JPH04176852A - Aluminum-zinc alloy hot-dipping method - Google Patents
Aluminum-zinc alloy hot-dipping methodInfo
- Publication number
- JPH04176852A JPH04176852A JP4210290A JP4210290A JPH04176852A JP H04176852 A JPH04176852 A JP H04176852A JP 4210290 A JP4210290 A JP 4210290A JP 4210290 A JP4210290 A JP 4210290A JP H04176852 A JPH04176852 A JP H04176852A
- Authority
- JP
- Japan
- Prior art keywords
- aluminum
- zinc alloy
- bath
- zinc
- plating
- 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
- 229910001297 Zn alloy Inorganic materials 0.000 title claims abstract description 69
- FJMNNXLGOUYVHO-UHFFFAOYSA-N aluminum zinc Chemical compound [Al].[Zn] FJMNNXLGOUYVHO-UHFFFAOYSA-N 0.000 title claims abstract description 18
- 238000007598 dipping method Methods 0.000 title abstract 4
- 238000007747 plating Methods 0.000 claims abstract description 72
- 229910000838 Al alloy Inorganic materials 0.000 claims abstract description 38
- 239000011701 zinc Substances 0.000 claims abstract description 28
- HCHKCACWOHOZIP-UHFFFAOYSA-N Zinc Chemical compound [Zn] HCHKCACWOHOZIP-UHFFFAOYSA-N 0.000 claims abstract description 24
- 229910052725 zinc Inorganic materials 0.000 claims abstract description 24
- 229910052782 aluminium Inorganic materials 0.000 claims abstract description 15
- 229910052710 silicon Inorganic materials 0.000 claims abstract description 5
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 claims description 50
- 238000000034 method Methods 0.000 claims description 20
- 238000007654 immersion Methods 0.000 claims description 6
- 239000010703 silicon Substances 0.000 claims description 3
- 230000007797 corrosion Effects 0.000 abstract description 21
- 238000005260 corrosion Methods 0.000 abstract description 21
- 229910000831 Steel Inorganic materials 0.000 abstract description 11
- 239000010959 steel Substances 0.000 abstract description 11
- 239000000463 material Substances 0.000 abstract description 6
- 239000010410 layer Substances 0.000 description 51
- 229910045601 alloy Inorganic materials 0.000 description 13
- 239000000956 alloy Substances 0.000 description 13
- 238000005246 galvanizing Methods 0.000 description 10
- 230000000052 comparative effect Effects 0.000 description 7
- NLXLAEXVIDQMFP-UHFFFAOYSA-N Ammonia chloride Chemical compound [NH4+].[Cl-] NLXLAEXVIDQMFP-UHFFFAOYSA-N 0.000 description 6
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 6
- 238000005406 washing Methods 0.000 description 6
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 6
- JIAARYAFYJHUJI-UHFFFAOYSA-L zinc dichloride Chemical compound [Cl-].[Cl-].[Zn+2] JIAARYAFYJHUJI-UHFFFAOYSA-L 0.000 description 6
- 238000004453 electron probe microanalysis Methods 0.000 description 5
- 238000004458 analytical method Methods 0.000 description 4
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 3
- 235000019270 ammonium chloride Nutrition 0.000 description 3
- 238000005238 degreasing Methods 0.000 description 3
- 210000001787 dendrite Anatomy 0.000 description 3
- 238000005259 measurement Methods 0.000 description 3
- 238000005554 pickling Methods 0.000 description 3
- 239000011592 zinc chloride Substances 0.000 description 3
- 235000005074 zinc chloride Nutrition 0.000 description 3
- 241000283160 Inia Species 0.000 description 2
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 2
- 239000007864 aqueous solution Substances 0.000 description 2
- 239000003795 chemical substances by application Substances 0.000 description 2
- 238000001816 cooling Methods 0.000 description 2
- 238000002844 melting Methods 0.000 description 2
- 230000008018 melting Effects 0.000 description 2
- 239000002344 surface layer Substances 0.000 description 2
- 229910018137 Al-Zn Inorganic materials 0.000 description 1
- 229910018573 Al—Zn Inorganic materials 0.000 description 1
- 102100024452 DNA-directed RNA polymerase III subunit RPC1 Human genes 0.000 description 1
- 101000689002 Homo sapiens DNA-directed RNA polymerase III subunit RPC1 Proteins 0.000 description 1
- KKCBUQHMOMHUOY-UHFFFAOYSA-N Na2O Inorganic materials [O-2].[Na+].[Na+] KKCBUQHMOMHUOY-UHFFFAOYSA-N 0.000 description 1
- 239000010953 base metal Substances 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- ZCDOYSPFYFSLEW-UHFFFAOYSA-N chromate(2-) Chemical compound [O-][Cr]([O-])(=O)=O ZCDOYSPFYFSLEW-UHFFFAOYSA-N 0.000 description 1
- 239000011247 coating layer Substances 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000005868 electrolysis reaction Methods 0.000 description 1
- 230000004907 flux Effects 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 239000011259 mixed solution Substances 0.000 description 1
- 239000003921 oil Substances 0.000 description 1
- 150000003839 salts Chemical class 0.000 description 1
- 239000000243 solution Substances 0.000 description 1
- 239000010935 stainless steel Substances 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
Landscapes
- Coating With Molten Metal (AREA)
Abstract
Description
本発明は鉄鋼材料に高耐食性を有するアルミニウム・亜
鉛合金めっ外被層を大気中で構成させるためのアルミニ
ウム・亜鉛合金溶融めっき法に関する。The present invention relates to an aluminum/zinc alloy hot-dip plating method for constructing an aluminum/zinc alloy coating layer having high corrosion resistance on a steel material in the atmosphere.
