JPH0673524A - Nitriding method of iron and steel surface - Google Patents
Nitriding method of iron and steel surfaceInfo
- Publication number
- JPH0673524A JPH0673524A JP25073992A JP25073992A JPH0673524A JP H0673524 A JPH0673524 A JP H0673524A JP 25073992 A JP25073992 A JP 25073992A JP 25073992 A JP25073992 A JP 25073992A JP H0673524 A JPH0673524 A JP H0673524A
- Authority
- JP
- Japan
- Prior art keywords
- alkali metal
- salt bath
- cyanate
- chloride
- weight
- 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
Landscapes
- Solid-Phase Diffusion Into Metallic Material Surfaces (AREA)
Abstract
Description
【０００１】[0001]
【発明の背景】鉄鋼製品の耐摩耗性の向上を目的として
表面の浸炭窒化による表面処理方法が行われている。変
態温度以下において溶融塩中に浸漬して実施する塩浴窒
化方法においては、かってはシアン化アルカリおよび炭
酸アルカリを主成分として含む塩浴が使用されていた
が、環境対策上シアン化アルカリの代りにシアン酸アル
カリが使用されている。例えばシアン酸カリウム、炭酸
カリウムおよび／または炭酸リチウムを含む塩浴は比較
的低い処理温度（例えば５５０℃以下）において耐摩耗
性、耐疲労性、耐食性にすぐれた緻密な（非多孔）硬化
層を与える。ところが熱間及び半熱間（温間）鍛造用金
型のように、耐摩耗性の他に耐かじり性にもすぐれてい
ることが要求される分野が存在する。BACKGROUND OF THE INVENTION A surface treatment method by carbonitriding a surface has been carried out for the purpose of improving wear resistance of steel products. In the salt bath nitriding method, which is carried out by immersing in molten salt below the transformation temperature, a salt bath containing alkali cyanide and alkali carbonate as the main components was used in the past. Alkali cyanate is used in. For example, a salt bath containing potassium cyanate, potassium carbonate and / or lithium carbonate forms a dense (non-porous) hardened layer excellent in wear resistance, fatigue resistance and corrosion resistance at a relatively low processing temperature (eg, 550 ° C. or lower). give. However, there are fields such as hot and semi-hot (warm) forging dies that are required to have excellent galling resistance in addition to wear resistance.
【０００２】アルカリ金属シアン酸塩および炭酸塩を主
体とする既知の塩浴剤を使用する窒化方法や気相で行わ
れるイオン窒化方法は、耐摩耗性を満足するものの、耐
摩耗性と耐かじり性の両方を満足する硬化層を得ること
は困難である。従って耐摩耗性にすぐれると同時に、耐
かじり性にもすぐれている硬化層を与える塩浴窒化方法
に対して要望が存在する。A nitriding method using a known salt bath agent mainly composed of an alkali metal cyanate and a carbonate and an ion nitriding method carried out in a gas phase satisfy wear resistance, but wear resistance and galling resistance. It is difficult to obtain a hardened layer that satisfies both properties. Therefore, there is a need for a salt bath nitriding method that provides a hardened layer that is excellent in abrasion resistance and at the same time excellent in galling resistance.
【０００３】[0003]
【本発明の概要】かかる要望は本発明によって解決され
る。本発明は、鉄鋼製品を変態温度以下の温度において
アルカリ金属シアン酸塩を含む溶融塩浴へ浸漬すること
よりなる鉄鋼表面窒化方法において、塩浴として、アル
カリ金属シアン酸塩６０〜９０重量部、アルカリ金属塩
化物１０〜４０重量部、および少量のアルカリ金属イオ
ウ化合物を含む塩浴を使用することを特徴とする鉄鋼表
面窒化方法に関する。SUMMARY OF THE INVENTION The need is met by the present invention. The present invention relates to a steel surface nitriding method, which comprises immersing a steel product in a molten salt bath containing an alkali metal cyanate at a temperature not higher than a transformation temperature, wherein 60 to 90 parts by weight of an alkali metal cyanate is used as a salt bath. It relates to a steel surface nitriding method characterized by using a salt bath containing 10 to 40 parts by weight of an alkali metal chloride and a small amount of an alkali metal sulfur compound.
【０００４】[0004]
【好ましい実施態様】本発明において「アルカリ金属」
とは、リチウム、ナトリウムおよびカリウムを意味す
る。従ってシアン酸塩、塩化物およびイオウ化合物のア
ルカリ金属種はこれらアルカリ金属のいずれでもよい
が、シアン酸塩としてはシアン酸カリウム、塩化物とし
ては塩化カリウムおよび塩化リチウムの等量混合物、イ
オウ化合物としてはチオ硫酸ナトリウムが好ましい。Preferred Embodiment In the present invention, "alkali metal"
Means lithium, sodium and potassium. Therefore, the alkali metal species of cyanate, chloride and sulfur compounds may be any of these alkali metals, but potassium cyanate as cyanate, an equivalent mixture of potassium chloride and lithium chloride as chloride, and sulfur compound as sulfur compound. Is preferably sodium thiosulfate.
