JPH07216527A - Pretreatment for nitridation of alloy containing chromium - Google Patents
Pretreatment for nitridation of alloy containing chromiumInfo
- Publication number
- JPH07216527A JPH07216527A JP2743494A JP2743494A JPH07216527A JP H07216527 A JPH07216527 A JP H07216527A JP 2743494 A JP2743494 A JP 2743494A JP 2743494 A JP2743494 A JP 2743494A JP H07216527 A JPH07216527 A JP H07216527A
- Authority
- JP
- Japan
- Prior art keywords
- alkali metal
- alloy
- nitridation
- pretreatment
- nitriding
- 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.)
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- Solid-Phase Diffusion Into Metallic Material Surfaces (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明はクロムを含有する各種合
金を窒化及び軟窒化処理する際の前処理方法に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pretreatment method for nitriding and soft nitriding various alloys containing chromium.
【０００２】[0002]
【従来の技術及びその問題点】クロムを含有する各種合
金、例えば不銹鋼、耐熱鋼あるいは含ニッケル耐熱合金
からなるエンジン等の耐熱、耐摩耗の構造部材及びエン
ジンバルブ、ピストンリング等の耐熱、耐摩耗の機械部
材の耐摩耗性、耐疲労性をより高めるために、従来より
これら部材に窒化及び軟窒化処理が施されている。これ
ら部材表面に窒化及び軟窒化処理を施す際、部材表面に
クロム酸化物不働態皮膜が形成されていることが多く、
このような不働態膜が形成されているまま処理すると、
窒化及び軟窒化処理が阻害され、均一で充分な深さで窒
化処理されなくなる。2. Description of the Related Art Heat-resistant and wear-resistant structural members for engines such as engines made of chromium-containing alloys such as stainless steel, heat-resistant steel or nickel-containing heat-resistant alloys, and heat-resistant and wear-resistant elements such as engine valves and piston rings. In order to further improve the wear resistance and fatigue resistance of the mechanical member, these members have conventionally been subjected to nitriding and soft nitriding treatments. When performing nitriding and soft nitriding treatments on these member surfaces, a chromium oxide passivation film is often formed on the member surface,
When processing is performed with such a passive film formed,
The nitriding and soft nitriding treatments are hindered, and the nitriding treatment is not performed at a uniform and sufficient depth.
【０００３】そのため、部材表面にクロム酸化物不働態
皮膜が形成されている部材に熱処理を施す場合、これら
部材をある種の酸に浸漬、あるいはハロゲン元素を含む
有機及び無機化合物を部材表面に塗布するか、それら化
合物を処理炉内に導入あるいは処理部材と一緒に装入
し、ハロゲン元素を含む有機及び無機化合物の熱分解生
成物であるハロゲン化水素、ハロゲンガスの作用により
部材表面を活性化させて窒化及び軟窒化処理を容易なら
しめる方法が採られている。Therefore, when heat-treating a member having a chromium oxide passivation film formed on the member surface, the member is dipped in a certain acid or an organic or inorganic compound containing a halogen element is applied to the member surface. Or, these compounds are introduced into the processing furnace or charged together with the processing member, and the surface of the member is activated by the action of hydrogen halide and halogen gas, which are thermal decomposition products of organic and inorganic compounds containing halogen elements. Then, a method of facilitating the nitriding and soft nitriding treatment is adopted.
