JP2001073112A - Alloy steel for structure - Google Patents
Alloy steel for structureInfo
- Publication number
- JP2001073112A JP2001073112A JP25182399A JP25182399A JP2001073112A JP 2001073112 A JP2001073112 A JP 2001073112A JP 25182399 A JP25182399 A JP 25182399A JP 25182399 A JP25182399 A JP 25182399A JP 2001073112 A JP2001073112 A JP 2001073112A
- Authority
- JP
- Japan
- Prior art keywords
- gaseous
- gas
- nitriding
- alloy steel
- current density
- 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
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- Solid-Phase Diffusion Into Metallic Material Surfaces (AREA)
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、耐摩耗性、耐食性
に優れた構造用合金鋼に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structural alloy steel having excellent wear resistance and corrosion resistance.
【０００２】[0002]
【従来の技術】構造用合金鋼は、各種装置、機械部品な
どの構造用材に用いられており、ロストワックス法等で
製造される。近年、複雑形状の部品などの機械構造用材
の用途において、耐摩耗性に優れ、耐食性が高い鋼の需
要が増加している。耐摩耗性を向上させる手段として、
各種の窒化処理により表面を硬化させることが行われて
いる。しかし、従来の窒化処理、例えばイオン窒化処理
により表面硬化された構造用合金鋼は、実質的な硬化層
として表面近傍に１０μｍから３００μｍ程度の厚さの
窒素原子の拡散層を有するが、該拡散層の上層表面に数
μｍから１５μｍ程度の厚さの硬くて脆い化合物層を有
するため耐食性が大きく低下していた。したがって高い
耐食性を要求される機械部品、構造材の場合は、窒化処
理後に発錆するため、窒化による表面硬化処理が適用で
きず耐摩耗性が不十分であった。2. Description of the Related Art Structural alloy steels are used for structural materials such as various devices and machine parts, and are manufactured by a lost wax method or the like. 2. Description of the Related Art In recent years, demands for steel having excellent wear resistance and high corrosion resistance have increased in applications of materials for machine structures such as parts having complicated shapes. As a means to improve wear resistance,
The surface is hardened by various nitriding treatments. However, a structural alloy steel surface-hardened by a conventional nitriding treatment, for example, an ion nitriding treatment, has a diffusion layer of nitrogen atoms having a thickness of about 10 μm to 300 μm near the surface as a substantially hardened layer. Since a hard and brittle compound layer having a thickness of several μm to about 15 μm was provided on the upper layer surface of the layer, the corrosion resistance was greatly reduced. Therefore, in the case of mechanical parts and structural materials that require high corrosion resistance, rust occurs after nitriding, so that surface hardening treatment by nitriding cannot be applied, and wear resistance is insufficient.
【０００３】[0003]
【発明が解決しようとする課題】本発明は、耐摩耗性、
耐食性に優れた構造用合金鋼を提供することを目的とす
る。SUMMARY OF THE INVENTION The present invention relates to
An object of the present invention is to provide a structural alloy steel having excellent corrosion resistance.
【０００４】[0004]
【課題を解決するための手段】本発明は鋭意研究の結
果、構造用合金鋼部材を３００℃〜６５０℃の温度に維
持して、アンモニアガスを主原料としたガスの存在下
で、該部材の表面に対して０．００１〜２．０ｍＡ／ｃ
ｍ２の電流密度、６００Ｖの印加電圧でのグロー放電を
行うイオン窒化法で表面硬化することにより、耐摩耗
性、耐食性に優れた構造用合金鋼が得られることがわか
った。According to the present invention, as a result of intensive studies, the structural alloy steel member is maintained at a temperature of 300 ° C. to 650 ° C., and the member is formed in the presence of a gas containing ammonia gas as a main raw material. 0.001 to 2.0 mA / c with respect to the surface of
It was found that a structural alloy steel having excellent wear resistance and corrosion resistance was obtained by performing surface hardening by an ion nitriding method in which glow discharge was performed at a current density of m2 and an applied voltage of 600 V.
