JPH03267380A - Combined surface treatment of cast iron material - Google Patents
Combined surface treatment of cast iron materialInfo
- Publication number
- JPH03267380A JPH03267380A JP6613290A JP6613290A JPH03267380A JP H03267380 A JPH03267380 A JP H03267380A JP 6613290 A JP6613290 A JP 6613290A JP 6613290 A JP6613290 A JP 6613290A JP H03267380 A JPH03267380 A JP H03267380A
- Authority
- JP
- Japan
- Prior art keywords
- cast iron
- treatment
- film
- surface treatment
- sample
- 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 31
- 239000000463 material Substances 0.000 title claims abstract 14
- 238000004381 surface treatment Methods 0.000 title claims description 31
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims abstract description 22
- 229910002804 graphite Inorganic materials 0.000 claims abstract description 22
- 239000010439 graphite Substances 0.000 claims abstract description 22
- 238000007747 plating Methods 0.000 claims abstract description 21
- 238000005121 nitriding Methods 0.000 claims abstract description 15
- 150000003839 salts Chemical class 0.000 claims abstract description 11
- 239000011159 matrix material Substances 0.000 claims abstract description 5
- 238000005868 electrolysis reaction Methods 0.000 claims abstract description 4
- 238000000034 method Methods 0.000 claims description 27
- 238000010438 heat treatment Methods 0.000 claims description 10
- 239000002131 composite material Substances 0.000 claims description 8
- 239000011248 coating agent Substances 0.000 claims description 3
- 238000000576 coating method Methods 0.000 claims description 3
- 239000011261 inert gas Substances 0.000 claims description 2
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical group [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims 1
- 238000005261 decarburization Methods 0.000 claims 1
- 239000001301 oxygen Substances 0.000 claims 1
- 229910052760 oxygen Inorganic materials 0.000 claims 1
- JEIPFZHSYJVQDO-UHFFFAOYSA-N iron(III) oxide Inorganic materials O=[Fe]O[Fe]=O JEIPFZHSYJVQDO-UHFFFAOYSA-N 0.000 abstract description 25
- 239000002932 luster Substances 0.000 abstract description 18
- 229910018104 Ni-P Inorganic materials 0.000 abstract description 14
- 229910018536 Ni—P Inorganic materials 0.000 abstract description 14
- 230000015572 biosynthetic process Effects 0.000 abstract description 8
- 238000005260 corrosion Methods 0.000 abstract description 7
- 230000007797 corrosion Effects 0.000 abstract description 4
- 230000003449 preventive effect Effects 0.000 abstract description 3
- SZVJSHCCFOBDDC-UHFFFAOYSA-N ferrosoferric oxide Chemical compound O=[Fe]O[Fe]O[Fe]=O SZVJSHCCFOBDDC-UHFFFAOYSA-N 0.000 abstract 2
- 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 abstract 2
- 230000000694 effects Effects 0.000 description 10
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 10
- 230000002265 prevention Effects 0.000 description 8
- 150000001875 compounds Chemical class 0.000 description 7
- 229910001220 stainless steel Inorganic materials 0.000 description 7
- 239000010935 stainless steel Substances 0.000 description 7
- 239000007789 gas Substances 0.000 description 5
- 230000003647 oxidation Effects 0.000 description 4
- 238000007254 oxidation reaction Methods 0.000 description 4
- 229910001296 Malleable iron Inorganic materials 0.000 description 3
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 3
- 238000001816 cooling Methods 0.000 description 3
- 238000005266 casting Methods 0.000 description 2
- 230000006641 stabilisation Effects 0.000 description 2
- 238000011105 stabilization Methods 0.000 description 2
- 238000010301 surface-oxidation reaction Methods 0.000 description 2
- 239000008399 tap water Substances 0.000 description 2
- 235000020679 tap water Nutrition 0.000 description 2
