JPH0678581B2 - Cold-rolled steel sheet with excellent press formability for Zn plating - Google Patents
Cold-rolled steel sheet with excellent press formability for Zn platingInfo
- Publication number
- JPH0678581B2 JPH0678581B2 JP62055326A JP5532687A JPH0678581B2 JP H0678581 B2 JPH0678581 B2 JP H0678581B2 JP 62055326 A JP62055326 A JP 62055326A JP 5532687 A JP5532687 A JP 5532687A JP H0678581 B2 JPH0678581 B2 JP H0678581B2
- Authority
- JP
- Japan
- Prior art keywords
- steel
- plating
- steel sheet
- hot
- press formability
- 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 - Fee Related
Links
- 239000010960 cold rolled steel Substances 0.000 title claims description 9
- 238000007747 plating Methods 0.000 title description 48
- 239000012535 impurity Substances 0.000 claims description 7
- 238000005246 galvanizing Methods 0.000 claims description 4
- 239000000126 substance Substances 0.000 claims 1
- 229910000831 Steel Inorganic materials 0.000 description 78
- 239000010959 steel Substances 0.000 description 78
- 229910001335 Galvanized steel Inorganic materials 0.000 description 10
- 230000000694 effects Effects 0.000 description 10
- 239000008397 galvanized steel Substances 0.000 description 10
- 238000005275 alloying Methods 0.000 description 7
- 238000000227 grinding Methods 0.000 description 6
- 239000000463 material Substances 0.000 description 6
- 238000000137 annealing Methods 0.000 description 5
- 229910000765 intermetallic Inorganic materials 0.000 description 5
- 238000004519 manufacturing process Methods 0.000 description 5
- 238000000034 method Methods 0.000 description 5
- 239000000203 mixture Substances 0.000 description 5
- ATJFFYVFTNAWJD-UHFFFAOYSA-N Tin Chemical compound [Sn] ATJFFYVFTNAWJD-UHFFFAOYSA-N 0.000 description 4
- 239000012298 atmosphere Substances 0.000 description 4
- 238000010438 heat treatment Methods 0.000 description 4
- 230000009257 reactivity Effects 0.000 description 4
- 239000006104 solid solution Substances 0.000 description 4
- 230000002411 adverse Effects 0.000 description 3
- 238000005098 hot rolling Methods 0.000 description 3
- 229920000298 Cellophane Polymers 0.000 description 2
- 229910001021 Ferroalloy Inorganic materials 0.000 description 2
- 230000015572 biosynthetic process Effects 0.000 description 2
- 238000005336 cracking Methods 0.000 description 2
- 230000007547 defect Effects 0.000 description 2
- 230000006866 deterioration Effects 0.000 description 2
- 238000002844 melting Methods 0.000 description 2
- 230000008018 melting Effects 0.000 description 2
- 230000003647 oxidation Effects 0.000 description 2
- 238000007254 oxidation reaction Methods 0.000 description 2
- 230000009467 reduction Effects 0.000 description 2
- 230000002829 reductive effect Effects 0.000 description 2
- 238000009849 vacuum degassing Methods 0.000 description 2
- 238000004804 winding Methods 0.000 description 2
- 229910000640 Fe alloy Inorganic materials 0.000 description 1
- 229910000655 Killed steel Inorganic materials 0.000 description 1
- 229910001297 Zn alloy Inorganic materials 0.000 description 1
- 230000005856 abnormality Effects 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- 239000000654 additive Substances 0.000 description 1
- 230000000996 additive effect Effects 0.000 description 1
- 238000001479 atomic absorption spectroscopy Methods 0.000 description 1
- 238000005452 bending Methods 0.000 description 1
- 239000004566 building material Substances 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 238000005097 cold rolling Methods 0.000 description 1
- 238000009749 continuous casting Methods 0.000 description 1
- 230000006378 damage Effects 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 239000006185 dispersion Substances 0.000 description 1
- 230000001747 exhibiting effect Effects 0.000 description 1
- 238000007654 immersion Methods 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 230000008595 infiltration Effects 0.000 description 1
- 238000001764 infiltration Methods 0.000 description 1
- 230000002401 inhibitory effect Effects 0.000 description 1
- 230000000670 limiting effect Effects 0.000 description 1
- 230000007246 mechanism Effects 0.000 description 1
- 239000000155 melt Substances 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000012299 nitrogen atmosphere Substances 0.000 description 1
- 230000001590 oxidative effect Effects 0.000 description 1
- 239000002244 precipitate Substances 0.000 description 1
- 230000008569 process Effects 0.000 description 1
- 238000010791 quenching Methods 0.000 description 1
- 230000000171 quenching effect Effects 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 238000001953 recrystallisation Methods 0.000 description 1
Landscapes
- Coating With Molten Metal (AREA)
Description
【発明の詳細な説明】 ＜産業上の利用分野＞ 本発明は、溶融Znめっき用冷延鋼板に係り、特にプレス
成形性に優れ、かつプレス加工時にめっき層の剥離が少
ない、溶融Znめっきまたは合金化溶融Znめっき用冷延鋼
板に関する。DETAILED DESCRIPTION OF THE INVENTION <Industrial field of application> The present invention relates to a cold-rolled steel sheet for hot-dip Zn plating, and particularly, it has excellent press formability and has little peeling of the plating layer during press working, or hot-dip Zn plating or The present invention relates to a cold rolled steel sheet for alloying hot dip Zn plating.
