JPH04193966A - Method for composite surface treatment of cast iron material - Google Patents
Method for composite surface treatment of cast iron materialInfo
- Publication number
- JPH04193966A JPH04193966A JP32490990A JP32490990A JPH04193966A JP H04193966 A JPH04193966 A JP H04193966A JP 32490990 A JP32490990 A JP 32490990A JP 32490990 A JP32490990 A JP 32490990A JP H04193966 A JPH04193966 A JP H04193966A
- Authority
- JP
- Japan
- Prior art keywords
- cast iron
- plating
- treatment
- graphite
- thickness
- 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
- 229910001018 Cast iron Inorganic materials 0.000 title claims abstract description 36
- 238000000034 method Methods 0.000 title claims description 32
- 238000004381 surface treatment Methods 0.000 title claims description 27
- 239000002131 composite material Substances 0.000 title claims description 7
- 239000000463 material Substances 0.000 title claims 5
- 238000007747 plating Methods 0.000 claims abstract description 43
- 238000011282 treatment Methods 0.000 claims abstract description 29
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims abstract description 24
- 229910002804 graphite Inorganic materials 0.000 claims abstract description 24
- 239000010439 graphite Substances 0.000 claims abstract description 24
- 238000010438 heat treatment Methods 0.000 claims abstract description 10
- 150000003839 salts Chemical class 0.000 claims abstract description 9
- 238000005266 casting Methods 0.000 claims abstract description 4
- 229910052782 aluminium Inorganic materials 0.000 claims description 15
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 claims description 15
- 238000009792 diffusion process Methods 0.000 claims description 13
- 239000004576 sand Substances 0.000 claims description 7
- 239000011248 coating agent Substances 0.000 claims description 5
- 238000000576 coating method Methods 0.000 claims description 5
- 239000011159 matrix material Substances 0.000 claims description 5
- 238000005868 electrolysis reaction Methods 0.000 claims description 4
- 238000005261 decarburization Methods 0.000 claims 1
- JEIPFZHSYJVQDO-UHFFFAOYSA-N iron(III) oxide Inorganic materials O=[Fe]O[Fe]=O JEIPFZHSYJVQDO-UHFFFAOYSA-N 0.000 abstract description 27
- 239000002932 luster Substances 0.000 abstract description 13
- 230000000694 effects Effects 0.000 abstract description 12
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical group [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 abstract description 6
- 239000003110 molding sand Substances 0.000 abstract description 4
- 229910015392 FeAl3 Inorganic materials 0.000 abstract description 2
- 230000007935 neutral effect Effects 0.000 abstract description 2
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 abstract 3
- 230000001105 regulatory effect Effects 0.000 abstract 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 10
- 230000002265 prevention Effects 0.000 description 8
- 230000015572 biosynthetic process Effects 0.000 description 6
- 229910001220 stainless steel Inorganic materials 0.000 description 6
- 239000010935 stainless steel Substances 0.000 description 6
- 229910001296 Malleable iron Inorganic materials 0.000 description 4
- 238000001816 cooling Methods 0.000 description 3
- 238000005260 corrosion Methods 0.000 description 3
- 238000010586 diagram Methods 0.000 description 3
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 2
- 230000007797 corrosion Effects 0.000 description 2
- 238000005238 degreasing Methods 0.000 description 2
