JPH0472017A - Production of baking hardening type hot-dip galvanized steel sheet having high workability - Google Patents
Production of baking hardening type hot-dip galvanized steel sheet having high workabilityInfo
- Publication number
- JPH0472017A JPH0472017A JP18216790A JP18216790A JPH0472017A JP H0472017 A JPH0472017 A JP H0472017A JP 18216790 A JP18216790 A JP 18216790A JP 18216790 A JP18216790 A JP 18216790A JP H0472017 A JPH0472017 A JP H0472017A
- Authority
- JP
- Japan
- Prior art keywords
- hot
- steel sheet
- amount
- less
- steel
- 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.)
- Pending
Links
- 229910001335 Galvanized steel Inorganic materials 0.000 title claims description 19
- 239000008397 galvanized steel Substances 0.000 title claims description 19
- 238000004519 manufacturing process Methods 0.000 title claims description 16
- 229910000831 Steel Inorganic materials 0.000 claims abstract description 52
- 239000010959 steel Substances 0.000 claims abstract description 52
- 238000000137 annealing Methods 0.000 claims abstract description 41
- 229910052748 manganese Inorganic materials 0.000 claims abstract description 11
- 239000000203 mixture Substances 0.000 claims abstract description 10
- 238000001953 recrystallisation Methods 0.000 claims abstract description 10
- 238000005097 cold rolling Methods 0.000 claims abstract description 9
- 229910052757 nitrogen Inorganic materials 0.000 claims abstract description 9
- 229910052698 phosphorus Inorganic materials 0.000 claims abstract description 9
- 238000005098 hot rolling Methods 0.000 claims abstract description 8
- 239000012535 impurity Substances 0.000 claims abstract description 8
- 238000005246 galvanizing Methods 0.000 claims abstract description 6
- 238000005096 rolling process Methods 0.000 claims abstract description 6
- 229910052710 silicon Inorganic materials 0.000 claims abstract description 5
- 238000005261 decarburization Methods 0.000 claims description 24
- 238000005266 casting Methods 0.000 claims description 9
- 230000032683 aging Effects 0.000 abstract description 11
- 229910052717 sulfur Inorganic materials 0.000 abstract description 6
- 229910052799 carbon Inorganic materials 0.000 abstract description 4
- 230000007423 decrease Effects 0.000 description 15
- 239000006104 solid solution Substances 0.000 description 15
- 239000010960 cold rolled steel Substances 0.000 description 8
- 239000000463 material Substances 0.000 description 8
- 238000000034 method Methods 0.000 description 8
- 238000007747 plating Methods 0.000 description 8
- 230000000694 effects Effects 0.000 description 7
- 238000007796 conventional method Methods 0.000 description 6
- 239000007787 solid Substances 0.000 description 6
- 230000003679 aging effect Effects 0.000 description 5
- 238000009849 vacuum degassing Methods 0.000 description 5
- 229910045601 alloy Inorganic materials 0.000 description 4
- 239000000956 alloy Substances 0.000 description 4
- 238000005275 alloying Methods 0.000 description 4
- 230000008859 change Effects 0.000 description 4
- 230000007547 defect Effects 0.000 description 4
- 230000009467 reduction Effects 0.000 description 4
- ATJFFYVFTNAWJD-UHFFFAOYSA-N Tin Chemical compound [Sn] ATJFFYVFTNAWJD-UHFFFAOYSA-N 0.000 description 3
- 239000003575 carbonaceous material Substances 0.000 description 3
- 238000010438 heat treatment Methods 0.000 description 3
- 238000000465 moulding Methods 0.000 description 3
- 229910052758 niobium Inorganic materials 0.000 description 3
- 239000002244 precipitate Substances 0.000 description 3
- 230000008569 process Effects 0.000 description 3
- 238000012545 processing Methods 0.000 description 3
- 238000012360 testing method Methods 0.000 description 3
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 2
- 229910001209 Low-carbon steel Inorganic materials 0.000 description 2
- 230000002411 adverse Effects 0.000 description 2
- 238000003483 aging Methods 0.000 description 2
- 230000008901 benefit Effects 0.000 description 2
- 229910052804 chromium Inorganic materials 0.000 description 2
- 239000011248 coating agent Substances 0.000 description 2
- 238000000576 coating method Methods 0.000 description 2
- 230000008094 contradictory effect Effects 0.000 description 2
- 239000013078 crystal Substances 0.000 description 2
- 230000006866 deterioration Effects 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 230000003647 oxidation Effects 0.000 description 2
- 238000007254 oxidation reaction Methods 0.000 description 2
- 238000005554 pickling Methods 0.000 description 2
- 238000004804 winding Methods 0.000 description 2
- 229910000976 Electrical steel Inorganic materials 0.000 description 1
- HCHKCACWOHOZIP-UHFFFAOYSA-N Zinc Chemical compound [Zn] HCHKCACWOHOZIP-UHFFFAOYSA-N 0.000 description 1
- 229910021529 ammonia Inorganic materials 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 230000000052 comparative effect Effects 0.000 description 1
- 238000009749 continuous casting Methods 0.000 description 1
- 229910052802 copper Inorganic materials 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 238000000354 decomposition reaction Methods 0.000 description 1
- 230000000550 effect on aging Effects 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 238000000227 grinding Methods 0.000 description 1
- 230000009931 harmful effect Effects 0.000 description 1
- 238000011835 investigation Methods 0.000 description 1
- 239000003973 paint Substances 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 238000007665 sagging Methods 0.000 description 1
- 238000009864 tensile test Methods 0.000 description 1
- 238000012546 transfer Methods 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
- 229910052725 zinc Inorganic materials 0.000 description 1
- 239000011701 zinc Substances 0.000 description 1
Landscapes
- Coating With Molten Metal (AREA)
- Heat Treatment Of Steel (AREA)
- Heat Treatment Of Sheet Steel (AREA)
Abstract
Description
【発明の詳細な説明】
（産業上の利用分野）
本発明は、加工性と時効性とに優れ、かつ２．５〜３．
９ｋｇ／＊ｍ”という適度の焼付硬化性を有する溶融亜
鉛めっき鋼板あるいは合金化溶融亜鉛めっき鋼板の製造
方法に関するものである。DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention has excellent processability and aging properties, and has a property of 2.5 to 3.
The present invention relates to a method for producing a hot-dip galvanized steel sheet or an alloyed hot-dip galvanized steel sheet having an appropriate bake hardenability of 9 kg/*m''.
（従来の技術）
近年、めっき鋼板、特に合金化溶融亜鉛めっき鋼板は、
耐食性、塗装性が良好なことから自動車用材料として急
速に需要が拡大しつつあり、それに伴って特に加工性に
ついてより一層の特性改善が求められている。(Prior art) In recent years, galvanized steel sheets, especially alloyed hot-dip galvanized steel sheets,
Because of its good corrosion resistance and paintability, its demand as an automotive material is rapidly expanding, and along with this, there is a need for further improvements in properties, particularly in terms of processability.
ところで、自動車用材料では複雑な形状にプレス成形で
きるような優れた加工性を有すると共に、省エネルギー
のための車体軽量化を考慮して、強度が高いｑとが要求
される。By the way, materials for automobiles are required to have excellent workability so that they can be press-formed into complex shapes, and also to have high strength in consideration of reducing the weight of the vehicle body for energy saving.
すなわち、優れた加工性を有するものとするためには降
伏点が低く、ｆ値が高いことが必要であり、一方、高強
度であるためには、降伏点が高いことが必要である。That is, in order to have excellent workability, it is necessary to have a low yield point and a high f value, and on the other hand, in order to have high strength, it is necessary to have a high yield point.
（発明が解決しようとする諜Ｂ）
ところで、強度が高い材料では一般に伸びやｔ値が低く
加工性が悪くなる傾向がある。(Intelligence B to be Solved by the Invention) By the way, materials with high strength generally have low elongation and t value, and tend to have poor workability.
