鉄鋼協会
第74回西山記念技術講座テキスト、P129〜）。こ
のような場合、メツキ密着性を改善させるために
は、成分設計の際に有害な鋼中元素を極力少なく
するか、あるいは亜鉛浴温を上昇させる方法等が
知られている（S.Harperら：Edited Proc. 11
th Int.Conference on Hot Dip Galvanizing，
Madrid， 1976，P11〜）。
また、CGLは短時間焼鈍であるために、通常
の鋼種をCGLだけで処理した鋼板はランクフオ
ード値（値）で代表される深絞り性が悪く、ま
た固溶Ｃが多量に残留しているために、腰折れと
呼ばれる表面欠陥や、時効劣化が現われやすい。
このような、深絞り用メツキ鋼板としての致命的
な欠陥を補うため、CGLでメツキを施した後の
鋼板をさらに箱型焼鈍炉にて過時効処理する方法
が従来から実施されているが、この方法は言うま
でもなくコスト上昇につながり好ましい方法とは
言えない。
一方、最近の製鋼技術の進歩により、深絞り冷
延鋼板用素材として特性の優れた極低Ｃ系鋼種が
工業的に安定製造されるようになり、溶融亜鉛メ
ツキ鋼板用素材としても使用されはじめた。この
方法では、鋼中において炭素化物を作り易い元素
すなわちTi，Nb，Ｂ等の元素を規定量添加し、
Ｎの固定をAlではなくTiとＢに分担させ、熱延
の仕上げ圧延以前に窒化物を析出させることによ
りコイル内の材質変動を少なくし、さらにNbに
よつてＣを固定するようにしたものであつた。こ
のように炭窒化物形成元素を添加してＣ，Ｎ等の
固溶元素を固定した鋼は、深絞り性および時効性
に優れ、深絞り用溶融亜鉛メツキ鋼板の素材とし
て最も適した鋼種の一つである。
［発明が解決しようとする課題］
このような深絞り用亜鉛メツキ鋼板として、本
発明者らはＣを0.001〜0.005％含む極低Ｃ系鋼種
にTi，ＢおよびNbを添加することにより深絞り
性に優れた深絞り用亜鉛メツキ鋼板の開発を行
い、先に特開昭58−110659号公報で提案した。し
かしながら、このような極低Ｃ系溶融亜鉛メツキ
鋼板を加工した場合、通常の加工方法（例えば
180°密着曲げ程度の加工）においては何ら問題な
いが、加工が衝撃的あるいは加工度が厳しい場合
（例えばデユポン衝撃試験など）には、メツキ層
の密着性がＣを0.01％程度含む一般的な溶融亜鉛
メツキ鋼板と比較して劣ることが判明した。
［課題を解決するための手段］
本発明者らは、上述の従来技術における問題点
を解決すべく数々の検討を行つた結果、極低Ｃ系
溶融亜鉛メツキ鋼板特有のメツキ層の密着性の低
下が、メツキした際に下地鋼板とメツキ層の界面
に形成される鉄−亜鉛合金相が、下地鋼板の結晶
粒界を起点として異常成長する現象（Outburst
反応）によつて起ること、さらに鋼中にＰを積極
的に添加することによつて、このOutburst反応
が効果的に抑制できるとの知見を得たことによ
り、本発明に到達したものである。以下その実験
データを引用しながら本発明の内容について詳述
する。
極低Ｃ系鋼種の熱延板を実験室的に脱炭焼鈍
し、固溶Ｃ量を変化させた材料について酸洗・冷
間圧延後、実機CGLで焼鈍及びメツキ（メツキ
溶温：470℃、浴中Al濃度：0.17％、合金化なし）
した。この材料について合金相厚さとメツキ密着
性との関係を調査した結果を第２図に示す。この
第２図から合金相の厚い方がメツキ密着性が悪い
ことが明らかで、特に鉄−亜鉛合金相の厚さが
1μｍをこえる場合はことに著るしい。また、メ
ツキ後の鋼中固溶Ｃ量と、メツキ後の合金化処理
していないメツキ鋼板のメツキ層−鋼板界面に形
成された鉄−亜鉛合金相の金属組織の発達状況と
の関係を第１図に示す。図に示す写真はメツキ層
断面の走査型電子顕微鏡観察結果であり、中央の
白い部分が鉄−亜鉛系合金相である。この第１図
から、鋼中の固溶Ｃ量が低下するとOutburst組
織（図中、代表例を矢印で示す）と呼ばれる合金
相の異常発生が多く観察され、特に固溶Ｃが
11ppm以下であると、ことに著るしいことがわか
つた。
以上の結果から、極低Ｃ系鋼種を溶融亜鉛メツ
キ鋼板に適用した場合に認められる加工が衝撃的
な場合等のメツキ密着性の低下が下地鋼板とメツ
キ層の界面に形成される鉄−亜鉛合金相の
Outburst量と関係し、Outburst量が多くなると、
メツキ密着性が低下することが明らかになつた。
次に、本発明者らは、メツキ密着性を低下させ
るOutburst組織がどのような条件下で形成され
るのかを調査した。試験に使用した鋼種はNbと
Ｂを添加した極低Ｃ系鋼種（Ｃ：0.0019％、Si：
0.01％、Mn：０、26％、Ｐ：0.005％、Al：0.006
％、Ｎ：0.0017％、Nb：0.020％．Ｂ：0.0010％）
であり、実験室的に0.6mmまで冷間圧延した後、
実機CGLにおいて焼鈍（800℃、約30秒）メツキ
（メツキ浴温：470℃、浴中Al濃度：0.16％）を施
し合金化処理をしないメツキ板を得た。このメツ
キ鋼板の鉄−亜鉛合金相および下地鋼板組織の走
査形電子顕微鏡観察結果を第３図に示す。第３図
中(a)図はη相（亜鉛相）を希塩酸で溶解した後上
方から観察した鉄−亜鉛合金相を示す。この(a)図
からNbやＢを添加することにより固溶Ｃおよび
固溶Ｎを無くした鋼種では、Outburst組織が多
量に形成されている。次に、(b)図は、(a)図のサン
プルの合金相を走査形電子顕微鏡観察後さらに希
塩酸にて溶解除去し、硝酸アルコールで下地鋼板
の結晶粒界を現出させ、同一視野を観察した結果
を示す。さらに(c)図は(a)図と(b)図のネガを重ね合
せて焼いたものである。これらの写真から、
Outburst組織は下地鋼板の結晶粒界を起点とし
て形成されていることが明らかとなつた。尚、第
３図(a)図および(b)図において符号Ａ−Ｅは、夫々
同一箇所であることを示し、(c)図においては、下
地鋼板の代表的結晶粒界を矢印で示した。
本発明においては、このようなOuburst組織の
形成を防止する方法について種々検討した結果、
鋼中にＰを積極的に添加することによつてメツキ
下地鋼板結晶粒界にＰを偏析させ、その結果下地
鋼板、結晶粒界部における鉄−亜鉛反応を抑制す
ることが可能であることを発見した。
なお、前述の特開昭58−110659号公報において
も、Ｐの添加量を規定しているが、その目的は単
に強度調整をするためであり、メツキ密着性を改
善するために軟質材であつても積極的にＰを添加
する本発明の技術思想とは根本的に異なるもので
ある。
本発明は、上記の知見によりなされたものであ
つて、Ｃ：0.001〜0.0035％、Si：0.10％以下、
Mn：0.06〜0.25％、Ｐ：0.025〜0.1％、Ｓ：0.001
〜0.020％、Sol.Al：0.01〜0.06％、Ｎ：0.0035％
以下、Ｏ：0.0050％以下、Nb：0.015〜0.035％、
更にＢ：0.0035％以下、Ti：0.030％以下の１種
又は２種を含有し、残りがFeおよび不可避不純
物からなり、溶融亜鉛メツキ後の鋼中固溶Ｃ量が
実質的に11ppm以下である溶融亜鉛メツキ鋼板で
あつて、メツキ−下地界面に生成した鉄−亜鉛合
金相の平均厚さが1μｍ以下であるものである。
［作用］
以下、本発明において成分組成およびその条件
を限定した理由と作用について説明する。
まず、鋼種をキルド鋼としたのは、添加する
Nb，Ti，Ｂ等の歩留りを向上させ、且つ鋼中介
在物の増加を防ぐためである。
Ｃは、深絞り性の観点からは少ないほうが望ま
しいが、現状の製鋼技術では耐火物や保温材から
の混入が避けられず、0.001％未満にするために
はコストの著しい上昇を招くため下限を0.001％
とした。又、前述したようにＣをNbで固定する
ため、Ｃに比例してNbの添加量が増し、その結
果再結晶温度が高くなるため、コスト上昇につな
がるので、Ｃの上限を0.0035％とした。また、溶
融亜鉛メツキ後の鋼中固有Ｃの量を11ppm以下に
