JPH022422B2 - - Google Patents
Info
- Publication number
- JPH022422B2 JPH022422B2 JP4694983A JP4694983A JPH022422B2 JP H022422 B2 JPH022422 B2 JP H022422B2 JP 4694983 A JP4694983 A JP 4694983A JP 4694983 A JP4694983 A JP 4694983A JP H022422 B2 JPH022422 B2 JP H022422B2
- Authority
- JP
- Japan
- Prior art keywords
- zinc
- powder
- corrosion resistance
- magnesium alloy
- chromate
- 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
Links
- HCHKCACWOHOZIP-UHFFFAOYSA-N Zinc Chemical compound [Zn] HCHKCACWOHOZIP-UHFFFAOYSA-N 0.000 claims description 49
- 239000011701 zinc Substances 0.000 claims description 35
- 238000000576 coating method Methods 0.000 claims description 34
- 229910052725 zinc Inorganic materials 0.000 claims description 34
- 238000005260 corrosion Methods 0.000 claims description 32
- 239000011248 coating agent Substances 0.000 claims description 31
- 230000007797 corrosion Effects 0.000 claims description 30
- 239000000843 powder Substances 0.000 claims description 25
- 229910000831 Steel Inorganic materials 0.000 claims description 21
- 239000010959 steel Substances 0.000 claims description 21
- 229910000861 Mg alloy Inorganic materials 0.000 claims description 19
- PGTXKIZLOWULDJ-UHFFFAOYSA-N [Mg].[Zn] Chemical compound [Mg].[Zn] PGTXKIZLOWULDJ-UHFFFAOYSA-N 0.000 claims description 18
- ZCDOYSPFYFSLEW-UHFFFAOYSA-N chromate(2-) Chemical compound [O-][Cr]([O-])(=O)=O ZCDOYSPFYFSLEW-UHFFFAOYSA-N 0.000 claims description 17
- 239000002131 composite material Substances 0.000 claims description 8
- 229910001297 Zn alloy Inorganic materials 0.000 claims description 5
- 230000000694 effects Effects 0.000 description 11
- 238000000227 grinding Methods 0.000 description 11
- 239000011651 chromium Substances 0.000 description 8
- JEIPFZHSYJVQDO-UHFFFAOYSA-N iron(III) oxide Inorganic materials O=[Fe]O[Fe]=O JEIPFZHSYJVQDO-UHFFFAOYSA-N 0.000 description 8
- 239000003973 paint Substances 0.000 description 8
- XEEYBQQBJWHFJM-UHFFFAOYSA-N iron Substances [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 7
- 229910052804 chromium Inorganic materials 0.000 description 6
- 239000000049 pigment Substances 0.000 description 6
- 239000010960 cold rolled steel Substances 0.000 description 5
- 239000007788 liquid Substances 0.000 description 5
- 239000011777 magnesium Substances 0.000 description 5
- 238000007747 plating Methods 0.000 description 5
- 238000003466 welding Methods 0.000 description 5
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 description 4
- NBIIXXVUZAFLBC-UHFFFAOYSA-N Phosphoric acid Chemical compound OP(O)(O)=O NBIIXXVUZAFLBC-UHFFFAOYSA-N 0.000 description 4
- 229910052742 iron Inorganic materials 0.000 description 4
- 229910052749 magnesium Inorganic materials 0.000 description 4
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 description 3
- 229910045601 alloy Inorganic materials 0.000 description 3
- 239000000956 alloy Substances 0.000 description 3
- 238000005452 bending Methods 0.000 description 3
- JOPOVCBBYLSVDA-UHFFFAOYSA-N chromium(6+) Chemical compound [Cr+6] JOPOVCBBYLSVDA-UHFFFAOYSA-N 0.000 description 3
- 230000007423 decrease Effects 0.000 description 3
- 238000010828 elution Methods 0.000 description 3
- 239000000203 mixture Substances 0.000 description 3
- 229910052719 titanium Inorganic materials 0.000 description 3
- 239000004908 Emulsion polymer Substances 0.000 description 2