そこでこれらの相反する要求特性を両立させる手法とし
て焼付硬化性鋼板と称されるものが開発されてきた（特
開昭６２−１１２７３１号公報、特開昭６１１５７６３
９号公報、特開昭６１−２６７５７号公報、特開昭５９
−３１８２７号公報、特開昭５７−７０２５８号公報）
。Therefore, as a method to achieve both of these contradictory required properties, a so-called bake-hardenable steel sheet has been developed (Japanese Patent Application Laid-Open No. 62-112731, Japanese Patent Application Laid-open No. 6115763).
9, JP-A-61-26757, JP-A-59
-31827, Japanese Patent Application Laid-open No. 57-70258)
.
この焼付硬化性とは鋼板の歪時効を利用したもので、塗
料の焼付時の熱によって鋼板が時効硬化し、降伏点が上
昇する特性のことで、成形時には降伏点が低くて加工し
易く、成形後の焼付塗装によって降伏点が上昇して強度
が高くなるので、前述した相反する要求特性を同時に満
たすことが可能である。This bake hardenability utilizes the strain aging of the steel plate, and is a property in which the steel plate ages and hardens due to the heat during baking of the paint and its yield point increases.When forming, the yield point is low and it is easy to process. Since the baking coating after molding increases the yield point and increases the strength, it is possible to simultaneously satisfy the above-mentioned contradictory required characteristics.
しかし、焼付硬化性を付与する際には注意が必要である
。つまり、焼付硬化性を大きくすることは鋼板を時効し
昌くすることであり、常温での時効硬化性が劣化して常
温時効を引き起こすことになる。そのため製造してから
成形するまでの間に時効硬化して降伏点が上昇し加工性
が低下するとともに、降伏点伸び（ＹＰＥ）が発生して
成形時にストレッチャーストレインと呼ばれる自動車用
の外板にとっては修復不可能な致命的なシワ状欠陥を生
じることになる。一般には焼付硬化量、つまり焼付後の
降伏点上昇が５ ｋｇ／ｍｓ”を越えると明確な常温時
効が生しるとされているが、本発明者の詳細な調査によ
れば、焼付硬化量が４ ｋｇ／ｍｍ”以上になると常温
時効性は無視できなくなると考えられる。However, care must be taken when imparting bake hardenability. In other words, increasing the bake hardenability is to age the steel plate and make it stiffer, which deteriorates the age hardenability at room temperature and causes room temperature aging. Therefore, between manufacturing and molding, age hardening increases the yield point and reduces workability, and yield point elongation (YPE) occurs during molding, which is called stretcher strain. This results in fatal wrinkle-like defects that cannot be repaired. Generally, it is said that clear room temperature aging occurs when the amount of bake hardening, that is, the increase in yield point after baking exceeds 5 kg/ms. However, according to detailed research by the inventor, the amount of bake hardening It is considered that when the temperature exceeds 4 kg/mm, the room temperature aging property cannot be ignored.
今までの焼付硬化性鋼板は冷延鋼板が主体であったので
、焼付硬化量を制御するには中低炭材を箱焼鈍してＮを
ＡＱＮとして固定し、余分のＣを析出させて固溶Ｃ量を
コントロールするのが常法であった。しかし、めっき鋼
板を製造する場合には、めっき処理の際の熱によって析
出したＣが再固溶し、めっき後に過時効処理を行っても
固溶Ｃ量のコントロールが難しいといった欠点がある。Until now, bake-hardenable steel sheets have mainly been cold-rolled steel sheets, so in order to control the amount of bake-hardening, medium-low carbon steel is box-annealed to fix N as AQN, and excess C is precipitated and hardened. The conventional method was to control the amount of dissolved C. However, when manufacturing a plated steel sheet, there is a drawback that the C precipitated by the heat during the plating process re-dissolves into solid solution, and it is difficult to control the amount of solute C even if an overaging treatment is performed after plating.
さらに最近では生産性の向上のために連続焼鈍が主流と
なりつつあり、中低炭材を使ったのでは固溶Ｃ量を十分
コントロールするのが困難であるといわれている。Furthermore, in recent years, continuous annealing has become mainstream in order to improve productivity, and it is said that it is difficult to sufficiently control the amount of solid solute C when medium-low carbon materials are used.
そこで連続焼鈍用の焼付硬化性鋼板として極低Ｃ材を使
用するといった技術が開発されている。Therefore, techniques have been developed to use extremely low C materials as bake-hardenable steel sheets for continuous annealing.
これは製鋼時に、真空脱ガス処理によりＣ，Ｎなどを十
分に低下させて、Ｎは熱間圧延後の巻取り時にＡＱＮと
して析出させ、またＣは、鋼中Ｃをすべて固溶Ｃとする
かあるいはＴｉ、 Ｎｂといった炭窒化物を少量添加し
て一部のＣをＴｉｃあるいはＮｂＣとしで析出させると
いった方法によって固溶Ｃ量をコントロールするといっ
たものである。しかし、焼付硬化量を特定範囲（例えば
２．５〜３．９ｋｇ／＋＋ｖ＋”）に適中させようとす
ると固溶Ｃ量をある程度狭い範囲内に納める必要がある
が、これらの方法では鋼中の固溶Ｃ量はＣ，Ｎ、 Ｔｉ
、 Ｎｂ、 Ｓなどの量によって変動するので、固溶Ｃ
量を十分にコントロールすることは困難で、また固溶Ｃ
量は鋳込み時にほとんど決定されてしまうために歩留り
が悪くなりコストも高くなる。唯一、Ｎｂを一部のＣを
ＮｂＣとして析出させた場合のみ、焼鈍温度によっては
ＮｂＣが再溶解することを利用して固溶Ｃ量を若干調整
することが可能であるが、これにはかなりの高温焼鈍が
必要であり、コストアンプは避けられないし炉の寿命も
縮む上、固溶Ｃ量の調整幅もわずかでそのメリットは小
さい。During steel manufacturing, C, N, etc. are sufficiently reduced through vacuum degassing treatment, N is precipitated as AQN during coiling after hot rolling, and all C in the steel is solid solution C. Alternatively, the amount of solid solute C is controlled by adding a small amount of carbonitride such as Ti or Nb to precipitate some C as TiC or NbC. However, in order to set the amount of bake hardening within a specific range (for example, 2.5 to 3.9 kg/++v+"), it is necessary to keep the amount of solid solute C within a somewhat narrow range, but these methods The solid solution C amount is C, N, Ti
, Nb, S, etc., so the solid solution C
It is difficult to control the amount sufficiently, and solid solution C
Since the amount is almost determined at the time of casting, yields are poor and costs are high. Only when Nb is precipitated with some C as NbC, it is possible to slightly adjust the amount of solid solute C by taking advantage of the fact that NbC re-dissolves depending on the annealing temperature, but this requires a considerable amount of High-temperature annealing is required, which inevitably increases costs and shortens the life of the furnace. Furthermore, the adjustment range for the amount of solid solute C is small, so the benefits are small.
本発明は、これらの問題点を解消し、加工性に優れた溶
融亜鉛めっき鋼板または合金化溶融亜鉛めっき鋼板の製
造方法を提供することを目的としている。An object of the present invention is to solve these problems and provide a method for producing a hot-dip galvanized steel sheet or an alloyed hot-dip galvanized steel sheet with excellent workability.
（課題を解決するための手段）
そこで、本発明者は前述された問題点を改善し加工性お
よび時効性に優れ、かつ適度の焼付硬化性を有する（合
金化）溶融亜鉛めっき鋼板を製造するために多くの実験
と試作を行った。(Means for Solving the Problems) Therefore, the present inventor improves the above-mentioned problems and produces a (alloyed) hot-dip galvanized steel sheet that has excellent workability and aging resistance, and has appropriate bake hardenability. For this purpose, we conducted many experiments and prototypes.