従来から鉄鋼材料の防食に対しては溶融亜鉛めっきが一
般的に行なわれている。近年、高耐食性の要求は益々強
くなり、表面処理鋼板では各種のアルミニウム・亜鉛合
金めっき製品が開発され、亜鉛鉄板よりも高耐食性を有
することからその需要も増大してきている。Hot-dip galvanizing has been commonly used to prevent corrosion of steel materials. In recent years, the demand for high corrosion resistance has become stronger, and various aluminum/zinc alloy plated products have been developed for surface-treated steel sheets, and the demand for these products is increasing because they have higher corrosion resistance than galvanized iron sheets.
しかしながら、構造物及びその部材については未だ溶融
亜鉛めっ外材が一般的であり、適用用途、例えば海岸等
塩害発生地域においては高耐食性を有するアルミニウム
・亜鉛合金めっ部材の適用が要望されている。
一方、３〜１０重量％のアルミニウムを含むアルミニウ
ム・亜鉛合金めっきは線材等には実用化されている（例
えば、特公昭６３−６３６２６号）が、高耐食性を有す
るアルミニウム・亜鉛合金めっき鋼板で施工した建造物
にあってもタイトフレーム等の支持物及びその部品は厚
みの関係等アルミニウム・亜鉛合金めっきの適用が困難
であり、異種材料、例えば溶融亜鉛めっき、ユニクロめ
っき１、 鉄、ステンレス等である。
これは、亜鉛めっき浴にアルミニウムが多量に含まれる
と、大気中で行う溶融めっきでは前処理で用いる７ラツ
クス（溶融亜鉛めっきでは塩化亜鉛及び塩化アンモニウ
ム）がアルミニウムと反応して７ラツクスを破壊し、良
好なめっきが得られないという問題があるためである。
従って、例えば、高耐食性鋼板（５５重量％Ａ１−Ｚｎ
合金めっき製品を用いた建造物においては、支持物及び
その部材が異種材料であると、支持物及びその部材の早
期劣化、又、鋼板との接触部では接触腐食（電食）を誘
起し、ｌＲ１ｌ１の寿命を著しく低下させている。
本発明は上記問題を解決するために為されたものであり
、その目的とするところは、溶融アルミニウム・亜鉛合
金浴のアルミニウム含有量を大きくでき、高耐食性を有
するアルミニウム・亜鉛合金めっき製品をｖｔ造するこ
とにある。However, hot-dip galvanized external materials are still common for structures and their components, and for applications such as coastal areas where salt damage occurs, there is a demand for aluminum/zinc alloy plated components with high corrosion resistance. . On the other hand, aluminum/zinc alloy plating containing 3 to 10% by weight of aluminum has been put into practical use for wire rods, etc. (e.g., Japanese Patent Publication No. 63-63626/1983); Even in the case of buildings that are constructed using aluminum/zinc alloy plating, it is difficult to apply aluminum/zinc alloy plating to supports such as tight frames and their parts due to their thickness. be. This is because when a galvanizing bath contains a large amount of aluminum, the 7lux (zinc chloride and ammonium chloride in hot-dip galvanizing) used in the pretreatment in hot-dip plating in the atmosphere reacts with aluminum and destroys the 7lux. This is because there is a problem that good plating cannot be obtained. Therefore, for example, highly corrosion-resistant steel plate (55% by weight A1-Zn
In buildings using alloy plated products, if the supports and their components are made of different materials, they will deteriorate prematurely, and contact corrosion (electrolytic corrosion) will occur at the parts where they come into contact with steel plates. This significantly reduces the lifespan of lR1l1. The present invention was made to solve the above problems, and its purpose is to increase the aluminum content of a molten aluminum/zinc alloy bath and to produce aluminum/zinc alloy plated products with high corrosion resistance. It is about building.
