JP2003253422A - Method for prolonging service life of tool such as mandrel and forming die, and tool of prolonged service life such as mandrel and forming die - Google Patents
Method for prolonging service life of tool such as mandrel and forming die, and tool of prolonged service life such as mandrel and forming dieInfo
- Publication number
- JP2003253422A JP2003253422A JP2002056853A JP2002056853A JP2003253422A JP 2003253422 A JP2003253422 A JP 2003253422A JP 2002056853 A JP2002056853 A JP 2002056853A JP 2002056853 A JP2002056853 A JP 2002056853A JP 2003253422 A JP2003253422 A JP 2003253422A
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- Japan
- Prior art keywords
- mandrel
- tool
- die
- life
- nitride layer
- 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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- Mounting, Exchange, And Manufacturing Of Dies (AREA)
- Forging (AREA)
- Solid-Phase Diffusion Into Metallic Material Surfaces (AREA)
- Physical Vapour Deposition (AREA)
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、冷間ローリング加
工に使用するマンドレルその他の金型などあるいは工具
の寿命延長技術に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique for extending the life of a tool such as a mandrel used for cold rolling, or a tool or the like.
【０００２】[0002]
【従来の技術】鋼炭素クロム鋼などのリング状粗形材か
らなるワークを冷間、温間、熱間で成形するローリング
加工は、マンドレルをリング状粗形材のリング孔に挿通
し、リング状粗形材の内周面に当接するマンドレルとリ
ング状粗形材の外周面に当接する成形ロール間でリング
状粗形材を回転転造しながら拡径するものである。特
に、自動車部品のように、コスト削減を図るものでは、
冷間ローリング加工によりニアネットシェープ化して後
工程の旋削加工などをできるだけ省工程して成形品が製
造される。ところで、このような冷間ローリング加工で
は、成形荷重が比較的大きく、また、これらの成形ロー
ルやマンドレルなどとリング状粗形材間に生じる摩擦力
が大きいことから、成形ロールやマンドレルに大きな負
荷がかかる。特にリング状成形品の内面形状を決定する
工具であるマンドレルは成形ロールに比して外径が細い
のでより大きな負荷がかかることとなり、マンドレルの
摩耗とヘアクラックが早期に発生して早期破損につなが
り、工具寿命が短く、コストアップにつながる問題があ
る。2. Description of the Related Art A rolling process for cold, warm, or hot forming of a work made of a ring-shaped rough material such as steel carbon chrome steel is performed by inserting a mandrel into a ring hole of the ring-shaped rough material. The diameter of the ring-shaped rough material is expanded while being rotationally rolled between the mandrel that contacts the inner peripheral surface of the ring-shaped rough material and the molding roll that contacts the outer peripheral surface of the ring-shaped rough material. Especially in the case of cost reduction such as automobile parts,
Near net shape is formed by cold rolling, and the molded product is manufactured by reducing the turning process in the subsequent process as much as possible. By the way, in such cold rolling, the forming load is relatively large, and the frictional force generated between these forming rolls and mandrels and the ring-shaped rough material is large, so that a large load is applied to the forming rolls and mandrels. Takes. In particular, the mandrel, which is a tool that determines the inner surface shape of the ring-shaped molded product, has a smaller outer diameter than the molding roll, so a larger load is applied, and wear and hair cracks on the mandrel occur early and cause early damage. However, there is a problem that the connection is short, the tool life is short, and the cost is increased.
【０００３】このような成形ロールやマンドレルの早期
破損の原因は、リング状粗形材との接触による疵や摩耗
の発生と繰り返し応力の増大による疲労強度不足と考え
られる。The cause of such early breakage of the forming roll and mandrel is considered to be the occurrence of flaws and wear due to contact with the ring-shaped rough material, and insufficient fatigue strength due to increase in repetitive stress.
【０００４】そこで、このような問題を解決するものと
して、例えば、マンドレルの疲労強度および硬度を向上
させるため、粉末ハイスによるマンドレルが考えられる
が、粉末ハイスは疲労強度および硬度の向上には寄与す
るが、その一方で靱性不足となり、一旦小さな疵が発生
すると割れ易くなる問題がある。そこでマンドレルの表
面に炭化チタンや窒化チタンなどのコーティング層を形
成する手段もあるが、そのためにはコーティング層の剥
離を防止するために下地処理の前工程を必要とし、処理
工程数が増えてコスト高となる問題がある。Therefore, as a solution to such a problem, for example, a mandrel made of powdered high speed steel is considered in order to improve the fatigue strength and hardness of the mandrel. The powder high speed steel contributes to the improvement of fatigue strength and hardness. However, on the other hand, there is a problem that the toughness becomes insufficient, and once a small flaw is generated, it is easily cracked. Therefore, there is also a means to form a coating layer of titanium carbide, titanium nitride, etc. on the surface of the mandrel, but for that purpose a pretreatment of the base treatment is required to prevent peeling of the coating layer, and the number of treatment steps increases and the cost is increased. There is a problem of becoming high.