その結果、真空脱ガス処理によっである程度Ｃ量を低下
させた極低炭素鋼に、Ｎを完全に固定させかつ深絞り性
を向上させるべく少量のＴｉを添加した鋼板を、連続焼
鈍中に露点を調整して鋼板中の固溶Ｃを脱炭することに
よって固溶Ｃ量をかなり正確にコントロールでき、それ
によって適度の焼付硬化性を持たせ得ること、およびめ
っき時のぬれ性を良好にするためにＳｉ、 Ｍｎの添加
量を押さえ、かつ、加工性を考慮してＭｎ、、Ｐの添加
範囲を限定することにより、目的とする特性を有する（
合金化）溶融亜鉛めっき鋼板を比較的安価で確実に製造
できることを知見し、本発明を完成させたものである。As a result, during continuous annealing, we added a small amount of Ti to completely fix N and improve deep drawability to ultra-low carbon steel whose C content had been reduced to some extent through vacuum degassing. By adjusting the dew point and decarburizing the solute C in the steel sheet, the amount of solute C can be controlled quite accurately, which allows for appropriate bake hardenability and good wettability during plating. By suppressing the amounts of Si and Mn added and limiting the range of addition of Mn, and P in consideration of processability, it is possible to achieve the desired characteristics (
The present invention was completed based on the discovery that hot-dip galvanized steel sheets (alloyed) can be manufactured reliably at a relatively low cost.
本発明に近い従来技術としては、前述したような極低炭
素材に少量のＴｉやＮｂを添加するといったものがあり
、その最適添加範囲については多く公表されているが（
特開昭５３−１１４７１７号公報、同５７−７０２５８
号公報、同５７−７９１６１号公報、同５９−３１８２
７号公報、同６１ ２６７５７号公報、同６１−１５７
６３９号公報および同６２−１１２７３１号公報）その
ほとんどについては固７８Ｃは鋳込み時に決まってしま
い、鋳込み後の再調整については何も述べておらず、ま
たは、ＮｂＣの再溶解を利用しているだけであり、これ
らの従来技術では固溶Ｃのコントロールは難しく、歩留
りが悪くなると思われる。As a conventional technique similar to the present invention, there is a technique in which a small amount of Ti or Nb is added to an ultra-low carbon material such as the one mentioned above, and the optimum range of addition thereof has been widely published (
JP-A-53-114717, JP-A No. 57-70258
Publication No. 57-79161, Publication No. 59-3182
Publication No. 7, Publication No. 61 26757, Publication No. 61-157
(No. 639 and No. 62-112731) In most of them, the hard 78C is determined at the time of casting, and nothing is said about readjustment after casting, or they just use remelting of NbC. Therefore, with these conventional techniques, it is difficult to control solid solution C, and it is thought that the yield will be poor.
また、極低炭素材を連続焼鈍によって脱炭するといった
技術については電磁鋼板を脱炭するといったものが多く
公表されているが、これらは脱炭して可能な限りＣを抜
き粒成長性を上げて、電磁特性の向上を図るためのもの
で、Ｃは少なければ少ない程良く、Ｃを調整するといっ
た思想はないし、脱炭によって著しく粒が成長して強度
低下を起こすなど、本発明の連続焼鈍脱炭とは目的や程
度かまった（異なる。In addition, many technologies have been published to decarburize ultra-low carbon materials by continuous annealing, such as decarburizing electrical steel sheets, but these decarburize and remove as much C as possible to increase grain growth. It is intended to improve electromagnetic properties, and the less C is, the better.There is no concept of adjusting C, and decarburization causes grains to grow significantly, resulting in a decrease in strength.The continuous annealing of the present invention It differs from decarburization in terms of purpose and degree.
すなわち、本発明は、鋳込み時の組成割合が、重量％に
て、
（１，： ０．００５０％以下、 Ｓｉ： ０．０４
％以下、Ｍｎ： ０．１０−０．６０％、 Ｐ：０．
０８０％以下、ただし Ｍｎ（％ｉ ＋ １０ Ｐ ｍ
≦１．２０Ｓ： ０．００２〜Ｏ，Ｏ１，Ｏ％、ＡＱ
： ０．０３０−０．１００％、Ｎ： ０．００３０
％以下、
Ｔｉ： −Ｎ（ト）〜（移Ｎ〜十−３〜）、残部：Ｆｅ
および不可避的不純物
よりなる鋼片を、熱間圧延後５０％以上の冷間圧延率に
て冷間圧延を行い、次いで、６点−３０℃以上＋１５’
Ｃ以下の雰囲気下で再結晶温度以上９００℃以下の温度
で４０秒以上の脱炭焼鈍を行い、該脱炭焼鈍後のＣを０
．００１０％以上０．００３０％未満とした上で、溶融
亜鉛めっきを施し、さらに伸率１．０％以上２．０％以
下の１！譬圧延を施すことを特徴とする、加工性および
時効性が良好で、かつ適度の焼付硬化性を有する溶融亜
鉛めっき鋼板の製造方法である。That is, in the present invention, the composition ratio at the time of casting is (1,: 0.0050% or less, Si: 0.04% by weight)
% or less, Mn: 0.10-0.60%, P: 0.
080% or less, but Mn(%i + 10 P m
≦1.20S: 0.002~O, O1, O%, AQ
: 0.030-0.100%, N: 0.0030
% or less, Ti: -N (g) ~ (transfer N ~ 10-3 ~), remainder: Fe
After hot rolling, a steel billet containing unavoidable impurities is cold rolled at a cold rolling rate of 50% or more, and then 6 points -30°C or more +15'
Decarburization annealing is performed for 40 seconds or more at a temperature higher than the recrystallization temperature and lower than 900°C in an atmosphere of C or lower, and the C after the decarburization annealing is reduced to 0.
．． 0.0010% or more and less than 0.0030%, hot-dip galvanizing is applied, and the elongation is 1.0% or more and 2.0% or less. This is a method for producing a hot-dip galvanized steel sheet that has good workability and aging properties and has appropriate bake hardenability, which is characterized by performing semi-rolling.
ここで、本発明における「加工性良好」とは、本発明の
製造方法にて製造された溶融亜鉛めっき鋼板または合金
化溶融亜鉛めっき鋼板における時効前の機械的特性にお
いて、ｙｐ≦２４ｋｇｆ／Ｍｍ” 、好ましくはＹＰ≦
２２ｋｇｆ／ｍｓ”、 Ｅ４２≧３７．５％（０，７５
ｔ）、好ましくＬｆＥｌ≧４０％（０，７５ｔ）、ト≧
１．５５（０，７５ｔ）好ましくはｆ≧１．７０（０，
７５ｔ） 、が−’）ＹＰＥ＝Ｏを満足していることで
あり、また、「時効性が良好」とは、１００℃Ｘ６０分
間の加速時効熱処理による時効後の機械的特性において
、ＹＰの劣化化ΔＹＰ≦＋”ｋｇ／ａｍ”、かつＹＰＥ
＝ Ｏ（降伏点伸び発生せず）を満足していることで
ある。Here, "good workability" in the present invention refers to mechanical properties before aging of the hot-dip galvanized steel sheet or the alloyed hot-dip galvanized steel sheet manufactured by the manufacturing method of the present invention, yp≦24 kgf/Mm" , preferably YP≦
22kgf/ms”, E42≧37.5% (0.75
t), preferably LfEl≧40% (0,75t), T≧
1.55 (0,75t) preferably f≧1.70 (0,
75t), satisfies -')YPE=O, and "good aging properties" means that the mechanical properties after aging due to accelerated aging heat treatment at 100°C for 60 minutes show that YP does not deteriorate. ΔYP≦+”kg/am”, and YPE
= O (yield point elongation does not occur).