＜従来の技術＞ 近年、溶融Znめっき鋼板の用途は、建材等の比較的軽加
工して使用されるもののほかに、自動車用など厳しいプ
レス加工を施こして、使用されるものに拡がってきてい
る。溶融Znめっき鋼板は、連続溶融Znめっき設備（以下
CGLという）で製造するのが経済的であり、現在、ほと
んどがこの方法で製造される。<Prior Art> In recent years, the applications of hot-dip galvanized steel sheets have expanded to those used for relatively light processing such as building materials, as well as those that are subjected to severe press processing for automobiles and the like. There is. Hot-dip galvanized steel sheet is a continuous hot-dip galvanizing facility (below
CGL) is economical to manufacture, and most of them are currently manufactured by this method.
＜発明が解決しようとする問題点＞ ところで、CGLでは鋼板の焼鈍がきわめて短時間でなさ
れるためプレス成形性に優れた鋼板を得るためには素材
鋼板を厳密に選択する必要がある。<Problems to be Solved by the Invention> In CGL, the steel sheet is annealed in an extremely short period of time, so that it is necessary to strictly select the material steel sheet in order to obtain a steel sheet excellent in press formability.
鋼中のＣやＮをそれぞれ0.02％以下とし、十分な量のTi
を添加し、ＣやＮをTiNやTiCとして鋼中で固定した鋼板
は、CGLにおける焼鈍のように短時間の加熱・急冷とい
う熱処理によっても高ランクフォード値（以下高値と
いう）および高延性を有する優れたプレス成形性を得る
ことが可能である。Each of C and N in steel is 0.02% or less, and a sufficient amount of Ti
A steel sheet in which C and N are fixed in the steel as TiN and TiC has high Rank Ford value (hereinafter referred to as high value) and high ductility even by heat treatment such as heating and quenching for a short time like annealing in CGL. It is possible to obtain excellent press formability.
一方、Ti添加鋼は通常の鋼より溶融Znとの反応性が高
く、Znめっきした時鋼板めっき層界面にZn−Fe合金が発
達し、めっき密着性に劣るという欠点を有していた。す
なわち、Ti添加鋼を用いることにより、プレス成形性に
優れた鋼板をCGLで製造することは可能であっても、こ
の場合は厳しいプレス成形に耐えるめっき層を得ること
が困難であった。On the other hand, the Ti-added steel has a higher reactivity with molten Zn than ordinary steel, and has a drawback that Zn-Fe alloy develops at the interface of the steel sheet plating layer during Zn plating, resulting in poor plating adhesion. That is, by using Ti-added steel, it is possible to produce a steel sheet having excellent press formability by CGL, but in this case, it was difficult to obtain a plating layer that can withstand severe press forming.