- FBPFZTCFMRRESA-JGWLITMVSA-N D-glucitol Chemical group OC[C@H](O)[C@@H](O)[C@H](O)[C@H](O)CO FBPFZTCFMRRESA-JGWLITMVSA-N 0.000 description 1
- 229910001141 Ductile iron Inorganic materials 0.000 description 1
- 229910001060 Gray iron Inorganic materials 0.000 description 1
- 229910001566 austenite 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
- 238000005238 degreasing Methods 0.000 description 1
- 238000005246 galvanizing Methods 0.000 description 1
- XEEYBQQBJWHFJM-UHFFFAOYSA-N iron Substances [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 230000007935 neutral effect Effects 0.000 description 1
- 150000004767 nitrides Chemical class 0.000 description 1
- 229910001562 pearlite Inorganic materials 0.000 description 1
- 238000005554 pickling Methods 0.000 description 1
- 238000002203 pretreatment Methods 0.000 description 1
- 239000004576 sand Substances 0.000 description 1
- 229910000859 α-Fe Inorganic materials 0.000 description 1
Landscapes
- Other Surface Treatments For Metallic Materials (AREA)
- Chemically Coating (AREA)
- Solid-Phase Diffusion Into Metallic Material Surfaces (AREA)
Abstract
Description
【発明の詳細な説明】
［産業上の利用分野コ
本発明は、基地中に黒鉛を膏する鋳鉄鋳物の表面に発生
する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 [Field of Industrial Application] The present invention relates to a method for preventing the formation of red rust on the surface of cast iron castings in which graphite is coated in the matrix.
［従来の技術］
黒鉛を基地中に存する鋳鉄９例えば焦心可鍛鋳鉄２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。[Prior Art] Cast iron containing graphite in its base, such as cored malleable cast iron, spheroidal graphite cast iron, vermicular cast iron, gray cast iron, etc., 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.
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１価格が高く汎用管継手としては使用しにくい、安
価でステンレス並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。Stainless steel pipe fittings are used as rust-free pipe fittings, but they are expensive and difficult to use as general-purpose pipe fittings.There is a need to develop a surface treatment method that is inexpensive and has the same rust prevention performance and metallic luster as stainless steel. .
今１）−船釣な耐食、耐摩耗性を示す表面処理方法とし
ては、窒化処理や無電解Ｎｉ−Ｐ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。1) Nitriding treatment, electroless Ni-P plating, etc. are known as surface treatment methods that exhibit corrosion resistance and wear resistance. Additionally, the gas joints are hot-dip galvanized.
鋳鉄表面への窒化処理に関するものとしては。Regarding nitriding treatment of cast iron surfaces.
特開昭Ｅ３４−５０８７号公報が窒化処理層の上に四三
酸化鉄を形成する方法が開示されている。JP-A-34-5087 discloses a method for forming triiron tetroxide on a nitrided layer.
また、米国特許登録７１−７４Ｅ３６Ｅ３Ｓ／４７号と
して溶融塩電解処理と呼ばれる脱スケール。Also, descaling is called molten salt electrolytic treatment as US Patent No. 71-74E36E3S/47.
脱黒鉛処理方法が開示されている。A degraphitization treatment method is disclosed.
［発明が解決しようとする課題］ 表面に黒鉛を有する鋳鉄表面への防錆効果は。[Problem to be solved by the invention] What is the rust prevention effect on cast iron surfaces with graphite on the surface?
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のに対し、該鋳鉄
表面に黒鉛が存在すると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２局部的に露出せる
基地との間に局部電池が構成されることによって赤錆が
生じることを明らかにした。従って、窒化処理や無電解
Ｎｉ−Ｐめっき等は、基地中に黒鉛を有する鋳鉄に対す
る各々単独の処理では防錆を目的とした表面処理法とし
ては完全なものとはいえない。It prevents rust by forming a film on the metal surface that is free of cracks and pinholes, but if graphite is present on the surface of the cast iron, the graphite will interfere with the formation of a surface treatment film on the surface of the cast iron. It was revealed that red rust occurs when a local battery is formed between two locally exposed bases that are not completely formed. Therefore, nitriding treatment, electroless Ni--P plating, etc. cannot be said to be a perfect surface treatment method for the purpose of rust prevention when used alone on cast iron having graphite in the matrix.