- 238000005121 nitriding Methods 0.000 description 2
- 238000005554 pickling Methods 0.000 description 2
- 239000000843 powder Substances 0.000 description 2
- 230000003449 preventive effect Effects 0.000 description 2
- 239000008399 tap water Substances 0.000 description 2
- 235000020679 tap water Nutrition 0.000 description 2
- 229910018084 Al-Fe Inorganic materials 0.000 description 1
- 229910018192 Al—Fe Inorganic materials 0.000 description 1
- 229910001141 Ductile iron Inorganic materials 0.000 description 1
- 229910001060 Gray iron Inorganic materials 0.000 description 1
- 229910000831 Steel Inorganic materials 0.000 description 1
- 239000013040 bath agent Substances 0.000 description 1
- 238000005219 brazing Methods 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 238000005246 galvanizing Methods 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-M hydroxide Chemical compound [OH-] XLYOFNOQVPJJNP-UHFFFAOYSA-M 0.000 description 1
- 238000007654 immersion Methods 0.000 description 1
- RYZCLUQMCYZBJQ-UHFFFAOYSA-H lead(2+);dicarbonate;dihydroxide Chemical compound [OH-].[OH-].[Pb+2].[Pb+2].[Pb+2].[O-]C([O-])=O.[O-]C([O-])=O RYZCLUQMCYZBJQ-UHFFFAOYSA-H 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 238000002203 pretreatment Methods 0.000 description 1
- 230000001603 reducing effect Effects 0.000 description 1
- 230000006641 stabilisation Effects 0.000 description 1
- 238000011105 stabilization Methods 0.000 description 1
- 239000010959 steel Substances 0.000 description 1
- 230000003746 surface roughness Effects 0.000 description 1
Abstract
Description
【発明の詳細な説明】
［産業上の利用分野］
本発明は、基地中に黒鉛を有する鋳鉄鋳物の表面への赤
錆の発生を防止する方法に関するものである。DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for preventing the formation of red rust on the surface of cast iron castings having graphite in the matrix.
［従来の技術］
黒鉛を基地中に有する鋳鉄、例えば焦心可鍛鋳鉄、球状
黒鉛鋳鉄、バーミキュラ鋳鉄、ねずみ鋳鉄などを冷水、
温水用給排水部品へ適用する場合においては、赤水の発
生防止のために、鋳鉄表面上の赤錆の発生を防止する必
要がある。現在は、錆びない管継手としてステンレス管
継手が使用されているが、価格が高く汎用管継手として
は使用しにくい。安価でステンレス基の防錆性能と金属
光沢を示す表面処理方法の開発が望まれている。[Prior art] Cast iron containing graphite in the matrix, such as cored malleable cast iron, spheroidal graphite cast iron, vermicular cast iron, and gray cast iron, is heated in cold water.
When applied to hot water supply and drainage parts, it is necessary to prevent the formation of red rust on the cast iron surface in order to prevent the formation of red water. Currently, stainless steel pipe fittings are used as rust-free pipe fittings, but they are expensive and difficult to use as general-purpose pipe fittings. It is desired to develop a surface treatment method that is inexpensive and exhibits the rust prevention performance and metallic luster of stainless steel.
今日、−膜内な耐食、耐摩耗性を示す表面処理方法とし
ては、溶融アルミニウムめっきや窒化処理や電気Ｎｉめ
っきや無電解Ｎｉめっき等が知られている。また、ガス
用継手には溶融亜鉛めっきが施されている。Today, hot-dip aluminum plating, nitriding, electric Ni plating, electroless Ni plating, and the like are known as surface treatment methods that exhibit internal corrosion and wear resistance. Additionally, the gas joints are hot-dip galvanized.
特開昭Ｅｉ１−１４４９４号公報には、鋳鉄表面に溶融
アルミニウムめっきを施した方法が、特開昭６０−６３
３３４号公報には、鋳鉄表面を脱黒鉛処理したのちＡＩ
及びアルミナ粉末中においてＡＩ拡散処理を施す方法が
開示されている。Japanese Unexamined Patent Publication No. 14494/1986 describes a method of applying hot-dip aluminum plating to the surface of cast iron, as disclosed in Japanese Patent Application Laid-Open No. 60-63 (1983).
Publication No. 334 discloses that after degraphitizing the cast iron surface, AI
and a method of performing AI diffusion treatment in alumina powder is disclosed.