【０００４】しかしながら、窒化及び軟窒化処理を施す
部材の表面を活性化する方法として、酸に浸漬する方法
は、酸による腐食に伴って発生する水素を部材が吸収す
ることにより引き起される水素脆化の欠点を有する。ま
た、ハロゲンを含む有機及び無機化合物の熱分解生成物
であるハロゲン化水素、ハロゲンガスの腐食作用を行な
わしめる方法は、切欠き部、狭い隙間部、不貫通の細い
穴の内部にそれらのガスが侵入しにくいことによる不均
一な腐食の欠点、あるいは処理炉内部の構成部材がそれ
らのガスにより不必要に腐食される等の欠点を有する。However, as a method for activating the surface of the member to be subjected to the nitriding and soft nitriding treatment, the method of immersing in an acid is a hydrogen generated by the member absorbing hydrogen generated by the corrosion by the acid. It has the disadvantage of brittleness. In addition, the method of performing the corrosive action of hydrogen halide and halogen gas, which are the thermal decomposition products of organic and inorganic compounds containing halogen, is to use those gases inside notches, narrow gaps, and small holes that do not penetrate. Has a drawback of non-uniform corrosion due to difficulty of invading, or a disadvantage that components inside the processing furnace are unnecessarily corroded by those gases.
【０００５】本発明の目的は、従来の如く、酸による水
素脆化の問題、及びハロゲン化水素、ハロゲンガスの作
用を用いる場合の不均一腐食及び不必要な腐食問題を伴
わない、クロム含有合金よりなる部材の表面を効果的に
活性化し、もって良好な窒化及び軟窒化処理を行ない得
る前処理方法を提供するにある。The object of the present invention is to eliminate the problems of hydrogen embrittlement due to acid, and nonuniform corrosion and unnecessary corrosion problems when using the action of hydrogen halide and halogen gas, as in the prior art. Another object of the present invention is to provide a pretreatment method capable of effectively activating the surface of a member made of, and performing good nitriding and soft nitriding treatment.
【０００６】[0006]
【問題点を解決するための手段】本発明では、クロム含
有合金表面を窒化及び軟窒化処理する際の前処理方法で
あって、該合金を、水酸化アルカリ金属、硝酸アルカリ
金属及び亜硝酸アルカリ金属の少なくとも１種を含んだ
溶融塩に浸漬することを特徴とする。本発明において、
水酸化アルカリ金属としては水酸化リチウム、水酸化ナ
トリウム及び水酸化カリウムから選ばれるいずれか１種
又は２種以上、硝酸アルカリ金属としては硝酸リチウ
ム、硝酸ナトリウム及び硝酸カリウムから選ばれるいず
れか１種又は２種以上、亜硝酸アルカリ金属としては亜
硝酸リチウム、亜硝酸ナトリウム及び亜硝酸カリウムか
ら選ばれるいずれか１種又は２種以上であり、これらが
単体又は２種以上含まれる溶融塩が用いられる。According to the present invention, there is provided a pretreatment method for nitriding and soft nitriding the surface of a chromium-containing alloy, the alloy comprising alkali metal hydroxide, alkali metal nitrate and alkali nitrite. It is characterized by being immersed in a molten salt containing at least one metal. In the present invention,
The alkali metal hydroxide is any one or two or more selected from lithium hydroxide, sodium hydroxide and potassium hydroxide, and the alkali metal nitrate is any one or two selected from lithium nitrate, sodium nitrate and potassium nitrate. As the alkali metal nitrite, one kind or two or more kinds selected from lithium nitrite, sodium nitrite and potassium nitrite can be used as the alkali metal nitrite, and a molten salt containing one or more kinds of these is used.
【０００７】[0007]
【作用】本発明では、クロム含有の合金よりなる部材を
前記したような溶融塩中に浸漬することにより、当該部
材表面に成形されているクロム酸化物不働態皮膜が、
（１）水酸化アルカリ金属との反応によりクロム酸アル
カリ金属化合物を生成し、溶融塩中に溶解する、及び／
又は（２）硝酸アルカリ金属、亜硝酸アルカリ金属との
反応により高次の酸化物に移行し、溶融塩中に過不働態
溶解する、ことにより、当該部材表面に活性化された面
が露出し、窒化及び軟窒化作用を容易ならしめる結果、
熱処理を促進させることになる。In the present invention, the chromium oxide passivation film formed on the surface of the member by immersing the member made of the chromium-containing alloy in the molten salt as described above,
(1) generating an alkali metal chromate compound by reaction with an alkali metal hydroxide and dissolving it in a molten salt; and /
Or (2) by reacting with alkali metal nitrate or alkali metal nitrite, it moves to a higher-order oxide and is passively dissolved in the molten salt, whereby the activated surface is exposed on the surface of the member. As a result of facilitating nitriding and soft nitriding,
It will accelerate the heat treatment.