【０００５】[0005]
【発明が解決しようとする課題】本発明が解決しようと
する課題は、上記の従来の手段の問題点を解決するもの
で、冷間ローリング加工用のマンドレルや成形金型など
の種々工具、すなわち、ダイ、パンチ、マンドレル、成
形ロールなどのワークと当接する成形部位あるいは作用
部位の耐摩耗性、耐熱性および耐疲労性などの向上を目
的として、これらの冷間ローリング加工用のマンドレル
や成形金型などあるいは種々の工具の鋼表面を改質処理
することにより、高寿命とした冷間ローリング加工用の
マンドレルや成形金型などあるいは種々の工具を提供す
ることである。SUMMARY OF THE INVENTION The problem to be solved by the present invention is to solve the problems of the above-mentioned conventional means, that is, various tools such as a mandrel for cold rolling and a molding die, that is, , Die, punches, mandrels, molding rolls, etc., for the purpose of improving wear resistance, heat resistance and fatigue resistance of the molding part or working part that comes into contact with the work, cold rolling mandrels and molding dies. It is an object of the present invention to provide a mandrel for cold rolling and a molding die which have a long life by modifying the steel surface of a mold or various tools and various tools.
【０００６】[0006]
【課題を解決するための手段】上記の課題を解決するた
めの本発明の手段は、請求項１の発明では、マンドレル
や成形金型などの工具の成形部位あるいは作用部位の鋼
材表面を窒化処理した後、ショットピーニング加工する
ことを特徴とするマンドレルあるいは金型などの工具の
高寿命化方法である。Means for Solving the Problems The means of the present invention for solving the above-mentioned problems is, in the invention of claim 1, nitriding a steel material surface of a forming portion or an operating portion of a tool such as a mandrel or a forming die. After that, it is a method of extending the life of a tool such as a mandrel or a die, which is characterized by performing shot peening.
【０００７】請求項２の発明では、マンドレルや成形金
型などの工具の成形部位あるいは作用部位の鋼材表面を
窒化処理した後、ＰＶＤによりＴｉＮ硬質被膜形成処理
することを特徴とするマンドレルあるいは金型などの工
具の高寿命化方法である。According to the second aspect of the present invention, the mandrel or the mold is characterized in that the steel material surface of the molding part or the working part of the tool such as the mandrel or the molding die is subjected to the nitriding treatment, and then the TiN hard coating is formed by PVD. It is a method of extending the life of tools such as.
【０００８】請求項３の発明では、マンドレルや成形金
型などの工具の成形部位あるいは作用部位の鋼材表面を
窒化処理した後、ＰＶＤによりＴｉＮ硬質被膜形成処理
し、さらにショットピーニング加工することを特徴とす
るマンドレルあるいは金型などの工具の高寿命化方法で
ある。According to the third aspect of the present invention, after nitriding the surface of the steel material at the forming portion or acting portion of a tool such as a mandrel or a forming die, a TiN hard coating is formed by PVD and then shot peening is performed. It is a method for extending the life of tools such as mandrels or dies.
【０００９】請求項４の発明では、窒化処理はプラズマ
ＣＶＤによる窒化処理であることを特徴とする請求項１
〜３のいずれか１項の手段のマンドレルあるいは金型な
どの工具の高寿命化方法である。In the invention of claim 4, the nitriding treatment is a nitriding treatment by plasma CVD.
3 is a method for extending the service life of a tool such as a mandrel or a mold according to any one of items 1 to 3.
【００１０】請求項５の発明では、マンドレルや成形金
型などの工具の鋼材表面に窒化層が形成され、かつショ
ットピーニング加工されていることを特徴とする高寿命
化されたマンドレルあるいは金型などの工具である。In a fifth aspect of the present invention, a mandrel or a mold having a long life is characterized in that a nitride layer is formed on the steel material surface of a tool such as a mandrel or a molding die and is shot peened. It is a tool of.
【００１１】請求項６の発明では、マンドレルや成形金
型などの工具の鋼材表面に窒化層およびＰＶＤによるＴ
ｉＮ硬質被膜層が形成されていることを特徴とする高寿
命化されたマンドレルあるいは金型などの工具である。According to the invention of claim 6, a nitride layer and PVD-based T are formed on the surface of a steel material of a tool such as a mandrel or a molding die.