さらに、米国特許登録７ｌ−７４６６６Ｓ／４７号とし
て溶融塩電解処理と呼ばれる脱スケール、脱黒鉛処理方
法が開示されている。Further, a descaling and degraphitization treatment method called molten salt electrolysis treatment is disclosed as US Patent No. 7l-74666S/47.
［発明が解決しようとする課題］
表面に黒鉛を宵する鋳鉄表面への防錆効果は、亀裂やピ
ンホールの無い皮膜を金属表面上へ形成することによっ
て錆の発生を防ぐものである。鋳鉄表面に鋳物砂や黒鉛
が存在すると鋳物砂や黒鉛に妨害されて該鋳鉄表面上に
表面処理皮膜が完全に形成されず、局部的に露出せる基
地との間に局部電池が構成され赤錆が生じることを本発
明者は明らかにした。従って、基地中に黒鉛を有する鋳
鉄や鋳物砂が付着している鋳鉄に対し、溶融アルミニウ
ムめっきや窒化処理や電気Ｎｉめつきや無電解Ｎ１めっ
き等の各々単独の処理は、防錆を目的とした表面処理法
として完全なものではない。[Problems to be Solved by the Invention] The antirust effect on the cast iron surface by coating graphite on the surface is to prevent the occurrence of rust by forming a film on the metal surface that is free of cracks and pinholes. If foundry sand or graphite exists on the cast iron surface, the surface treatment film will not be completely formed on the cast iron surface due to interference from the foundry sand or graphite, and a local battery will be formed between the locally exposed base and red rust will occur. The inventor has clarified that this occurs. Therefore, individual treatments such as hot-dip aluminum plating, nitriding treatment, electrolytic Ni plating, and electroless N1 plating for cast iron with graphite in the matrix or cast iron with foundry sand attached are for the purpose of rust prevention. However, it is not a perfect surface treatment method.
また、ガス用継手には溶融亜鉛めっきが施されるが、防
錆性能を保証するためにＪＩＳ規格では最低７０μｍ以
上の厚い膜厚を指示している。従って上記ガス用継手は
、めっき処理を施した後に、ネジ切り加工しているため
にネジ部の防錆には効果がない。Furthermore, gas joints are coated with hot-dip galvanizing, but the JIS standard requires a thick coating of at least 70 μm in order to guarantee anti-corrosion performance. Therefore, since the gas fitting is plated and then threaded, it is ineffective in preventing rust on the threaded portion.
特開昭６１−１４４９４号公報のものは、鋳鉄表面への
めっき方法であるが、処理表面の黒鉛除去が考慮されて
いないために、黒鉛の妨害による不完全な表面処理皮膜
の間に生成する赤錆を完全に防止することは困難である
。The method disclosed in JP-A No. 61-14494 is a method of plating cast iron surfaces, but since it does not take into consideration the removal of graphite from the treated surface, it is possible that graphite will form between incomplete surface treatment films due to interference from graphite. It is difficult to completely prevent red rust.
また、特開昭６０−６３３６４号公報のものは、鋳鉄表
面を脱黒鉛処理したのちＡ１及びアルミナ粉末中におい
て９５０°Ｃ以上の高温でもってＡＩ拡散処理を施すた
めに熱ひずみが生しると共に処理表面の面粗さ及び色合
いが悪くなるという問題がある。In addition, in the method disclosed in JP-A-60-63364, after the cast iron surface is degraphitized, AI diffusion treatment is performed in A1 and alumina powder at a high temperature of 950°C or higher, which causes thermal strain and There is a problem that the surface roughness and color tone of the treated surface deteriorate.
また、米国特許登録７１−７４６６６Ｓ／４７号のもの
は鋳鉄表面の脱黒鉛処理方法として知られているが、こ
れは鋳鉄のロウ付けの際の濡れ性を改善するための前処
理方法として利用されており、防錆効果を改善するため
の溶融アルミニウムめっき処理の前処理としての検討は
なされていない。Additionally, U.S. Patent No. 71-74666S/47 is known as a method for degraphitizing the surface of cast iron, which is used as a pretreatment method to improve wettability during brazing of cast iron. Therefore, no study has been conducted as a pretreatment for hot-dip aluminum plating to improve the rust prevention effect.