【０００５】これら塩の好ましい配合割合は、シアン酸
カリウム７５〜８５重量部、塩化カリウム５〜１５重量
部、塩化リチウム５〜１５重量部、チオ硫酸ナトリウム
２重量部未満例えば０．５重量部である。The preferred blending ratio of these salts is 75 to 85 parts by weight of potassium cyanate, 5 to 15 parts by weight of potassium chloride, 5 to 15 parts by weight of lithium chloride, and less than 2 parts by weight of sodium thiosulfate, for example, 0.5 parts by weight. is there.
【０００６】シアン酸アルカリは、塩浴中で例えば、 ＫＯＣＮ→２ＫＣＮ＋Ｋ2 ＣＯ3 ＋ＣＯ＋２Ｎ のように反応し、さらに生成したＫ2 ＣＯ3 と、 ２ＫＯＣＮ＋Ｋ2 ＣＯ3 →Ｋ2 Ｏ＋３ＣＯ＋２Ｎ のように反応し、浸炭に必要なＣＯと窒化に必要なＮを
供給する。先に述べたように、シアン酸アルカリ単独ま
たはそれと炭酸アルカリを主成分とする塩浴では比較的
緻密な硬化層が形成され、耐摩耗性にはすぐれるが、耐
かじり性を満足しない。しかしながら塩浴へ適当量の塩
化アルカリおよびチオ硫酸アルカリを加えることによ
り、浸炭および窒化によって高い硬度の緻密な拡散層の
表面に比較的軟かく、かつ粘い多孔質層が形成され、こ
の多孔質層の存在によって耐かじり性が発現することが
わかった。このため本発明の塩浴剤の組成は、１００重
量部あたり、シアン酸アルカリ６０重量部以上を含まな
ければならないが、塩化アルカリを少なくとも１０重量
部、およびチオ硫酸アルカリを多くとも２重量部未満含
まなければならない。塩化アルカリおよびチオ硫酸アル
カリの割合が少な過ぎると耐かじり性の向上に役立つ多
孔層の発達が十分でなく、反対に多過ぎると耐摩耗性の
拡散層の発達が不十分となる。Alkali cyanate reacts in a salt bath, for example, KOCN → 2KCN + K 2 CO 3 + CO + 2N, and further reacts with K 2 CO 3 produced as 2KOCN + K 2 CO 3 → K 2 O + 3CO + 2N, Supply CO required for carburizing and N required for nitriding. As described above, a salt bath containing alkali cyanate alone or a salt bath containing alkali carbonate and alkali carbonate as a main component forms a relatively dense hardened layer and has excellent wear resistance, but does not satisfy galling resistance. However, by adding an appropriate amount of alkali chloride and alkali thiosulfate to the salt bath, a relatively soft and viscous porous layer is formed on the surface of the dense diffusion layer with high hardness by carburizing and nitriding. It has been found that the presence of the layer develops galling resistance. Therefore, the composition of the salt bath of the present invention must contain 60 parts by weight or more of alkali cyanate per 100 parts by weight, but at least 10 parts by weight of alkali chloride and less than 2 parts by weight of alkali thiosulfate. Must be included. If the proportions of alkali chloride and alkali thiosulfate are too small, the porous layer, which helps improve the galling resistance, will not be sufficiently developed, while if too large, the abrasion resistant diffusion layer will be insufficiently developed.
【０００７】本発明は、一般の塩浴窒化処理と同様な操
作によって実施することができる。すなわちＡｌ，Ｃ
ｒ，Ｔｉ，Ｖ，Ｍｎ，Ｓｉなどの窒素と親和性の高い元
素を含む特殊鋼に適用することができる。特に、耐摩耗
性に加え、耐かじり性が要求される熱間または半熱間鍛
造用金型などに適用し、表面に多孔質層を有しない窒化
硬化層を有する金型に比較してその寿命を約２倍に延長
することができた。The present invention can be carried out by an operation similar to a general salt bath nitriding treatment. That is, Al, C
It can be applied to special steels containing elements having a high affinity with nitrogen such as r, Ti, V, Mn and Si. In particular, in addition to wear resistance, it is applied to hot or semi-hot forging dies that require galling resistance, compared with dies having a nitrided hardened layer that does not have a porous layer on its surface. We were able to extend the lifespan by a factor of two.