限定したのは、前述のように、極低Ｃ系溶融亜鉛
メツキ鋼板に特有のメツキ密着性の劣化をもたら
すOutburst反応が11ppm以下で特に顕著となる
が、実はこの固溶Ｃの領域で以下にも述べるよう
に、本発明による特有の効果が発揮できるからで
らある。
Siは、メツキ密着性に対して有害な元素である
ため、特に高度の加工性を要求される場合には添
加しないほうが良い。上限値はメツキ密着性によ
つて規定される。第４図はSi添加量とメツキ密着
性の関係を表わすグラフである。この第４図から
衝撃曲げ試験の評点を４以上とするためにはSiの
上限値を0.10％とする必要がある。
Mnは、本発明において深絞り性およびメツキ
密着性には寄与せず、製鋼作業として特に添加し
なくても良い。通常の製鋼作業（Mn含有量を低
減するための特別な作業を必要としない）で限ら
れるMn量の下限から、その下限を0.06％とし、
上限を材質劣化を防止するため0.50％とした。し
かし、後述するＳ％関連で0.18〜0.25％とするこ
とがコスト上最も好ましい。
Ｓは、本発明の鋼では深絞り性やメツキ密着性
に影響を与えないので、製鋼段階で容易に脱硫で
きる0.001％を下限とした。又、Ｓ％が0.020％を
越えるとMnが0.25％でMn／Ｓが12.5以下とな
り、熱延での脆化に起因する表面傷が増加するの
で上限を0.020％とした。
Sol.Alは、脱ガス精練後Nb，Ti，Ｂを添加す
る前に、鋼中Ｏを脱酸するために添加される。そ
の結果、それら添加元素の歩留りが一定となり、
正確に添加量を制御することが可能となる。下限
を0.010％としたのは、これ未満ではNb，Ti，Ｂ
の添加量がばらつくためであり、上限を0.060％
としたのは、これを超えるとBNよりもAlNの微
細な析出物が出てきて再結晶温度が高くなるため
である。
Ｎは、少ないほうが好ましい。その理由はＢ及
びTiの添加量が少なくてすみ、コスト的にも有
利であるばかりでなく、析出する窒化物も少なく
なり、再結晶温度、粒成長、表面欠陥など総ての
点で好ましいからである。上限値を0.0035％とし
たのは、主として表面欠陥の理由からであり、Ｎ
がこの値を越えるとＢ及びTiの必要添加量が増
し、その結果表面欠陥が増加するためである。
Ｏは、0.0050％を越えると鋼中介在物が増加す
るため、鋼中の加工性が低下し、さらにNb，Ｂ
及びTiの添加量と材質の相関が乱れるために、
これを上限とした。
Nbは、Ｃ量によつてその必要添加量が決めら
れるが、下限値の0.015％未満ではＣの固定が不
充分で深絞り性の向上が望めない。その理由はＮ
を固定すべきＢ，Ti，Al等が添加されていても、
少量のNbがＮと結合するためと推定される。上
限値の0.035％を越えると再結晶温度が高くなる
傾向が認められる。その理由はNbCの量が多く
なるためで、Ｃが少ないとＢが添加されていても
Nb（Ｃ＋Ｎ）のようにＮにも結び付きNbの析出
物が増加するためと推定される。
Ｂは、Ｎの限定理由で述べたことと同じで、上
限値を0.0035％とした。その理由はＢがこの量を
超えるとスラブの表面欠陥が増加し、鋼板の表面
品質が悪くなるからである。
Tiは、コスト的に少ないほうが好ましいが、
上限値を0.030％としたのはTiCが生成するのを
防止するためである。Tiが0.030％を超えると
TiCが生成しやすく、鋼の再結晶温度が高くなる
傾向がある。
Ｐは、本発明の場合、溶融亜鉛メツキ後の鋼中
固溶Ｃが11ppm以下の極低Ｃ鋼のメツキ密着性を
改善するための積極的に添加含有させる。下限値
はOutburst組織の抑制効果で規定される。第５
図はＰ添加量と合金相の量及びメツキ密着性との
関係を表わす。この第５図からＰが0.025％以下
では合金相の異常成長を抑制できないことがわか
る。NbやTiの単独添加鋼では、Ｐを添加すると
添加量とともに値が低下する傾向が認められる
が、Nb添加鋼にＢ及びTiの１種又は２種を添加
すると、Ｐを多量に添加しても値は殆んど低下
しない。Ｐの上限値は合金化反応の不均一性によ
つて規定される。鋼中にＰを多量に添加すると合
金化時に焼けむらと呼ばれる合金化反応の不均一
性を生じるため、Ｐの上限値を0.1％とした。
さらに、第８図は第１表に示した７個の鋼につ
いて、とくにＣとＰの含有量の関係をプロツトし
たグラフである。図の横軸に全Ｃ量、縦軸にＰ量
を示して、実施例鋼Ａ，Ｂ，Ｃ，Ｄ（黒丸ドツト）
と比較鋼Ｅ，Ｆ，Ｇ（白丸ドツト）とを図示した。
図から明らかなように、第２表および第３表に
示したメツキ密着性やその他の特性のよい実施例
鋼Ａ，Ｂ，Ｃ及びＤはＣ（炭素）が10〜35ppm、
Ｐが0.025〜0.10％の点線枠内に分布するのに対
してほぼ同量のＣを含有する特性不良の比較鋼Ｅ
及びＧ（ＦはSi量が特許請求の範囲の含有量外の
ため除外する）はとくにＰ量が0.025％未満の枠
内に存在している。以上のことから、前記合金鋼
のOutburst組織の抑制にＰが大きく作用してい
ることが裏付けされている。なお、第８図には、
参考のため、特開昭58−110659号公報に記載され
たデータも示した。
次に、本発明の深絞り用溶融亜鉛メツキ鋼板の
製造方法について述べる。
まず、メツキ浴温は430℃以上とし500℃以下が
望ましい。その理由は、実操業面からの理由であ
る。すなわち、CGLにおけるメツキ厚さの制御
は現在ガスワイピング法により行われている。こ
れはメツキ後の鋼板表面にノズルから高圧のガス
を吹き付けることによつて余剰のメツキを下方へ
払い落とす方法である。この方法では、メツキ浴
温が低い場合にはワイピングを行う以前にメツキ
層が凝固してしまい、メツキ厚さの制御ができな
くなるため、メツキ浴温の下限を430℃とした。
また、上限を500℃としているが、その理由は、
鋼中のＰによるOutburst組織抑制効果が500℃で
は無くなるためである。すなわち、本発明の主旨
は下地鋼板の結晶粒界にＰを偏析させることによ
つて結晶粒界におけるFe原子の拡散を抑制する
ところにあることから、メツキ浴温を高めて拡散
反応を活発に起こさせるとＰの効果がなくなり、
Outburst組織が生成してしまうことからメツキ
密着性が低下する。このような理由から、メツキ
浴温は430℃〜500℃とするのが最良条件である。
メツキ浴中Al濃度も同様にメツキ密着性に対
して異存性が高い。すなわち、メツキ浴中のAl
は鉄と亜鉛の合金化反応を抑制するために添加さ
れている。従つて、Al濃度が0.05％よりも低い場
合には、鋼中にＰが添加されていても鉄−亜鉛合
金相が多量に生成され、メツキ密着性が低下する
ことから、その下限値を0.05％としている。
このように、本発明では鋼中への積極的なＰの
添加、メツキ浴温、メツキ浴中Al濃度を複合規
制することにより顕著な効果が得られる。
なお、本発明はメツキ後合金化処理をする合金
化溶融亜鉛メツキ鋼板についても密着性向上の効
果を発揮する。
［実施例］
以下本発明の実施例について説明する。
(1) 実施例 １
第１表に示す鋼は転炉出鋼後、50トンあるいは
250トンの脱ガス精練設備で低Ｃおよば低Ｎ化を
図り、鋼塊またはCC鋳片として製造されたもの
である。これらのスラブを所定の方法で手入れ
後、3.2mm厚さの熱延コイルとした。熱延条件は、
加熱温度1150℃、仕上出口温度910℃、巻取温度
700℃であつた。次に、このコイルを酸洗・冷圧
し、0.7mm厚さの冷延コイルとし、NOFタイプの
連続溶融亜鉛メツキライン（CGL）に通板した。
CGLにおける主なメツキ条件は、焼鈍温度750
〜780℃、焼鈍時間約30秒、メツキ浴温465℃、メ
ツキ浴組成0.17％Al−0.22％Pbであつた。
尚、ここで鋼Ａ，Ｂ，Ｃ，Ｄは本発明鋼であ
り、鋼Ｅ，Ｆ，Ｇは比較鋼である。
第２表は、第１表に示された各鋼の合金相の厚
さおよびメツキ密着性を示している。この第２表
から明らかなように、本発明鋼の合金相の厚さは