- 229920002125 Sokalan® Polymers 0.000 description 2
- 229910009369 Zn Mg Inorganic materials 0.000 description 2
- 229910007573 Zn-Mg Inorganic materials 0.000 description 2
- NIXOWILDQLNWCW-UHFFFAOYSA-N acrylic acid group Chemical group C(C=C)(=O)O NIXOWILDQLNWCW-UHFFFAOYSA-N 0.000 description 2
- 229910000147 aluminium phosphate Inorganic materials 0.000 description 2
- 229940117975 chromium trioxide Drugs 0.000 description 2
- WGLPBDUCMAPZCE-UHFFFAOYSA-N chromium trioxide Inorganic materials O=[Cr](=O)=O WGLPBDUCMAPZCE-UHFFFAOYSA-N 0.000 description 2
- GAMDZJFZMJECOS-UHFFFAOYSA-N chromium(6+);oxygen(2-) Chemical compound [O-2].[O-2].[O-2].[Cr+6] GAMDZJFZMJECOS-UHFFFAOYSA-N 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 229910052750 molybdenum Inorganic materials 0.000 description 2
- 229910052759 nickel Inorganic materials 0.000 description 2
- 239000004584 polyacrylic acid Substances 0.000 description 2
- 239000007787 solid Substances 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- OYPRJOBELJOOCE-UHFFFAOYSA-N Calcium Chemical compound [Ca] OYPRJOBELJOOCE-UHFFFAOYSA-N 0.000 description 1
- 229920000298 Cellophane Polymers 0.000 description 1
- 229910001335 Galvanized steel Inorganic materials 0.000 description 1
- 229910007567 Zn-Ni Inorganic materials 0.000 description 1
- 229910007614 Zn—Ni Inorganic materials 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- 239000007864 aqueous solution Substances 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 229910052791 calcium Inorganic materials 0.000 description 1
- 239000011575 calcium Substances 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- KRVSOGSZCMJSLX-UHFFFAOYSA-L chromic acid Substances O[Cr](O)(=O)=O KRVSOGSZCMJSLX-UHFFFAOYSA-L 0.000 description 1
- 229910052802 copper Inorganic materials 0.000 description 1
- 239000003822 epoxy resin Substances 0.000 description 1
- 238000005530 etching Methods 0.000 description 1
- AWJWCTOOIBYHON-UHFFFAOYSA-N furo[3,4-b]pyrazine-5,7-dione Chemical compound C1=CN=C2C(=O)OC(=O)C2=N1 AWJWCTOOIBYHON-UHFFFAOYSA-N 0.000 description 1
- 239000008397 galvanized steel Substances 0.000 description 1
- 239000000314 lubricant Substances 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 229920000647 polyepoxide Polymers 0.000 description 1
- 230000003449 preventive effect Effects 0.000 description 1
- 229920005989 resin Polymers 0.000 description 1
- 239000011347 resin Substances 0.000 description 1
- 150000003839 salts Chemical class 0.000 description 1
- 229920006395 saturated elastomer Polymers 0.000 description 1
- 238000007789 sealing Methods 0.000 description 1
- 239000000243 solution Substances 0.000 description 1
- 239000007921 spray Substances 0.000 description 1
- NVKTUNLPFJHLCG-UHFFFAOYSA-N strontium chromate Chemical compound [Sr+2].[O-][Cr]([O-])(=O)=O NVKTUNLPFJHLCG-UHFFFAOYSA-N 0.000 description 1
- 239000000758 substrate Substances 0.000 description 1
- 230000003746 surface roughness Effects 0.000 description 1
- 238000009864 tensile test Methods 0.000 description 1
- 238000010998 test method Methods 0.000 description 1
- 238000005406 washing Methods 0.000 description 1
- 230000037303 wrinkles Effects 0.000 description 1
- NDKWCCLKSWNDBG-UHFFFAOYSA-N zinc;dioxido(dioxo)chromium Chemical compound [Zn+2].[O-][Cr]([O-])(=O)=O NDKWCCLKSWNDBG-UHFFFAOYSA-N 0.000 description 1