【０００８】以下に実施例をもって本発明をさらに詳し
く説明するが、本発明はこれら実施例のみに限定されな
い。The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.
【０００９】[0009]
シアン酸カリウム ８０重量部 塩化カリウム １０重量部 塩化リチウム １０重量部 チオ硫酸ナトリウム ０．５重量部 よりなる塩浴剤を溶融し、５７０℃にて試験片（材質Ｄ
Ｈ３２鋼）を５時間または１０時間浸漬し、窒化処理を
行った。Potassium cyanate 80 parts by weight Potassium chloride 10 parts by weight Lithium chloride 10 parts by weight Sodium thiosulfate 0.5 parts by weight A salt bath agent is melted, and a test piece (material D
H32 steel) was immersed for 5 hours or 10 hours for nitriding treatment.
【００１０】顕微鏡写真により、全体で深さ約０．４ｍ
ｍまで窒素および炭素の拡散層が達していることが観察
されたが、表面に窒素、酸素および炭素に富む多孔質層
が観察された。A micrograph shows a total depth of about 0.4 m
It was observed that a diffusion layer of nitrogen and carbon reached up to m, but a porous layer rich in nitrogen, oxygen and carbon was observed on the surface.
【００１１】そこで表面からの深さに沿ってビッカース
硬さ（Ｈｖ）の硬度分布を測定したところ、図１のグラ
フに示す結果を得た。When the hardness distribution of Vickers hardness (Hv) was measured along the depth from the surface, the results shown in the graph of FIG. 1 were obtained.
【００１２】〔耐かじり試験（Ｆａｖｉｌｌｅ試験）〕
窒化処理または無処理ＳＫＤ６１のピンと、無処理ＳＫ
Ｈ９のＶブロック間に２００ｋｇｆの一定荷重をかけ、
ピンを回転させた時のトルクの経時変化を測定した。結
果を図２のグラフに示す。焼入焼戻処理後表面処理をし
ていないピンは時間と共にトルクが上昇し、６０秒経過
後トルクは１００ｋｇｆ・ｃｍをこえ、かじりの状態を
呈した。イオン窒化処理したピンは３０秒経過してトル
ク１００ｋｇｆ・ｃｍまで上昇したが、その後９０〜１
００ｋｇｆ・ｃｍを推移した。本発明方法によって窒化
処理したものは、最高約６０ｋｇｆ・ｃｍまでしかトル
クが上昇せず、５０〜６０ｋｇｆ・ｃｍで安定化した。[Gal Resistance Test (Favil Test)]
Nitrided or untreated SKD61 pins and untreated SK
Apply a constant load of 200 kgf between the V blocks of H9,
The change with time of the torque when the pin was rotated was measured. The results are shown in the graph of FIG. After the quenching and tempering treatment, the torque of the pin not subjected to the surface treatment increased with time, and after 60 seconds, the torque exceeded 100 kgf · cm and exhibited a galling state. The torque of the ion-nitrided pin increased to 100 kgf · cm after 30 seconds, but 90 to 1
It has remained at 00 kgf · cm. The nitriding treatment by the method of the present invention increased the torque only up to about 60 kgf · cm, and was stabilized at 50 to 60 kgf · cm.
【図１】本発明による窒化処理試験片の表面からの深さ
に沿ったビッカース硬さ（Ｈｖ）分布を示すグラフ。FIG. 1 is a graph showing a Vickers hardness (Hv) distribution along the depth from the surface of a nitriding test piece according to the present invention.
【図２】本発明によって処理した試験片の耐かじり性を
無処理試験片およびイオン窒化試験片と比較したグラ
フ。FIG. 2 is a graph comparing the galling resistance of test pieces treated according to the invention with untreated and ion-nitrided test pieces.
Claims (3)
ルカリ金属シアン酸塩を含む溶融塩浴へ浸漬することよ
りなる鉄鋼表面窒化方法において、塩浴として、アルカ
リ金属シアン酸塩６０〜９０重量部、アルカリ金属塩化
物１０〜４０重量部、および少量のアルカリ金属イオウ
化合物を含む塩浴を使用することにより耐摩耗性と耐か
じり性にすぐれた硬化層を得ることを特徴とする鉄鋼製
品表面窒化方法。1. In a steel surface nitriding method comprising immersing a steel product in a molten salt bath containing an alkali metal cyanate at a temperature not higher than a transformation temperature, 60 to 90 parts by weight of an alkali metal cyanate is used as a salt bath. Surface nitriding of steel products characterized by obtaining a hardened layer having excellent wear resistance and galling resistance by using a salt bath containing 10 to 40 parts by weight of an alkali metal chloride and a small amount of an alkali metal sulfur compound. Method.