【０００８】本発明においては、被処理合金を、水酸化
アルカリ金属、硝酸アルカリ金属及び亜硝酸アルカリ金
属の少なくとも１種を含んだ溶融塩に浸漬することから
なり、より具体的には、ＬｉＯＨ，ＮａＯＨ，ＫＯＨ
（水酸化アルカリ金属）、ＬｉＮＯ3，ＮａＮＯ3，ＫＮ
Ｏ3（硝酸アルカリ金属）、ＬｉＮＯ2，ＮａＮＯ2，Ｋ
ＮＯ2（亜硝酸アルカリ金属）の単体、もしくは２種以
上を含んだ溶融塩に浸漬するものであり、それらの好ま
しい例として、ＬｉＯＨ，ＮａＯＨ，ＫＯＨのいずれか
から選ばれる１種又は２種以上（水酸化アルカリ金属グ
ループ単独）、ＬｉＯＨ，ＮａＯＨ，ＫＯＨのいずれか
から選ばれる１種又は２種以上と、ＬｉＮＯ3，ＮａＮ
Ｏ3，ＫＮＯ3のいずれかから選ばれる１種又は２種以上
との組合せ（水酸化アルカリ金属グループ＋硝酸アルカ
リ金属グループ）、ＬｉＯＨ，ＮａＯＨ，ＫＯＨのいず
れかから選ばれる１種又は２種以上と、ＬｉＮＯ3，Ｎ
ａＮＯ3，ＫＮＯ3のいずれかから選ばれる１種又は２種
以上と、ＬｉＮＯ2，ＮａＮＯ2，ＫＮＯ2のいずれかか
ら選ばれる１種又は２種以上との組合せ（水酸化アルカ
リ金属グループ＋硝酸アルカリ金属グループ＋亜硝酸ア
ルカリ金属グループ）たものが考えられる。このよう
に、本発明に使用する溶融塩としてその中に水酸化アル
カリ金属が含まれることが好ましい。In the present invention, the alloy to be treated is immersed in a molten salt containing at least one of alkali metal hydroxide, alkali metal nitrate and alkali metal nitrite. More specifically, LiOH, NaOH, KOH
(Alkali metal hydroxide), LiNO 3 , NaNO 3 , KN
O 3 (alkali metal nitrate), LiNO 2 , NaNO 2 , K
It is immersed in a simple substance of NO 2 (alkali metal nitrite) or a molten salt containing two or more kinds thereof, and as a preferable example thereof, one kind or two kinds or more selected from any one of LiOH, NaOH and KOH. (Alkali metal hydroxide group alone), one or more selected from LiOH, NaOH, KOH, and LiNO 3 , NaN
One or a combination of two or more selected from O 3 and KNO 3 (alkali metal hydroxide group + alkali metal nitrate group), and one or more selected from LiOH, NaOH and KOH. And LiNO 3 , N
a combination of one or more selected from any of aNO 3 and KNO 3 and one or more selected from any of LiNO 2 , NaNO 2 and KNO 2 (alkali metal hydroxide group + nitric acid) Alkali metal group + alkali metal nitrite group) is considered. Thus, it is preferable that the molten salt used in the present invention contains an alkali metal hydroxide therein.