A tool such as a mandrel or a die having a long life, which is characterized in that an iN hard coating layer is formed.
【００１２】請求項７の発明では、マンドレルや成形金
型などの工具の鋼材表面に窒化層およびＰＶＤによるＴ
ｉＮ硬質被膜層が形成され、かつショットピーニング加
工されていることを特徴とする高寿命化されたマンドレ
ルあるいは金型などの工具である。According to the invention of claim 7, a nitride layer and PVD-based T are formed on the surface of a steel material of a tool such as a mandrel or a molding die.
A tool such as a mandrel or a mold having a long life, which is characterized in that an iN hard coating layer is formed and shot peening is performed.
【００１３】請求項８の発明では、窒化層はプラズマＣ
ＶＤによる窒化層であることを特徴とする請求項５〜７
のいずれか１項の手段の高寿命化されたマンドレルある
いは金型などの工具である。In the invention of claim 8, the nitride layer is plasma C
A nitrided layer formed by VD, which is characterized in that
It is a tool such as a mandrel or a mold, which has a long service life according to any one of the above items.
【００１４】[0014]
【発明の実施の形態】本発明のマンドレルや成形金型な
どの工具は、粗形材に接触する成形部位の鋼材表面に窒
化層、特にプラズマＣＶＤによる窒化層、またはＰＶＤ
によるＴｉＮ硬質被膜層が形成され、若しくは、窒化
層、特にプラズマＣＶＤによる窒化層およびＰＶＤによ
るＴｉＮ硬質被膜層の複合層が形成されており、さらに
必要によりショットピーニング加工されており、これら
の窒化層、特にプラズマＣＶＤによる窒化層やＴｉＮ硬
質被膜層により表面硬度が向上し、さらにショットピー
ニングによりＡ３変態点以上の温度域での急熱、急冷が
瞬時に繰り返され焼入れ効果と加工硬化による加工強化
が行われている。さらに、ショットピーニングしたもの
は、工具表面に微細な断面円弧状をなす無数の凹部から
なる油溜まりを形成することで潤滑効果を向上して摩耗
防止をしている。BEST MODE FOR CARRYING OUT THE INVENTION A tool such as a mandrel or a molding die according to the present invention has a nitride layer, particularly a plasma CVD nitride layer, or PVD on a surface of a steel material at a molding portion which comes into contact with a rough material.
A TiN hard coating layer is formed, or a composite layer of a nitride layer, particularly a nitride layer formed by plasma CVD and a TiN hard coating layer formed by PVD is formed, and further shot peened, if necessary. In particular, the surface hardness is improved by the nitride layer and the TiN hard coating layer formed by plasma CVD, and the rapid peening and quenching in the temperature range above the A3 transformation point are instantaneously repeated by shot peening. Has been done. Further, in the shot peened one, an oil sump consisting of innumerable recesses having a fine arc shape in cross section is formed on the tool surface to improve the lubrication effect and prevent wear.
【００１５】本発明におけるマンドレルや成形金型など
の工具の鋼材は、特に限定されるものではないが、ダイ
ス用鋼、特に靱性の高いＳＫＤ１１改良鋼やマトリック
スハイスなどが好ましい。本発明では窒化層の形成によ
り表面硬化させているので、Ａｌ、Ｃｒ、Ｍｏ、Ｔｉや
Ｖなどから選ばれる少なくとも１種の窒化促進元素が添
加された鋼部材とする。The steel material for tools such as the mandrel and the molding die in the present invention is not particularly limited, but steel for dies, particularly SKD11 improved steel having high toughness, matrix high speed steel and the like are preferable. In the present invention, since the surface is hardened by forming the nitride layer, the steel member contains at least one nitriding promoting element selected from Al, Cr, Mo, Ti and V.
【００１６】これらの窒化されるマンドレルや成形金型
などの工具の母材鋼材の硬さは低過ぎると耐摩耗性が低
下し、ワークの粗形材との接触による疵が発生し易く、
一方高過ぎると靱性不足により脆くなるので、５０〜６
７ＨＲＣとする。If the hardness of the base material steel material of the tool such as the mandrel or the molding die to be nitrided is too low, the wear resistance is deteriorated and a flaw is apt to occur due to the contact with the rough shape material of the work,
On the other hand, if it is too high, it becomes brittle due to lack of toughness, so 50 to 6
7HRC.