【０００５】[0005]
【発明の実施の形態】従来、構造用合金鋼を窒化処理す
ると、化合物層を形成させずに窒素原子が拡散した硬化
層だけを形成させるのは困難であると考えられていた。
しかし、本発明によれば化合物層を形成させずに硬化層
だけが形成された構造用合金鋼が得られることが分かっ
た。その理由を以下に述べる。従来の窒化処理ではプラ
ズマの電流密度が高いため、窒素分子イオンの高いエネ
ルギーにより部材表面が強くスパッタリングされるた
め、部材表面の耐食性が低下した化合物層が形成され
る。一方、本発明の場合はアンモニアを主原料とするガ
スの存在下で窒化反応に有用な活性種を発生させるた
め、低電流密度で窒化処理が行える。その結果、窒素分
子イオンが殆ど存在せずスパッタリング効果が非常に小
さくてすむので、耐食性の高いＦｅ３Ｎが分散した窒化
層が形成される。本発明による構造用合金鋼は、表面硬
さ１０００ＨＶ０．１以上、塩水噴霧試験の結果、１０
０時間を経過しても発錆しないため、複雑形状の部品、
機械構造材に使用可能である。DESCRIPTION OF THE PREFERRED EMBODIMENTS It has been considered that it is difficult to form only a hardened layer in which nitrogen atoms are diffused without forming a compound layer when a structural alloy steel is nitrided.
However, according to the present invention, it was found that a structural alloy steel in which only a hardened layer was formed without forming a compound layer was obtained. The reason is described below. In the conventional nitriding treatment, since the current density of the plasma is high, the surface of the member is strongly sputtered by the high energy of the nitrogen molecular ions, so that a compound layer having reduced corrosion resistance on the surface of the member is formed. On the other hand, in the case of the present invention, an active species useful for the nitridation reaction is generated in the presence of a gas containing ammonia as a main raw material. As a result, since there is almost no nitrogen molecular ion and the sputtering effect is very small, a nitride layer in which Fe3N having high corrosion resistance is dispersed is formed. The structural alloy steel according to the present invention has a surface hardness of 1000 HV or more and a salt spray test of 10 or more.
Since it does not rust even after 0 hours, parts with complicated shapes,
It can be used for machine structural materials.
【０００６】本発明において、窒化反応における構造用
合金鋼部材の温度を３００〜６５０℃に維持することが
好ましい。３００℃未満では窒化反応が極めて遅く、６
５０℃を越えると一旦形成された窒化物が分解し、窒化
が起こらないという問題が起こる。加熱手段としては、
電気加熱、ガス加熱などがあるが、電気加熱が使いやす
い。加熱源としては窒化処理を行う真空チャンバー内に
配置するか、その外側に配置して加熱すると自動制御シ
ステムと組み合わせてプログラムされた昇温や温度維持
が容易に出来る。In the present invention, it is preferable to maintain the temperature of the structural alloy steel member in the nitriding reaction at 300 to 650 ° C. If the temperature is lower than 300 ° C., the nitriding reaction is extremely slow.
If the temperature exceeds 50 ° C., the nitride once formed is decomposed, and a problem occurs that nitriding does not occur. As the heating means,
There are electric heating and gas heating, but electric heating is easy to use. When the heating source is disposed in a vacuum chamber for performing the nitriding treatment or is disposed outside the same, heating can be performed in combination with an automatic control system to facilitate programmed temperature rise and temperature maintenance.
【０００７】本発明において、窒化のためのガスとし
て、アンモニアガスと水素ガスを用いるのは、アンモニ
アガスはプラズマ化電流密度が低い範囲においてアンモ
ニアラジカルとして安定であるためである。なお、放電
によるアンモニアガスのラジカル化を安定に行うための
補助ガスとして水素ガスを、プラズマを安定させるため
にＡｒガス等の不活性ガスを添加することもできる。In the present invention, the reason that ammonia gas and hydrogen gas are used as the gas for nitriding is that ammonia gas is stable as ammonia radical in a range where the plasma current density is low. In addition, a hydrogen gas can be added as an auxiliary gas for stably performing the radicalization of ammonia gas by electric discharge, and an inert gas such as an Ar gas can be added for stabilizing plasma.
【０００８】構造用合金部材の表面に、かけるプラズマ
化電流を０．００１〜２．０ｍＡ／ｃｍ２とするのは、
この電流密度の範囲においてのみ、余計な熱を殆ど発生
させることがなくグロー放電でアンモニアガスをプラズ
マ化することができるからである。電流密度が０．００
１ｍＡ／ｃｍ２未満ではプラズマ化を充分起こすことが
できず、２．０ｍＡ／ｃｍ２を越えると、構造用合金部
材の表面で局部的な過熱状態を生じたり、スリット内や
溝内部に有効な窒化処理が行われないので良くない。The reason why the plasma current applied to the surface of the structural alloy member is set to 0.001 to 2.0 mA / cm 2 is as follows.
This is because ammonia gas can be turned into plasma by glow discharge with almost no unnecessary heat generated only in this current density range. Current density is 0.00
If it is less than 1 mA / cm 2, it cannot sufficiently generate plasma, and if it exceeds 2.0 mA / cm 2, a local overheating state occurs on the surface of the structural alloy member, or an effective nitriding treatment in the slit or groove. Is not good.