【０００９】なお、水酸化アルカリ金属グループ単独の
場合の溶融塩温度範囲は、３００〜６５０℃、水酸化ア
ルカリ金属グループ＋硝酸アルカリ金属グループを組み
合わせる場合、水酸化アルカリ金属グループの量は１０
〜４０重量％とし、その温度範囲は３００〜５００℃、
また水酸化アルカリ金属グループ＋硝酸アルカリ金属グ
ループ＋亜硝酸アルカリ金属グループを組み合わせる場
合、水酸化アルカリ金属グループの量は１０〜４０重量
％とし、その温度範囲は２５０〜４５０℃が適当であ
る。When the alkali metal hydroxide group is used alone, the molten salt temperature range is 300 to 650 ° C. When the alkali metal hydroxide group + the alkali metal nitrate group is combined, the amount of the alkali metal hydroxide group is 10.
-40% by weight, the temperature range is 300-500 ° C,
When the alkali metal hydroxide group + alkali metal nitrate group + alkali nitrite group is combined, the amount of the alkali metal hydroxide group is 10 to 40% by weight, and the temperature range is preferably 250 to 450 ° C.
【００１０】[0010]
【実施例１】水酸化カリウム４０重量％、水酸化ナトリ
ウム４０重量％、硝酸ナトリウム２０重量％、温度３５
０℃の溶融塩中にＳＵＨ １１材の試験片を２０分間浸
漬し、前処理を行なったものと、行なわなかったものと
に、５５０℃×６時間のアンモニアガス窒化処理を行な
った。その結果、前処理を行なった試験片には、８８μ
ｍの均一な全窒化層が形成されたのに対し、前処理を行
なわなかった試験片には、３３μｍの均一な全窒化層が
形成されたにすぎなかった。Example 1 Potassium hydroxide 40% by weight, sodium hydroxide 40% by weight, sodium nitrate 20% by weight, temperature 35
A test piece of SUH 11 material was dipped in a molten salt at 0 ° C. for 20 minutes, and ammonia gas nitriding treatment was performed at 550 ° C. × 6 hours on the pretreated sample and the non-pretreated sample. As a result, the pretreated test piece had
m uniform all-nitrided layer was formed, whereas a 33 μm uniform all-nitrided layer was only formed on the test piece that was not pretreated.
【００１１】[0011]
【実施例２】水酸化カリウム４０重量％、水酸化ナトリ
ウム４０重量％、硝酸ナトリウム２０重量％、温度３５
０℃の溶融塩中にＳＵＨ ３５材の試験片を２０分間浸
漬し、前処理を行なったものと、行なわなかったものと
に、５７０℃×３０分の塩浴軟窒化処理を行なった。そ
の結果、前処理を行なった試験片には、２３μｍの均一
な窒化物層が形成されたのに対し、前処理を行なわなか
った試験片には、０〜１０μｍの窒化物層が不均一に形
成された。Example 2 40 wt% potassium hydroxide, 40 wt% sodium hydroxide, 20 wt% sodium nitrate, temperature 35
A test piece of SUH 35 material was dipped in a molten salt at 0 ° C. for 20 minutes, and pre-treated and non-treated were subjected to a salt bath nitrocarburizing treatment at 570 ° C. for 30 minutes. As a result, a 23 μm uniform nitride layer was formed on the pretreated test piece, whereas a 0-10 μm nitride layer was nonuniform on the non-pretreated test piece. Been formed.
【００１２】[0012]
【実施例３】実施例２と同一の３５０℃の溶融塩中に、
ＳＵＳ ２０１材の試験片を２０分間浸漬し、前処理を
行なったものと、行なわなかったものとに、５７０℃×
３０分の塩浴軟窒化処理を行なった。その結果、前処理
を行なった試験片には、１７μｍの均一な窒化物層が形
成されたのに対し、前処理を行なわなかった試験片に
は、０〜１０μｍの窒化物層が不均一に形成された。Example 3 In the same molten salt at 350 ° C. as in Example 2,
A test piece of SUS 201 material was dipped for 20 minutes, and 570 ° C. was applied to each of those that were pretreated and those that were not pretreated.