【００１７】ワークと当接するマンドレルや成形金型な
どの工具表面に形成の窒化層中には、一般に白層部が存
在するが、この白層部は、他の部分よりも硬くて脆い窒
化化合物である。そこで窒化層中に白層部が存在する
と、この白層部から亀裂が発生し易く、亀裂伝播を抑制
するために不利となる。そこで、窒化層の最表面から２
００μｍ深さまでの範囲において、白層部の占める面積
率を５．０％以下、好ましくは３．０％以下とする。窒
化層における白層部を減少しまたは無くすには、窒化処
理におけるガス混合比や加熱温度や加熱時間を適宜調整
することで行える。A white layer portion is generally present in the nitride layer formed on the surface of a tool such as a mandrel or a molding die that comes into contact with a work. This white layer portion is harder and more brittle than other portions. Is. Therefore, if a white layer portion is present in the nitrided layer, a crack is likely to occur from this white layer portion, which is disadvantageous because crack propagation is suppressed. Therefore, 2 from the outermost surface of the nitride layer
In the range up to the depth of 00 μm, the area ratio occupied by the white layer portion is 5.0% or less, preferably 3.0% or less. The white layer portion in the nitriding layer can be reduced or eliminated by appropriately adjusting the gas mixing ratio, the heating temperature and the heating time in the nitriding treatment.
【００１８】窒化層の深さは最表面から１０〜１７０μ
ｍとし、好ましくは２０〜１２０μｍとし、最も好まし
くは５０〜１００μｍとする。窒化層の深さが浅過ぎる
と、処理時のバラツキにより窒化層の製造が困難とな
り、一方、窒化層は工具母材と比して亀裂伝播速度が速
いことから、窒化層に一旦亀裂が発生すると窒化層の深
さ方向の全体に亀裂が伝播する。このため窒化層が深過
ぎるとき窒化層中に一旦亀裂が発生すると、より大きな
亀裂に発展してしまうことになる。そこで、窒化層の深
さは１７０μｍ以下とする。The depth of the nitride layer is 10 to 170 μm from the outermost surface.
m, preferably 20 to 120 μm, and most preferably 50 to 100 μm. If the depth of the nitrided layer is too shallow, it is difficult to manufacture the nitrided layer due to variations during processing.On the other hand, the nitrided layer has a higher crack propagation rate than the tool base material, so cracks occur once in the nitrided layer. Then, cracks propagate throughout the depth of the nitride layer. For this reason, if a crack is generated in the nitride layer when the nitride layer is too deep, it will develop into a larger crack. Therefore, the depth of the nitride layer is set to 170 μm or less.
【００１９】マンドレルや成形金型などの工具表面への
窒化層の形成方法は種々あり、ＮＨ 3ガスを用いる通常
の窒化層の形成方法、Ｎ2およびＮＨ3ガスイオン窒化処
理方法やシアン基浴を用いる塩浴窒化処理方法があり、
特にプラズマＣＶＤ法による窒化層の形成方法としては
ＮＨ3ガスおよびＨ2ガスをプラズマ中で分子あるいは分
子ラジカル種として熱せられた被処理工具表面に付着す
る窒化処理方法による。For tool surfaces such as mandrels and molding dies
There are various methods for forming the nitride layer, and NH 3Usually with gas
Of forming nitrided layer of N2And NH3Gas ion nitriding process
There is a treatment method and a salt bath nitriding method using a cyan-based bath,
Particularly as a method for forming a nitride layer by the plasma CVD method,
NH3Gas and H2Gas or molecules in the plasma
Adhere to the surface of the tool to be heated which is heated as a child radical species
It depends on the nitriding method.
【００２０】上記した窒化層における白層部を減少しま
たは無くすために、例えば、ＮＨ3ガスを用いる通常の
窒化処理の場合は処理温度を４００〜５００℃とし、処
理時間を１〜５時間とする。Ｎ2およびＮＨ3ガスイオン
窒化処理方法の場合は処理温度４００〜５００℃、処理
時間１〜５時間とする。特にプラズマＣＶＤによる場合
は、処理温度４００〜５００℃、処理時間２〜１０時間
とする。In order to reduce or eliminate the white layer portion in the above-mentioned nitrided layer, for example, in the case of normal nitriding treatment using NH 3 gas, the treatment temperature is 400 to 500 ° C. and the treatment time is 1 to 5 hours. To do. In the case of the N 2 and NH 3 gas ion nitriding method, the processing temperature is 400 to 500 ° C. and the processing time is 1 to 5 hours. Particularly in the case of plasma CVD, the processing temperature is 400 to 500 ° C. and the processing time is 2 to 10 hours.