（作用）
本発明にあって上述のようにめっき鋼板の成分組成およ
び製造条件を限定する理由は次のとおりである。(Function) The reason why the composition and manufacturing conditions of the plated steel sheet are limited as described above in the present invention is as follows.
Ｃ：
Ｃは、極低炭素−丁１添加鋼では固溶ＣまたはＴｔＣと
して存在するが、このうちの固溶Ｃが焼付硬化性を有す
るようにする作用や耐二次加工跪性を向上させる作用が
あり、そのためには固溶Ｃは最低０．００１０％以上の
存在を必要とする。C: C exists as solid solution C or TtC in ultra-low carbon-T1 addition steel, but solid solution C has the effect of providing bake hardenability and improving secondary processing resistance. Therefore, solid solution C must be present in an amount of at least 0.0010%.
一方、Ｃは過度に存在すると時効硬化性が劣化して時効
し易くなり、加工性が悪化すると共に、加工時にストレ
ッチャーストレインを生じ易くなるので０．００３０％
未満であることが必要であるが、好ましくは０．００２
０％以下である。On the other hand, if C is present in an excessive amount, the age hardenability will deteriorate and aging will occur easily, resulting in poor workability and easy to cause stretcher strain during processing, so 0.0030%
It needs to be less than 0.002, preferably 0.002
It is 0% or less.
現在の真空脱ガス処理技術ではＣを上述した範囲内に常
時適中させることは極めて困難であるが本発明では露点
と焼鈍温度をコントロールすることにより再結晶焼鈍時
に同時に脱炭処理を行うので、Ｃ量は鋳込み時には０．
００５０％以下であればよい。しかし、鋳込み時のＣが
高い程、短時間で十分な脱炭を行うのが困難となってい
くので、０．００４０％以下であることが望ましい。With the current vacuum degassing technology, it is extremely difficult to constantly keep C within the above range, but in the present invention, by controlling the dew point and annealing temperature, decarburization is performed simultaneously during recrystallization annealing. The amount is 0 at the time of casting.
It is sufficient if it is 0.0050% or less. However, the higher the C content during casting, the more difficult it becomes to perform sufficient decarburization in a short period of time, so it is desirable that the C content be 0.0040% or less.
Ｓｉ：
Ｓｉは、高張力鋼板等においては強度を高めるために添
加する元素であるが、本発明のようなめっき綱板製造の
場合には、連続焼鈍中にＳｉが表面濃化を起こして、溶
融亜鉛との付着張力が著しく低下し、めっき付着性が悪
化して不めっきを起こし易くなる。Si: Si is an element added to increase the strength of high-strength steel sheets, etc., but in the case of manufacturing plated steel sheets as in the present invention, Si causes surface concentration during continuous annealing. The adhesion tension with molten zinc is significantly reduced, plating adhesion deteriorates, and non-plating is likely to occur.
本発明のように、良好なめっき鋼板を製造するためには
Ｓｉは０．０４％以下であることが必要である。In order to produce a good plated steel sheet as in the present invention, Si needs to be 0.04% or less.
好ましくは、０．０２％以下である。Preferably it is 0.02% or less.
Ｍｎ：
Ｍｎは、一般に溶鋼中に不純物元素として混入するＳを
固定してその有害な作用を低減させるとともにＳｉと同
様に鋼板の強度を高めるために有効な元素である。通常
の極低Ｃ，Ｔｉ添加鋼ではかなりのＳはＴｊと結合する
のでＳ固定のためのＭｎ添加はあまり必要ないが、本発
明のようにＴｉ添加量が少量の場合、ある程度の添加は
必要である。また強度の面からもＳｉの添加量が少ない
分はＭｎとＰで強度を出す必要がある。しかしＭｎの添
加量が増加すると強度上昇とともに伸びが低下し、特に
ｆ値の低下する傾向が大きいし、さらにＳｉと同様表面
濃化によるめっき性への悪影響も若干ある。Mn: Mn is an effective element for fixing S, which is generally mixed as an impurity element in molten steel, reducing its harmful effects, and, like Si, for increasing the strength of steel sheets. In ordinary ultra-low C, Ti-added steel, a considerable amount of S combines with Tj, so Mn addition for S fixation is not very necessary, but when the amount of Ti added is small as in the present invention, a certain amount of addition is necessary. It is. Also, from the viewpoint of strength, it is necessary to increase the strength with Mn and P to compensate for the small amount of Si added. However, as the amount of Mn added increases, the strength increases and the elongation decreases, with a particularly strong tendency for the f value to decrease.Furthermore, like Si, surface concentration has a slight adverse effect on plating properties.
以上のような理由により−ｎは０．１０〜０．６０％と
する。For the above reasons, -n is set to 0.10 to 0.60%.
Ｐ：
ＰもＳｉ、 Ｍｎと同様に鋼板の強度を高める作用が大
きい元素であり、しかも伸びやｆ値に対してはＭｎと比
較してそれを低下させる作用が小さい、しかし、その影
響力が少ないとはいえ、やはり伸び、Ｙ′値を低下させ
る傾向はあり、特に０．１％以上のＰを添加した場合に
は伸びの劣化が著しく、また粒界に偏析することで粒界
脆化を引き起こし、耐−次加工脆性が悪化する。しかも
、Ｐが多いと表面に部分的に濃化した部分で合金化処理
速度差を生じることによるスジ状の模様が発生し易くな
り、この傾向は鋳込み条件やスラブ加熱条件にもよるが
Ｐが０．０８％を越えると起こり易くなる。以上のよう
な理由により、Ｐは０．０８０％以下とするが、好まし
くは０．０７０％以下である。P: Like Si and Mn, P is an element that has a strong effect on increasing the strength of steel sheets, and has a smaller effect on lowering elongation and f-value than Mn. However, its influence is Although the amount is small, it still tends to lower the elongation and Y' value, and especially when P is added in an amount of 0.1% or more, the elongation deteriorates significantly, and it also segregates at the grain boundaries, causing grain boundary embrittlement. This causes deterioration of the embrittlement resistance. Moreover, if there is a large amount of P, streak-like patterns are likely to occur due to differences in alloying processing speed in partially concentrated areas on the surface, and although this tendency depends on casting conditions and slab heating conditions, P If it exceeds 0.08%, it becomes more likely to occur. For the above reasons, P is set to 0.080% or less, preferably 0.070% or less.
ＭｎとＰの複合添加：
ＭｎおよびＰは強度を高める元素であり、添加量が多い
と強度上昇に伴って伸び、ｆ値の低下が起こる。このた
め、Ｍｎ、 Ｐの双方の添加量が同時に多くなると本発
明のような加工性良好な綱板が得られなくなる。Combined addition of Mn and P: Mn and P are elements that increase strength, and when added in large amounts, elongation occurs as the strength increases and the f value decreases. Therefore, if the amounts of both Mn and P added are increased at the same time, a steel plate with good workability as in the present invention cannot be obtained.
従って、−船釣にはＭｎ（ト）＋ｌ０Ｐ（ト）≦１．２
０とする。Therefore, - for boat fishing, Mn (g) + l0P (g) ≦1.2
Set to 0.
ただし、強度３５．５ ｋｇｆ／ｍ＋＊”以上を確保す
るためにはある程度以上の添加は必要である。この場合
、０．９５＜Ｍｎ＋％Ｊ＋１０Ｐ ｍ≦１．２０とする
。したがって、通常はＭｎ〜＋ＩＯＰ〜＜０．９５であ
れば十分である。However, to ensure a strength of 35.5 kgf/m + ~+IOP~<0.95 is sufficient.
Ｅ２、Ｐ値を好ましい範囲に保つことを重視する場合に
はむしろ、この範囲に納めることが必要である。If it is important to keep the E2 and P values within a preferable range, it is necessary to keep them within this range.