全て0.6μ以下であり、比較鋼と比べて合金相の発
達が抑制されていることがわかる。更に、メツキ
密着性をみると180°密着曲げのように比較的厳し
くない条件では差異は殆んど現われないが、デユ
ポン衝撃試験のよに衝撃的に加工される場合には
メツキ密着性に及ぼす合金相厚さの影響が明瞭に
現われている。
第３表は、第１表に示された各鋼の材料特性値
を示している。この第３表から本発明鋼は優れた
深絞り性（値が1.8以上）を有していることが
明らかである。
(2) 実施例 ２
第１表に示した鋼種の内、鋼Ａ，Ｂ及び鋼Ｅ，
Ｆの冷延板を使用し、実験室的に溶融亜鉛メツキ
を行ない、メツキ密着性に及ぼすメツキ浴温及び
浴中Al量の影響を調査した。尚、主なメツキ条
件は焼鈍温度750℃、焼鈍時間30秒であり、炉内
雰囲気は25％H2−N2Balであつた。
第６図にメツキ密着性とメツキ浴温の関係を、
又第７図にメツキ密着性と浴中Al量の関係をそ
れぞれ示す。これらの第６，７図から明らかなよ
うに、メツキ密着性は本発明の製造方法で限定す
る430℃≦メツキ浴温≦500℃、及び浴中Al量0.05
％以上において優れた値を示している。
[Industrial Field of Application] The present invention relates to a hot-dip galvanized steel sheet for deep drawing with excellent plating adhesion. [Prior Art] In recent years, the use of hot-dip galvanized steel sheets has expanded due to social demands for resource and energy conservation, and at the same time, demands for quality have also been increasing. Hot-dip galvanized steel sheets for automobiles are one such example. Galvanized steel sheets have come to be used in parts where cold-rolled steel sheets were previously used to prevent salt damage in cold regions, and as a result, a high degree of workability is required. It's starting to feel like this. When a galvanized steel sheet undergoes processing such as press forming, cracks occur in the plating layer in highly processed areas, and in some cases, the plating layer peels off from the steel sheet. In this case, the peeled off plating pieces build up on a press mold or the like and create scratches on the product surface, and the peeling exposes the iron base, which reduces the corrosion resistance of the plated steel sheet after processing. Such poor plating adhesion has been studied for silicon-killed steel and other high-strength hot-dip galvanized steel sheets, and the cause is that elements that are more easily oxidized than Fe, such as Si and Al, contained in the steel. It is thought that this is because they are selectively oxidized in the annealing furnace in the continuous hot-dip galvanizing line (hereinafter referred to as CGL) and remain at the interface of the galvanized layer even after galvanizing (Hito et al.: Japan Iron and Steel Institute No. 74). 1st Seishan Memorial Technology Lecture Text, P129~). In such cases, methods known to improve plating adhesion include minimizing the amount of harmful elements in the steel during component design, or increasing the zinc bath temperature (S.Harper et al. :Edited Proc. 11
th Int.Conference on Hot Dip Galvanizing，
Madrid, 1976, P11~). In addition, since CGL is annealed for a short time, steel plates made from ordinary steel types treated only with CGL have poor deep drawability as represented by the Rankford value, and a large amount of solid solute C remains. Therefore, surface defects called buckling and aging deterioration are likely to appear.
In order to compensate for such fatal defects in plated steel sheets for deep drawing, a method has been used in the past in which the steel plates that have been plated with CGL are further subjected to over-aging treatment in a box-type annealing furnace. Needless to say, this method increases costs and cannot be said to be a preferable method. On the other hand, with recent advances in steelmaking technology, ultra-low C steel grades with excellent characteristics have become industrially and stably manufactured as materials for deep-drawn cold-rolled steel sheets, and are also beginning to be used as materials for hot-dip galvanized steel sheets. Ta. In this method, elements that easily form carbonides in steel, such as Ti, Nb, and B, are added in specified amounts,