A salt bath nitrocarburizing treatment was performed for 30 minutes. As a result, a 17 μm uniform nitride layer was formed on the pretreated test piece, whereas a 0-10 μm nitride layer was nonuniform on the non-pretreated test piece. Been formed.
【００１３】[0013]
【実施例４】硝酸ナトリウム３５重量％、硝酸カリウム
３５重量％、水酸化ナトリウム３０重量％、温度３００
℃の溶融塩中に、ＳＵＳ ２０１材の試験片を２０分間
浸漬し、前処理を行なったものと、行なわなかったもの
とに、５７０℃×２０分の塩浴軟窒化処理を行なった。
その結果、前処理を行なった試験片には、１５μｍの均
一な窒化物層が形成されたのに対し、前処理を行なわな
かった試験片には、０〜５μｍの窒化物層が不均一に形
成された。Example 4 35 wt% sodium nitrate, 35 wt% potassium nitrate, 30 wt% sodium hydroxide, temperature 300
A test piece of SUS 201 material was immersed in a molten salt at a temperature of 20 ° C. for 20 minutes, and pretreatment and non-pretreatment were subjected to a salt bath nitrocarburizing treatment at 570 ° C. for 20 minutes.
As a result, a 15 μm uniform nitride layer was formed on the pretreated test piece, while a 0 to 5 μm nitride layer was nonuniform on the non-pretreated test piece. Been formed.
【００１４】[0014]
【実施例５】水酸化ナトリウム５０重量％、水酸化カリ
ウム５０重量％、温度４００℃の溶融塩中に、ＳＵＳ
２０１材の試験片を２０分間浸漬し、前処理を行なった
ものと、行なわなかったものとに、５７０℃×２０分の
塩浴軟窒化処理を行なった。その結果、前処理をおこな
った試験片には１５μｍの均一な窒化物層が形成された
のに対し、前処理を行なわなかった試験片には０〜５μ
ｍの窒化物層が不均一に形成された。Example 5 50% by weight of sodium hydroxide, 50% by weight of potassium hydroxide, SUS in a molten salt at a temperature of 400 ° C.
A test piece of 201 material was immersed for 20 minutes, and a pretreatment and a non-pretreatment were subjected to a salt bath nitrocarburizing treatment at 570 ° C. for 20 minutes. As a result, a uniform nitride layer of 15 μm was formed on the pre-treated test piece, while 0 to 5 μm was formed on the non-pre-treated test piece.
The nitride layer of m was formed nonuniformly.
【００１５】[0015]
【実施例６】硝酸カリウム３５重量％、亜硝酸ナトリウ
ム３５重量％、水酸化ナトリウム３０重量％、温度３０
０℃の溶融塩中に、ＳＵＳ ２０１材の試験片を２０分
間浸漬し、前処理を行なったものと、行なわなかったも
のとに、５７０℃×２０分の塩浴軟窒化処理を行なっ
た。その結果、前処理を行なった試験片には１５μｍの
均一な窒化物層が形成されたのに対し、前処理を行なわ
なかった試験片には０〜１０μｍの窒化物層が不均一に
形成された。以上、実施例１〜６の条件及び結果を表１
及び表２に示す。Example 6 Potassium nitrate 35% by weight, sodium nitrite 35% by weight, sodium hydroxide 30% by weight, temperature 30
A test piece of SUS 201 material was dipped in a molten salt at 0 ° C. for 20 minutes, and pretreatment and non-pretreatment were subjected to a salt bath nitrocarburizing treatment at 570 ° C. for 20 minutes. As a result, a 15 μm uniform nitride layer was formed on the pretreated test piece, whereas a 0 to 10 μm nitride layer was unevenly formed on the non-pretreated test piece. It was The conditions and results of Examples 1 to 6 are shown in Table 1 above.
And shown in Table 2.