Landscapes
- Paints Or Removers (AREA)
- Application Of Or Painting With Fluid Materials (AREA)
- Laminated Bodies (AREA)
Description
本発明はジンクリツチ塗膜を形成した溶接性塗
装鋼板において、塗装原板としてめつき鋼板を用
いることにより防食性を向上させ、かつジンクリ
ツチ塗膜として亜鉛粉末と亜鉛―マグネシウム合
金粉末とを含有するものを形成することにより加
工時の耐パウダリング性および防食性を向上させ
た溶接性塗装鋼板に関する。
近年自動車車体の下廻りやドアなど防食を必要
とする部分にはジンクリツチ塗料を塗装した溶接
性塗装鋼板が使用されている。従来このような鋼
板としては冷延鋼板にクロメート系皮膜を介して
ジンクリツチ塗料を塗装したものであつたが、最
近は洗濯機の部材等により耐食性の良いものが望
まれている。原板が冷延鋼板では防食性が不十分
で、赤錆発生の問題があることからさらに高防食
性のものが要求されている。また従来のジンクリ
ツチ塗料は亜鉛粉末を含有させただけのものであ
つたため加工時にパウダリングが起るという問題
もあつた。
本発明はこれらの問題を解決したジンクリツチ
塗料塗装の溶接性塗装鋼板を提供するものであ
る。
本発明は従来原板として冷延鋼板を用いていた
ため防食性が不十分であつた点に鑑み、これに代
えて亜鉛を主成分とする亜鉛合金を電気めつきし
た複合電気めつき鋼板を用い、原板的に防食性を
向上させようとするものである。
またジンクリツチ塗料としては亜鉛粉末だけで
なく、これに亜鉛―マグネシウム合金粉末を添加
し、耐パウダリング性および溶接性を向上させる
とともに、塗膜的にも防食性を向上させようとす
るものである。
以下本発明を詳細に説明する。
本発明の溶接性塗装鋼板は模式的に示せば添付
図面の第１図に示す如く、亜鉛を主成分とする亜
鉛合金のめつき層１を有する複合電気めつき鋼板
２の表面にクロメート系皮膜３が形成され、さら
にこのクロメート系皮膜３の上に亜鉛粉末４と亜
鉛―マグネシウム合金粉末５とを含有するジンク
リツチ塗膜６が形成されたものである。
上記複合電気めつき鋼板２はめつき層１の表面
が適度に粗化されているので、クロメート系皮膜
３の付着量が増大し、防食性が向上するととも
に、スポツト溶接などにおいてはめつき層１と溶
接チツプとの間隔が短くなり、通電性が向上して
溶接性が良好となる。またジンクリツチ塗膜６に
アンカー効果を付与し、塗膜密着性も向上する。
本発明に用いるこの複合電気めつき鋼板として
は、めつき層１にNi、Co、Ti、Al、Fe、Cr、
Cu、Mg、Moなど耐食性元素を１種または２種
以上含有するもので、例えばZn―13％Ni、Zn―
（８〜16％）Ni―（0.5〜３％）Co、Zn―（１〜
70％）Fe、Zn―（１〜70％）Fe―（0.001〜２
％）Ti、Zn―（１〜70％）Fe―Al―Mg―Ti、
Zn―（５〜20％）Ni―（0.02〜５％）Ti、Zn―
（８〜16％）Ni―１％Mo、Zn―（８〜16％）Ni
―２％Cr.などがある。これらの亜鉛合金のめつ
き層は組成の異なるものを複層にしたものでもよ
く、またその複層の中に純亜鉛めつきを組込んで
もよい。例えば鋼素地側からZn―Fe／Zn、Zn／
Zn―Fe、Zn―Ni／Zn―Fe.などの如くである。
クロメート系皮膜３は反応型クロメート処理
（例えばクロム酸単味のものやそれにエツチング
剤を添加したもの）、ノーリンスの塗布型クロメ
ート処理、あるいは電解クロメートなど公知のク
ロメート処理法で形成したものでよい。しかし
種々検討してみると下記の組成のような塗布型ク
ロメート処理液によるのが防食、塗膜密着性上好
ましい。
処理液 １
(a) 40〜50％が３価状態に還元されている三酸化
クロム10重量部
(b) 燐酸（100％H3PO4）３〜４重量部
(c) ポリアクリル酸４〜５重量部
(d) アクリルエマルジヨン重合体固形分17〜20重
量部
(e) 水溶液にするための水200〜4000重量部
処理液 ２
前記処理液１の組成において、(a)の三酸化クロ
ムが６価クロムのすべてまたは一部が３価の状態
に還元され、６価クロム量／３価クロム量の比が
０〜2.3になつた処理液。
本発明の場合クロメート系皮膜３の付着量管理
は皮膜に含有される全クロム量で行い、この全ク
ロム量が10〜50mg／m2になるようにする。これは
10mg／m2未満であると防食性が乏しくなり、また
塗膜密着性も安定せず、常に良好な密着性が得ら
れないからである。一方50mg／m2を超えると防食
性は向上するが、塗膜密着性が低下してプレス加
工などで剥離しやすくなる。
ジンクリツチ塗膜６は従来の亜鉛粉末のみを含
有するジンクリツチ塗膜に亜鉛―マグネシウム合
金粉末を添加することにより加工時の耐パウダリ
ング性および防食性を向上させたもので、両粉末
の混合比はZn粉末／Zn―Mg合金粉末＝50／50〜
98／２になるようにする。亜鉛粉末に対する亜鉛
―マグネシウム合金粉末の添加量上限を50％にし
たのは50％を超えてもパウダリング性や防食性の
向上効果は50％の場合とあまり変らず、コスト高
になるからである。一方下限を２％にしたのは２
％未満であると添加効果が得られず、耐パウダリ
ング性、防食性とも亜鉛粉末単独の場合とほとん
ど変らなくなるからである。
またジンクリツチ塗膜６の亜鉛粉末と亜鉛―マ
グネシウム合金粉末の合計含有量は60％未満であ
ると通電性が低下し、電気溶接性が悪くなるので
60％以上含有させる。しかし91％を超えると耐加
工剥離性が低下するので、91％以下になるように
する。
上記両粉末を含有する塗膜の樹脂としては分子
量１〜10万の直鎖状エポキシ系樹脂が品質的、作
業的に好ましい。
塗膜（乾燥塗膜）厚は2μ未満であると防食性
が乏しくなるので2μ以上にする。しかし50μを超
えると表面粗度を大きくしても通電性が改善され
ないので、50μ以下になるようにする。
なお防食性に関し亜鉛粉末と亜鉛―マグネシウ
ム合金粉末だけでは耐食性が不十分で、さらに高
度の防食性を必要とする場合には防錆顔料を添加
することも可能である。防錆顔料としてはストロ
ンチウムクロメート、ジンククロメート、鉛酸カ
ルシウムなどが適当で、これらのものを0.2〜５
％添加する。５％を超えて添加すると、塗膜表面
より６価クロムなどの溶出が著しくなり、防食効
果も飽和して添加増量効果が小さい。また用途が
外観を必要とする用途である場合顔料を添加して
着色することも可能である。
本発明の場合上述のようにジンクリツチ塗膜に
亜鉛粉末とともに亜鉛―マグネシウム合金粉末を
含有させると加工時の耐パウダリング性や防食性
が向上するのであるが、その理由は次のように考
えられる。
まず耐パウダリングの向上であるが、これは亜
鉛―マグネシウム合金粉末の硬度が亜鉛より著し
く高いことによるものと考えられる。すなわち一
般にプレス加工時粉末の硬度が高い場合金型への
粉末の付着は少くなるので、亜鉛粉末より硬度の
高い亜鉛―マグネシウム合金粉末の場合金型への
付着は少くなり、その結果耐パウダリング性が向
上するものと考えられる。
一方防食性の向上は亜鉛―マグネシウム合金が
亜鉛のガルバニツク作用を抑制するためと考えら
れる。マグネシウムは電位的には亜鉛より卑であ
るが、腐食環境におかれた場合安定な腐食生成物
を生じるとともに、亜鉛に対して、亜鉛のガルバ
ニツク作用を緩和させる。従つて詳細は不明であ
るが、亜鉛―マグネシウム合金も同様な作用を有
するものと推定される。このためこの合金を含有
させると亜鉛の自己消費的な積極的ガルバニツク