このような欠点を解決するために特公昭57−3334号公報
に記載されているように、浴中のAl含有量を高くし、溶
融Zn浴中に浸漬する際の鋼板温度を低くするなどのめっ
き法の改良や、特公昭60−48571号公報に記載されてい
るように、鋼中Ti量をできるだけ低減する、などの鋼成
分の検討がなされている。In order to solve such a drawback, as described in JP-B-57-3334, the Al content in the bath is increased, and the steel plate temperature when immersed in the molten Zn bath is lowered. Studies have been made on steel components such as improvement of plating method and reduction of Ti content in steel as much as possible as described in JP-B-60-48571.
しかしながら、浴中のAl濃度を高くすると、Znめっき後
において合金化処理を施こす鋼板を製造する場合には合
金化処理が困難になり、また一基のCGLで溶融Znめっき
鋼板と合金化溶融Znめっき鋼板の双方を製造する場合に
は浴組成の調整に時間を要し、経済的な損失が大きい。
そこで浸入板温を下げると、不めっきが出易くなる。ま
た鋼中Ti量を低減してめっき性の改善を図ると、鋼板の
プレス成形性が劣化する。したがって、Ti添加鋼を用い
てプレス成形性に優れた溶融Znめっき鋼板を安定して製
造することは、これらの手段を講じても困難であった。However, if the Al concentration in the bath is increased, the alloying process becomes difficult when producing a steel sheet that undergoes alloying treatment after Zn plating. When both Zn-plated steel sheets are manufactured, it takes time to adjust the bath composition, resulting in a large economical loss.
Therefore, if the infiltration plate temperature is lowered, non-plating is likely to occur. Further, if the amount of Ti in the steel is reduced to improve the plating property, the press formability of the steel sheet deteriorates. Therefore, it is difficult to stably produce a hot-dip galvanized steel sheet excellent in press formability using Ti-added steel even by taking these means.
また、溶融Znめっき鋼板のみならず、合金化溶融Znめっ
き鋼板の製造においても、Ti添加鋼は速かに合金化が進
行するため、過合金になり易くプレス成形時にパウダリ
ングを起し易いなどの問題があった。すなわち、プレス
成形性に優れた溶融Znめっき鋼板ならびに合金化溶融Zn
めっき鋼板は、プレス成形時にめっき層の剥離がほとん
ど生じないことも必要である。Further, not only hot-dip Zn-plated steel sheet, but also in the production of alloyed hot-dip Zn-plated steel sheet, since Ti-added steel is rapidly alloyed, it is easy to become over-alloyed and easily cause powdering during press forming. There was a problem. That is, hot-dip galvanized steel sheet excellent in press formability and alloyed hot-dip Zn
It is also necessary for the plated steel sheet that peeling of the plated layer hardly occurs during press forming.
したがって、めっき条件に関して一般鋼と同等の制約条
件で、プレス成形性が優れかつ良好なめっき密着性およ
び合金化処理特性が得られるTi添加鋼の溶融Znめっき素
材の開発が求められていた。Therefore, there has been a demand for the development of a hot-dip Zn-plated material for Ti-added steel, which has excellent press formability, good plating adhesion, and good alloying characteristics under the same restrictions on plating conditions as general steel.
本発明は、上記のような事情に鑑みなされたものであっ
て、プレス成形性に優れ、かつプレス加工時にめっき層
の剥離が少ない溶融または合金化溶融Znめっき用冷延鋼
板を提供することを目的とする。The present invention has been made in view of the above circumstances, it is excellent in press formability, and peeling of the plating layer during press working is less likely to provide a cold-rolled steel sheet for molten or alloyed molten Zn plating. To aim.
＜問題点を解決するための手段＞ 本発明は、化学成分として重量パーセントにて、 C:0.01％以下、 Si:0.02〜0.1％、 S:0.02％以下、 N:0.01％以下 Al:0.03〜0.1％、Ti:0.02％以上でかつ 〔有効Ti〕＝Ti−48/12 Ｃ−48/14 Ｎ−48/32Sで定義
される〔有効Ti〕とSiの比Si/〔有効Ti〕＞１およAl/Si
＞1.5を満たし、残部がFeおよび不可避的不純物からな
ることを特徴とするプレス成形性に優れた溶融Znめっき
用冷延鋼板である。<Means for Solving Problems> In the present invention, C: 0.01% or less, Si: 0.02-0.1%, S: 0.02% or less, N: 0.01% or less Al: 0.03- 0.1%, Ti: 0.02% or more and [effective Ti] = Ti-48 / 12 C-48 / 14 N-48 / 32S [effective Ti] to Si ratio Si / [effective Ti]> 1 And Al / Si
A cold-rolled steel sheet for hot-dip galvanizing excellent in press formability, characterized by satisfying> 1.5, and the balance being Fe and inevitable impurities.