本発明のアルミニウム・亜鉛合金溶融めっき方法は、被
めっき物を４５０〜６００℃の溶融亜鉛浴に浸漬し、被
めっき物を溶融亜鉛浴から取り出しな後直ちに４５０〜
６５０℃の溶融アルミニウム・亜鉛合金浴に浸漬するこ
とを特徴とするものであり、このＩＲＩ＆により上記課
題が解決されたものである。
［作用］
溶融アルミニウム・亜鉛合金めっき裕の温度を４５０〜
６５０℃としているので、アルミニウムの含有量を大き
くして高耐食性を有するアルミニウム・亜鉛合金めっき
製品を製造することができるものである。
以下本発明の詳細な説明する。
本発明にあっては被めっき物としては主に鋼板の加工品
が採用される。−船釣に鋼板は厚み２゜３〜１６ｍ５＋
の範囲のものが採用される。
この被めっき物がまず一般の溶融亜鉛めっきと同様にし
て脱脂−水洗一酸洗一水洗一フラックス処理と前処理さ
れて溶融亜鉛浴に浸漬される。脱脂は、ＮａＯＨ又はＮ
ａＯＨ十Ｎａ２Ｏ・２Ｓ１０２・ｎＨ２Ｏの水溶液に浸
漬（油脂分の落ちが悪い場合は電解付与）し、水洗して
行なう。酸洗はＨＣＩ水溶液に浸漬し、水洗して行なう
。ブラックス処理は、塩化亜鉛と塩化アンモニウムの混
合溶液で処理される。７ラツクス処理した後は、被めっ
ト物は予熱されて７ラツクスが乾燥される。予熱温度は
１５０〜３００°Ｃ１好ましくは２００〜２５０℃であ
る。この予熱により被めっき物に付着した７ラツクスの
水分を蒸発させると共に次のめっき浴の温度との温度差
を小さくして正常なめっきを行うようにする。尚、予熱
温度が３００℃を超えると７ラツクスが破壊して被めっ
ト物が酸化してしまう。
溶融亜鉛浴は４５０〜６００℃であり、−船釣に行なわ
れているめっき温度（４４０〜４８０℃）よりも相当高
く、これによりめっき層全体にＦｅ−Ｚｎ合金層が形成
されることになる。この溶融亜鉛浴の温度は薄くて均質
なＦ、ｅ−Ｚｎ合金層を形成させるためには、好ましく
は５００〜５６０”Ｃである。浸漬時間は１０秒〜５分
である。即ち、小物とか薄物の場合は１０秒程度であり
、厚物では１８０秒、大型加工品にあっては５分位であ
る。
次に、溶融亜鉛浴から取り出した被めっき物は、溶融フ
ルミニツム・亜鉛合金浴に浸漬される。この場合、被め
っき物を溶融亜鉛浴から取り出した後、直ちに、即ち、
被めっき物の温度が大きく低下しないで、且つ表面のＦ
ｅ−Ｚｎ合金層の外側の純亜鉛層が酸化しない間に、溶
融アルミニウム・亜鉛合金浴に浸漬するのが、作業性を
向上させる響
ためにも好ましい。もちろん、溶融亜鉛めっき後、−度
冷却された後に被めっト物を、溶融アルミニウム・亜鉛
合金浴に浸漬してもよいが、この場合にはめっき層が厚
くなり、その合金層も厚くなり、不均質となって、表面
層も品質的に不安定になる恐れがある。溶融アルミニウ
ム・亜鉛合金浴は３０〜６０重量％のアルミニウムを含
有しており、そのめっき温度はアルミニツム含有量に対
応させて４５０〜６５０℃である。即ち、アルミニウム
・亜鉛合金はアルミニウム含有量により融点が変わるも
のであり、例えば３０％ｌは５２０℃、４０％ＡＩは５
５０℃、５０％Ａ［は５７０℃、５５％ＡＩは５９０°
Ｃ１６０％Ａｎは６００℃であり、めっき温度は通常こ
れら融点よりも３０〜５０℃高温で実施される。又、こ
の溶融アルミニウム・亜鉛合金浴には０．５〜３．０重
量％のシリコン（Ｓｌ）が含まれており、このシリコン
により合金層の成長の抑制及びめっき密着性の向上がも
たらされる。シリコンの代わり１ニマグネシウム（Ｍ
ｇ）を０゜１〜３．０重量％、好ましくは０．１〜２．
０重量％添加してもよい。浸漬時間は１０秒〜５分であ
る。即ち、小物とか薄物の場合は１０秒程度であり、厚
物では１８０秒、大型加工品にあっては５分位である。
浸漬時間が短いとめつき組織が不均質となり、逆に長す
ぎると、合金層が厚くなり、めっト層の表層の厚みが小
さくなって耐食性が低下する。
このように溶融亜鉛めっきを施した被めっき物を溶融ア
ルミニウム・亜鉛合金浴に浸漬することにより、被めっ
き物のめつき層であるＦｅ−Ｚｎ合金層はアルミニウム
・亜鉛合金浴中のＡＰがＦｅ−Ｚｎ合金層に拡散し、Ｆ
ｅと選択的に反応してＦｅ−Ａｆ合金層を形成すること
になる。このためＦｅ−Ｚｎ合金層のＦｅは不足し、Ｚ
ｎが洛中に溶出するという反応が継続される。そして、
アルミニウム・亜鉛合金めっき中にＦｅ−Ａ２合金層が
析出し、ＦｅＡｌＺｎ−８ｉを含む新しい合金層が形成
されて、その上にＡｌ−Ｚｎのデンドライト組織が生成
した新しくアルミニウム・亜鉛合金めっき層が形成され
る。この後は素早く冷却し、めっき層を凝固安定させて
整ったデンドライト組織を生成させる。冷却は例えば、
１１℃／ｓｅｃである。ゆっくり冷却すると、デンドラ
イトが大きくなり、粒間（Ｚ ｎ ’）ッチな組織）が
大きくなり耐食性が低下してしまい、一方、急冷すると
冷却方向に結晶が方向性ができてクラックが発生しやす
い。尚、めっき層には初期防食のためクロメート処理を
施してもよい。
本発明はいわゆる二段階めっき方法であるが、得られた
アルミニウム・亜鉛合金めっき製品は連続めつきライン
で製ｉされたアルミニウム・亜鉛合金めっき品の組織と
類似しており、高耐食性を有し、実用価値の高いもので
ある。
本発明は高アルミニウム・亜鉛合金めっき（Ａｆ：３０
重量％以上）を行なうのに好適であるが、アルミニウム
が３０重量％以下のめっきにも適用可能なことはいうま
でもない。
次に本発明の詳細な説明する。
（実施例１〜４）
被めっき物として厚み２．３ＩｎＩａ及び４．５舶論、
輻５０１、長さ１００■の熱延鋼板並びに厚み１６１、
幅４０＋ａｍ、ｉさ１００Ｈの厚鋼板の加工品を用い、
前処理として通常の溶融亜鉛めっきで行なわれている脱
脂−水洗−酸洗−水洗−７ラツクス処理（塩化亜鉛と塩
化アンモニワムの水溶液）を行った後、予熱！＆置で７
ラフクスを乾燥させ、被めっき物を約１５０〜２００℃
に予熱した。
次いで、被めっき物を４６５℃及び６００℃に加熱した
溶融亜鉛浴に２０秒及び９０秒浸漬さた。
この後、被めっき物を取り出し、６００℃及び６３０℃
にｌｌ！整した５５重量％Ａ１．１．６重量％Ｓｉを含