作用は緩和され、めつき層や塗膜より必要以上の
亜鉛の溶出が抑制され、防食性が向上するものと
考えられる。
本発明の場合このようにジンクリツチ塗膜６に
亜鉛粉末とともに亜鉛―マグネシウム合金粉末を
含有させると亜鉛粉末のみの場合より耐パウダリ
ング性、防食性は向上するが、さらに防食性を高
めたい場合には前述の如く防錆顔料を添加する。
この防錆顔料の添加作用は亜鉛―マグネシウム合
金粉末に類似し、防錆顔料自体の防食作用のほ
か、亜鉛の過剰な溶出を抑制する作用を有する。
本発明の場合亜鉛―マグネシウム合金粉末のマ
グネシウム含有量についてはとくに限定しない
が、工業的規模で製造できる１〜５％含有のもの
が作業的、品質的に好ましい。これは亜鉛の場合
マグネシウムを添加すると第２図に示すように急
激に硬度が上昇し、溶接性上問題がないので、防
食性のためには任意の含有量のものを使用できる
からである。
次に実施例により本発明の作用効果を説明す
る。
第１表は板厚0.8mmの複合電気めつき鋼板また
は冷延鋼板（ダル仕上）を原板とし、これに全ク
ロム量20mg／m2のクロメート系皮膜と種々の膜厚
のジンクリツチ塗膜とを下記条件により形成した
溶接性塗装鋼板を示したものであり、また第２表
はこの鋼板の性能を調査した結果を示したもので
ある。
(1) クロメート系皮膜の形成条件
三酸化クロム酸10重量部、リン酸３重量部、ポ
リアクリル酸５重量部、アクリルエマルジヨン重
合体固形分18重量部、水2000重量部、Cr+6／Cr+3
＝1.4からなる塗布型クロメート処理液をロール
コート法で塗布。
(2) ジンクリツチ塗膜の形成条件
ロールコートにより塗装し、これを250℃（板
温）で60秒間焼付。
The present invention provides a weldable coated steel sheet with a zinc-rich coating, which improves corrosion resistance by using a galvanized steel plate as the base plate for coating, and which contains zinc powder and zinc-magnesium alloy powder as the zinc-rich coating. The present invention relates to a weldable coated steel sheet that has improved powdering resistance and corrosion resistance during processing by forming the same. In recent years, weldable coated steel sheets coated with zinc-rich paint have been used for areas that require corrosion protection, such as the underside of automobile bodies and doors. Conventionally, such steel sheets have been cold-rolled steel sheets coated with a zinc-rich paint via a chromate film, but recently there has been a demand for materials with good corrosion resistance for use in washing machine components and the like. If the original plate is a cold-rolled steel sheet, the corrosion resistance is insufficient and there is a problem of red rust, so there is a demand for a material with even higher corrosion resistance. Furthermore, since conventional zinc-rich paints contained only zinc powder, there was a problem in that powdering occurred during processing. The present invention provides a weldable coated steel sheet coated with zinc-rich paint that solves these problems. In view of the fact that conventionally cold-rolled steel sheets were used as original sheets, which resulted in insufficient corrosion resistance, the present invention uses a composite electroplated steel sheet electroplated with a zinc alloy containing zinc as the main component. This is intended to improve the corrosion resistance of the original plate. In addition, zinc-rich paints contain not only zinc powder but also zinc-magnesium alloy powder to improve powdering resistance and weldability, as well as to improve the corrosion resistance of the paint film. . The present invention will be explained in detail below. The weldable painted steel sheet of the present invention is schematically shown in FIG. 1 of the attached drawings, and a chromate-based coating is formed on the surface of a composite electroplated steel sheet 2 having a zinc alloy plating layer 1 containing zinc as the main component. A zinc-rich coating film 6 containing zinc powder 4 and zinc-magnesium alloy powder 5 is further formed on this chromate-based film 3. Since the surface of the plating layer 1 of the above-mentioned composite electroplated steel sheet 2 is appropriately roughened, the amount of the chromate-based film 3 deposited increases, the corrosion resistance is improved, and the plating layer 1 is easily removed during spot welding. The distance from the welding tip is shortened, the current conductivity is improved, and weldability is improved. Further, an anchor effect is imparted to the zinc-rich coating film 6, and coating film adhesion is also improved. This composite electroplated steel sheet used in the present invention includes Ni, Co, Ti, Al, Fe, Cr,