【００２１】さらにＰＶＤによるＴｉＮ硬質被膜形成処
理は、真空中で電子ビームやレーザーなどによりＴｉを
加熱蒸発させてマンドレルや成形金型などの工具表面へ
析出させ、さらにＮ2ガスなどのイオンビームを照射し
てＴｉＮの硬質被膜を生成するものであり、処理温度は
３００〜３７０℃で膜厚は約３μｍに形成する。Further, in the TiN hard film forming treatment by PVD, Ti is heated and evaporated in a vacuum by an electron beam or a laser to deposit on a tool surface such as a mandrel or a molding die, and further an ion beam such as N 2 gas is applied. Irradiation produces a hard film of TiN. The processing temperature is 300 to 370 ° C. and the film thickness is about 3 μm.
【００２２】以上の窒化層、特にプラズマＣＶＤによる
窒化層に、ＰＶＤによるＴｉＮ硬質被膜を複合して形成
することで表面近傍の硬さは約２０００〜２５００ＨＶ
とすることができ、疲労強度は、これらの複合による重
畳効果により高められ、亀裂の発生および伝播が抑制さ
れる。By forming a composite TiN hard coating by PVD on the above-mentioned nitride layer, particularly the nitride layer by plasma CVD, the hardness in the vicinity of the surface is about 2000-2500 HV.
The fatigue strength is increased by the superposition effect of these composites, and the generation and propagation of cracks are suppressed.
【００２３】本発明の手段は、上記の窒化層、特にプラ
ズマＣＶＤによる窒化層や、ＰＶＤによるＴｉＮ硬質被
膜、あるいはこれらの複合層を形成し、さらにこれらの
層をショットピーニングする。このショットピーニング
の条件は、ショット粒径を４０〜２００μｍとし、ショ
ット粒の硬度を被ショット品の硬度と同等以上とするも
ので５０〜６７ＨＲＣとする。さらにショットの噴射速
度は１００ｍ／ｓ以上とする。ショット粒径が４０μｍ
より小さいと、ショットによる硬化層の厚さが不足し、
２００μｍを超えると表面層の剥離や面粗度の悪化を招
くこととなる。ショットの噴射速度は１００ｍ／ｓ未満
では焼入れ効果や硬化効果が十分に得られず小さい。The means of the present invention forms the above-mentioned nitrided layer, particularly a nitrided layer formed by plasma CVD, a TiN hard coating formed by PVD, or a composite layer thereof, and further shot peening these layers. The conditions for this shot peening are such that the shot grain size is 40 to 200 μm, the hardness of the shot grains is equal to or higher than the hardness of the shot product, and is 50 to 67 HRC. Further, the shot injection speed is set to 100 m / s or more. Shot particle size is 40μm
If it is smaller, the thickness of the hardened layer due to shots will be insufficient,
If it exceeds 200 μm, peeling of the surface layer and deterioration of surface roughness will be caused. If the shot injection speed is less than 100 m / s, the quenching effect and the hardening effect cannot be sufficiently obtained, and the shot speed is small.
【００２４】[0024]
【実施例】以下に、実施例として実験例を示す。表１に
本実施例で使用する改良ＳＫＤ１１鋼の供試材のＦｅに
含有される化学成分を示す。EXAMPLES Below, experimental examples will be shown as examples. Table 1 shows the chemical composition contained in Fe of the test material of the improved SKD11 steel used in this example.
【００２５】[0025]
【表１】 [Table 1]
【００２６】上記供試材を１３０３Ｋで１．８ｋｓ保持
後、空冷により焼入れし、焼戻しを７９３Ｋで３．６ｋ
ｓ保持後空冷を２回繰り返し行った。この状態の裸材、
さらにプラズマＣＶＤによる窒化処理による窒化材、Ｐ
ＶＤによりＴｉＮ硬質被膜形成処理した表面硬質処理材
（ＰＶＤ材）、およびプラズマＣＶＤによる窒化処理と
ＰＶＤによりＴｉＮ硬質被膜形成処理による複合材につ
いての処理条件を表２に示す。さらに図２に各処理材の
断面硬さ分布を示す。窒化硬化深さは約５０μｍであ
り、表面近傍の硬さは約１０００ＨＶである。ＴｉＮ硬
質被膜硬さは約２０００ないし２５００ＨＶである。After holding the above test material at 1303 K for 1.8 ks, it is quenched by air cooling and tempered at 793 K at 3.6 k.