む溶融アルミニウム・亜鉛合金浴に２０〜９０秒間浸漬
させ、これを取り出してたれ切りを行い冷却してめっき
層を凝固安定させた。
めっき条件を第１表に示し、めっき厚み及び耐食性（Ｊ
ＩＳ Ｚ２３７１ ５ＳＴ）の測定結果を第２表に示
す。
実施例１について、めっ外層断面なＥＰＭＡにより線分
析したところ第１図に示すようにアルミニウム・亜鉛合
金めっき層が形成されていることを示しており、目的と
する高アルミニウム・亜鉛合金めっきを得ることかでか
だ。
又、第２図は被めっき物を溶融亜鉛浴に浸漬した後、水
冷しめっき層を凝固安定させた状態のＥＰＭＡによるめ
っき層断面の線分析の結果を示しており、めっき層の厚
みは約７０μｍはめっき温度が高いことにより、めっき
層全体がＦｅ−Ｚｎ合金層であることを示している。尚
、ＡＩの存在が認められるが、これは亜鉛めっ外でのＦ
ｅ−Ｚｎ合金層の抑制のため溶融亜鉛浴に約０．２％の
１を添加した地金を使用していることによる。
更に、第３図及び第４図に実施例１のめっき層断面及び
溶融亜鉛浴に浸漬した後、水冷しめっき層を凝固安定さ
せた状態のＥＰＭＡによるめっき層断面のＳＥＭ写真を
示しておく。図中、Ａは鋼板、Ｂはめっき層、Ｃは合金
層である。
このことから、第１段階の溶融亜鉛浴で得られるめっき
層は、第２段階のアルミニウム・亜鉛合金浴に浸漬する
ことにより、アルミニウム・亜鉛合金浴中のＡＩがＦｅ
−Ｚｎ合金層に拡散し、Ｆｅと選択的に反応してＦｅ−
Ａ１合金層を形成することにより、アルミニウム・亜鉛
合金めっきの新たな合金層が置換形成されたことを証明
しており、第５図に示す１段階法によるアルミニウム・
亜鉛合金めっき製品のめっき層とほぼ同様な１ｉＩＬ織
であることが判る。
（比較例２）
溶融亜鉛めっき浴に浸漬しないで、５５重１％Ａ１．１
．６重量％Ｓｉを含む溶融アルミニウム・亜鉛浴にのみ
浸漬した以外は実施例２と同様にしてアルミニウム・亜
鉛合金めっきを行った。
めっき条件を第１表に示し、めっき厚み及び耐食性の測
定結果を第２表に示す。
（比較例３）
溶融アルミニウム・亜鉛浴に浸漬しないで、溶融亜鉛め
っき浴のみに浸漬した以外は実施例１と同様にして亜鉛
めっきを行った。
めっき条件を第１表に示し、めっき厚み及び耐食性の測
定結果を第２表に示す。
（比較例４）
被めっき物として厚み１６ｍｍ、輻４０釦鋤、長さ８０
ａ＋ｍの厚鋼板の加工品を用いてユニクロめっきを行っ
た。
めっき条件を！Ｊ１表に示し、めっき厚み及び耐試料め
っき法Ｚｎめっき＾１．−Ｚｎめっき厚み（−ン
温度（”Ｃ）１度じＣ）時間
実施例１２．３ ２段階法 ６００ ６００２２．
３．２段階法 ４６５ ６３０３４．５ ２段階法
４６５ ６３０４１６２段階法 ４６５ ６
００
比較例１ ２，３ １段階法 ６３０２０．
５ １段階法 ６１０３１６１段階法 ４６
５
４３．０ ユニクロ
片面めっき厚みμ 耐食性（時間）
（合金層の厚みμ ５００ １０００ １５００実施
例１ ２５ ０ ０ ０
比較例１ ６５ ０ ０ Ｘ３ １３５
Ｘ ＸＸ ＸＸＸ４ＸＸ−
第２表の結果より、本発明の実施例のものにあっては、
耐食性は比較例１よりも優れており、比較例２と同等で
あることが理解できる。The aluminum-zinc alloy hot-dip plating method of the present invention involves immersing the object to be plated in a hot-dip zinc bath at a temperature of 450 to 600°C, and immediately after removing the object from the hot-dip zinc bath.
It is characterized by being immersed in a molten aluminum/zinc alloy bath at 650°C, and the above-mentioned problems have been solved by this IRI&. [Function] Temperature of molten aluminum/zinc alloy plating is 450~
Since the temperature is 650°C, it is possible to increase the aluminum content and produce aluminum-zinc alloy plated products with high corrosion resistance. The present invention will be explained in detail below. In the present invention, processed steel plates are mainly used as the objects to be plated. - Thickness of steel plate for boat fishing is 2゜3~16m5+
Those within the range of will be adopted. The object to be plated is first pretreated in the same manner as in general hot-dip galvanizing, including degreasing, water washing, pickling, water washing, and flux treatment, and then immersed in a hot-dip zinc bath. For degreasing, use NaOH or N