＜作 用＞ 本発明者らは、Ti添加鋼の冷延鋼板の溶融Znめっき性に
ついて鋭意検討した結果、鋼中にSiを微量共存せしめた
時にTi添加鋼の溶融Znめっき特性は著しく改善されるこ
とを見出し、さらにかかるSiの効果を有効ならしめるた
めには、Siに対し一定量以上のAlを含有せしめることが
適当であることを明らかにし、本発明を完成させるに至
ったのである。<Working> As a result of diligent studies on the hot-dip Zn plating property of the cold-rolled steel sheet of Ti-added steel, the present inventors have found that the hot-dip Zn-plating characteristics of the Ti-added steel are remarkably improved when a small amount of Si coexists in the steel. The inventors have found that it is appropriate to contain Si in a certain amount or more in order to make the effect of Si effective, and have completed the present invention.
以下に、本発明の成分限定理由を詳しく説明する。The reasons for limiting the components of the present invention will be described in detail below.
C:Cは、鋼中に不可避的不純物元素として含有され、鋼
板のプレス成形性を阻害する元素である。Tiを十分に添
加し、TiCとして鋼中に固定されるとその害は著しく軽
減されるものの、0.01％以上含有するとTiCとしてＣを
固定するのに必要なTi量が増加し、かつ多量にTiCが鋼
中に分散することによる材質劣化が著しいため、0.01％
以下とする。C: C is an element contained in steel as an unavoidable impurity element and inhibiting the press formability of the steel sheet. If Ti is sufficiently added and it is fixed as TiC in the steel, the damage is remarkably reduced, but if it is contained in an amount of 0.01% or more, the amount of Ti necessary to fix C as TiC is increased and a large amount of TiC is added. 0.01% because the material deterioration caused by the dispersion of
Below.
Si:Alキルド鋼の場合、通常0.01〜0.02％程度のSiが不
純物として含有される。一般に鋼中のSiは、溶融金属の
濡れ性を阻害し不めっき欠陥の発生を助長することか
ら、溶融Znめっき鋼板の素材としては可及的に低減する
ことが好ましいとされていた。しかし、Ti添加鋼の場
合、0.02％以上0.1％以下の範囲でSiを含有することに
より、溶融Znとの反応性が抑制され良好なめっき密着性
が得られる。なお、Siを0.1％以上含有すると不めっき
欠陥が発生し易くなるのである。In the case of Si: Al killed steel, usually 0.01 to 0.02% of Si is contained as an impurity. In general, Si in steel impedes the wettability of molten metal and promotes the generation of non-plating defects, so it has been considered preferable to reduce Si as much as possible as a raw material for the galvanized steel sheet. However, in the case of Ti-added steel, by containing Si in the range of 0.02% or more and 0.1% or less, the reactivity with molten Zn is suppressed and good plating adhesion is obtained. If Si is contained in an amount of 0.1% or more, non-plating defects are likely to occur.
S:Sは、鋼中に不純物元素として通常0.01〜0.02％含有
され、鋼板を熱間圧延する際に熱間脆性による割れの原
因となる。しかし、Tiを添加した場合、TiSまたはTi2S
として固定されるからこのような悪影響は消滅する。た
だし、過剰にＳを含有すると必要なTi添加量が増大し、
コストアップの要因となるので、0.02％を上限とする。S: S is usually contained in steel in an amount of 0.01 to 0.02% as an impurity element and causes cracking due to hot brittleness during hot rolling of a steel sheet. However, when Ti is added, TiS or Ti 2 S
This adverse effect disappears because it is fixed as. However, if S is contained excessively, the required Ti addition amount increases,
Since it will increase the cost, 0.02% is set as the upper limit.