さらに、従来の前記各種の表面処理方法では、例え防錆
効果が得られたとしても処理表面の色が黒色もしくは灰
色であり、防錆効果を持ちかつステンレス並の金属光沢
を必要とするものへの適用には無理がある。Furthermore, with the various conventional surface treatment methods mentioned above, even if an anti-rust effect is achieved, the color of the treated surface is black or gray. is unreasonable to apply.
本発明の目的は防錆効果をもち、かつ銀白色の金属光沢
を付与する表面処理方法を提供することにある。An object of the present invention is to provide a surface treatment method that has an anticorrosive effect and imparts a silvery white metallic luster.
［課題を解決するための手段］
上記問題を解決するために本発明においては、まず、溶
融塩電解処理法によって表面処理皮膜の形成を妨害する
鋳鉄表面から約５０μｍ程度の深さまでの表面に露出し
た鋳物砂及び黒鉛を除去した後に該鋳鉄表面上に防錆効
果を持たせるために溶融アルミニウムめっきを１μｍ〜
３０μｍ程度施し、さらに大気雰囲気中でもって６５０
°Ｃ以上の試料温度で拡散熱処理を施すことによって試
料表面にＦ ｅ Ａ ｌ ３の拡散皮膜を０． ５μｍ
〜３０μｍ程度形成する。即ち、溶融塩電解処理でもっ
て防錆皮膜の形成を妨害する鋳鉄表面上の鋳物砂及び黒
鉛を除去することによって該鋳鉄表面全体への均一で完
全な防錆皮膜の形成を可能にしたものである。つぎに、
本処理表面上に銀白色の金属光沢を付与する目的で少な
くとも１層以上のＮｉめっき皮膜を合計膜厚で５μｍ〜
３０μｍ程度被覆する。[Means for Solving the Problems] In order to solve the above problems, the present invention first uses a molten salt electrolytic treatment method to expose the surface of cast iron to a depth of about 50 μm, which interferes with the formation of a surface treatment film. After removing the molding sand and graphite, hot-dip aluminum plating is applied to the surface of the cast iron to a thickness of 1 μm or more to provide a rust-preventing effect.
Approximately 30μm, and even in the atmosphere, it is 650μm.
A diffusion film of F e Al 3 is formed on the surface of the sample by performing diffusion heat treatment at a sample temperature of 0.9 °C or higher. 5μm
Form approximately 30 μm. That is, by removing the foundry sand and graphite on the cast iron surface that interfere with the formation of a rust preventive film through molten salt electrolytic treatment, it is possible to form a uniform and complete rust preventive film over the entire surface of the cast iron. be. next,
For the purpose of imparting a silver-white metallic luster to the treated surface, at least one Ni plating film is applied with a total thickness of 5 μm or more.
Cover approximately 30 μm.
［作用コ
基地中に黒鉛を保有する鋳鉄表面への単独の表面処理で
は完全な防錆効果を示さなかったものが、表面処理皮膜
の形成を妨害する鋳鉄表面の鋳物砂や黒鉛を除去した後
に溶融アルミニウムめっきを施した後に、拡散熱処理で
もって鋳鉄表面に ＦｅＡｌ３の拡散層を形成すること
によって完全な防錆効果を発揮させ、さらにその処理皮
膜の上に表面を美麗にする目的で少なくとも１層以上の
Ｎｉめっき皮膜を薄く被覆することにを特徴とする本発
明の複合表面処理を施すことによって、優れた防錆効果
を示すとともにその外観は銀白色のステンレス並の金属
光沢を保持できる優れたものである。[Single surface treatment of cast iron surfaces containing graphite in the active matrix did not show a complete rust prevention effect, but after removing foundry sand and graphite from the cast iron surface that interfere with the formation of the surface treatment film, After applying hot-dip aluminum plating, a diffusion layer of FeAl3 is formed on the cast iron surface using diffusion heat treatment to achieve a complete rust prevention effect, and at least one layer is added on top of the treated film to make the surface beautiful. By applying the composite surface treatment of the present invention, which is characterized by coating a thin Ni plating film as described above, it exhibits an excellent rust prevention effect and has an excellent appearance that maintains a silvery white metallic luster comparable to that of stainless steel. It is something.