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。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, the above-mentioned gas fittings are plated.
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。Since it is threaded, it is not effective in preventing rust on the threaded part.
特公昭６４−５０８７号公報のものは熱処理にて表面に
ソルバイト組織を形成後その上に窒化層及び四三酸化鉄
層を形成する技術であり、フェライト、パーライト、オ
ーステナイトといった基地組織へ適用された表面処理技
術ではなく、また処理表面の黒鉛除去が考慮されてない
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 technology disclosed in Japanese Patent Publication No. 64-5087 is a technique in which a sorbite structure is formed on the surface by heat treatment, and then a nitride layer and a triiron tetroxide layer are formed thereon, and it is applied to base structures such as ferrite, pearlite, and austenite. Since the technique is not a surface treatment technique and the removal of graphite from the treated surface is not taken into consideration, it is difficult to completely prevent red rust that forms between incomplete surface treatment films due to the interference of graphite.
また、米国特許登録７１−７４Ｅ３ｆ３ＢＳ／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慣れ性を改善するための
前処理方法とし°Ｃ利用されており、防錆効果を改善す
るための窒化処理の前処理としての検討はなされていな
い。In addition, US Patent No. 71-74E3f3BS/47 is known as a method for degraphitizing the surface of cast iron, but this is a pretreatment method to improve the ease of brazing cast iron. However, no study has been made as a pretreatment for nitriding 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。Furthermore, in the various conventional surface treatment methods described above.
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。Even if an anti-corrosion effect could be obtained, the treated surface would be black or gray, making it difficult to apply it to products that require an anti-rust effect and a metallic luster comparable to stainless steel.
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。[Means to solve the problem] In order to solve the above-mentioned problem, in the present invention.
ます、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
に露出した黒鉛を除去した後に耐食。First, the graphite exposed on the cast iron surface to a depth of approximately 50 μm, which interferes with the formation of a surface treatment film, is removed using the molten salt electrolytic treatment method, and then corrosion resistant.
耐摩耗性向上のために窒化処理９例えば塩浴軟窒化処理
を施し、該鋳鉄表面にＦｅ−Ｎ化合物層を約１〜３０μ
ｍ程度形成する。さらに水蒸気雰囲気中等で熱処理を施
すことによって、該Ｆｅ−Ｎ化合物層表面にＦｅ５Ｏａ
の皮膜を１〜３０μｍ程度形成させる。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
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。その後
９本処理表面上に銀白色の金属光沢を付与する目的で無
電解Ｎｉ−Ｐめっき皮膜を５μｍ〜２０μｍ程度被覆す
る。もちろん、窒化処理皮膜上にＦｅ３０ａの皮膜形成
処理を行うことなくＦｅ−Ｎ化合物層上に無電解Ｎｉ−
Ｐめっき処理を施しても良い。In order to improve wear resistance, nitriding treatment 9, for example, salt bath nitrocarburizing treatment, is performed to form a Fe-N compound layer of about 1 to 30 μm on the surface of the cast iron.
Form about m. Furthermore, by performing heat treatment in a steam atmosphere etc., Fe5Oa is added to the surface of the Fe-N compound layer.
A film of about 1 to 30 μm is formed. That is, by removing the graphite on the surface of the cast iron that obstructs 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. Thereafter, an electroless Ni-P plating film with a thickness of about 5 μm to 20 μm is coated on the treated surfaces of the nine pieces for the purpose of imparting a silvery white metallic luster. Of course, the electroless Ni-
P plating treatment may also be applied.
次に、Ｎｉ −Ｐの皮膜の密着性を向上させる目的で大
気中で該めっき皮膜の金属光沢が保持される４００℃以
下の温度で熱処理を施す、また大気中で３００″Ｃ以上
の熱処理を行うと該めっき皮膜が酸化されて金属光沢が
無くなり色斑が生じることから、３００℃以上の熱処理
は不活性ガス雰囲気中９例えばＡｒガスやＮ２ガス中で
行う。Next, in order to improve the adhesion of the Ni-P film, heat treatment is performed in the air at a temperature of 400°C or lower to maintain the metallic luster of the plating film, and heat treatment is performed in the air at a temperature of 300"C or higher. If this is done, the plating film will be oxidized, lose its metallic luster, and cause color spots, so the heat treatment at 300° C. or higher is carried out in an inert gas atmosphere, for example, Ar gas or N2 gas.