After holding s, air cooling was repeated twice. Bare material in this state,
Further, a nitriding material by the nitriding treatment by plasma CVD, P
Table 2 shows the processing conditions for the surface hard treated material (PVD material) subjected to the TiN hard coating formation treatment by VD and the composite material subjected to the nitriding treatment by plasma CVD and the TiN hard coating formation treatment by PVD. Further, FIG. 2 shows the cross-sectional hardness distribution of each treated material. The nitriding hardening depth is about 50 μm, and the hardness near the surface is about 1000 HV. The TiN hard coating hardness is about 2000 to 2500 HV.
【００２７】[0027]
【表２】 [Table 2]
【００２８】表２に示す各処理材を小野式回転曲げ疲労
試験機を用いて常温にて疲労試験を実施した。その後Ｓ
ＥＭを用いて破面観察を行った。図１に各種表面処理材
の応力（Ｓ）−繰り返し数（Ｎ）のＳ−Ｎ曲線を示す。
この図１から判るように、低サイクル側において、窒化
材の疲労強度は大幅に向上した。ＰＶＤ材の疲労強度は
裸材よりも若干高くなったが、複合材の疲労強度は１０
4よりも低サイクル側において裸材よりも低くなった。
しかし、高サイクル側では、これらの処理剤の疲労強度
は裸材よりも高く、複合材の疲労強度が最も高かった。Each treated material shown in Table 2 was subjected to a fatigue test at room temperature using an Ono type rotary bending fatigue tester. Then S
The fracture surface was observed using EM. FIG. 1 shows an SN curve of stress (S) -repetition number (N) of various surface-treated materials.
As can be seen from FIG. 1, the fatigue strength of the nitride material was significantly improved on the low cycle side. The fatigue strength of the PVD material was slightly higher than that of the bare material, but the fatigue strength of the composite material was 10
It became lower than the bare material on the cycle side lower than 4 .
However, on the high cycle side, the fatigue strength of these treatment agents was higher than that of the bare material, and the fatigue strength of the composite material was the highest.
【００２９】図３にσa＝１６００ＭＰａ、Ｎf＝９．３
×１０3で破断したプラズマＣＶＤによる窒化材の疲労
破面の一例を示す。破壊起点は炭化物の割れであり、フ
ィッシュアイを呈していた。裸材と比べてこの窒化材の
破壊起点はより内部に移行しており、疲労強度の向上は
圧縮残留応力により表面亀裂発生が抑制されたことによ
ると考えられる。In FIG. 3, σ a = 1600 MPa and N f = 9.3.
An example of the fatigue fracture surface of the nitride material by plasma CVD fractured at × 10 3 is shown. The fracture starting point was a crack of carbide, which was fisheye. Compared with the bare material, the fracture starting point of this nitride material has moved to the inside, and it is considered that the improvement in fatigue strength is due to the suppression of surface crack generation due to compressive residual stress.
【００３０】図４に高サイクル側におけるb＝１１９０
ＭＰａ、Ｎf＝８．３６×１０4で破断したＰＶＤ材の疲
労破面の一例を示す。明瞭な破壊起点は認められなかっ
た。破断起点位置は裸材と顕著な違いは無いが、フィッ
シュアイ破壊した場合、内部亀裂はＴｉＮコーティング
膜で停留している。ＴｉＮコーティング膜は内部から表
面へ進展する亀裂伝播の抑制に硬化があると考えられ、
従って複合材でも同様の硬化がある。In FIG. 4, b = 1190 on the high cycle side.
An example of a fatigue fracture surface of a PVD material fractured at MPa and N f = 8.36 × 10 4 is shown. No clear starting point of failure was observed. Although the position of the starting point of breakage is not significantly different from that of the bare material, when the fish eye breaks, the internal crack remains at the TiN coating film. It is considered that the TiN coating film has hardening to suppress crack propagation that propagates from the inside to the surface.
Therefore, there is a similar cure in composites.
【００３１】次いで、冷間ローリング加工用のマンドレ
ルのプラズマＣＶＤによる窒化材にショット粒径５０μ
ｍ、ショット粒硬度を５８〜６０ＨＲＣ、ショット速度
１５０ｍ／ｓでショットピーニングを施した。このマン
ドレルを使用して、高炭素軸受鋼材からなるリンク゛粗
形材を冷間ローリング加工した。外径φ９１×肉厚１
５．８５×幅２６．８のリンク゛粗形材を外径φ１２１
×内径φ９６．８×幅２６．８のリング製品とした。こ
の結果、従来の表面処理を施さないマンドレルは製品８
０００個で１本の割合で交換の必要があったが、本発明
の表面処理したマンドレルは製品２００００個で１本の
割合で交換すればよく、２．５倍にその寿命が延びた。Next, a mandrel for cold rolling is used as a nitride material by plasma CVD, and the shot grain size is 50 μm.
m, the shot grain hardness was 58 to 60 HRC, and the shot speed was 150 m / s. Using this mandrel, a rough link material made of high carbon bearing steel material was cold-rolled. Outer diameter φ91 x wall thickness 1
5.85 × width 26.8 Link rough material with outer diameter φ121
A ring product having an inner diameter of 96.8 and a width of 26.8. As a result, the conventional mandrel which is not surface treated is the product 8
Although it was necessary to replace the 000 pieces at a rate of one, the surface-treated mandrel of the present invention needs to be replaced at a rate of 20,000 pieces of the mandrel, and the life is extended to 2.5 times.