This is done by immersing it in an aqueous solution of aOH+Na2O.2S102.nH2O (if the oil and fat are difficult to remove, apply electrolysis) and washing with water. Pickling is performed by immersing in an aqueous HCI solution and washing with water. Blacks treatment is performed using a mixed solution of zinc chloride and ammonium chloride. After the 7 lux treatment, the object to be plated is preheated and the 7 lux is dried. The preheating temperature is 150-300°C, preferably 200-250°C. This preheating evaporates 7 lux of moisture adhering to the object to be plated, and reduces the temperature difference with the next plating bath to ensure normal plating. Note that if the preheating temperature exceeds 300°C, the 7 lux will be destroyed and the plated object will be oxidized. The temperature of the molten zinc bath is 450-600°C, which is considerably higher than the plating temperature used for boat fishing (440-480°C), which results in the formation of an Fe-Zn alloy layer over the entire plating layer. . The temperature of this molten zinc bath is preferably 500 to 560"C in order to form a thin and homogeneous F, e-Zn alloy layer. The immersion time is 10 seconds to 5 minutes. It takes about 10 seconds for thin objects, 180 seconds for thick objects, and about 5 minutes for large processed items.Next, the object to be plated is removed from the hot-dip zinc bath and placed in a hot-dip Fulminitum zinc alloy bath. In this case, immediately after removing the object to be plated from the molten zinc bath, i.e.
The temperature of the plated object does not drop significantly, and the surface F
It is preferable to immerse the e-Zn alloy layer in the molten aluminum/zinc alloy bath while the outer pure zinc layer is not oxidized in order to improve workability. Of course, after hot-dip galvanizing, the object to be plated may be immersed in a molten aluminum/zinc alloy bath after being cooled by −0.0 degrees, but in this case, the plating layer will be thicker, and the alloy layer will also be thicker. , the surface layer may become non-uniform and unstable in terms of quality. The molten aluminum-zinc alloy bath contains 30-60% by weight of aluminum, and the plating temperature is 450-650°C, depending on the aluminum content. In other words, the melting point of an aluminum-zinc alloy changes depending on the aluminum content; for example, 30% AI is 520°C, 40% AI is 5
50°C, 50% A [is 570°C, 55% AI is 590°
The temperature of C160%An is 600°C, and the plating temperature is usually 30 to 50°C higher than these melting points. Furthermore, this molten aluminum/zinc alloy bath contains 0.5 to 3.0% by weight of silicon (Sl), which suppresses the growth of the alloy layer and improves plating adhesion. 1 dimagnesium (M) instead of silicon
g) in an amount of 0.1 to 3.0% by weight, preferably 0.1 to 2.