なお、Ｎｉめっき皮膜の厚さが５μｍ以下の被覆では金
属光沢を示さず基地の色が該めっき皮膜を通して現れる
。In addition, when the thickness of the Ni plating film is 5 μm or less, no metallic luster is exhibited and the base color appears through the plating film.
口実施例コ
本発明の表面処理方法の一例として以下の実施例に従っ
て説明する。EXAMPLE As an example of the surface treatment method of the present invention, the following example will be described.
本実施例方法は、 （イ）脱黒鉛処理、 （ロ）溶融ア
ルミニウムめっき処理、 （ハ）拡散熱処理、（ニ）電
気Ｎｉめっき処理、 （ホ）皮膜の安定化熱処理の工程
からなる。以下各工程を詳細に説明する。The method of this example consists of the following steps: (a) degraphitization treatment, (b) hot-dip aluminum plating treatment, (c) diffusion heat treatment, (d) electrolytic Ni plating treatment, and (e) film stabilization heat treatment. Each step will be explained in detail below.
（イ）溶融塩電解処理による脱黒鉛処理工程ます、前処
理として焦心可鍛鋳鉄試料表面の黒鉛を除去する目的で
、水酸化す） ＩＪウムと中性塩類とからなる浴温度４
６０℃のアルカリ性酸化還元浴中に該試料を浸漬し、電
解処理により該試料表面を清浄にする。電解手順は（１
）該試料を陰極に保持して還元作用により該試料表面の
砂及び酸化皮膜を除去する。 （２）該試料を陽極に保
持して酸化作用により該試料表面の黒鉛を塩浴剤との反
応で除去する。 （３）前記（２）の工程で該試料表面
に生しる酸化皮膜を該試料を再度陰極に保持することに
より還元作用にて除去する。(B) Degraphitization process by molten salt electrolysis treatment. As a pretreatment, hydroxide is used for the purpose of removing graphite on the surface of the cored malleable cast iron sample.) A bath consisting of IJium and neutral salts at a temperature of 4.
The sample is immersed in an alkaline redox bath at 60°C, and the sample surface is cleaned by electrolytic treatment. The electrolysis procedure is (1
) The sample is held at the cathode and sand and oxide film on the sample surface are removed by reducing action. (2) The sample is held at the anode and the graphite on the surface of the sample is removed by reaction with a salt bath agent by oxidation. (3) The oxide film formed on the surface of the sample in step (2) is removed by reduction by holding the sample again at the cathode.
その後、空冷及び水冷にて室温まで冷却したのち、約８
０°Ｃの場にて洗浄する。After that, after cooling to room temperature by air cooling and water cooling,
Wash at 0°C.
（ロ）溶融アルミニウムめっき処理工程前記（イ）の工
程が完了した試料を脱脂処理、酸洗い処理等の工程を少
なくとも１回以上施して表面を清浄、活性化したのち該
試料表面に耐食性及び耐摩耗性を付与する目的で溶融ア
ルミニウムめっき処理を施し、アルミニウム皮膜を１０
μｍ〜３０μｍ程度形成する。(B) Hot-dip aluminum plating process The sample that has undergone the process in (A) above is subjected to at least one process such as degreasing and pickling to clean and activate the surface. Hot-dip aluminum plating is applied for the purpose of imparting wear resistance, and the aluminum film is coated with 10% aluminum coating.