Ｓ：
Ｓは、鋼中に不可避的不純物として含有され、鋼板の延
性やｔ値を低下させるし、熱間加工時の脆化の原因にも
なる。また通常の極低炭素−Ｔｉ添加鋼では熱間圧延前
の例えばスラブ加熱中にＴｉと結合するので合金コスト
を上昇させるとともにＴｉＳによる粗大析出物に起因す
るヘゲ欠陥の原因となる０本発明では、ＴｉはＳを全部
固定する程多量には添加しないので合金コストは上昇し
ないが、Ｓｉが多くなると必要Ｍｎ量が増加するので０
．０１％以下であることが必要である。しかし、Ｓｉが
極端に少なくなるとＴｉをＮ／１４≦Ｔｉ／４８≦Ｎ／
１４＋Ｓ／３２の範囲に添加することが難しくなってく
るので下限を０．００２％とする。これによりＳはＴｉ
がＮを固定はするがＣまでは固定しないようなりッショ
ンのような役目を果たす。S: S is contained as an unavoidable impurity in steel, reduces the ductility and t-value of steel sheets, and also causes embrittlement during hot working. In addition, in ordinary ultra-low carbon-Ti added steel, it combines with Ti before hot rolling, for example during slab heating, which increases alloy cost and causes heave defects due to coarse precipitates due to TiS. In this case, Ti is not added in such a large amount as to fix all the S, so the alloy cost does not increase, but as Si increases, the required amount of Mn increases.
．． It is necessary that it be 0.01% or less. However, when Si becomes extremely low, Ti is reduced to N/14≦Ti/48≦N/
Since it becomes difficult to add in the range of 14+S/32, the lower limit is set to 0.002%. As a result, S becomes Ti
acts like a cushion, fixing N but not C.
ＡＱ：
ＡＱは、鋼の脱酸のために添加され、Ｔｉが酸化されて
失われ添加歩留を低下させたりあるいは延性を悪化さす
る鋼中非金属介在物（酸化物）が生成するのを抑制する
働きがあり、また、常温時効を起こす原因となり、延性
にも悪影響を及ぼすＮをＡＱＮとして固定する作用もあ
る元素である。AQ: AQ is added to deoxidize the steel, and prevents the formation of nonmetallic inclusions (oxides) in the steel that reduce the addition yield due to the loss of Ti through oxidation or deteriorate the ductility. It is an element that has the function of suppressing N, and also has the function of fixing N as AQN, which causes aging at room temperature and has an adverse effect on ductility.
しかし、本発明のような極低炭素−Ｔｉ添加鋼の場合に
は、Ｎ量を下げているし、Ｎの大部分はＴｉで固定され
るので、Ｎの固定のためには特に添加をする必要はない
。しかも、添加量が多くなると合金コストが上昇すると
ともに、ＡＱｚＯｓなどの介在物が増加し、延性の劣化
やヘゲ、フクレと呼ばれる表面欠陥の原因となる。However, in the case of ultra-low carbon-Ti-added steel like the present invention, the amount of N is lowered, and most of the N is fixed by Ti, so it is necessary to specifically add it to fix N. There's no need. Moreover, when the amount added increases, the alloy cost increases, and inclusions such as AQzOs increase, which causes deterioration of ductility and surface defects called bald spots and blisters.
このような理由により、本発明ではＡＱは０．０３〜０
．１０％とする。For these reasons, in the present invention, AQ is 0.03 to 0.
．． 10%.
Ｎは、Ｓと同様に鋼中に不可避的不純物として含有され
、固溶していれば鋼板の延性やｔ値を低下させるととも
に、常温時効を起こしてストレッチャーストレインが住
しる原因になる元素である。Like S, N is an element that is contained as an unavoidable impurity in steel, and if it is dissolved in solid solution, it reduces the ductility and t-value of the steel sheet, and causes aging at room temperature, causing stretcher strain. It is.
また、本発明のような極低炭素−Ｔｉ添加鋼の場合には
、Ｓと同様に、かつ、Ｓよりも優先的に熱間圧延前に大
部分がＴｉＮとして固定されるので、その含有量が多く
なるとそれを固定するにａ・要なＴｉ量が増加して合金
コストの上昇を招くとともに、析出したＴｉＮが全伸び
やＦ値に悪影響を与え、析出物が粗大な場合にはヘゲ欠
陥の原因となることもある。In addition, in the case of ultra-low carbon-Ti added steel like the present invention, most of it is fixed as TiN before hot rolling, similar to and preferentially than S, so its content is If the amount of Ti increases, the amount of Ti required to fix it will increase, leading to an increase in alloy cost, and the precipitated TiN will have a negative effect on the total elongation and F value, and if the precipitates are coarse, it will cause sagging. It may also cause defects.
このような理由により、Ｎは０．００３０％以下とする
が、好ましくは０．００２０％以下である。For these reasons, N is set to 0.0030% or less, preferably 0.0020% or less.
Ｔｉ：
Ｔｉは通常の極低炭素−Ｔｉ添加鋼においては延性、ｆ
（！！、時効性などに悪影響を及ぼす鋼中の固溶Ｎ、Ｓ
、Ｃを析出物として固定することによって除去するとと
もに、成形性を向上させることを目的としで添加する。Ti: Ti is ductile and f in ordinary ultra-low carbon-Ti added steel.
(!!, solid solution N and S in steel that have a negative effect on aging properties, etc.)
, C is removed by fixing them as precipitates, and is added for the purpose of improving formability.
しかし、固？８Ｃをすべて固定してしまうと、焼付硬化
性は消失してしまうことになるので、Ｃがすべて固定さ
れてしまう程多量にＴｉを添加してはいけない。さいわ
いＴｉはＡ（！＝ Ｎｂ、 Ｍｎなどに先立って熱間圧
延前にＮやＳを固定し、しかる後にＣを固定するので、
Ｃと結合する前に優先的にＮ、Ｓと結合してＴｉＮ、Ｔ
ｉＳとして消費される。このためＴｉ／４８≦Ｎ／１４
＋ Ｓ／３２であれば、Ｃと結合するＴｉはほとんど
ない。つまり、全Ｃ量が多ければ一部のＣがＴｉと結合
してもかまわないが、そうすると固溶Ｃのコントロール
が難しくなって、安定製造性が低下する。But hard? If all 8C is fixed, the bake hardenability will be lost, so Ti should not be added in such a large amount that all C is fixed. Fortunately, for Ti, N and S are fixed before hot rolling before A (! = Nb, Mn, etc.), and then C is fixed.
It preferentially combines with N and S before combining with C to form TiN and T.
Consumed as iS. Therefore, Ti/48≦N/14
+ If S/32, there is almost no Ti bonded to C. In other words, if the total amount of C is large, it is okay for some C to bond with Ti, but if this happens, it becomes difficult to control the solid solution C, and stable productivity decreases.
一方、わずかでもＮが固定されていないと、これらのＮ
が前述したように特性に対して悪影響を与えるのでＮ／
１４≦Ｔｉ／４８であることが必要である。On the other hand, if N is not fixed even slightly, these N
As mentioned above, N/
It is necessary that 14≦Ti/48.
以上のような理由により、Ｔｉ添加量はＮ／１４≦Ｔｉ
／４８≦Ｎ／１４ ＋ Ｓ／３２を満足する範囲とする
。For the above reasons, the amount of Ti added should be N/14≦Ti.
The range satisfies /48≦N/14 + S/32.
その他、付随不純物としては、Ｃｕ、 Ｃｒ、０等は不
純物量である限り特に制限されないが、Ｅ！、？値を確
保するためには、好ましくはＣｕ：０．１％未満、Ｃｒ
：０．１％未満、ｏ：ｏ、ｏｏｓ％未満に制限する。Other incidental impurities such as Cu, Cr, 0, etc. are not particularly limited as long as they are in an impurity amount, but E! ,? In order to secure the value, preferably Cu: less than 0.1%, Cr
: less than 0.1%, o: limited to less than o, oos%.