［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。[Single surface treatment of cast iron surfaces containing graphite in the active matrix did not show a complete rust prevention effect.]
表面処理皮膜の形成を妨害する鋳鉄表面の黒鉛を除去し
た後に窒化処理及び酸化処理により表面にＦｅａｏ４の
皮膜を形成し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無電解Ｎｉ−Ｐ
めっき皮膜を薄く被覆すること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。なお、無電解Ｎｉ−Ｐ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。After removing the graphite on the surface of the cast iron that interferes with the formation of the surface treatment film, a Feao4 film is formed on the surface by nitriding and oxidation treatment to achieve a complete rust prevention effect, and the surface is also beautiful on top of the treated film. Electroless Ni-P
By applying the composite surface treatment of the present invention, which is characterized by coating with a thin plating film, 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. Incidentally, when the electroless Ni--P plating film has a thickness of 5 μm or less, it does not exhibit metallic luster and the color of the base appears through the plating film.
［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] An example of the surface treatment method of the present invention will be explained according to the following example.
本実施例方法は、 （イ）脱黒鉛処理、 （ロ）窒化処
理、 （ハ）表面酸化処理、 （ニ）無電解Ｎｉ−Ｐ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) nitridation treatment, (c) surface oxidation treatment, (d) electroless Ni-P 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ず、前処
理として試料表面の黒鉛を除去する目的で、水酸化ナト
リウムと中性塩類とからなる浴温度４６０ ’Ｃのアル
カリ性酸化還元洛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。(a) Degraphitization process by molten salt electrolysis treatment First, as a pretreatment, the sample was placed in an alkaline redox bath containing sodium hydroxide and neutral salts at a temperature of 460'C in order to remove graphite on the sample surface. The surface of the sample is cleaned by electrolytic treatment. The electrolysis procedure is as follows: (1) The sample is held at the cathode and sand and oxide film on the sample surface are removed by reduction 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℃の湯にて洗浄する。After that, after cooling to room temperature by air cooling and water cooling,
Wash with 0℃ hot water.
（ロ）窒化処理工程
試料表面に耐食性及び耐摩耗性を付与する目的で該試料
を約３５０℃に余熱後、約５８０°Ｃの温度で塩浴軟窒
化処理を約１時間施し表面にＦｅ−Ｎの化合物層を５μ
ｍ〜３０μｍ程度形成する。(b) Nitriding process In order to impart corrosion resistance and wear resistance to the sample surface, the sample was preheated to about 350°C and then subjected to salt bath nitrocarburizing treatment at a temperature of about 580°C for about 1 hour to coat the surface with Fe- N compound layer is 5μ
The thickness is approximately 30 μm to 30 μm.
（ハ）表面酸化処理工程
前記（ロ）の処理工程が終了後に浴温度約３８０°Ｃの
塩浴中に約１５分程度該試料を浸漬し該試料Ｆｅ−Ｎ化
合物層の表面または化合物層中にＦｅ５０．ＪＩを１μ
ｍ〜３０μｍ程度形成後、水冷にて室温まで冷却したの
ち６０℃の湯にて洗浄後乾燥する。(c) Surface oxidation treatment step After the treatment step (b) above is completed, the sample is immersed in a salt bath with a bath temperature of about 380°C for about 15 minutes, and the sample is immersed on the surface of the Fe-N compound layer or inside the compound layer. Fe50. JI 1μ
After forming a film with a thickness of about 30 μm to 30 μm, the film is cooled to room temperature with water, washed with hot water at 60° C., and then dried.
本酸化処理工程の他に約４００℃の水蒸気雰囲気中での
酸化処理により該Ｆｅ−Ｎ化合物層表面もしくは化合物
層中にＦｅ３０ａ層を形成させても良い。In addition to this oxidation treatment step, an Fe30a layer may be formed on the surface of the Fe-N compound layer or in the compound layer by oxidation treatment in a steam atmosphere at about 400°C.