The fixation of N is shared by Ti and B instead of Al, and nitrides are precipitated before finish rolling of hot rolling to reduce material fluctuations within the coil, and C is fixed by Nb. It was hot. Steel in which solid solution elements such as C and N are fixed by adding carbonitride-forming elements in this way has excellent deep drawability and aging resistance, and is the most suitable steel type as a material for hot-dip galvanized steel sheets for deep drawing. There is one. [Problems to be Solved by the Invention] The present inventors developed a galvanized steel sheet for deep drawing by adding Ti, B, and Nb to an ultra-low C steel grade containing 0.001 to 0.005% C. We developed a galvanized steel sheet for deep drawing with excellent properties and proposed it earlier in JP-A-58-110659. However, when processing such ultra-low C hot-dip galvanized steel sheets, normal processing methods (e.g.
However, if the processing is impactful or the degree of processing is severe (such as the Dupont impact test), the adhesion of the plating layer may be less than 0.01% C. It was found to be inferior to hot-dip galvanized steel sheets. [Means for Solving the Problems] The present inventors have conducted numerous studies to solve the problems in the prior art described above, and as a result, the inventors have found that the adhesion of the plating layer, which is unique to ultra-low C hot-dip galvanized steel sheets, has been improved. Outburst is a phenomenon in which the iron-zinc alloy phase that forms at the interface between the base steel sheet and the plating layer during plating abnormally grows starting from the grain boundaries of the base steel sheet.
The present invention was achieved based on the knowledge that this outburst reaction can be effectively suppressed by actively adding P to the steel. be. The content of the present invention will be described in detail below while citing the experimental data. Hot-rolled sheets of ultra-low C steel were decarburized and annealed in the laboratory, and the materials with varying amounts of solid solute C were pickled and cold-rolled, then annealed and plated using an actual CGL machine (plating melting temperature: 470°C). , Al concentration in bath: 0.17%, no alloying)
did. Figure 2 shows the results of investigating the relationship between alloy phase thickness and plating adhesion for this material. From this figure 2, it is clear that the thicker the alloy phase, the worse the plating adhesion, especially the thicker the iron-zinc alloy phase.
If it exceeds 1 μm, it is particularly noticeable. In addition, we investigated the relationship between the amount of solid solute C in the steel after plating and the development status of the metal structure of the iron-zinc alloy phase formed at the plating layer-steel plate interface of the plating steel sheet that has not been alloyed after plating. Shown in Figure 1. The photograph shown in the figure is the result of scanning electron microscope observation of the cross section of the plating layer, and the white part in the center is the iron-zinc alloy phase. Figure 1 shows that when the amount of solute C in steel decreases, abnormal formation of an alloy phase called an outburst structure (a typical example is indicated by an arrow in the figure) is often observed.