【００１６】[0016]
【表１】 [Table 1]
【００１７】[0017]
【表２】 [Table 2]
【００１８】[0018]
【発明の効果】以上のような本発明によれば、クロム含
有合金表面にクロム酸化物不働態皮膜が形成されている
場合にも、これら部材表面を従来の如き問題点を有さず
に活性化することができ、その後の窒化及び軟窒化処理
が著しく容易かつ均一に促進される。As described above, according to the present invention, even when a chromium oxide passivation film is formed on the surface of a chromium-containing alloy, the surfaces of these members can be activated without causing problems as in the prior art. And the subsequent nitriding and soft nitriding treatments are significantly facilitated and evenly promoted.
─────────────────────────────────────────────────────
─────────────────────────────────────────────────── ───
【手続補正書】[Procedure amendment]
【提出日】平成６年６月２３日[Submission date] June 23, 1994
【手続補正１】[Procedure Amendment 1]
【補正対象書類名】明細書[Document name to be amended] Statement
【補正対象項目名】００１７[Correction target item name] 0017
【補正方法】変更[Correction method] Change
【補正内容】[Correction content]
【００１７】[0017]
【表２】 [Table 2]
Claims (2)
理する際の前処理方法であって、該合金を、水酸化アル
カリ金属、硝酸アルカリ金属及び亜硝酸アルカリ金属の
少なくとも１種を含んだ溶融塩に浸漬することを特徴と
するクロム含有合金の窒化前処理方法。1. A pretreatment method for nitriding and soft nitriding the surface of a chromium-containing alloy, which comprises melting the alloy containing at least one of alkali metal hydroxide, alkali metal nitrate and alkali metal nitrite. A method for pre-nitriding a chromium-containing alloy, which comprises immersing in a salt.
酸化リチウム、水酸化ナトリウム及び水酸化カリウムか
ら選ばれるいずれか１種又は２種以上、硝酸アルカリ金
属が硝酸リチウム、硝酸ナトリウム及び硝酸カリウムか
ら選ばれるいずれか１種又は２種以上、亜硝酸アルカリ
金属が亜硝酸リチウム、亜硝酸ナトリウム及び亜硝酸カ
リウムから選ばれるいずれか１種又は２種以上であり、
これらが単体又は２種以上含まれることを特徴とする請
求項１記載のクロム含有合金の窒化前処理方法。2. As a molten salt, alkali metal hydroxide is selected from one or more selected from lithium hydroxide, sodium hydroxide and potassium hydroxide, and alkali metal nitrate is selected from lithium nitrate, sodium nitrate and potassium nitrate. 1 or 2 or more, and the alkali metal nitrite is any 1 or 2 or more selected from lithium nitrite, sodium nitrite and potassium nitrite,
The nitriding pretreatment method for a chromium-containing alloy according to claim 1, wherein these are contained alone or in combination of two or more.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP02743494A JP3302812B2 (en) | 1994-01-31 | 1994-01-31 | Pre-nitriding method for chromium-containing alloy |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP02743494A JP3302812B2 (en) | 1994-01-31 | 1994-01-31 | Pre-nitriding method for chromium-containing alloy |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH07216527A true JPH07216527A (en) | 1995-08-15 |
| JP3302812B2 JP3302812B2 (en) | 2002-07-15 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP02743494A Expired - Lifetime JP3302812B2 (en) | 1994-01-31 | 1994-01-31 | Pre-nitriding method for chromium-containing alloy |
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| JP (1) | JP3302812B2 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2014205883A (en) * | 2013-04-12 | 2014-10-30 | パーカー熱処理工業株式会社 | Salt-bath soft nitriding treatment method |
-
1994
- 1994-01-31 JP JP02743494A patent/JP3302812B2/en not_active Expired - Lifetime
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2014205883A (en) * | 2013-04-12 | 2014-10-30 | パーカー熱処理工業株式会社 | Salt-bath soft nitriding treatment method |
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| Publication number | Publication date |
|---|---|
| JP3302812B2 (en) | 2002-07-15 |
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