N:NもＣと同様、鋼中に不可避的不純物として含有さ
れ、かつ鋼板のプレス成形性を阻害する。Ti添加鋼で
は、鋼中でTiNとして固定されておりプレス成形性を阻
害することはないが、ＮをTiNとして固定するために必
要なTi添加量が増大し、コストアップとなる。したがっ
て、Ｎを0.01％以下とする。Like C, N: N is also contained as an unavoidable impurity in the steel and impairs the press formability of the steel sheet. The Ti-added steel is fixed as TiN in the steel and does not impair the press formability, but the Ti addition amount necessary for fixing N as TiN increases, resulting in an increase in cost. Therefore, N is set to 0.01% or less.
Al:Alは、鋼中にTiを添加する際脱酸剤として使用する
ことにより、Tiの歩留りを向上せしめ、清浄な表面を得
るために有効である。このためには、鋼中に酸可溶Alと
して0.01％程度含有せしめることが有効であるが、本発
明ではさらに鋼中Siが鋼板の溶融Znめっきとの反応性を
抑制し、良好な密着性を有するZnめっき層を形成せしめ
るための効果を顕著に発現させるために、さらに積極的
にAlを添加する必要がある。Al添加量が少ない場合、鋼
中のSiは焼鈍に際し、焼鈍雰囲気により選択酸化されて
表面にSiの酸化物層を形成し、表面直下のSi量が低下す
る。Al: Al is effective as a deoxidizing agent when Ti is added to steel to improve the yield of Ti and to obtain a clean surface. For this purpose, it is effective to contain about 0.01% as acid-soluble Al in the steel, but in the present invention, Si in the steel further suppresses the reactivity with the hot dip Zn plating of the steel sheet, and good adhesion In order to remarkably bring about the effect of forming the Zn plating layer having Al, it is necessary to add Al more positively. When the amount of Al added is small, Si in the steel is selectively oxidized in the annealing atmosphere during the annealing to form an oxide layer of Si on the surface, and the amount of Si immediately below the surface decreases.
Alを添加することにより、Alが選択酸化されることにな
るから、Siの酸化が防止されて、鋼中に固溶したSiは鋼
板と溶融Znとの過剰反応を有効に防止する。このような
Alの効果が有効であるためには、Alを0.03％以上、かつ
Al/Si＞1.5とする必要がある。しかるに鋼中Al量が0.1
％を超えると鋼板の延性が劣化するため、添加するAlは
0.1％以下とする。Since Al is selectively oxidized by adding Al, Si is prevented from being oxidized, and Si dissolved in steel effectively prevents excessive reaction between the steel sheet and molten Zn. like this
In order for the effect of Al to be effective, Al is 0.03% or more, and
Al / Si> 1.5 is required. However, the Al content in steel is 0.1.
%, The ductility of the steel sheet deteriorates.
0.1% or less.
Tg:Tiを鋼中に添加することにより、C,N,SをそれぞれTi
C,TiNおよびTi2SまたはTiSとして固定し、これら不純物
元素が鋼板のプレス成形性に及ぼす悪影響を消滅せし
め、高い延性と高値を有する鋼板を製造することが可
能である。このようなTiの効果を十分に発現せしめるた
めには、C,N,Sを析出物として固定するのに相当する量
のTiが必要であり、さらに余剰のTiを含有せしめること
が好ましい。しかしながら余剰のTiが多くなると、鋼板
と溶融Znめっきとの反応性が亢進し、めっき密着性の劣
化を招来する。By adding Tg: Ti to the steel, C, N, and S are added to the Ti
By fixing as C, TiN and Ti 2 S or TiS, it is possible to eliminate the adverse effects of these impurity elements on the press formability of the steel sheet, and manufacture a steel sheet having high ductility and high value. In order to fully exhibit such an effect of Ti, an amount of Ti corresponding to fixing C, N, and S as a precipitate is necessary, and it is preferable to add an excess of Ti. However, if the excess Ti increases, the reactivity between the steel sheet and the hot-dip Zn plating will increase, and the adhesion of the plating will deteriorate.