It may be added in an amount of 0% by weight. The immersion time is 10 seconds to 5 minutes. That is, for small or thin items, it takes about 10 seconds, for thick items, it takes 180 seconds, and for large processed items, it takes about 5 minutes. If the immersion time is too short, the plated structure will become inhomogeneous, while if the immersion time is too long, the alloy layer will become thicker and the thickness of the surface layer of the plated layer will become smaller, resulting in lower corrosion resistance. By immersing the hot-dip galvanized workpiece in the molten aluminum/zinc alloy bath, the Fe-Zn alloy layer, which is the plating layer of the workpiece, is formed so that the AP in the aluminum/zinc alloy bath is - Diffused into the Zn alloy layer, F
It selectively reacts with e to form a Fe-Af alloy layer. Therefore, Fe in the Fe-Zn alloy layer becomes insufficient, and Z
The reaction continues with n eluting into the liquid. and,
A Fe-A2 alloy layer is precipitated during aluminum-zinc alloy plating, a new alloy layer containing FeAlZn-8i is formed, and a new aluminum-zinc alloy plating layer with an Al-Zn dendrite structure is formed on top of it. be done. After this, it is quickly cooled to stabilize the plating layer and form a well-organized dendrite structure. For example, cooling
The temperature is 11°C/sec. When cooled slowly, the dendrites become larger and the intergranular (Zn') structure becomes larger, reducing corrosion resistance. On the other hand, when cooled rapidly, the crystals become oriented in the direction of cooling, making cracks more likely to occur. . Note that the plating layer may be subjected to chromate treatment for initial corrosion protection. Although the present invention is a so-called two-step plating method, the resulting aluminum/zinc alloy plated product has a structure similar to that of the aluminum/zinc alloy plated product manufactured on a continuous plating line, and has high corrosion resistance. , has high practical value. The present invention uses high aluminum/zinc alloy plating (Af: 30
It goes without saying that it is suitable for plating with an aluminum content of 30% by weight or less. Next, the present invention will be explained in detail. (Examples 1 to 4) Thicknesses of 2.3 InIa and 4.5 InIa as objects to be plated,
Hot rolled steel plate with diameter 501, length 100cm and thickness 161,
Using a processed product of thick steel plate with a width of 40+am and an i diameter of 100H,
After performing the pretreatment of degreasing, washing with water, pickling, washing with water, and 7-lux treatment (aqueous solution of zinc chloride and ammonium chloride), which is carried out in normal hot-dip galvanizing, preheating! & place 7
Dry Ruffus and heat the object to be plated to about 150-200℃
preheated to. Next, the objects to be plated were immersed in molten zinc baths heated to 465°C and 600°C for 20 seconds and 90 seconds. After this, the object to be plated was taken out and heated to 600°C and 630°C.
Nill! It was immersed for 20 to 90 seconds in a molten aluminum/zinc alloy bath containing 55 wt % A1.1.6 wt % Si, taken out, dripped and cooled to solidify and stabilize the plating layer. The plating conditions are shown in Table 1, and the plating thickness and corrosion resistance (J
IS Z2371 5ST) measurement results are shown in Table 2. Regarding Example 1, line analysis using EPMA of the cross section of the outer plating layer showed that an aluminum/zinc alloy plating layer was formed as shown in Figure 1, and the desired high aluminum/zinc alloy plating was achieved. It's a big thing to get. In addition, Figure 2 shows the results of line analysis of the cross section of the plating layer by EPMA in a state where the water-cooled plating layer is solidified and stabilized after the object to be plated is immersed in a hot-dip zinc bath, and the thickness of the plating layer is approximately 70 μm indicates that the entire plating layer is an Fe-Zn alloy layer due to the high plating temperature. In addition, the presence of AI is recognized, but this is due to F outside the zinc plating.
This is due to the use of a base metal in which about 0.2% of 1 is added to the molten zinc bath in order to suppress the e-Zn alloy layer. Further, FIGS. 3 and 4 show SEM photographs of a cross section of the plating layer of Example 1 and a cross section of the EPMA plating layer in a state where the water-cooled plating layer was solidified and stabilized after being immersed in a molten zinc bath. In the figure, A is a steel plate, B is a plating layer, and C is an alloy layer. From this, the plating layer obtained in the first step molten zinc bath is immersed in the second step aluminum/zinc alloy bath, so that the AI in the aluminum/zinc alloy bath becomes Fe.