ムであり、アルカリ金属塩化物が塩化カリウムおよび塩
化リチウムの混合物であり、アルカリ金属イオウ化合物
がチオ硫酸ナトリウムである請求項１の方法。2. The method of claim 1 wherein the alkali metal cyanate is potassium cyanate, the alkali metal chloride is a mixture of potassium chloride and lithium chloride, and the alkali metal sulfur compound is sodium thiosulfate.
部、塩化カリウム５〜１５重量部、塩化リチウム５〜１
５重量部、チオ硫酸ナトリウム１重量部未満を含んでい
る請求項２の方法。3. A salt bath comprising 75 to 85 parts by weight of potassium cyanate, 5 to 15 parts by weight of potassium chloride, and 5 to 1 of lithium chloride.
The method of claim 2 comprising 5 parts by weight and less than 1 part by weight sodium thiosulfate.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP25073992A JPH0673524A (en) | 1992-08-25 | 1992-08-25 | Nitriding method of iron and steel surface |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP25073992A JPH0673524A (en) | 1992-08-25 | 1992-08-25 | Nitriding method of iron and steel surface |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH0673524A true JPH0673524A (en) | 1994-03-15 |
Family
ID=17212324
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP25073992A Pending JPH0673524A (en) | 1992-08-25 | 1992-08-25 | Nitriding method of iron and steel surface |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0673524A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2014510840A (en) * | 2011-03-11 | 2014-05-01 | アシュ．エー．エフ | Molten salt bath and method for nitriding steel machine parts |
| JP2015086409A (en) * | 2013-10-29 | 2015-05-07 | トヨタ自動車株式会社 | Surface treatment method of metal |
| CN106967945A (en) * | 2016-01-14 | 2017-07-21 | 杭州巨星科技股份有限公司 | Rare earth-sulfide for stainless steel urges the QPQ techniques for oozing low temperature QPQ compositions and stainless steel knife altogether |
-
1992
- 1992-08-25 JP JP25073992A patent/JPH0673524A/en active Pending
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2014510840A (en) * | 2011-03-11 | 2014-05-01 | アシュ．エー．エフ | Molten salt bath and method for nitriding steel machine parts |
| JP2015086409A (en) * | 2013-10-29 | 2015-05-07 | トヨタ自動車株式会社 | Surface treatment method of metal |
| CN106967945A (en) * | 2016-01-14 | 2017-07-21 | 杭州巨星科技股份有限公司 | Rare earth-sulfide for stainless steel urges the QPQ techniques for oozing low temperature QPQ compositions and stainless steel knife altogether |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US9260775B2 (en) | Low alloy steel carburization and surface microalloying process | |
| EP0122762B1 (en) | Corrosion resistant steel components and method of manufacture thereof | |
| US3885995A (en) | Process for carburizing high alloy steels | |
| US3303063A (en) | Liquid nitriding process using urea | |
| JPH0210229B2 (en) | ||
| JP6194057B2 (en) | Surface treatment agent for steel and surface treatment method for steel | |
| US4264380A (en) | Nitride casehardening process and the nitrided product thereof | |
| US20070193659A1 (en) | Method for nitriding metal in salt bath and metal manufactured using the same | |
| JPH0125823B2 (en) | ||
| JPH0673524A (en) | Nitriding method of iron and steel surface | |
| US5228929A (en) | Thermochemical treatment of machinery components for improved corrosion resistance | |
| US3535169A (en) | Friction elements especially resistant to wear by abrasion | |
| US4163680A (en) | Process for carbonitriding steel and cast iron articles | |
| JP7397029B2 (en) | Carburizing method for steel parts and method for manufacturing steel parts | |
| KR100862217B1 (en) | Method for manufacturing high corrosion-resistant and high wear- resistant steel materials by 2 step gas nitriding or gas nitrocarburizing | |
| US3892597A (en) | Method of nitriding | |
| Dawes et al. | Reappraisal of nitrocarburizing and nitriding vvhen applied to design and manufacture of non-alloy steel automobile components | |
| US4342605A (en) | Gas soft-nitriding method | |
| US20100055496A1 (en) | Steel having high strength | |
| JP2009108411A (en) | Method for hardening surface of work piece made of stainless steel, and molten salt bath for realizing the method | |
| JPH06184727A (en) | Method for hardening surface of part made of steel | |
| KR100922619B1 (en) | Steel having high strength and methode for manufacturing the same | |
| GB2328953A (en) | A process for hardening high alloy steels | |
| EP0059803B1 (en) | A process for case hardening steel | |
| JPH06184728A (en) | Surface treatment of steel products |