このようなTiの弊害を抑制するためには、鋼中Si量に対
し、 〔有効Ti〕＝Ti−48/12 Ｃ−48/14 Ｎ−48/32Sで定義
される〔有効Ti〕が、Si/〔有効Ti〕＞１となるように
制御することが必要である。余剰のTiが、鋼板と溶融Zn
の反応性を亢進するのに対し、鋼中SiがこのようなTiの
影響を小さくする機構については明らかではないが、以
下のように推定される。In order to suppress such an adverse effect of Ti, [effective Ti] defined as [effective Ti] = Ti−48 / 12 C−48 / 14 N−48 / 32S with respect to the amount of Si in steel, It is necessary to control Si / [effective Ti]> 1. Excess Ti is steel plate and molten Zn
While the mechanism by which Si in steel reduces the effect of Ti is not clear, it is presumed to be as follows.
一般に溶融Znめっき浴には、めっき密着性を劣化せしめ
るFe−Zn合金層が過度にめっき層と鋼板界面に形成され
るのを防ぐために微量のAlを添加し、Fe−Alの金属間化
合物を形成せしめることが行われている。しかし鋼中に
固溶したTiが存在すると、溶融Zn浴中のAlと金属間化合
物を形成し、Fe−Al金属間化合物の形成を阻害する。し
たがって、鋼中に固溶Tiが存在する場合、めっき密着性
の劣化を防ぐためには浴中のAl量を増量することが必要
となる。しかし、固溶TiとともにSiが鋼中に存在する場
合、TiはAlより先にSiと金属間化合物を形成し、Fe−Al
の金属間化合物の形成を阻害しなくなる。Generally, in a molten Zn plating bath, a trace amount of Al is added in order to prevent the Fe-Zn alloy layer that deteriorates the plating adhesion from being excessively formed at the interface between the plating layer and the steel sheet, and the Fe-Al intermetallic compound is added. It is being formed. However, the presence of solid solution Ti in the steel forms an intermetallic compound with Al in the molten Zn bath and inhibits the formation of the Fe-Al intermetallic compound. Therefore, when solid solution Ti is present in steel, it is necessary to increase the amount of Al in the bath in order to prevent deterioration of plating adhesion. However, when Si is present in the steel together with solid solution Ti, Ti forms an intermetallic compound with Si before Al, and Fe--Al
It does not hinder the formation of the intermetallic compound.
このようなSiの効果を顕現せしめるためには、鋼中に存
在する固溶Tiに対し一定量以上のSiの存在することが必
要である。In order to manifest such an effect of Si, it is necessary that Si is present in a certain amount or more with respect to the solid solution Ti present in the steel.
上記の如く添加元素を調整した鋼は、以下の製造条件を
コントロールすることにより、優れたプレス成形性とめ
っき密着性を有する溶融めっき鋼板、あるいは耐パウダ
リング性に優れた合金化溶融めっき鋼板とすることがで
きる。Steel with the additive elements adjusted as described above is a hot-dip steel sheet having excellent press formability and plating adhesion, or an alloyed hot-dip steel sheet having excellent powdering resistance, by controlling the following production conditions. can do.
溶製は、未脱酸転炉溶鋼を真空脱ガス装置を用後、種々
の合金鉄を所要量添加して本発明鋼の成分組成範囲に調
整し溶製鋼とする。この溶鋼は通常連続鋳造法でスラブ
に製造する。得られたスラブを通常の熱延条件即ち、仕
上温度Ar3点以上、巻取温度500〜650℃で熱延し熱延鋼
板を得る。熱延鋼板は酸洗後冷間圧延するが、その際の
冷延圧下率は40％以上、好ましくは65％〜90％とする。For melting, the undeoxidized converter molten steel is adjusted to the composition range of the steel of the present invention by adding a required amount of various ferroalloys after using a vacuum degassing device to obtain molten steel. This molten steel is usually manufactured into a slab by a continuous casting method. The obtained slab is hot-rolled under normal hot-rolling conditions, that is, a finishing temperature Ar of 3 points or more and a winding temperature of 500 to 650 ° C. to obtain a hot-rolled steel sheet. The hot-rolled steel sheet is pickled and cold-rolled, and the cold-rolling reduction rate at that time is 40% or more, preferably 65% to 90%.