【０００９】本発明ではプラズマ化のためのグロー放電
を発生する放電は直流放電でも高周波放電でも良い。本
発明で窒化を行う真空チャンバーには基本的にグロー放
電用電極、プラズマ化ガス用配管とを備え、真空ポンプ
に接続された排気管を備えたものであればどのような形
式のものでもよい。In the present invention, the discharge for generating the glow discharge for generating plasma may be a DC discharge or a high-frequency discharge. The vacuum chamber for performing nitridation according to the present invention basically includes a glow discharge electrode and a plasma gas pipe, and may be of any type as long as it has an exhaust pipe connected to a vacuum pump. .
【００１０】[0010]
【実施例】図１は実施例に用いたイオン窒化装置を示す
概略図で、１は真空チャンバー、２は加熱ヒーター、３
は直流電極、４は構造用合金鋼、５は直流電源、６は排
気管、７は真空ポンプ、８はバルブ、９はノズル、１０
は導入管、１１はバルブ、１２はマスフローコントロー
ラー、１３は窓、１４はレンズ、１５は光ファイバー、
１６は分光器である。すなわち、真空チャンバー１に
は、外周壁に加熱ヒーター２が埋設され、内部に直流電
源５に接続された直流電極３が配置され、下部に排気管
６が圧力調整用バルブ８を介して真空ポンプ７に接続さ
れている。ＮＨ３ガス、Ｈ２ガス、Ａｒガス等の原料ガ
スはそれぞれマスフローコントローラー１２、バルブ１
１、導入管１０を介してノズル９から真空チャンバー１
内に供給される。窓１３は金属部材４の表面近傍のプラ
ズマ発光を観測するために設けられたもので、石英ガラ
ス製でその外側には同じく石英ガラス製のレンズ１４が
設置され、このレンズの焦点位置に石英ガラス製の光フ
ァイバー１５の端面が配置され、この光ファイバーの一
方は分光器１６の入光スリット部に接続されている。構
造用合金鋼４は直流電極３の上面に設置される。 （実施例１）ＳＣＭ４３５の試料を、イオン窒化炉に設
置し、保持温度が５００℃、保持時間が３時間、電流密
度が０．５ｍＡ／ｃｍ２の条件で窒化を行った。 （実施例２）ＳＣＭ４３５の試料を、イオン窒化炉に設
置し、保持温度が４００℃、保持時間が１２時間、電流
密度が０．５ｍＡ／ｃｍ２の条件で窒化を行った。 （実施例３）ＳＣＭ４３５の試料を、イオン窒化炉に設
置し、保持温度が６００℃、保持時間が１．５時間、電
流密度が０．５ｍＡ／ｃｍ２の条件で窒化を行った。 （比較例１）ＳＣＭ４３５の試料に従来のイオン窒化処
理を行った。上記試料について表面硬さＨＶ０．１、お
よびＪＩＳ Ｚ ２３７１ 塩水噴霧試験の結果を表１
に示す。FIG. 1 is a schematic view showing an ion nitriding apparatus used in an embodiment, wherein 1 is a vacuum chamber, 2 is a heater,
Is a DC electrode, 4 is a structural alloy steel, 5 is a DC power supply, 6 is an exhaust pipe, 7 is a vacuum pump, 8 is a valve, 9 is a nozzle, 10
Is an introduction pipe, 11 is a valve, 12 is a mass flow controller, 13 is a window, 14 is a lens, 15 is an optical fiber,
Reference numeral 16 denotes a spectroscope. That is, in the vacuum chamber 1, a heater 2 is buried in an outer peripheral wall, a DC electrode 3 connected to a DC power supply 5 is disposed inside, and an exhaust pipe 6 is provided in a lower part through a pressure adjusting valve 8 through a vacuum pump. 7 is connected. Source gases such as NH3 gas, H2 gas and Ar gas are supplied to the mass flow controller 12 and the valve 1 respectively.