The thickness is approximately 30 μm to 30 μm.
（ハ）拡散処理工程
前記（ロ）の処理工程が終了後に試料表面温度７００°
Ｃでもって約１時間大気雰囲気中で拡散熱処理を施し、
表面処理皮膜と該鋳鉄表面との間でＦｅとＡＩの相互拡
散をおこして、０゜５μｍ以上のＦ ｅ Ａ ｌ ３の
拡散皮膜を形成する。(c) Diffusion treatment process After the treatment process in (b) above is completed, the sample surface temperature is 700°.
Diffusion heat treatment was performed with C in an air atmosphere for about 1 hour,
Mutual diffusion of Fe and AI is caused between the surface treatment film and the cast iron surface to form a diffusion film of Fe Al 3 of 0°5 μm or more.
（ニ）電気Ｎｉめっき処理工程
試料表面に銀白色の金属光沢を付与する目的で、前記（
ハ）の工程が完了した試料を脱脂処理、酸洗い処理等の
工程を少なくとも１回以上施して表面を清浄、活性化し
たのち該試料表面に電気Ｎｉめっき処理を約５μｍ〜３
０ｕｍ程度の膜厚で施す。めっき処理は、液温６０℃の
光沢Ｎｉめっき洛中で、電流密度ＩＡ〜３Ａ／ｄｍ２の
条件で行なった。処理時間は必要膜厚によって選択した
。(d) Electro Ni plating treatment process In order to impart a silvery white metallic luster to the sample surface, the above (
After completing the step c), the sample is subjected to degreasing treatment, pickling treatment, etc. at least once to clean and activate the surface, and then electrolytic Ni plating treatment is applied to the sample surface to a thickness of approximately 5 μm to 3 μm.
Apply to a film thickness of approximately 0 um. The plating treatment was carried out in a bright Ni plating machine with a liquid temperature of 60° C. and a current density of IA to 3 A/dm 2 . The processing time was selected depending on the required film thickness.
また、電気Ｎｉめっき処理において第１層を耐食性に優
れる半光沢Ｎｉめっきとし、第２層を光沢Ｎｉめっきと
しても良い。Furthermore, in the electro-Ni plating process, the first layer may be made of semi-bright Ni plating which has excellent corrosion resistance, and the second layer may be made of bright Ni plating.
膜厚５μｍ以下では基地の色が透けて見えるために金属
光沢を得ることが出来ず、また３０μｍ以上では総合皮
膜厚さが厚くなり使用できない。If the film thickness is less than 5 μm, the color of the base will show through, making it impossible to obtain metallic luster, and if it is more than 30 μm, the total film thickness will become too thick to be used.
以上のような複合表面処理を施すことにより、鋳鉄表面
に全体で約５０μｍ以下の膜厚で、防錆性能をもちかつ
銀白色の金属光沢ををする表面処理皮膜を形成すること
が可能になる。By performing the above composite surface treatment, it is possible to form a surface treatment film on the cast iron surface with a total thickness of approximately 50 μm or less, which has rust prevention properties and a silvery white metallic luster. .
このように防錆効果を萄する表面処理の皮膜厚さを、総
合膜厚で５０μｍ以下、望ましくは３０μｍ以下に抑え
ることにより、ネジ加工部などの組合せ精度等が問題に
なる部分への適用が可能になる。In this way, by keeping the total film thickness of the surface treatment that maximizes the rust prevention effect to 50 μm or less, preferably 30 μm or less, it can be applied to areas where assembly accuracy is a problem, such as threaded parts. It becomes possible.
第１図は、上記実施例に従って処理された試料の表面処
理皮膜状況を示したものであるが、鋳鉄表面に露出して
いた黒鉛が除去された跡の穴５に表面処理皮膜が侵入し
ている様子を示している。Figure 1 shows the state of the surface treatment film of the sample treated according to the above example, and the surface treatment film invaded the holes 5 where graphite exposed on the cast iron surface was removed. It shows that there is.