ついで、この冷延鋼板をセンジミア型連続溶融めっきラ
インにおいて溶融Znめっき処理および必要に応じて合金
化処理を行うが、この際焼鈍温度は再結晶温度以上、Ar
3点以下の範囲とする。また焼鈍雰囲気は、鋼板の酸化
を防止するために３％以上のH2を含有するN2雰囲気とす
る。特に鋼板を加熱するに際し直火式無酸化加熱炉を用
いる場合は、Siの酸化を防ぐためにH2を５％以上含有す
るN2雰囲気とし、かつ雰囲気の露点を−15℃以下に保持
することが好ましい。Then, this cold-rolled steel sheet is subjected to hot-dip Zn plating treatment and alloying treatment as necessary in a Sendzimir-type continuous hot-dip galvanizing line, where the annealing temperature is above the recrystallization temperature, Ar.
The range is 3 points or less. Further, the annealing atmosphere is an N 2 atmosphere containing 3% or more of H 2 in order to prevent oxidation of the steel sheet. In particular, when using a direct-fired non-oxidizing heating furnace to heat the steel sheet, in order to prevent the oxidation of Si, the atmosphere should be N 2 containing 5% or more of H 2 , and the dew point of the atmosphere should be kept at -15 ° C or lower. Is preferred.
溶融Znめっきの条件は、通常のめっき浴組成、浴温およ
び浴への浸入板温の範囲で行って差し支えない。すなわ
ち、浴温は420〜500℃、浴中のAl濃度は0.08〜0.2％、
浸入板温は浴温−30℃から浴温＋30℃の範囲で行うこと
によって、密着性および表面性状ともに良好なめっきが
可能である。The conditions for hot-dip Zn plating may be such that the composition of the ordinary plating bath, the bath temperature, and the temperature of the plate immersed in the bath are acceptable. That is, the bath temperature is 420 to 500 ° C, the Al concentration in the bath is 0.08 to 0.2%,
If the immersion plate temperature is in the range of bath temperature -30 ° C to bath temperature + 30 ° C, plating with good adhesion and surface quality can be achieved.
また、合金化する場合にも、同様の条件でめっきし、そ
の直後に450〜600℃の範囲で加熱すれば、パウダリング
性のよい合金化溶融Znめっき鋼板が得られる。Further, in the case of alloying, plating under the same conditions and immediately after that, heating in the range of 450 to 600 ° C., an alloyed hot-dip Zn plated steel sheet with good powdering property can be obtained.
＜実施例＞ 以下に、本発明の実施例について説明する。<Examples> Examples of the present invention will be described below.
未脱酸転炉溶鋼を真空脱ガス装置で脱炭し、Al脱酸後、
種々の合金鉄を所要量添加して本発明の成分組成範囲の
溶融鋼を得た。この溶融を連続鋳造でスラブにし、熱延
温度890℃、巻取温度600℃で熱間圧延し、酸洗後冷間圧
延した。Undeoxidized converter molten steel is decarburized with a vacuum degassing device, and after deoxidizing with Al,
Various kinds of ferroalloys were added in the required amounts to obtain molten steel having the composition range of the present invention. This melt was continuously cast into a slab, hot rolled at a hot rolling temperature of 890 ° C. and a winding temperature of 600 ° C., pickled and cold rolled.
これらの方法で得られた素材成分を比較鋼とともに第１
表に示し、それらの材料試験結果を第２表に示した。Material composition obtained by these methods is
The results are shown in Table 2 and the material test results thereof are shown in Table 2.
また、種々の条件で溶融Znめっき鋼板および合金化処理
溶融Znめっき鋼板を製造し、めっき層特性（めっき構
造、Fe濃度、パウダリング性、めっき密着性等）を調べ
た結果を第３表および第４表にそれぞれ示した。 In addition, hot-dip galvanized steel sheets and alloyed hot-dip galvanized steel sheets were manufactured under various conditions, and the results of examining the plating layer characteristics (plating structure, Fe concentration, powdering property, plating adhesion, etc.) are shown in Table 3 and The results are shown in Table 4.