次に、本発明によれば熱間圧延後圧下率５０％以上の冷
間圧延を行うが、冷間圧延率、つまり圧下率５０％未満
では再結晶焼鈍後に好ましい集合組織が得られにくく、
高いＹ値を得ることが難しくなる。Next, according to the present invention, cold rolling is performed with a reduction rate of 50% or more after hot rolling, but if the cold rolling rate, that is, the reduction rate is less than 50%, it is difficult to obtain a preferable texture after recrystallization annealing.
It becomes difficult to obtain a high Y value.
引き続いて行われる脱炭焼鈍、通常は連続脱炭焼鈍およ
びスキンパスは次のような条件で行う。The subsequent decarburization annealing, usually continuous decarburization annealing and skin pass, is performed under the following conditions.
本発明においては、この再結晶焼鈍時に雰囲気ガス中に
水蒸気を吹き込むことにより露点を上昇させて同時に脱
炭を行う。このときの脱炭雰囲気はＡＸガス （アンモ
ニア分解ガス）十Ｎ２の混合ガスに水蒸気を吹き込んだ
ものである。In the present invention, during this recrystallization annealing, water vapor is blown into the atmospheric gas to raise the dew point and decarburize at the same time. The decarburizing atmosphere at this time was one in which steam was blown into a mixed gas of AX gas (ammonia decomposition gas) and N2.
なお、通常の連続焼鈍によるめっき鋼板製造プロセスに
おいては冷間圧延を行った後の再結晶焼鈍は還元性雰囲
気（ｎ点は一５０″Ｃ以下）で行うのが普通である。In addition, in the process of manufacturing a plated steel sheet by normal continuous annealing, recrystallization annealing after cold rolling is usually performed in a reducing atmosphere (n point is -50''C or less).
鋳込み組成が本発明の成分範囲に成分を調整され、上述
のようにして冷間圧延された鋼板はこの連続焼鈍脱炭中
に再結晶化すると同時に、鋼中にあるＣのうちの固溶Ｃ
のみが脱炭されて８１（量が低下し時効性が改善される
が、この脱炭量は鋼中の固溶Ｃ量が多い程多くなり、逆
にその量が少ない場合は少なくなるので、鋼中の固溶Ｃ
量をある特定の範囲内に収束させることは容易である。The steel sheet whose casting composition has been adjusted to the composition range of the present invention and which has been cold rolled as described above recrystallizes during this continuous annealing and decarburization, and at the same time, the solid solution C of the C in the steel is recrystallized.
81 (the amount decreases and aging properties are improved, but the amount of decarburized increases as the amount of solid solute C in the steel increases, and conversely decreases when the amount is small. Solid solution C in steel
It is easy to converge the quantity within a certain range.
また、この脱炭は焼鈍温度が高い程、あるいは露点の高
い程促進されるので、焼鈍前の冷延鋼板のＣ値に応じた
条件を設定すれば、最終製品である焼鈍材の鋼中固溶Ｃ
量を特定の範囲内に収束させることはさらに容易となる
。In addition, this decarburization is accelerated as the annealing temperature or dew point increases, so if the conditions are set according to the C value of the cold rolled steel sheet before annealing, it is possible to Molten C
It becomes easier to converge the quantity within a certain range.
なお、焼鈍温度を高くすれば脱炭と同時に粒成長が進ん
で強度の低下が起こるが、露点調整のみによる脱炭では
結晶粒径はあまり変化せず強度や伸びなどの機械的特性
もほとんど変わらずに焼付硬化量のみが低下する。Note that if the annealing temperature is increased, grain growth will proceed at the same time as decarburization, resulting in a decrease in strength, but decarburization by only adjusting the dew point will not change the grain size much, and mechanical properties such as strength and elongation will also hardly change. Only the amount of bake hardening decreases.
そこで本発明における脱炭焼鈍条件であるが、まず、露
点が一３０°Ｃ未満では脱炭力が乏しくＣ量が高い場合
に十分な脱炭をすることが困難であり、また露点が＋１
５°Ｃを越えると鋼板表面の酸化が激しくなって、めっ
き密着性が悪化しパウダリング性不良を生じ易くなる。Therefore, regarding the decarburization annealing conditions in the present invention, firstly, if the dew point is less than 130°C, the decarburization power is poor, and if the C content is high, it is difficult to perform sufficient decarburization.
If the temperature exceeds 5°C, oxidation of the surface of the steel sheet becomes intense, which deteriorates plating adhesion and tends to cause poor powdering properties.
このような理由により、露点は一３０℃以上＋１５°Ｃ
以下とするが、好ましくは一２０°Ｃ〜−１Ｏ°Ｃであ
る。For this reason, the dew point is -30℃ or more +15℃
The temperature is below, preferably -20°C to -10°C.
次に、焼鈍温度と時間であるが、焼鈍温度は通常の冷延
鋼板の製造の際と同様に再結晶温度以上であれば良い。Next, regarding the annealing temperature and time, the annealing temperature may be equal to or higher than the recrystallization temperature, as in the production of ordinary cold rolled steel sheets.
ただし、この際の焼鈍温度が高過ぎると結晶粒の著しい
粗大化が起こるので上限を９００°Ｃとする。好ましく
は７５０〜８５０°Ｃである。However, if the annealing temperature at this time is too high, significant coarsening of crystal grains will occur, so the upper limit is set at 900°C. Preferably it is 750-850°C.
焼鈍時間については、再結晶後の適度な粒成長が起こり
、かつ、ある程度の脱炭が進むためには最低４０秒程度
は必要であり、好ましくは６０秒以上である方が良い。Regarding the annealing time, a minimum of about 40 seconds is required in order for appropriate grain growth to occur after recrystallization and for decarburization to proceed to a certain extent, and preferably 60 seconds or more.
なお、これらの脱炭焼鈍条件は、できれば焼鈍前のコイ
ルのＣ値に応じた条件を設定した方が良いことは言うま
でもない。It goes without saying that these decarburization annealing conditions are preferably set in accordance with the C value of the coil before annealing.
このように本発明によれば固溶Ｃの制御はこの脱炭焼鈍
処理を通じて非常に精度良く行うことができそれによる
焼付硬化量も正確にコントロールできるようになる。As described above, according to the present invention, the solid solution C can be controlled with high accuracy through this decarburization annealing treatment, and the amount of bake hardening thereby can also be accurately controlled.
そして、その後の溶融亜鉛めっき処理や合金化処理方法
は慣用法で行えばよく、特に制限されない
最後に、スキンパス伸率条件であるが、本発明によれば
、綱板には焼鈍めっき後ではＹＰＥが若干残っており、
その量はＢ）ｌ量が高い程大きい傾向がある。このため
ＢＨ量が高い程、ＹＰＥを消滅させるには大きな伸び率
が必要となるわけであるが、完全に消滅させようとする
と最低でも１．０％以上は必要である。しかしスキンパ
スでの伸び率をあまり高くするとＹＰの上昇や、Ｅｌ、
ｒ値の低下を招くので上限を２．０％とする。The subsequent hot-dip galvanizing treatment and alloying treatment method may be carried out by a conventional method.Finally, the skin pass elongation condition is not particularly limited.According to the present invention, the steel sheet is coated with YPE after annealing. There are some remains,
B) The amount tends to be larger as the l amount is higher. For this reason, the higher the BH content, the greater the elongation rate required to eliminate YPE, but in order to completely eliminate YPE, at least 1.0% or more is required. However, if the growth rate in the skin pass is too high, YP will increase, El,
Since this causes a decrease in the r value, the upper limit is set at 2.0%.