It was found that when the concentration was 11 ppm or less, it was particularly significant. From the above results, it is clear that when ultra-low C steel is applied to hot-dip galvanized steel sheets, the decrease in plating adhesion caused by the impact of processing is caused by the iron-zinc formation formed at the interface between the base steel sheet and the galvanized layer. alloy phase
Related to the Outburst amount, when the Outburst amount increases,
It became clear that plating adhesion decreased. Next, the present inventors investigated under what conditions outburst structures that reduce plating adhesion are formed. The steel used in the test was an ultra-low C steel with Nb and B added (C: 0.0019%, Si:
0.01%, Mn: 0, 26%, P: 0.005%, Al: 0.006
%, N: 0.0017%, Nb: 0.020%. B: 0.0010%)
After being cold rolled to 0.6mm in the laboratory,
Annealing (800°C, approximately 30 seconds) and plating (plating bath temperature: 470°C, Al concentration in bath: 0.16%) was performed in an actual CGL machine to obtain a plated plate without alloying treatment. FIG. 3 shows the results of scanning electron microscope observation of the iron-zinc alloy phase of this plated steel sheet and the underlying steel sheet structure. Figure 3 (a) shows the iron-zinc alloy phase observed from above after dissolving the η phase (zinc phase) with dilute hydrochloric acid. From this figure (a), a large amount of outburst structure is formed in steel types in which solute C and solute N are eliminated by adding Nb and B. Next, in Figure (b), after observing the alloy phase of the sample in Figure (a) with a scanning electron microscope, it was further dissolved and removed with dilute hydrochloric acid, and the grain boundaries of the underlying steel sheet were exposed with nitric alcohol. The observed results are shown. Furthermore, figure (c) is the result of overlapping the negatives of figures (a) and (b) and printing them. From these photos,
It became clear that the outburst structure was formed starting from the grain boundaries of the base steel sheet. Note that in Figures 3(a) and 3(b), the symbols A-E indicate the same locations, and in Figure 3(c), arrows indicate typical grain boundaries of the underlying steel sheet. . In the present invention, as a result of various studies on methods for preventing the formation of such Ooburst tissue,
By actively adding P to the steel, it is possible to segregate P at the grain boundaries of the base steel sheet, and as a result, it is possible to suppress the iron-zinc reaction at the grain boundaries of the base steel sheet. discovered. Note that the above-mentioned Japanese Patent Application Laid-Open No. 58-110659 also stipulates the amount of P added, but the purpose is simply to adjust the strength, and the purpose of this is only to adjust the strength, and to improve plating adhesion. However, this is fundamentally different from the technical idea of the present invention, which actively adds P. The present invention was made based on the above findings, and includes C: 0.001 to 0.0035%, Si: 0.10% or less,
Mn: 0.06-0.25%, P: 0.025-0.1%, S: 0.001
~0.020%, Sol.Al: 0.01~0.06%, N: 0.0035%
Below, O: 0.0050% or less, Nb: 0.015 to 0.035%,
Furthermore, it contains one or two of B: 0.0035% or less and Ti: 0.030% or less, and the remainder consists of Fe and unavoidable impurities, and the amount of solid solute C in the steel after hot-dip galvanizing is substantially 11 ppm or less. This is a hot-dip galvanized steel sheet in which the average thickness of the iron-zinc alloy phase formed at the galvanized-substrate interface is 1 μm or less. [Effect] The reason and effect of limiting the component composition and conditions in the present invention will be explained below. First, the reason why we chose killed steel is because of the addition of
This is to improve the yield of Nb, Ti, B, etc., and to prevent an increase in inclusions in the steel. It is desirable to have a small amount of C from the perspective of deep drawability, but with the current steelmaking technology, contamination from refractories and heat insulating materials is unavoidable, and reducing it to less than 0.001% will result in a significant increase in cost, so the lower limit has to be set. 0.001%
And so. In addition, as mentioned above, since C is fixed with Nb, the amount of Nb added increases in proportion to C, resulting in a higher recrystallization temperature, which leads to an increase in cost, so the upper limit of C was set at 0.0035%. . In addition, the reason why the amount of inherent C in the steel after hot-dip galvanizing is limited to 11 ppm or less is because, as mentioned above, the outburst reaction that causes deterioration of plating adhesion, which is unique to ultra-low C type hot-dip galvanized steel sheets, is 11 ppm or less. This is particularly noticeable in the solid solution C region, but this is because, as will be described below, the unique effects of the present invention can be exerted in this solid solution C region. Since Si is an element harmful to plating adhesion, it is better not to add it especially when high workability is required. The upper limit is determined by plating adhesion. FIG. 4 is a graph showing the relationship between the amount of Si added and plating adhesion. From FIG. 4, in order to obtain a rating of 4 or higher in the impact bending test, the upper limit of Si needs to be 0.10%. Mn does not contribute to deep drawability and plating adhesion in the present invention, and does not need to be particularly added during steelmaking operations. The lower limit of Mn amount is set at 0.06% from the lower limit of the amount of Mn that is limited in normal steelmaking operations (no special operations are required to reduce the Mn content).
The upper limit was set at 0.50% to prevent material deterioration. However, in terms of S%, which will be described later, it is most preferable to set the content to 0.18 to 0.25% in terms of cost. Since S does not affect deep drawability or plating adhesion in the steel of the present invention, the lower limit was set at 0.001%, which allows for easy desulfurization at the steel manufacturing stage. Furthermore, if S% exceeds 0.020%, Mn is 0.25% and Mn/S is 12.5 or less, which increases surface flaws due to embrittlement during hot rolling, so the upper limit was set at 0.020%. Sol.Al is added to deoxidize O in the steel after degassing and before adding Nb, Ti, and B. As a result, the yield of these added elements becomes constant,
It becomes possible to accurately control the amount added. The reason for setting the lower limit to 0.010% is that below this, Nb, Ti, and B
This is because the amount added varies, and the upper limit is set at 0.060%.
The reason for this is that if this temperature is exceeded, fine precipitates of AlN will appear rather than BN, and the recrystallization temperature will become higher. The smaller the number of N, the better. The reason for this is that the amount of B and Ti added is small, which is not only advantageous in terms of cost, but also reduces the amount of nitrides that precipitate, which is favorable in terms of recrystallization temperature, grain growth, surface defects, etc. It is. The upper limit was set at 0.0035% mainly due to surface defects, and N
This is because if exceeds this value, the required amounts of B and Ti to be added will increase, resulting in an increase in surface defects. If O exceeds 0.0050%, inclusions in the steel will increase, resulting in a decrease in workability in the steel.