なお、第３表において、「めっき密着性」の判定は試料
を180゜密着曲げテストを行ったのち曲げ部分を目視観
察したもので、〇：めっき層異常なし、△：めっき層に
亀裂発生、×：めっき層が一部剥離、＃：めっき層が全
面剥離の４段階で評価した。また、第４表において、
「Fe濃度」はめっき層を酸溶解して原子吸光法によって
定量したものであり、「パウダリング性」は合金化溶融
Znめっき鋼板を90゜曲げ後曲げ部をもとの平板上にもど
し、圧縮側曲げ部のめっき層をセロテープ剥離し、セロ
テープに付着した量から目視判定で下記の５段階に評価
したものである。In Table 3, the "plating adhesion" was determined by conducting a 180 ° adhesion bending test on the sample and then visually observing the bent portion. ◯: No abnormality in the plating layer, △: cracking in the plating layer, Poor: The plating layer was partly peeled off, and #: the plating layer was completely peeled off. In addition, in Table 4,
"Fe concentration" is the amount of the plating layer dissolved in acid and quantified by atomic absorption spectrometry. "Powderability" is alloying melting.
The Zn-plated steel sheet was bent 90 °, the bent portion was returned to the original flat plate, the plating layer on the compression-side bent portion was peeled off with a cellophane tape, and the amount adhered to the cellophane tape was evaluated visually by the following five grades. .
これらの表から明らかなように、本発明鋼は、 いずれも高値、高い延性を示し、かつめっき密着性お
よびパウダリング性に優れた溶融Znめっき鋼板および合
金化溶融Znめっき鋼板の製造が可能となった。 As is clear from these tables, the steel of the present invention, All of them are capable of producing hot-dip galvanized steel sheets and alloyed hot-dip galvanized steel sheets exhibiting high price, high ductility, and excellent plating adhesion and powdering property.
＜発明の効果＞ 以上説明したように、本発明によれば、Ti添加鋼の冷延
鋼板を素材とすることによって、プレス成形性に優れ、
かつめっき密着性およびパウダリング性に優れた溶融Zn
めっきおよび合金化溶融Znめっき鋼板を製造することが
可能となったので、これによって厳しい絞り加工を行う
自動車用表面処理鋼板として、ますます需要の拡大が期
待できる。<Effects of the Invention> As described above, according to the present invention, by using a cold-rolled steel sheet of Ti-added steel as a material, excellent press formability,
In addition, molten Zn with excellent plating adhesion and powdering properties
Since it has become possible to manufacture galvanized and alloyed hot-dip galvanized steel sheets, it can be expected that demand for this will increase even further as surface-treated steel sheets for automobiles that undergo severe drawing work.
Claims (1)
される〔有効Ti〕とSiの比Si/〔有効Ti〕＞１およびAl/
Si＞1.5を満たし、残部がFeおよび不可避的不純物から
なることを特徴とするプレス成形性に優れた溶融Znめっ
き用冷延鋼板。[Claim 1] C: 0.01% or less, Si: 0.02 to 0.1%, S: 0.02% or less, N: 0.01% or less Al: 0.03 to 0.1%, Ti: 0.02% or more by weight as chemical components And [effective Ti] = Ti-48 / 12 C-48 / 14 N-48 / 32S ratio of [effective Ti] and Si Si / [effective Ti]> 1 and Al /
A cold-rolled steel sheet for hot-dip galvanizing excellent in press formability, characterized by satisfying Si> 1.5 with the balance being Fe and inevitable impurities.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP62055326A JPH0678581B2 (en) | 1987-03-12 | 1987-03-12 | Cold-rolled steel sheet with excellent press formability for Zn plating |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP62055326A JPH0678581B2 (en) | 1987-03-12 | 1987-03-12 | Cold-rolled steel sheet with excellent press formability for Zn plating |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS63223143A JPS63223143A (en) | 1988-09-16 |
| JPH0678581B2 true JPH0678581B2 (en) | 1994-10-05 |
Family
ID=12995416
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP62055326A Expired - Fee Related JPH0678581B2 (en) | 1987-03-12 | 1987-03-12 | Cold-rolled steel sheet with excellent press formability for Zn plating |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0678581B2 (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2697771B2 (en) * | 1990-07-07 | 1998-01-14 | 株式会社 神戸製鋼所 | Alloyed hot-dip galvanized cold-rolled steel sheet for deep drawing having a plating film with excellent adhesion and method for producing the same |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5857490A (en) * | 1981-10-02 | 1983-04-05 | Toa Gurauto Kogyo Kk | Muddy water composition for stabilizing excavated surface |
-
1987
- 1987-03-12 JP JP62055326A patent/JPH0678581B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPS63223143A (en) | 1988-09-16 |
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