【００３２】[0032]
【発明の効果】以上説明したように、本発明はマンドレ
ルあるいは成形金型などの工具の成形部位あるいは作用
部位の鋼材表面を窒化処理、特にプラズマＣＶＤによる
窒化処理あるいはＰＶＤによりＴｉＮ硬質被膜形成処理
やこれらの複合処理層を形成し、さらにこれらの表面処
理層にショットピーニングしているので、本発明による
マンドレルあるいは成形金型などの工具はその寿命が大
幅に延長された。As described above, according to the present invention, the surface of the steel material at the forming portion or acting portion of the tool such as the mandrel or the forming die is subjected to the nitriding treatment, particularly the nitriding treatment by plasma CVD or the TiN hard coating forming treatment by PVD. Since these composite treatment layers are formed and shot peening is performed on these surface treatment layers, the life of the tool such as the mandrel or molding die according to the present invention is greatly extended.
【図１】マンドレルあるいは成形金型などの工具などの
疲労試験結果を示すグラフである。FIG. 1 is a graph showing fatigue test results for tools such as a mandrel or a molding die.
【図２】マンドレルあるいは成形金型などの工具など表
面層の断面硬さの深さ方向の分布を示すグラフである。FIG. 2 is a graph showing a distribution of cross-sectional hardness of a surface layer of a tool such as a mandrel or a molding die in a depth direction.
【図３】プラズマＣＶＤによる窒化材の疲労破面の一例
を示す写真である。FIG. 3 is a photograph showing an example of a fatigue fracture surface of a nitride material by plasma CVD.
【図４】ＰＶＤ材の疲労破面の一例を示すミクロ写真で
ある。FIG. 4 is a micrograph showing an example of a fatigue fracture surface of a PVD material.
───────────────────────────────────────────────────── フロントページの続き (51)Int.Cl.7 識別記号 ＦＩ テーマコート゛(参考） Ｃ２３Ｃ 8/38 Ｃ２３Ｃ 8/38 14/06 14/06 Ａ // Ｂ２１Ｊ 13/02 Ｂ２１Ｊ 13/02 Ｌ Ｆターム(参考） 4E050 JA01 JB09 JB10 JD03 JD04 JD07 4E087 ED03 4K028 AA02 AB01 BA02 BA12 4K029 AA02 AA29 BA60 BC02 BD05 CA09 DB20 DB21 FA01 ─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. 7 Identification code FI theme code (reference) C23C 8/38 C23C 8/38 14/06 14/06 A // B21J 13/02 B21J 13/02 LF Term (reference) 4E050 JA01 JB09 JB10 JD03 JD04 JD07 4E087 ED03 4K028 AA02 AB01 BA02 BA12 4K029 AA02 AA29 BA60 BC02 BD05 CA09 DB20 DB21 FA01
Claims (8)
部位あるいは作用部位の鋼材表面を窒化処理した後、シ
ョットピーニング加工することを特徴とするマンドレル
あるいは金型などの工具の高寿命化方法。1. A method for extending the life of a tool such as a mandrel or a die, which comprises subjecting a steel material surface of a forming portion or an acting portion of a tool such as a mandrel or a forming die to a nitriding treatment and then performing a shot peening process.
部位あるいは作用部位の鋼材表面を窒化処理した後、Ｐ
ＶＤによりＴｉＮ硬質被膜形成処理することを特徴とす
るマンドレルあるいは金型などの工具の高寿命化方法。2. A steel material surface of a tool forming portion or an operating portion of a tool such as a mandrel or a molding die is nitrided, and then P
A method for extending the life of a tool such as a mandrel or a die, characterized by performing a TiN hard film forming treatment by VD.