また、皮膜そのものも連続性を保っている。Furthermore, the film itself maintains continuity.
第２図は、上記実施例における脱黒鉛処理工程（イ）を
省略した試料における表面処理皮膜の状況を示したもの
であるが、鋳鉄表面に露出してぃる黒鉛の上部には表面
処理皮膜が形成されにくく、黒鉛によって皮膜が不連続
６になっている様子を示している。Figure 2 shows the state of the surface treatment film in a sample in which the degraphitization treatment step (a) in the above example was omitted. The graph shows that the film is difficult to form and the film is discontinuous due to graphite.
第３図は、水温２５℃の水道水に１週間浸漬した際の１
０個の試料表面に生じた赤錆の平均発生状況を示したも
のである。脱黒鉛処理を施さずに溶融アルミニウムめっ
き処理をした後拡散熱処理をした試料Ａでは試料表面全
面に亘って錆が生じたのに対し、脱黒鉛処理後に溶融ア
ルミニウムめっき処理及び６５０°Ｃでの拡散熱処理を
施した試料Ｂは、錆の発生は大幅に改善される。しかし
、両者とも金属光沢の維持が出来ない。一方、本発明の
試料Ｃでは、１週間浸漬したのちも錆の発生は認められ
ず、表面の金属光沢も試験開始当初の状態を維持できた
。Figure 3 shows the results of 1 week of immersion in tap water at a water temperature of 25°C.
This figure shows the average occurrence of red rust on the surface of 0 samples. In sample A, which was subjected to hot-dip aluminum plating without degraphitization and then diffusion heat treatment, rust occurred over the entire surface of the sample, whereas rust was generated over the entire surface of the sample. In sample B, which was subjected to heat treatment, the occurrence of rust was significantly improved. However, both cannot maintain metallic luster. On the other hand, in Sample C of the present invention, no rust was observed even after being immersed for one week, and the metallic luster on the surface remained as it was at the beginning of the test.
［発明の効果コ
以上の説明で明らかなように、本発明による複合表面処
理方法を、ステンレスよりも価格的に安価な鋳鉄鋳物に
適用して、表面に生じる赤錆の発生を防止でき、かつ銀
白色のステンレス並の金属光沢を維持することが可能に
なり、現在錆びない管継手として使用されている高価な
ステ／レス管継手の代替品として、また赤水の発生が問
題になる冷水や温水用の給排水用部品等への適用が可能
になる。[Effects of the Invention] As is clear from the above explanation, the composite surface treatment method of the present invention can be applied to cast iron castings, which are cheaper than stainless steel, to prevent the occurrence of red rust on the surface, and to prevent the occurrence of red rust on the surface. It is now possible to maintain the same metallic luster as white stainless steel, and can be used as a replacement for the expensive steel/stainless steel pipe fittings that are currently used as rust-free pipe fittings, and for cold water and hot water where the generation of red water is a problem. It becomes possible to apply it to water supply and drainage parts, etc.