このようにして本発明により製造された溶融亜鉛めっき
鋼板について得られる機械的特性について云えば、合金
化溶融亜鉛めっき鋼板の伸び（Ｅｌ）は、合金化処理さ
れているめっき皮膜が硬質であるためにその影響を受け
て、強度が同レベルの冷延鋼板と比較して２〜３％程度
低くなる傾向があり、同様の理由によりｒ値も０．２〜
０．３程度低くなる。Regarding the mechanical properties obtained for the hot-dip galvanized steel sheet thus manufactured according to the present invention, the elongation (El) of the alloyed hot-dip galvanized steel sheet is due to the hardness of the alloyed coating film. As a result, the strength tends to be about 2 to 3% lower than that of cold-rolled steel sheets of the same level, and for the same reason, the r value also decreases by 0.2 to 3%.
It becomes lower by about 0.3.
次に、本発明を実施例によって更に具体的に説明するが
、本発明はこれにより限定されるものではない。Next, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited thereto.
実施例１
転炉で溶製し、真空脱ガス処理を施した第１表に組成成
分を示す２種類の溶鋼を常法に従って連続鋳造を行った
後、温度１２００°Ｃに加熱して熱間圧延し、約６００
°Ｃで巻取り、酸洗後、圧下率７５％の冷間圧延を施し
て０．７５ｍ−の冷延鋼板を製造した。Example 1 Two types of molten steel, whose compositions are shown in Table 1, were melted in a converter and subjected to vacuum degassing treatment. After continuous casting according to a conventional method, the steel was heated to a temperature of 1200°C and hot-casted. Rolled, about 600
After winding at °C and pickling, cold rolling was performed at a rolling reduction of 75% to produce a 0.75 m cold rolled steel plate.
次に、これらの冷延鋼板を種々の露点のＮ２＋水蒸気雰
囲気下にて温度を変えて約６０秒の脱炭焼鈍を施した後
、機械的特性とＣの分析調査を行った。Next, these cold-rolled steel sheets were subjected to decarburization annealing for about 60 seconds at varying temperatures in an N2 + steam atmosphere with various dew points, and then mechanical properties and C were analyzed.
なお、本例の試験ではできるだけ特性に誤差のはいる要
因を少なくするために、めっきは付着させず、また引張
試験はスキンパスを施こさずに実施した。ただし、ＢＨ
性試験については、約１，５％の調質圧延を行い、陵伏
点伸びを完全に消してから実施した。この際ＹＰも測定
した。これらの調査結果を同じく第１表にまとめて示す
。In the test of this example, no plating was applied and the tensile test was conducted without applying a skin pass in order to minimize the factors that would cause errors in the properties. However, BH
The strength test was conducted after temper rolling of about 1.5% was performed to completely eliminate the elongation at the depression point. At this time, YP was also measured. The results of these investigations are also summarized in Table 1.
第１表から明らかなように焼鈍中に露点を上昇させて脱
炭を行うと鋼中Ｃが減少してＢＨ量が低下する。この脱
炭量は鋼中Ｃが多い程多くまた温度が高い程、露点が高
い程多くなる。As is clear from Table 1, when decarburization is performed by increasing the dew point during annealing, C in the steel decreases and the BH amount decreases. The amount of decarburization increases as the C content in the steel increases, and as the temperature and dew point increase.
なお、脱炭焼鈍温度を上げるとＴＳの低下も同時に起こ
るが、これは粒成長によるものと思われる。It should be noted that when the decarburization annealing temperature is increased, the TS also decreases, which is thought to be due to grain growth.
また露点上昇のみによる脱炭では結晶粒径はあまり変化
せずＴＳやＥｉ！、もほとんど変わらずにＢ）Ｉ量のみ
が低下する。In addition, when decarburizing only by increasing the dew point, the crystal grain size does not change much and TS and Ei! , B) only the amount of I decreases, with almost no change.
実施例２
各鋼組成を第２表に示す供試鋼を転炉で溶製し、真空脱
ガス処理を施してから、常法に従って連続鋳造を行った
後、温度１２００℃に加熱して熱間圧延し、約６９０°
Ｃで巻取り、酸洗後、圧下率７５％の冷間圧延を施して
０．７５ｍｍの冷延鋼板を製造した。Example 2 Test steels whose compositions are shown in Table 2 were melted in a converter, subjected to vacuum degassing treatment, and then continuously cast according to a conventional method. Rolled for about 690°
After winding with C and pickling, cold rolling was performed at a reduction ratio of 75% to produce a cold rolled steel sheet of 0.75 mm.
次に、これらの冷延鋼板に対し第３表に示す条件下で８
００°Ｃ前後×約６０秒程の連続焼鈍を露点を６０〜＋
２０°Ｃの間に調整したＡＸガスとＮ２ガスに水蒸気を
吹き込んだ雰囲気下にて施した後、約４６０°Ｃまで冷
却して溶融亜鉛めっきを行い、次に合金化炉にて５００
〜６００’ＣＸｌ０秒の合金化処理し、次いで伸び率１
．０〜２．０％のスキンバスを施して、合金化溶融亜鉛
めっき鋼板を製造した。Next, these cold-rolled steel sheets were subjected to 8
Continuous annealing for about 60 seconds at around 00°C to a dew point of 60 to +
After applying it in an atmosphere where steam is blown into AX gas and N2 gas adjusted to 20°C, it is cooled to about 460°C to perform hot-dip galvanizing, and then in an alloying furnace for 500°C.
~600'CXl0 seconds alloying treatment, then elongation rate 1
．． A 0-2.0% skin bath was applied to produce an alloyed hot-dip galvanized steel sheet.
これらの鋼板の成分組成および調査した機械的特性を再
結晶焼鈍条件およびスキンバス条件とともに第３表にま
とめて示す。なお、成分あるいは製造条件が本発明のそ
れらとは、はずれた材月を比較材として示す。The composition of these steel sheets and the mechanical properties investigated are summarized in Table 3 together with the recrystallization annealing conditions and skin bath conditions. In addition, a material whose components or manufacturing conditions differ from those of the present invention is shown as a comparison material.
第３表に示す結果より明らかなように、本発明によるめ
っき鋼板は比較用めっき鋼板に比べて、加工性が優れ、
時効硬化を起こし難い上に、２．５〜３．９ｋｇ／ｍｓ
”の焼付硬化性を存するので自動車用材料、特ムこ外装
材に対しては非常に適している。As is clear from the results shown in Table 3, the plated steel sheet according to the present invention has superior workability compared to the comparative plated steel sheet.
In addition to being hard to cause age hardening, it is 2.5 to 3.9 kg/ms.
Because of its bake hardenability, it is very suitable for automobile materials and special exterior materials.
（発明の効果）
本発明は以上説明したように構成されているから、成形
性にすぐれ成形後の焼付硬化によって強度が向上する溶
融亜鉛めっき鋼板を製造することができ、産業上きわめ
て有用である。(Effects of the Invention) Since the present invention is constructed as described above, it is possible to produce a hot-dip galvanized steel sheet that has excellent formability and improves strength through bake hardening after forming, and is extremely useful industrially. .
Claims (3)
０５０％以下、Ｓｉ：０．０４％以下、Ｍｎ：０．１０
〜０．６０％、Ｐ：０．０８０％以下、ただしＭｎ（％
）＋１０Ｐ（％）≦１．２０Ｓ：０．００２〜０．０１
０％、Ａｌ：０．０３０〜０．１００％、Ｎ：０．００
３０％以下、 Ｔｉ：４８／１４Ｎ（％）〜｛４８／１４Ｎ（％）＋４
８／３２Ｓ（％）｝、残部：Ｆｅおよび不可避的不純物 よりなる鋼片を、熱間圧延後５０％以上の冷間圧延率に
て冷間圧延を行い、次いで、露点−３０℃以上＋１５℃
以下の雰囲気下で再結晶温度以上９００℃以下の温度で
４０秒以上の脱炭焼鈍を行い、該脱炭焼鈍後のＣを０．
００１０％以上０．００３０％未満とした上で、溶融亜
鉛めっきを施し、さらに伸率１．０％以上２．０％以下
の調質圧延を施すことを特徴とする、加工性および時効
性が良好で、かつ適度の焼付硬化性を有する溶融亜鉛め
っき鋼板の製造方法。(1) Composition ratio at the time of casting is C: 0.0 in weight%
050% or less, Si: 0.04% or less, Mn: 0.10
~0.60%, P: 0.080% or less, however, Mn (%
)+10P(%)≦1.20S: 0.002-0.01
0%, Al: 0.030-0.100%, N: 0.00
30% or less, Ti: 48/14N (%) ~ {48/14N (%) + 4
8/32S (%)}, balance: Fe and unavoidable impurities A steel billet is cold rolled at a cold rolling rate of 50% or more after hot rolling, and then the dew point is -30°C or more +15°C
Decarburization annealing is performed for 40 seconds or more at a temperature higher than the recrystallization temperature and lower than 900°C in the following atmosphere, and the C after the decarburization annealing is 0.