Contains one or more corrosion-resistant elements such as Cu, Mg, Mo, etc. For example, Zn-13%Ni, Zn-
(8-16%) Ni-(0.5-3%) Co, Zn-(1-
70%) Fe, Zn―(1~70%)Fe―(0.001~2
%) Ti, Zn-(1~70%) Fe-Al-Mg-Ti,
Zn-(5~20%)Ni-(0.02-5%)Ti, Zn-
(8~16%)Ni-1%Mo, Zn-(8~16%)Ni
-2% Cr. etc. These zinc alloy plating layers may be made up of multiple layers having different compositions, and pure zinc plating may be incorporated into the multiple layers. For example, from the steel base side, Zn-Fe/Zn, Zn/
Such as Zn-Fe, Zn-Ni/Zn-Fe. The chromate-based film 3 may be formed by a known chromate treatment method such as a reactive chromate treatment (for example, chromate alone or an etching agent added thereto), a no-rinse coating type chromate treatment, or an electrolytic chromate treatment. However, after various studies, it is preferable to use a coating type chromate treatment liquid having the composition shown below in terms of corrosion protection and coating adhesion. Treatment liquid 1 (a) 10 parts by weight of chromium trioxide, 40-50% reduced to trivalent state (b) 3-4 parts by weight of phosphoric acid (100% H 3 PO 4 ) (c) 4-4 parts by weight of polyacrylic acid 5 parts by weight (d) Acrylic emulsion polymer solid content 17-20 parts by weight (e) 200-4000 parts by weight of water for making an aqueous solution Treatment liquid 2 In the composition of the treatment liquid 1, (a) chromium trioxide A treatment liquid in which all or part of the hexavalent chromium is reduced to a trivalent state, and the ratio of the amount of hexavalent chromium to the amount of trivalent chromium is 0 to 2.3. In the case of the present invention, the amount of deposited chromate film 3 is controlled by the total amount of chromium contained in the film, and the total amount of chromium is controlled to be 10 to 50 mg/m 2 . this is
If it is less than 10 mg/m 2 , corrosion resistance will be poor and coating film adhesion will not be stable, making it impossible to always obtain good adhesion. On the other hand, if it exceeds 50 mg/m 2 , corrosion resistance improves, but the adhesion of the coating decreases and it becomes easy to peel off during press working. Zinc-rich coating film 6 has improved powdering resistance and corrosion resistance during processing by adding zinc-magnesium alloy powder to the conventional zinc-rich coating film containing only zinc powder, and the mixing ratio of both powders is Zn powder/Zn-Mg alloy powder = 50/50~
Make it 98/2. The reason why the upper limit of the amount of zinc-magnesium alloy powder added to zinc powder was set at 50% was that even if it exceeds 50%, the improvement effect on powdering properties and anticorrosion properties will not be much different from when it is 50%, and the cost will increase. be. On the other hand, the lower limit was set to 2%.