第１図は焦心可鍛鋳鉄に脱黒鉛処理を施した後、溶融ア
ルミニウムめっき処理及び電気Ｎｉめっき処理した試料
の表面処理皮膜状況を示す図。
第２図は焦心可鍛鋳鉄に脱黒鉛処理を施さすに、溶融ア
ルミニウムめっき処理及び電気Ｎ１めっき処理した試料
の表面処理皮膜と黒鉛の関係を示す図。
第３図は、水温２５℃の水道水に１週間浸漬した際の試
料表面に生じる赤錆の平均発生状況と金属光沢の状況を
示す図。
１：電気Ｎｉめっき皮膜
２：Ａｌ−Ｆｅめっき皮膜
３：黒鉛
４：Ｆｅ基地
５：黒鉛脱落跡
６：めっき皮膜の不連続部
°ご）
第１図
′４
第２図FIG. 1 is a diagram showing the state of the surface treatment film of a sample that has been subjected to degraphitization treatment on cored malleable cast iron, followed by hot-dip aluminum plating treatment and electrolytic Ni plating treatment. FIG. 2 is a diagram showing the relationship between the surface treatment film and graphite of a sample subjected to hot-dip aluminum plating and electro-N1 plating when core malleable cast iron is subjected to degraphitization treatment. FIG. 3 is a diagram showing the average occurrence of red rust and metallic luster on the surface of a sample when immersed in tap water at a water temperature of 25° C. for one week. 1: Electrolytic Ni plating film 2: Al-Fe plating film 3: Graphite 4: Fe base 5: Traces of graphite falling off 6: Discontinuous parts of plating film (Fig. 1'4 Fig. 2)
Claims (3)
処理により表面の脱鋳物砂及び／又は脱黒鉛処理を行う
工程、（ロ）溶融アルミニウムめっき処理を皮膜厚さで
１０μｍ以上施す工程、（ハ）６５０℃以上の表面温度
で試料の肉厚に依存した時間に亘って大気雰囲気中で拡
散熱処理を施す工程からなることを特徴とする鋳鉄材料
の複合表面処理方法。1. (a) A process of removing casting sand and/or degraphitizing the surface of a cast iron material having graphite in the matrix by molten salt electrolysis treatment, (b) A process of applying hot-dip aluminum plating to a coating thickness of 10 μm or more, ( c) A method for composite surface treatment of cast iron materials, comprising the step of performing diffusion heat treatment in the air at a surface temperature of 650° C. or higher for a time depending on the wall thickness of the sample.
を追加することを特徴とする請求項１記載の鋳鉄材料の
複合表面処理方法。2. 2. The composite surface treatment method for cast iron materials according to claim 1, further comprising adding a decarburization treatment step by heat treatment before the step (a).
上に少なくとも１層以上のＮｉめっき皮膜を各々１μｍ
以上、各層合計で５μｍ以上の膜厚でもって被覆するこ
とを特徴とする請求項１記載の鋳鉄材料の複合表面処理
方法。3. At least one layer of Ni plating film of 1 μm each is formed on the surface treatment film formed by the step (c) above.
2. The composite surface treatment method for cast iron material according to claim 1, wherein each layer is coated with a total thickness of 5 μm or more.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP32490990A JPH04193966A (en) | 1990-11-27 | 1990-11-27 | Method for composite surface treatment of cast iron material |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP32490990A JPH04193966A (en) | 1990-11-27 | 1990-11-27 | Method for composite surface treatment of cast iron material |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH04193966A true JPH04193966A (en) | 1992-07-14 |
Family
ID=18170976
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP32490990A Pending JPH04193966A (en) | 1990-11-27 | 1990-11-27 | Method for composite surface treatment of cast iron material |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH04193966A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR20000046430A (en) * | 1998-12-31 | 2000-07-25 | 이재희 | Method for removing graphite on surface of casting product |
| US6579380B2 (en) * | 1997-11-12 | 2003-06-17 | Ablation Technologies Inc. | Method and apparatus for cleaning molds used in the glass fabrication industry |
| CN104651569A (en) * | 2015-03-02 | 2015-05-27 | 江西省科学院应用物理研究所 | Surface modification method of cast iron |
-
1990
- 1990-11-27 JP JP32490990A patent/JPH04193966A/en active Pending
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6579380B2 (en) * | 1997-11-12 | 2003-06-17 | Ablation Technologies Inc. | Method and apparatus for cleaning molds used in the glass fabrication industry |
| KR20000046430A (en) * | 1998-12-31 | 2000-07-25 | 이재희 | Method for removing graphite on surface of casting product |
| CN104651569A (en) * | 2015-03-02 | 2015-05-27 | 江西省科学院应用物理研究所 | Surface modification method of cast iron |
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