（ニ）無電解Ｎｉ −Ｐ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。(d) Electroless Ni-P plating treatment process For the purpose of imparting a silvery white metallic luster to the sample surface.
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無電解Ｎｉ−Ｐめっき処理を
約５μｍ〜２０μｍ程度の膜厚て施す。After completing the step (c) above, the sample is subjected to degreasing treatment, pickling treatment, etc. at least once to clean and activate the surface, and then electroless Ni-P plating treatment is applied to the sample surface to a thickness of about 5 μm or more. Apply a film with a thickness of about 20 μm.
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２０μｍ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 20 μm, the total film thickness will become too thick to be used.
（ホ）皮膜の安定化熱処理工程
試料表面のＮｉ −Ｐめっき皮膜と基地との密着性を向
上させる目的で、前記（ニ）の工程が終了したのち約２
００°Ｃの温度で約１時間大気雰囲気中で熱処理を施す
。(e) Film stabilization heat treatment process In order to improve the adhesion between the Ni-P plating film on the sample surface and the base, approximately
Heat treatment is performed in an air atmosphere at a temperature of 00°C for about 1 hour.
以上のような複合表面処理を施すことにより。By applying the above-mentioned composite surface treatment.
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。It becomes possible to form a surface treatment film with a total thickness of about 50 μm or less on the surface of cast iron, which has rust prevention properties and has a silvery white metallic luster.
このように防錆効果を有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 has an anti-corrosion 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. become.
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に表面処理皮膜が侵入して
いる様子を示している。また、皮膜そのものも連続性を
保っている。Figure 1 shows the state of the surface treatment film of the sample treated according to the above example, and the surface treatment film invades the holes where graphite that was exposed on the cast iron surface was removed. It shows the situation. 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いる黒鉛の上部には表面
処理皮膜が形成されに＜＜。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. Formed <<.
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。It shows how the film is discontinuous 6 due to graphite.
第３図は、水温１０℃の水道水に１週間浸漬した際の１
２個の試料表面に生じる赤錆の平均発生状況を示したも
のであるが、脱黒鉛処理を施さずに窒化処理及び無電解
Ｎｉ−Ｐめっき処理を施した試料Ａでは、金属光沢は維
持されるものの試料表面に錆が生じたのに対し、脱黒鉛
処理を施して窒化処理した試料Ｂでは、錆の発生が大幅
に低下したが金属光沢が消滅してしまう、一方９本発明
の試料Ｃでは、１週間浸漬したのちも錆の発生はほとん
ど認められず５表面の金属光沢も試験開始当初の状態を
維持している。Figure 3 shows the results after being immersed in tap water at a temperature of 10°C for one week.
This shows the average occurrence of red rust on the surfaces of two samples. Sample A, which was subjected to nitriding and electroless Ni-P plating without degraphitizing, maintains its metallic luster. Rust occurred on the surface of the sample, whereas in sample B, which was subjected to degraphitization treatment and nitriding treatment, the occurrence of rust was significantly reduced, but the metallic luster disappeared, while in sample C of the present invention, the rust occurred. Even after being immersed for one week, almost no rust was observed, and the metallic luster on the surface remained as it was at the beginning of the test.
［発明の効果］
以上の説明で明らかなように９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１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
ステン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 according to 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 It is now possible to maintain the same metallic luster as white stainless steel, and can be used as a replacement for the expensive stainless steel pipe fittings that are currently used as rust-free pipe fittings, and for cold water and hot water supply and drainage where the generation of red water is a problem. This makes it possible to apply it to industrial parts, etc.