And because the correlation between the amount of Ti added and the material quality is disturbed,
This was set as the upper limit. The required amount of Nb to be added is determined by the amount of C, but if it is less than the lower limit of 0.015%, fixation of C will be insufficient and no improvement in deep drawability can be expected. The reason is N
Even if B, Ti, Al, etc. are added to fix the
It is presumed that this is because a small amount of Nb combines with N. When the upper limit of 0.035% is exceeded, the recrystallization temperature tends to increase. The reason is that the amount of NbC increases, and if C is small, even if B is added.
It is presumed that this is because Nb also binds to Nb like Nb (C+N) and the number of Nb precipitates increases. For B, the upper limit is set to 0.0035%, which is the same as stated in the reason for limiting N. The reason is that if B exceeds this amount, surface defects in the slab will increase and the surface quality of the steel sheet will deteriorate. It is preferable for Ti to be less in terms of cost, but
The reason for setting the upper limit to 0.030% is to prevent TiC from being generated. When Ti exceeds 0.030%
TiC tends to form easily and the recrystallization temperature of steel tends to increase. In the case of the present invention, P is actively added to improve the plating adhesion of ultra-low C steel in which solid solute C in the steel after hot-dip galvanizing is 11 ppm or less. The lower limit is determined by the suppressive effect of the outburst tissue. Fifth
The figure shows the relationship between the amount of P added, the amount of alloy phase, and plating adhesion. It can be seen from FIG. 5 that when P is less than 0.025%, abnormal growth of the alloy phase cannot be suppressed. In steel with single additions of Nb or Ti, when P is added, the value tends to decrease with the addition amount, but when one or both of B and Ti are added to Nb-added steel, a large amount of P is added. However, the value hardly decreases. The upper limit of P is determined by the heterogeneity of the alloying reaction. If a large amount of P is added to the steel, non-uniformity of the alloying reaction called uneven burning occurs during alloying, so the upper limit of P was set at 0.1%. Further, FIG. 8 is a graph plotting the relationship between the C and P contents for the seven steels shown in Table 1. The total C content is shown on the horizontal axis of the figure, and the P content is shown on the vertical axis. Example steels A, B, C, and D (black circle dots)
and comparative steels E, F, and G (white circle dots). As is clear from the figure, the example steels A, B, C, and D shown in Tables 2 and 3, which have good plating adhesion and other properties, have a C (carbon) content of 10 to 35 ppm.
Comparative steel E with poor properties contains almost the same amount of C while P is distributed within the dotted line frame of 0.025 to 0.10%
and G (F is excluded because the amount of Si is outside the content range of the claims) is particularly present in a range where the amount of P is less than 0.025%. From the above, it is confirmed that P has a large effect on suppressing the outburst structure of the alloy steel. Furthermore, in Figure 8,
For reference, data described in Japanese Unexamined Patent Publication No. 110659/1982 is also shown. Next, a method for manufacturing a hot-dip galvanized steel sheet for deep drawing according to the present invention will be described. First, the temperature of the plating bath should preferably be 430°C or higher and 500°C or lower. The reason for this is from the perspective of actual operation. That is, the plating thickness in CGL is currently controlled by the gas wiping method. This method involves spraying high-pressure gas from a nozzle onto the surface of the steel sheet after plating to remove excess plating downward. In this method, if the plating bath temperature is low, the plating layer will solidify before wiping, making it impossible to control the plating thickness, so the lower limit of the plating bath temperature was set at 430°C.
Also, the upper limit is set at 500℃, and the reason is that
This is because the outburst structure suppressing effect of P in steel disappears at 500°C. That is, since the gist of the present invention is to suppress the diffusion of Fe atoms at the grain boundaries by segregating P at the grain boundaries of the base steel sheet, it is possible to increase the plating bath temperature to activate the diffusion reaction. If you let it happen, the effect of P will disappear,
Plating adhesion deteriorates due to the formation of outburst tissue. For these reasons, it is best to set the plating bath temperature to 430°C to 500°C. Similarly, the Al concentration in the plating bath is highly dependent on plating adhesion. In other words, Al in the plating bath
is added to suppress the alloying reaction between iron and zinc. Therefore, if the Al concentration is lower than 0.05%, a large amount of iron-zinc alloy phase will be generated even if P is added to the steel, and the plating adhesion will decrease, so the lower limit is set to 0.05%. %. As described above, in the present invention, significant effects can be obtained by actively adding P to the steel, controlling the plating bath temperature, and the Al concentration in the plating bath in combination. Note that the present invention also exhibits the effect of improving adhesion on alloyed hot-dip galvanized steel sheets that undergo alloying treatment after plating. [Examples] Examples of the present invention will be described below. (1) Example 1 The steel shown in Table 1 is produced in a 50 ton or
It is manufactured as a steel ingot or CC slab using a 250-ton degassing smelting facility to achieve low C and N content. After cleaning these slabs in a prescribed manner, they were made into hot-rolled coils with a thickness of 3.2 mm. The hot rolling conditions are
Heating temperature 1150℃, finishing outlet temperature 910℃, winding temperature
It was 700℃. Next, this coil was pickled and cold-pressed to form a cold-rolled coil with a thickness of 0.7 mm, and passed through a NOF type continuous hot-dip galvanizing line (CGL). The main plating conditions in CGL are annealing temperature 750
The temperature was ~780°C, the annealing time was about 30 seconds, the plating bath temperature was 465°C, and the plating bath composition was 0.17% Al-0.22% Pb. Note that steels A, B, C, and D are the steels of the present invention, and steels E, F, and G are comparison steels. Table 2 shows the thickness of the alloy phase and plating adhesion of each steel shown in Table 1. As is clear from Table 2, the thickness of the alloy phase in the steel of the present invention is all 0.6 μm or less, and it can be seen that the development of the alloy phase is suppressed compared to the comparative steel. Furthermore, when looking at plating adhesion, there is almost no difference under relatively non-severe conditions such as 180° close bending, but there is no difference in plating adhesion when subjected to impact processing such as the Dupont impact test. The influence of alloy phase thickness is clearly visible. Table 3 shows material property values for each steel shown in Table 1. It is clear from Table 3 that the steel of the present invention has excellent deep drawability (value of 1.8 or more). (2) Example 2 Among the steel types shown in Table 1, steel A, B and steel E,
Hot-dip galvanizing was carried out in the laboratory using a cold-rolled sheet of F, and the effects of the plating bath temperature and the amount of Al in the bath on plating adhesion were investigated. The main plating conditions were an annealing temperature of 750° C. and an annealing time of 30 seconds, and the atmosphere in the furnace was 25% H 2 -N 2 Bal. Figure 6 shows the relationship between plating adhesion and plating bath temperature.