If the amount is less than %, no effect will be obtained by adding the zinc powder, and the powdering resistance and anticorrosion properties will be almost the same as those of zinc powder alone. In addition, if the total content of zinc powder and zinc-magnesium alloy powder in the zinc-rich coating 6 is less than 60%, the electrical conductivity will decrease and the electric weldability will deteriorate.
Contain 60% or more. However, if it exceeds 91%, the resistance to peeling due to processing decreases, so it should be kept below 91%. As the resin for the coating film containing both of the above powders, a linear epoxy resin having a molecular weight of 10,000 to 100,000 is preferable in terms of quality and workability. If the thickness of the coating film (dry coating film) is less than 2μ, corrosion resistance will be poor, so it should be 2μ or more. However, if it exceeds 50μ, the conductivity will not be improved even if the surface roughness is increased, so it should be set to 50μ or less. Regarding corrosion resistance, if zinc powder and zinc-magnesium alloy powder alone do not provide sufficient corrosion resistance and a higher level of corrosion resistance is required, it is also possible to add a rust preventive pigment. Suitable anti-rust pigments include strontium chromate, zinc chromate, and calcium leadate.
%Added. If it is added in an amount exceeding 5%, the elution of hexavalent chromium etc. from the coating film surface becomes significant, the anticorrosive effect is saturated, and the effect of increasing the amount added is small. In addition, if the application requires an appearance, it is also possible to add a pigment to color the product. In the case of the present invention, as mentioned above, when the zinc-rich coating film contains zinc powder and zinc-magnesium alloy powder, the powdering resistance and corrosion resistance during processing are improved, and the reason is thought to be as follows. . First, there is an improvement in powdering resistance, which is thought to be due to the fact that the hardness of the zinc-magnesium alloy powder is significantly higher than that of zinc. In other words, in general, if the powder is hard during press working, less powder will adhere to the mold, so if the zinc-magnesium alloy powder is harder than zinc powder, it will adhere less to the mold, resulting in powder resistance. This is thought to improve performance. On the other hand, the improvement in corrosion resistance is thought to be due to the zinc-magnesium alloy suppressing the galvanic action of zinc. Magnesium is electrically less noble than zinc, but when placed in a corrosive environment it produces stable corrosion products and also alleviates the galvanic effect of zinc on zinc. Therefore, although the details are unknown, it is presumed that zinc-magnesium alloy has a similar effect. Therefore, it is thought that when this alloy is contained, the self-consuming positive galvanic action of zinc is alleviated, and the elution of more than necessary zinc from the plated layer or coating is suppressed, thereby improving corrosion resistance. In the case of the present invention, when the zinc-rich coating film 6 contains zinc powder and zinc-magnesium alloy powder as described above, the powdering resistance and corrosion resistance are improved compared to the case of using only zinc powder, but when it is desired to further increase the corrosion resistance, Add anti-rust pigments as described above.