第１図は焦心可鍛鋳鉄に脱黒鉛処理を施した後。
窒化処理及び無電解Ｎｉ−Ｐめっき処理した試料の表面
処理皮膜状況を示したもの。
第２図は焦心可鍛鋳鉄に脱黒鉛処理を施さずに。
窒化処理及び無電解Ｎｉ−Ｐめっき処理した試料の表面
処理皮膜と黒鉛の関係を示したちの第３図は、水温１０
℃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したものである。
第１図
１：Ｎｉ−Ｐめっき層
２：ＦｅａＯ４層
３：Ｆｅ−Ｎ層
４：黒鉛
５：Ｆｅ基地
６：めっき不連続部
５Figure 1 shows cored malleable cast iron after being degraphitized. This figure shows the state of the surface treatment film of a sample subjected to nitriding treatment and electroless Ni-P plating treatment. Figure 2 shows cored malleable cast iron without degraphitization treatment. Figure 3 shows the relationship between the surface treatment film and graphite of a sample subjected to nitriding treatment and electroless Ni-P plating treatment.
This figure shows the average occurrence of red rust and metallic luster on the sample surface when immersed in tap water at ℃ for one week. Figure 1: Ni-P plating layer 2: FeaO4 layer 3: Fe-N layer 4: Graphite 5: Fe base 6: Plating discontinuity 5
Claims (5)
処理により表面の脱黒鉛処理を行う工程，（ロ）窒化処
理を施す工程，（ハ）該鋳鉄材料の処理表面上に無電解
Ｎｉ−Ｐめっき皮膜を５μｍ以上の膜厚で被覆する工程
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 step of degraphitizing the surface of a cast iron material having graphite in the matrix by molten salt electrolysis treatment, (b) A step of performing a nitriding treatment, (c) A step of applying electroless Ni- on the treated surface of the cast iron material. A composite surface treatment method for cast iron materials, comprising the step of coating with a P plating film with a thickness of 5 μm or more.
にＦｅ＿３Ｏ＿４の皮膜を形成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, wherein a Fe_3O_4 film is formed on the surface treatment film formed in the step (b).
を追加する事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. 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).
４００℃以下の試料表面温度でもって試料の肉厚に応じ
た時間に亘り，大気雰囲気中で熱処理を施すことを特徴
とする請求項１記載の鋳鉄材料の複合表面処理方法。4. 2. The method according to claim 1, wherein the surface treatment film formed in step (c) is subjected to heat treatment in an atmospheric atmosphere at a sample surface temperature of 400° C. or lower for a time corresponding to the wall thickness of the sample. Composite surface treatment method for cast iron materials.
３００℃以上の試料表面温度でもって試料の肉厚に応じ
た時間に亘り，酸素と置換した不活性ガス雰囲気中で熱
処理を施す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。5. The surface treatment film formed in the step (c) is heat-treated at a sample surface temperature of 300° C. or higher for a period of time depending on the thickness of the sample in an inert gas atmosphere substituted with oxygen. A composite surface treatment method for cast iron materials according to claim 1.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP6613290A JPH03267380A (en) | 1990-03-16 | 1990-03-16 | Combined surface treatment of cast iron material |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP6613290A JPH03267380A (en) | 1990-03-16 | 1990-03-16 | Combined surface treatment of cast iron material |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH03267380A true JPH03267380A (en) | 1991-11-28 |
Family
ID=13307037
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP6613290A Pending JPH03267380A (en) | 1990-03-16 | 1990-03-16 | Combined surface treatment of cast iron material |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH03267380A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2008525639A (en) * | 2004-12-23 | 2008-07-17 | ユナイテッド テクノロジーズ コーポレイション | Compositions and methods for enhancing the properties of components containing iron |
| JP2008169485A (en) * | 2008-01-08 | 2008-07-24 | Jfe Steel Kk | Method for manufacturing nitrided component |
-
1990
- 1990-03-16 JP JP6613290A patent/JPH03267380A/en active Pending
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2008525639A (en) * | 2004-12-23 | 2008-07-17 | ユナイテッド テクノロジーズ コーポレイション | Compositions and methods for enhancing the properties of components containing iron |
| JP4919968B2 (en) * | 2004-12-23 | 2012-04-18 | ユナイテッド テクノロジーズ コーポレイション | Compositions and methods for enhancing the properties of components containing iron |
| JP2008169485A (en) * | 2008-01-08 | 2008-07-24 | Jfe Steel Kk | Method for manufacturing nitrided component |
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