Furthermore, Fig. 7 shows the relationship between plating adhesion and the amount of Al in the bath. As is clear from these Figures 6 and 7, plating adhesion is limited by the production method of the present invention at 430°C ≦ plating bath temperature ≦ 500°C, and the amount of Al in the bath is 0.05.
% or higher.
【表】【table】
【表】【table】
【表】
［発明の効果］
以上説明した実施例の効果からも明らかなよう
に、本発明によれば極低Ｃ系鋼種の成分組成を改
善し、溶融亜鉛メツキ鋼板のメツキ密着性に悪影
響を与えるOutburst組織の発生を抑制し、メツ
キ−下地界面の鉄−亜鉛合金相の平均厚さを1μ
ｍ以下としたことにより、従来のものより深絞り
性なかんずく加工度の高い場合にも充分耐えるこ
とのできるメツキ密着性を有する深絞り用溶融亜
鉛メツキ鋼板が得られた。[Table] [Effects of the Invention] As is clear from the effects of the examples described above, according to the present invention, the composition of ultra-low C steel grades is improved, and there is no negative effect on the plating adhesion of hot-dip galvanized steel sheets. This suppresses the occurrence of outburst structures and reduces the average thickness of the iron-zinc alloy phase at the metal-substrate interface to 1 μm.
m or less, a hot-dip galvanized steel sheet for deep drawing was obtained which has plating adhesion that can sufficiently withstand deep drawing properties, especially when the degree of working is higher than that of conventional products.
第１図は鋼中固溶Ｃ量と、メツキ鋼板のメツキ
層−鋼板界面に生成した鉄−亜鉛系合金相の金属
組織の発達状況との関係を示す走査型電子顕微鏡
写真、第２図は鉄−亜鉛系合金相の厚さとメツキ
密着性との関係を示すグラフ、第３図(a)(b)(c)はメ
ツキ鋼板の鉄−亜鉛系合金相及び下地鋼板組織を
示す走査型電子顕微鏡写真であり、(a)はη相（亜
鉛相）を希塩酸で溶解した後の鉄−亜鉛合金相を
示し、(b)は前記(a)のサンプルの合金相を更に希塩
酸で溶解除去し、硝酸アルコールで下地鋼板の結
晶粒界を示し、(c)は前記(a)と(b)の写真を重ね焼き
した写真、第４図はメツキ密着性とSi添加量との
関係を示すグラフ、第５図はＰ添加量と合金相の
量及びメツキ密着性との関係を示すグラフ、第６
図はメツキ密着性とメツキ浴温の関係を示すグラ
フ、第７図はメツキ密着性と浴中Al量との関係
を示すグラフ、第８図は実施例鋼Ａ，Ｂ，Ｃ，Ｄ
及び比較例鋼Ｅ，Ｆ，ＧのＣとＰとの含有量の関
係を示すために第１表からプロツトしたグラフで
ある。
Figure 1 is a scanning electron micrograph showing the relationship between the amount of solid solute C in steel and the development of the metal structure of the iron-zinc alloy phase formed at the interface between the plating layer and the steel plate of a plated steel sheet. A graph showing the relationship between the thickness of the iron-zinc alloy phase and plating adhesion. Figure 3 (a), (b), and (c) are scanning electronic graphs showing the iron-zinc alloy phase of the plated steel sheet and the structure of the underlying steel sheet. These are micrographs, (a) shows the iron-zinc alloy phase after dissolving the η phase (zinc phase) with dilute hydrochloric acid, and (b) shows the alloy phase of the sample in (a) further dissolved and removed with dilute hydrochloric acid. , showing the grain boundaries of the underlying steel sheet using nitric alcohol, (c) is a photograph obtained by overlaying the photographs of (a) and (b) above, and Figure 4 is a graph showing the relationship between plating adhesion and Si addition amount. , Figure 5 is a graph showing the relationship between the amount of P added, the amount of alloy phase, and plating adhesion.
The figure is a graph showing the relationship between plating adhesion and plating bath temperature, Figure 7 is a graph showing the relationship between plating adhesion and Al content in the bath, and Figure 8 is a graph showing the relationship between plating adhesion and Al content in the bath.
and is a graph plotted from Table 1 to show the relationship between the C and P contents of Comparative Example Steels E, F, and G.