The effect of adding this anti-rust pigment is similar to that of zinc-magnesium alloy powder, and in addition to the anti-corrosion effect of the anti-rust pigment itself, it also has the effect of suppressing excessive elution of zinc. In the case of the present invention, the magnesium content of the zinc-magnesium alloy powder is not particularly limited, but one containing 1 to 5%, which can be manufactured on an industrial scale, is preferred from the viewpoint of workability and quality. This is because, in the case of zinc, when magnesium is added, the hardness increases rapidly as shown in Figure 2, and there is no problem with weldability, so any content can be used for corrosion protection. Next, the effects of the present invention will be explained with reference to Examples. Table 1 shows composite electroplated steel sheets or cold-rolled steel sheets (dull finish) with a thickness of 0.8 mm as original sheets, and chromate-based coatings with a total chromium content of 20 mg/m 2 and zinc-rich coatings with various thicknesses. Table 2 shows a weldable painted steel plate formed under the following conditions, and Table 2 shows the results of investigating the performance of this steel plate. (1) Formation conditions for chromate film: 10 parts by weight of chromic acid trioxide, 3 parts by weight of phosphoric acid, 5 parts by weight of polyacrylic acid, 18 parts by weight of acrylic emulsion polymer solids, 2000 parts by weight of water, Cr +6 / Cr +3
Apply a coating type chromate treatment solution consisting of = 1.4 using the roll coating method. (2) Conditions for forming a zinc-rich coating: Paint by roll coating and bake at 250℃ (board temperature) for 60 seconds.
【表】【table】
【表】
また塗膜性能は次の要領で調査した。
(1) 塗膜密着性
JIS G3312の着色亜鉛鉄板の試験法に準じて折
曲げ試験を行つた。折曲げ試験は曲げ内側の間隔
枚数０枚（0t）、２枚（2t）、４枚（4t）で180度
密着折曲げ加工を行つた後加工部塗膜にセロテー
プを貼付け、それを急激にひきはがすセロテープ
剥離を行い、次の基準により評価した。[Table] The coating film performance was also investigated in the following manner. (1) Paint film adhesion A bending test was conducted according to the JIS G3312 test method for colored galvanized iron plates. In the bending test, 180-degree close bending was performed using 0 sheets (0t), 2 sheets (2t), and 4 sheets (4t) at intervals on the inside of the bend, and then sellotape was pasted on the coating film of the processed part, and the sheet was suddenly bent. The cellophane tape was peeled off and evaluated according to the following criteria.
【表】
(2) 耐パウダリング性
試験片をブランク径360mmに切断後防錆潤滑油
（オイルコートZ2、出光興産製）を塗布して300ト
ン油圧プレス機によりポンチ径200mm、ポンチ
R13mm、ダイスR4mm、絞り高さ65mm、全しわ押
え22トンの条件で塗面が外側になるようにして円
筒深絞り試験を行い、試験後ダイス金型に付着し
たパウダーを研摩紙でこすりとり、その量を目視
で評価して次の基準で評価した。[Table] (2) Powdering resistance After cutting the test specimen into blanks with a diameter of 360 mm, they were coated with anti-corrosion lubricant (Oil Coat Z 2 , manufactured by Idemitsu Kosan) and punched with a punch diameter of 200 mm using a 300-ton hydraulic press machine.
A cylindrical deep drawing test was conducted with the coated surface facing outward under the conditions of radius 13 mm, die radius 4 mm, drawing height 65 mm, and a wrinkle presser of 22 tons. After the test, the powder adhering to the die mold was scraped off with abrasive paper. The amount was visually evaluated and evaluated according to the following criteria.
【表】
(3) 防食性
試験片にあらかじめめつき層または鋼素地に達
するクロスカツトと、内側間隔２枚（2t）の180
度折曲げとを施し、端面をシールすることなく
JIS Ｚ―2371に基く塩水噴霧試験に供し、赤錆の
発生するまでの時間を調査した。
(4) 溶接性
下記溶接条件でスポツト溶接を行つた後溶接試
験片を引張試験し、引張りせん断強度350Kgｆ未
満の強度のものの発生率を調査した。[Table] (3) Corrosion resistance A cross cut that reaches the pre-plated layer or steel substrate on the test piece, and 180 mm with two inner gaps (2 tons)
with multiple bends without sealing the end face.