1. A vacuum chamber 1 from a nozzle 9 through an introduction pipe 10
Supplied within. The window 13 is provided for observing plasma emission near the surface of the metal member 4, and is made of quartz glass. A lens 14 made of quartz glass is installed outside the quartz glass, and quartz glass is placed at the focal position of the lens. One end of this optical fiber is connected to the light entrance slit of the spectroscope 16. The structural alloy steel 4 is installed on the upper surface of the DC electrode 3. (Example 1) A sample of SCM435 was placed in an ion nitriding furnace, and nitriding was performed at a holding temperature of 500 ° C, a holding time of 3 hours, and a current density of 0.5 mA / cm 2. (Example 2) A sample of SCM435 was placed in an ion nitriding furnace, and nitriding was performed under the conditions of a holding temperature of 400 ° C, a holding time of 12 hours, and a current density of 0.5 mA / cm 2. Example 3 A sample of SCM435 was placed in an ion nitriding furnace, and nitriding was performed under the conditions of a holding temperature of 600 ° C., a holding time of 1.5 hours, and a current density of 0.5 mA / cm 2. Comparative Example 1 A sample of SCM435 was subjected to a conventional ion nitriding treatment. Table 1 shows the results of surface hardness HV0.1 and JIS Z2371 salt spray test for the above samples.
Shown in
【００１１】 （表１） 表面硬さ ＨＶ０．１ 塩水噴霧試験（１００時間後） 実施例 １ １０００ 発錆無し 実施例 ２ １１００ 発錆無し 実施例 ３ １２００ 発錆無し 比較例 １ １２００ 発錆(Table 1) Surface hardness HV0.1 Salt spray test (after 100 hours) Example 1 1000 No rusting Example 2 1100 No rusting Example 3 1200 No rusting Comparative example 1 1200 Rusting
【００１２】[0012]
【発明の効果】本発明によれば、耐摩耗性に優れ、耐食
性が高い表面硬化された構造用合金鋼を提供することが
出来る。According to the present invention, a surface-hardened structural alloy steel having excellent wear resistance and high corrosion resistance can be provided.
【図１】この発明を実施するためのイオン窒化装置の全
体構成を示す概略図である。FIG. 1 is a schematic diagram showing an overall configuration of an ion nitriding apparatus for carrying out the present invention.
１ 真空チャンバー ２ 加熱ヒーター ３ 直流電極 ４ 金属部材 ５ 直流電源 ６ 排気管 ７ 真空ポンプ ８ バルブ ９ ノズル １０ 導入管 １１ バルブ １２ マスフローコントローラー １３ 窓 １４ レンズ １５ 光ファイバー １６ 分光器 DESCRIPTION OF SYMBOLS 1 Vacuum chamber 2 Heater 3 DC electrode 4 Metal member 5 DC power supply 6 Exhaust pipe 7 Vacuum pump 8 Valve 9 Nozzle 10 Introducing pipe 11 Valve 12 Mass flow controller 13 Window 14 Lens 15 Optical fiber 16 Spectroscope
Claims (2)
硬さが１０００ＨＶ０．１以上であり、ＪＩＳ Ｚ ２
３７１ 塩水噴霧試験の結果、１００時間を経過しても
発錆しない構造用合金鋼。1. Surface hardened by an ion nitriding method, the surface hardness is 1000 HV0.1 or more, and JIS Z 2
371 Structural alloy steel that does not rust even after 100 hours as a result of the salt spray test.
３００℃〜６５０℃の温度に維持して、アンモニアガス
を主原料としたガスの存在下で、該部材の表面に対して
０．００１〜２．０ｍＡ／ｃｍ２の電流密度、６００ｖ
の印加電圧でのグロー放電を行う方法である請求項１に
記載の構造用合金鋼。2. An ion nitriding method comprising: maintaining a structural alloy steel member at a temperature of 300 ° C. to 650 ° C .; 001-2.0 mA / cm 2 current density, 600 v
The structural alloy steel according to claim 1, which is a method for performing glow discharge at an applied voltage.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP25182399A JP2001073112A (en) | 1999-09-06 | 1999-09-06 | Alloy steel for structure |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP25182399A JP2001073112A (en) | 1999-09-06 | 1999-09-06 | Alloy steel for structure |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JP2001073112A true JP2001073112A (en) | 2001-03-21 |
Family
ID=17228459
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP25182399A Pending JP2001073112A (en) | 1999-09-06 | 1999-09-06 | Alloy steel for structure |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2001073112A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111843407A (en) * | 2020-07-29 | 2020-10-30 | 扬州大学 | Nitriding device and nitriding processing method for 304 stainless steel spiral reamer |
-
1999
- 1999-09-06 JP JP25182399A patent/JP2001073112A/en active Pending
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111843407A (en) * | 2020-07-29 | 2020-10-30 | 扬州大学 | Nitriding device and nitriding processing method for 304 stainless steel spiral reamer |
| CN111843407B (en) * | 2020-07-29 | 2021-11-02 | 扬州大学 | Nitriding device and nitriding processing method for 304 stainless steel spiral reamer |
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