部位あるいは作用部位の鋼材表面を窒化処理した後、Ｐ
ＶＤによりＴｉＮ硬質被膜形成処理し、さらにショット
ピーニング加工することを特徴とするマンドレルあるい
は金型などの工具の高寿命化方法。3. After nitriding the surface of the steel material at the forming portion or acting portion of a tool such as a mandrel or a forming die, P
A method for extending the life of a tool such as a mandrel or a die, characterized by performing a TiN hard film forming treatment by VD and further performing shot peening.
理であることを特徴とする請求項１〜３のいずれか１項
に記載のマンドレルあるいは金型などの工具の高寿命化
方法。4. The method for extending the life of a tool such as a mandrel or a mold according to claim 1, wherein the nitriding treatment is a nitriding treatment by plasma CVD.
表面に窒化層が形成され、かつショットピーニング加工
されていることを特徴とする高寿命化されたマンドレル
あるいは金型などの工具。5. A tool such as a mandrel or a mold having a long life in which a nitride layer is formed on a steel material surface of a tool such as a mandrel or a molding die and shot peening is performed.
表面に窒化層およびＰＶＤによるＴｉＮ硬質被膜層が形
成されていることを特徴とする高寿命化されたマンドレ
ルあるいは金型などの工具。6. A tool such as a mandrel or a mold having a long life, characterized in that a nitride layer and a TiN hard coating layer of PVD are formed on the steel surface of a tool such as a mandrel or a molding die.
表面に窒化層およびＰＶＤによるＴｉＮ硬質被膜層が形
成され、かつショットピーニング加工されていることを
特徴とする高寿命化されたマンドレルあるいは金型など
の工具。7. A mandrel or metal having a long service life, characterized in that a nitride layer and a TiN hard coating layer by PVD are formed on the steel surface of a tool such as a mandrel or a molding die, and shot peening is performed. Tools such as molds.
あることを特徴とする請求項５〜７のいずれか１項に記
載の高寿命化されたマンドレルあるいは金型などの工
具。8. A tool such as a mandrel or a mold having a long life as described in any one of claims 5 to 7, wherein the nitride layer is a plasma CVD nitride layer.
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|---|---|---|---|
| JP2002056853A JP2003253422A (en) | 2002-03-04 | 2002-03-04 | Method for prolonging service life of tool such as mandrel and forming die, and tool of prolonged service life such as mandrel and forming die |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2002056853A JP2003253422A (en) | 2002-03-04 | 2002-03-04 | Method for prolonging service life of tool such as mandrel and forming die, and tool of prolonged service life such as mandrel and forming die |
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|---|---|
| JP2003253422A true JP2003253422A (en) | 2003-09-10 |
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|---|---|---|---|
| JP2002056853A Pending JP2003253422A (en) | 2002-03-04 | 2002-03-04 | Method for prolonging service life of tool such as mandrel and forming die, and tool of prolonged service life such as mandrel and forming die |
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| Country | Link |
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| JP2007029992A (en) * | 2005-07-26 | 2007-02-08 | National Institute Of Advanced Industrial & Technology | Die and its manufacturing method |
| JP2007167885A (en) * | 2005-12-21 | 2007-07-05 | Univ Meijo | Method for treating surface of pressing tool and pressing tool surface treated by the method |
| JP2008302430A (en) * | 2007-05-09 | 2008-12-18 | Kyushu Univ | Mold and method for manufacturing mold |
| WO2013123396A1 (en) * | 2012-02-17 | 2013-08-22 | Alcoa Inc. | Dies for shaping containers and methods for making same |
| CN105112884A (en) * | 2015-09-18 | 2015-12-02 | 上虞市宏恩精密机械有限公司 | PCVD surface treating method for aluminum alloy hollow tube extrusion mold |
| CN105729314A (en) * | 2016-04-11 | 2016-07-06 | 中国北方车辆研究所 | Shot blasting process selection method for floating support friction piece |
| JP2017508621A (en) * | 2014-01-07 | 2017-03-30 | ヴァローレック ドイチュラント ゲーエムベーハー | Rolling rod as internal tool in the manufacture of seamless metal hollow bodies and a method of manufacturing metal hollow bodies |
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| CN105729314A (en) * | 2016-04-11 | 2016-07-06 | 中国北方车辆研究所 | Shot blasting process selection method for floating support friction piece |
| CN105729314B (en) * | 2016-04-11 | 2019-07-12 | 中国北方车辆研究所 | A kind of shot-blast process selection method of floating support friction plate |
| CN114875354A (en) * | 2022-05-05 | 2022-08-09 | 常州市方正型钢有限公司 | High-strength seamless deformed steel and processing technology thereof |
| CN114875354B (en) * | 2022-05-05 | 2023-09-05 | 常州市方正型钢有限公司 | High-strength seamless deformed steel and processing technology thereof |
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