It was subjected to a salt spray test based on JIS Z-2371, and the time required for red rust to develop was investigated. (4) Weldability After spot welding under the following welding conditions, the welded specimens were subjected to a tensile test, and the incidence of welding with a tensile shear strength of less than 350 Kgf was investigated.
【表】【table】
【表】
第２表より原板に亜鉛を主成分とする亜鉛合金
のめつきされた複合電気めつき鋼板を用いたもの
は冷延鋼板を用いたものより著しく赤錆が発生し
にくい。またジンクリツチ塗膜中に亜鉛―マグネ
シウム合金粉末を添加したものは耐パウダリング
性および防食性に優れている。[Table] Table 2 shows that those using composite electroplated steel sheets plated with a zinc alloy containing zinc as the main component are significantly less likely to develop red rust than those using cold-rolled steel sheets. Furthermore, zinc-magnesium alloy powder added to the zinc-rich coating has excellent powdering resistance and corrosion resistance.
第１図は本発明の塗装鋼板の模式断面図、第２
図はZn―Mg合金のMg量と硬度との関係を示す
グラフである。
１…めつき層、２…複合電気めつき鋼板、３…
クロメート系皮膜、４…亜鉛粉末、５…亜鉛―マ
グネシウム合金粉末、６…ジンクリツチ塗膜。
Figure 1 is a schematic sectional view of the painted steel plate of the present invention, Figure 2
The figure is a graph showing the relationship between the Mg content and hardness of Zn-Mg alloys. 1... Plated layer, 2... Composite electroplated steel plate, 3...
Chromate film, 4... Zinc powder, 5... Zinc-magnesium alloy powder, 6... Zinc-rich coating film.
Claims (1)
鋼板上にクロメート系皮膜を介して亜鉛粉末と亜
鉛―マグネシウム合金粉末とを60重量％以上含有
するジンクリツチ塗膜が形成されていることを特
徴とする防食性の優れた溶接性塗装鋼板。 ２ 亜鉛粉末／亜鉛―マグネシウム合金粉末の比
が50／50〜98／２で、塗膜中の両者の合計含有量
が60〜91重量％であることを特徴とする特許請求
の範囲第１項に記載の防食性の優れた溶接性塗装
鋼板。[Claims] 1. A zinc-rich coating film containing 60% by weight or more of zinc powder and zinc-magnesium alloy powder is formed on a composite electroplated steel sheet electroplated with zinc alloy via a chromate-based film. A weldable painted steel sheet with excellent corrosion resistance. 2. Claim 1, characterized in that the ratio of zinc powder/zinc-magnesium alloy powder is 50/50 to 98/2, and the total content of both in the coating film is 60 to 91% by weight. A weldable painted steel plate with excellent corrosion resistance as described in .
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP4694983A JPS59171643A (en) | 1983-03-18 | 1983-03-18 | Weldable coated steel plate having excellent corrosion protection |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP4694983A JPS59171643A (en) | 1983-03-18 | 1983-03-18 | Weldable coated steel plate having excellent corrosion protection |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS59171643A JPS59171643A (en) | 1984-09-28 |
| JPH022422B2 true JPH022422B2 (en) | 1990-01-18 |
Family
ID=12761542
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP4694983A Granted JPS59171643A (en) | 1983-03-18 | 1983-03-18 | Weldable coated steel plate having excellent corrosion protection |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS59171643A (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS61152444A (en) * | 1984-12-25 | 1986-07-11 | 川崎製鉄株式会社 | Coated steel plate having excellent weldability, workabilityand corrosion resistance |
| JPS62170340A (en) * | 1986-01-24 | 1987-07-27 | 川崎製鉄株式会社 | Organic coating steel plate having excellent baking hardenability |
| DE3833119A1 (en) * | 1988-09-29 | 1990-04-12 | Sep Tech Studien | METHOD FOR CHROMING AND LACQUERING METAL SURFACES WITH WATER-DETUMABLE VARNISHES |
| JP7313611B2 (en) * | 2018-01-25 | 2023-07-25 | 木田精工株式会社 | High corrosion resistance plating method |
-
1983
- 1983-03-18 JP JP4694983A patent/JPS59171643A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS59171643A (en) | 1984-09-28 |
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