- Diffuses into the Zn alloy layer and reacts selectively with Fe to form Fe-
This proves that by forming the A1 alloy layer, a new alloy layer of aluminum/zinc alloy plating was formed by substitution, and the aluminum/zinc alloy plating was performed using the one-step method shown in Figure 5.
It can be seen that the 1iIL weave is almost similar to the plating layer of zinc alloy plated products. (Comparative Example 2) 55 weight 1% A1.1 without immersion in hot dip galvanizing bath
．． Aluminum/zinc alloy plating was performed in the same manner as in Example 2 except that the sample was immersed only in a molten aluminum/zinc bath containing 6% by weight of Si. The plating conditions are shown in Table 1, and the measurement results of plating thickness and corrosion resistance are shown in Table 2. (Comparative Example 3) Zinc plating was performed in the same manner as in Example 1, except that the sample was not immersed in the molten aluminum/zinc bath but only in the hot dip galvanizing bath. The plating conditions are shown in Table 1, and the measurement results of plating thickness and corrosion resistance are shown in Table 2. (Comparative Example 4) Thickness: 16 mm, diameter: 40 button spade, length: 80 mm
Unichrome plating was performed using a processed product of A+M thick steel plate. Plating conditions! Table J1 shows the plating thickness and sample-resistant plating method Zn plating^1. -Zn plating thickness (-n
Temperature ("C) 1 degree C) Time Example 12.3 Two-step method 600 60022.
3.2 step method 465 63034.5 2 step method 465 6304162 step method 465 6
00 Comparative Example 1 2,3 One-step method 63020.
5 1 step method 6103161 step method 46
5 43.0 Unichrome single-sided plating thickness μ Corrosion resistance (hours) (Alloy layer thickness μ 500 1000 1500 Example 1 25 0 0 0 Comparative example 1 65 0 0 X3 135
X XX XXX4XX- From the results in Table 2, in the examples of the present invention,
It can be seen that the corrosion resistance is superior to Comparative Example 1 and equivalent to Comparative Example 2.
本発明にあっては、被めっき物を４５０〜６００℃の溶
融亜鉛浴に浸漬し、溶融亜鉛浴から取り出した後直ちに
４５０〜６５０℃の溶融アルミニウム・亜鉛合金浴に浸
漬するので、第１段階の溶融亜鉛浴で得られるめっき層
は、第２段階のアルミニウム・亜鉛合金浴に浸漬するこ
とにより、アルミニウム・亜鉛合金浴中のＡ？！＋’Ｆ
ｅ Ｚｎ合金層に拡散し、Ｆｅと選択的に反応してＦ
ｅ−Ａｌ合金層を形成することにより、アルミニウム・
亜鉛合金めっきの新たな合金層が置換形成され、アルミ
ニウムの含有量を大きくして高耐食性を有するアルミニ
ウム・亜鉛合金めっき製品を製造することができるもの
である。In the present invention, the object to be plated is immersed in a molten zinc bath at a temperature of 450 to 600°C, and immediately after being taken out from the molten zinc bath, it is immersed in a molten aluminum/zinc alloy bath at a temperature of 450 to 650°C. The plating layer obtained in the hot-dip zinc bath is immersed in the second stage aluminum-zinc alloy bath to form the A? ! ＋'F
e It diffuses into the Zn alloy layer and reacts selectively with Fe to form F.
By forming an e-Al alloy layer, aluminum
A new alloy layer is formed by replacing the zinc alloy plating, and the aluminum content can be increased to produce an aluminum-zinc alloy plated product with high corrosion resistance.