0.0010% or more and less than 0.0030%, hot-dip galvanizing, and temper rolling with an elongation of 1.0% or more and 2.0% or less. A method for producing a hot-dip galvanized steel sheet having good and appropriate bake hardenability.
項１記載の溶融亜鉛めっき鋼板の製造方法。(2) The method for producing a hot-dip galvanized steel sheet according to claim 1, wherein Mn (%) + 10P (%)≦0.95.
であり、引張強度が３５．５Ｋｇｆ／ｍｍ＾２以上であ
る請求項１記載の溶融亜鉛めっき鋼板の製造方法。(3) 0.95<Mn(%)+10P(%)≦1.20
The method for producing a hot-dip galvanized steel sheet according to claim 1, wherein the steel sheet has a tensile strength of 35.5 Kgf/mm^2 or more.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP18216790A JPH0472017A (en) | 1990-07-10 | 1990-07-10 | Production of baking hardening type hot-dip galvanized steel sheet having high workability |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP18216790A JPH0472017A (en) | 1990-07-10 | 1990-07-10 | Production of baking hardening type hot-dip galvanized steel sheet having high workability |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH0472017A true JPH0472017A (en) | 1992-03-06 |
Family
ID=16113523
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP18216790A Pending JPH0472017A (en) | 1990-07-10 | 1990-07-10 | Production of baking hardening type hot-dip galvanized steel sheet having high workability |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0472017A (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR100241304B1 (en) * | 1995-12-26 | 2000-03-02 | 이구택 | The manufacturing method for cold rolling steel sheet with excellent chemical properties |
| EP1149928A1 (en) * | 1999-11-08 | 2001-10-31 | Kawasaki Steel Corporation | Hot dip galvanized steel plate excellent in balance of strength and ductility and in adhesiveness between steel and plating layer |
| CN111850262A (en) * | 2020-06-22 | 2020-10-30 | 鞍钢蒂森克虏伯汽车钢有限公司 | Production method of ultra-low carbon baking hardening continuous hot-dip galvanized steel sheet |
| CN111850263A (en) * | 2020-06-22 | 2020-10-30 | 鞍钢蒂森克虏伯汽车钢有限公司 | Production method for improving aging resistance of continuous hot-dip galvanizing baking hardened steel plate |
-
1990
- 1990-07-10 JP JP18216790A patent/JPH0472017A/en active Pending
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR100241304B1 (en) * | 1995-12-26 | 2000-03-02 | 이구택 | The manufacturing method for cold rolling steel sheet with excellent chemical properties |
| EP1149928A1 (en) * | 1999-11-08 | 2001-10-31 | Kawasaki Steel Corporation | Hot dip galvanized steel plate excellent in balance of strength and ductility and in adhesiveness between steel and plating layer |
| EP1149928A4 (en) * | 1999-11-08 | 2002-06-05 | Kawasaki Steel Co | Hot dip galvanized steel plate excellent in balance of strength and ductility and in adhesiveness between steel and plating layer |
| US6558815B1 (en) | 1999-11-08 | 2003-05-06 | Kawasaki Steel Corporation | Hot dip Galvanized steel plate excellent in balance of strength and ductility and in adhesiveness between steel and plating layer |
| CN111850262A (en) * | 2020-06-22 | 2020-10-30 | 鞍钢蒂森克虏伯汽车钢有限公司 | Production method of ultra-low carbon baking hardening continuous hot-dip galvanized steel sheet |
| CN111850263A (en) * | 2020-06-22 | 2020-10-30 | 鞍钢蒂森克虏伯汽车钢有限公司 | Production method for improving aging resistance of continuous hot-dip galvanizing baking hardened steel plate |
| CN111850262B (en) * | 2020-06-22 | 2022-07-26 | 鞍钢蒂森克虏伯汽车钢有限公司 | Production method of ultra-low carbon baking hardening continuous hot-dip galvanized steel sheet |
| CN111850263B (en) * | 2020-06-22 | 2022-07-26 | 鞍钢蒂森克虏伯汽车钢有限公司 | Production method for improving aging resistance of continuous hot-dip galvanizing baking hardened steel plate |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN109097705B (en) | 800 MPa-grade cold-rolled hot-galvanized dual-phase steel and production method thereof | |
| US7879160B2 (en) | Cold rolled dual-phase steel sheet | |
| US7959747B2 (en) | Method of making cold rolled dual phase steel sheet | |
| WO2002012580A1 (en) | Cold rolled steel sheet and hot rolled steel sheet excellent in bake hardenability and resistance to ordinary temperature aging and method for their production | |
| JP2009035814A (en) | High-strength hot-dip galvanized steel sheet and process for producing the same | |
| JP3002379B2 (en) | Manufacturing method of high-strength cold-rolled galvannealed steel sheets for automobiles with excellent formability, paint bake hardenability and little change in paint bake hardenability | |
| JP2761095B2 (en) | Method for producing high strength galvanized steel sheet with excellent bending workability | |
| JP3263143B2 (en) | Bake hardening type high strength alloyed hot-dip galvanized steel sheet excellent in workability and method for producing the same | |
| JP2862186B2 (en) | Manufacturing method of hot-dip galvanized high-strength thin steel sheet with excellent elongation | |
| JP2004018911A (en) | High-tensile strength cold-rolled steel plate having excellent elongation property and elongation-flanging property, and method for manufacturing the same | |
| CN114207172B (en) | High-strength steel sheet, high-strength member, and method for producing same | |
| JPH0472017A (en) | Production of baking hardening type hot-dip galvanized steel sheet having high workability | |
| JPH02194126A (en) | Manufacture of steel sheet having baking hardenability | |
| JPH10298662A (en) | Production of cold rolled steel sheet and galvannealed steel sheet excellent in coating/baking hardenability and its production | |
| JP2003064446A (en) | Cold rolled steel sheet and plated cold rolled steel sheet each having excellent strain age hardening characteristic and free from degradation due to room- temperature aging, and manufacturing method of them | |
| JPS582248B2 (en) | Manufacturing method for hot-dip galvanized steel sheet with excellent workability | |
| JPH03211228A (en) | Production of steel sheet with baking hardenability | |
| JP4930393B2 (en) | Cold rolled steel sheet manufacturing method | |
| JP3376882B2 (en) | Manufacturing method of high tensile alloyed hot-dip galvanized steel sheet with excellent bendability | |
| JP2010530030A (en) | Cold rolled steel sheet and method for producing the same | |
| JP3111462B2 (en) | Manufacturing method of high-strength bake hardenable steel sheet | |
| JP2003321714A (en) | Method of producing galvanized cold rolled steel sheet having excellent strain aging hardening property | |
| JP2975774B2 (en) | Alloyed hot-dip galvanized steel sheet and method for producing the same | |
| JP3111456B2 (en) | Manufacturing method of bake hardening ultra deep drawing steel sheet | |
| JP2808014B2 (en) | Manufacturing method of good workability cold rolled steel sheet with excellent bake hardenability |