Claims (1)
Mn：0.08〜0.50％、Ｐ：0.025〜0.1％、Ｓ：0.001
〜0.020％、Sol Al：0.01〜0.08％、Ｎ：0.0035％
以下、Ｏ：0.0050％以下、Nb：0.015〜0.035％、
更にＢ：0.0035％以下、Ti：0.030％以下の１種
又は２種を含有し、残りがFeおよび不可避不純
物からなり、溶融亜鉛メツキ後の鋼中固溶Ｃ量が
実質的に11ppm以下である溶融亜鉛メツキ鋼板で
あつて、メツキ−下地界面に生成した鉄−亜鉛合
金相の平均厚さが1μｍ以下であることを特徴と
するメツキ密着性の優れた深絞り用溶融亜鉛メツ
キ鋼板。1 C: 0.001 to 0.0035%, Si: 0.10% or less,
Mn: 0.08-0.50%, P: 0.025-0.1%, S: 0.001
~0.020%, Sol Al: 0.01~0.08%, N: 0.0035%
Below, O: 0.0050% or less, Nb: 0.015 to 0.035%,
Furthermore, it contains one or two of B: 0.0035% or less and Ti: 0.030% or less, and the remainder consists of Fe and unavoidable impurities, and the amount of solid solute C in the steel after hot-dip galvanizing is substantially 11 ppm or less. A hot-dip galvanized steel sheet for deep drawing with excellent plating adhesion, characterized in that the average thickness of the iron-zinc alloy phase formed at the plating-substrate interface is 1 μm or less.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP18258284A JPS6160860A (en) | 1984-09-03 | 1984-09-03 | Zinc plated steel sheet for deep drawing, superior in plating adhesion and its manufacture |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP18258284A JPS6160860A (en) | 1984-09-03 | 1984-09-03 | Zinc plated steel sheet for deep drawing, superior in plating adhesion and its manufacture |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS6160860A JPS6160860A (en) | 1986-03-28 |
| JPH0413419B2 true JPH0413419B2 (en) | 1992-03-09 |
Family
ID=16120801
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP18258284A Granted JPS6160860A (en) | 1984-09-03 | 1984-09-03 | Zinc plated steel sheet for deep drawing, superior in plating adhesion and its manufacture |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS6160860A (en) |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0696749B2 (en) * | 1987-03-16 | 1994-11-30 | 株式会社神戸製鋼所 | Method for manufacturing steel sheet with fused zinc plating |
| JP2610948B2 (en) * | 1988-06-29 | 1997-05-14 | 川崎製鉄 株式会社 | Manufacturing method of galvannealed steel sheet with excellent spot weldability |
| JPH0627313B2 (en) * | 1988-12-19 | 1994-04-13 | 川崎製鉄株式会社 | Method for producing alloyed hot-dip galvanized steel sheet having excellent powdering resistance |
| US5997664A (en) * | 1996-04-01 | 1999-12-07 | Nkk Corporation | Method for producing galvanized steel sheet |
| BE1011066A3 (en) * | 1997-03-27 | 1999-04-06 | Cockerill Rech & Dev | Niobium steel and method for manufacturing flat products from it. |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS58110659A (en) * | 1981-12-25 | 1983-07-01 | Nippon Kokan Kk <Nkk> | Galvanized steel plate for deep drawing and its manufacture |
| JPS5974231A (en) * | 1982-10-20 | 1984-04-26 | Nippon Steel Corp | Production of ultradeep drawing galvanized steel sheet |
| JPS5974232A (en) * | 1982-10-20 | 1984-04-26 | Nippon Steel Corp | Production of bake hardenable galvanized steel sheet for ultradeep drawing having extremely outstanding secondary processability |
-
1984
- 1984-09-03 JP JP18258284A patent/JPS6160860A/en active Granted
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS58110659A (en) * | 1981-12-25 | 1983-07-01 | Nippon Kokan Kk <Nkk> | Galvanized steel plate for deep drawing and its manufacture |
| JPS5974231A (en) * | 1982-10-20 | 1984-04-26 | Nippon Steel Corp | Production of ultradeep drawing galvanized steel sheet |
| JPS5974232A (en) * | 1982-10-20 | 1984-04-26 | Nippon Steel Corp | Production of bake hardenable galvanized steel sheet for ultradeep drawing having extremely outstanding secondary processability |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS6160860A (en) | 1986-03-28 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| EP2580359B1 (en) | Method of producing an austenitic steel | |
| JP3459500B2 (en) | High-strength galvannealed steel sheet excellent in formability and plating adhesion and method for producing the same | |
| WO2020148948A1 (en) | High-strength hot-dip galvanized steel sheet and method for manufacturing same | |
| JP2009235532A (en) | High strength steel sheet having excellent deep drawability, and method for producing the same | |
| JPH0413419B2 (en) | ||
| KR910009975B1 (en) | Hot-dip aluminum coated steel strip having excellent strength and oxidation resistance at elevated temperatures and process for production there of | |
| JP2004211140A (en) | Hot-dip galvanized steel sheet and manufacturing method therefor | |
| JP2565038B2 (en) | Method for producing high-strength galvannealed steel sheet with excellent strength-ductility balance and film properties | |
| JP5087813B2 (en) | High-tensile hot-dip galvanized steel sheet with excellent plating properties and method for producing the same | |
| JP3020846B2 (en) | Manufacturing method of high-strength hot-dip galvanized steel sheet | |
| JPH06102810B2 (en) | Method for producing galvannealed steel sheet for deep drawing with excellent secondary workability | |
| JPH06306531A (en) | Cold rolled steel sheet for machining excellent in baking hardenability and surface treated steel sheet | |
| JPH0154413B2 (en) | ||
| JP3602263B2 (en) | Manufacturing method of high strength hot-dip galvanized steel sheet with excellent deep drawability | |
| JPH07102344A (en) | Continuously annealed cold rolled steel sheet well balanced between deep drawability and resistance to deep drawing brittleness | |
| JPH0699760B2 (en) | Method for producing steel plate with hot dip zinc for ultra deep drawing | |
| JP2697771B2 (en) | Alloyed hot-dip galvanized cold-rolled steel sheet for deep drawing having a plating film with excellent adhesion and method for producing the same | |
| JP3915345B2 (en) | Manufacturing method of high-tensile hot-dip steel sheet | |
| JP2549539B2 (en) | Method for producing hot dip galvanized steel sheet for ultra deep drawing | |
| JP2001192795A (en) | High tensile strength hot dip plated steel plate and producing method therefor | |
| JP2514298B2 (en) | Method for producing galvannealed steel sheet with excellent press formability | |
| JP3106782B2 (en) | Method for producing high-strength cold-rolled steel sheet and surface-treated steel sheet excellent in bake hardenability and deep drawability | |
| JP2505038B2 (en) | Manufacturing method of hot-dip galvanized steel sheet for processing | |
| JPH0833948A (en) | Manufacture of baking hardening type cold rolled steel sheet excellent in surface quality | |
| JP4325233B2 (en) | Composite structure type high-tensile cold-rolled steel sheet and hot-dip galvanized steel sheet excellent in deep drawability and strain age hardenability, and methods for producing them |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| LAPS | Cancellation because of no payment of annual fees |