第１図は本発明により製造されたアルミニウム・亜鉛合
金めっき製品のめっき層のＥＰＭＡによる線分析を示す
グラフ、第２図は本発明における溶融亜鉛めっきのめっ
き層のＥＰＭＡによる線分析を示すグラフ、第３図は同
上のアルミニウム・亜鉛合金めっき製品のめっき層の金
属組織の状態を示すＳＥＭ写真、第４図は溶融亜鉛めっ
きのめっき層の金属組織の状態を示すＳＥＭ写真、第５
図は１段階法によるアルミニウム・亜鉛合金めっき製品
のめっき層の金属組織の状態を示すＳＥＭ写真であって
、ＡはｆＲ板、Ｂはめっき層、Ｃは合金層である。
代理人 弁理士 石 １）長 七
第１図
第２図
図面の浄書
隼４図
第５図
手続補正書く方式）
％式％
２、発明の名称
アルミニウム・亜鉛合金溶融めっき方法３、補正をする
者
事件との関係 特許出願人
名 称 大同鋼板株式会社
４、代理人
郵便番号 ５３０
５、補正命令の日付
平成３年８月２７日（発送口）
６、補正により増加する請求項の数 なし７、ｍ正の対
象FIG. 1 is a graph showing a line analysis by EPMA of a plating layer of an aluminum/zinc alloy plated product manufactured according to the present invention, and FIG. 2 is a graph showing a line analysis by EPMA of a plating layer of hot-dip galvanizing in the present invention. Fig. 3 is an SEM photograph showing the state of the metallographic structure of the plating layer of the same aluminum/zinc alloy plated product as above, Fig. 4 is an SEM photo showing the state of the metallographic structure of the plating layer of hot-dip galvanizing, and Fig. 5
The figure is an SEM photograph showing the state of the metallographic structure of the plating layer of an aluminum/zinc alloy plated product by the one-step method, where A is the fR plate, B is the plating layer, and C is the alloy layer. Agent Patent Attorney Ishi 1) Head 7 Figure 1 Figure 2 Drawings Jyoto 4 Figure 5 Procedural Amendment Method) % Formula % 2. Title of Invention Aluminum Zinc Alloy Hot Dip Plating Method 3. Person Making the Amendment Relationship to the case Patent applicant name Daido Steel Co., Ltd. 4 Agent postal code 530 5 Date of amendment order August 27, 1991 (shipping address) 6 Number of claims increased by amendment None 7 m positive object
Claims (4)
浸漬し、被めっき物を溶融亜鉛浴から取り出した後、４
５０〜６５０℃の溶融アルミニウム・亜鉛合金浴に浸漬
することを特徴とするアルミニウム・亜鉛合金溶融めっ
き方法。(1) After immersing the object to be plated in a molten zinc bath at 450 to 600°C and taking out the object to be plated from the molten zinc bath,
An aluminum/zinc alloy hot-dip plating method characterized by immersion in a molten aluminum/zinc alloy bath at 50 to 650°C.
０℃であることを特徴とする請求項１記載のアルミニウ
ム・亜鉛合金溶融めっき方法。(2) Molten aluminum/zinc alloy bath is 550-65
The aluminum-zinc alloy hot-dip plating method according to claim 1, characterized in that the temperature is 0°C.
重量％のアルミニウムが含まれていることを特徴とする
請求項１又は２記載のアルミニウム・亜鉛合金溶融めっ
き方法。(3) 30 to 60 for molten aluminum/zinc alloy bath
The aluminum-zinc alloy hot-dip plating method according to claim 1 or 2, characterized in that the aluminum-zinc alloy hot-dip plating method contains % by weight of aluminum.
．０重量％のシリコンが含まれていることを特徴とする
請求項１、２又は３記載のアルミニウム・亜鉛合金溶融
めっき方法。(4) 0.5 to 3 for molten aluminum/zinc alloy bath
．． The aluminum-zinc alloy hot-dip plating method according to claim 1, 2 or 3, characterized in that 0% by weight of silicon is contained.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP4210290A JPH04176852A (en) | 1990-02-22 | 1990-02-22 | Aluminum-zinc alloy hot-dipping method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP4210290A JPH04176852A (en) | 1990-02-22 | 1990-02-22 | Aluminum-zinc alloy hot-dipping method |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH04176852A true JPH04176852A (en) | 1992-06-24 |
Family
ID=12626621
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP4210290A Pending JPH04176852A (en) | 1990-02-22 | 1990-02-22 | Aluminum-zinc alloy hot-dipping method |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH04176852A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5853806A (en) * | 1995-01-10 | 1998-12-29 | Nihon Parkerizing Co., Ltd. | Process for hot dip-coating steel material with molten aluminum alloy by one-stage coating method using flux and bath of molten aluminum alloy metal |
| CN102912274A (en) * | 2012-10-26 | 2013-02-06 | 常熟市强盛冲压件有限公司 | Surface galvanizing technology for guide hook of drop-out fuse |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5032043A (en) * | 1973-07-24 | 1975-03-28 | ||
| JPS5230233A (en) * | 1975-09-02 | 1977-03-07 | Nippon Kokan Kk | Melttplating method of aluminummzing alloy |
-
1990
- 1990-02-22 JP JP4210290A patent/JPH04176852A/en active Pending
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5032043A (en) * | 1973-07-24 | 1975-03-28 | ||
| JPS5230233A (en) * | 1975-09-02 | 1977-03-07 | Nippon Kokan Kk | Melttplating method of aluminummzing alloy |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5853806A (en) * | 1995-01-10 | 1998-12-29 | Nihon Parkerizing Co., Ltd. | Process for hot dip-coating steel material with molten aluminum alloy by one-stage coating method using flux and bath of molten aluminum alloy metal |
| CN102912274A (en) * | 2012-10-26 | 2013-02-06 | 常熟市强盛冲压件有限公司 | Surface galvanizing technology for guide hook of drop-out fuse |
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