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JP4639317B2 - Roll manufacturing method - Google Patents

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JP4639317B2
JP4639317B2 JP2005275813A JP2005275813A JP4639317B2 JP 4639317 B2 JP4639317 B2 JP 4639317B2 JP 2005275813 A JP2005275813 A JP 2005275813A JP 2005275813 A JP2005275813 A JP 2005275813A JP 4639317 B2 JP4639317 B2 JP 4639317B2
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roll
spraying
hardness
sprayed
thermal spray
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JP2007084884A (en
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博昭 古田
京一郎 大野
英昭 永吉
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Fujico Co Ltd
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Description

本発明は、例えば、製鉄設備又は製紙設備に使用可能なロールの製造方法に関する。 The present invention relates to a method for manufacturing a roll that can be used in, for example, an iron manufacturing facility or a paper manufacturing facility.

従来、例えば、製鉄設備の圧延において、圧延材の高品質化と省エネルギー化を図るため、その表層部に、より過酷な圧延条件に耐え、且つ長寿命とすることが可能な硬質クロム層を形成したロールが使用されている。
しかし、この硬質クロム層は、ロール本体の周囲にクロムめっきを施して形成したものであるため、めっき層の厚みを更に厚くすることに限度があり、しかも耐摩耗性の更なる向上を図ることも困難であった。
そこで、クロムめっきの代替プロセスとして、例えば、特許文献1のように、ロール本体の周囲にWCサーメットの溶射被膜を形成する方法が開示されている。これにより、ロールの耐摩耗性をクロムめっきが施されたロールよりも向上できる。
Conventionally, for example, in rolling of steel manufacturing facilities, in order to improve the quality and energy saving of the rolled material, a hard chrome layer that can withstand more severe rolling conditions and have a long life is formed on the surface layer portion. Used rolls.
However, since this hard chrome layer is formed by applying chrome plating around the roll body, there is a limit to further increasing the thickness of the plating layer, and further improving wear resistance. It was also difficult.
Therefore, as an alternative process of chrome plating, for example, a method of forming a sprayed coating of WC cermet around the roll body as disclosed in Patent Document 1 is disclosed. Thereby, the abrasion resistance of a roll can be improved rather than the roll by which chromium plating was given.

特開平2−187206号公報JP-A-2-187206

しかしながら、WCサーメットを使用した溶射被膜とロール本体の硬度の差は大きく、溶射被膜のロール本体への密着性は、クロムめっきよりも大幅に劣るため(クロムめっきの約1/2程度)、ロールの使用の際に溶射被膜がロール本体から剥離し易くなる問題がある。このため、ロールの接触面圧が高くなる使用環境下では、溶射法で溶射被膜を形成したロールがあまり普及していない。 However, the difference in hardness between the thermal spray coating using WC cermet and the roll body is large, and the adhesion of the thermal spray coating to the roll body is significantly inferior to chromium plating (about 1/2 of the chromium plating). There is a problem that the sprayed coating is easily peeled off from the roll body during use. For this reason, in the use environment where the contact surface pressure of a roll becomes high, the roll which formed the sprayed coating by the thermal spraying method has not spread widely.

本発明はかかる事情に鑑みてなされたもので、ロール本体と溶射被膜との密着性を従来よりも向上させ、溶射法により製造したロールの使用範囲を広げることが可能なロールの製造方法を提供することを目的とする。 The present invention has been made in view of such circumstances, and provides a method for producing a roll capable of improving the adhesion between a roll body and a thermal spray coating as compared with the conventional one and expanding the use range of a roll produced by a thermal spraying method. The purpose is to do.

前記目的に沿う第1の発明に係るロールの製造方法は、ロール本体の表層部をHv700以上Hv950以下に硬化させ、その表面に、WC系複合材料からなって結合材を含む硬質セラミックスを、造粒して10μm以上60μm以下とした溶射粉末の溶射速度が800m/秒を超え1200m/秒以下でかつ火炎温度が2000℃以上3000℃以下で高速溶射し、気孔率が0.1体積%以上1体積%以下の溶射被膜を形成する。 Method for manufacturing a roll according to the first aspect of the invention along the object, the surface portion of the roll body is cured to Hv700 or more Hv950 or less, on the surface thereof, a hard ceramics containing binder consists WC-based composite material, concrete The spraying speed of the sprayed powder having a particle size of 10 μm or more and 60 μm or less is higher than 800 m / second and 1200 m / second or lower, and the flame temperature is 2000 ° C. or higher and 3000 ° C. or lower, and the porosity is 0.1 volume% or higher 1 A sprayed coating having a volume% or less is formed.

また、第1の発明に係るロールの製造方法において、前記ロール本体の表層部は、硬化肉盛層の形成又は焼入れにより硬化させることが好ましい。 Moreover, in the manufacturing method of the roll which concerns on 1st invention, it is preferable to harden the surface layer part of the said roll main body by formation or hardening of a hardening build-up layer.

請求項1、2記載のロールの製造方法は、ロール本体の表層部を硬化させ、その表面に規定した溶射速度で硬質セラミックスの溶射を行うので、ロール本体の表層部の硬度を硬質セラミックスで構成される溶射被膜の硬度に近づけ、ロール本体からの溶射被膜の剥離を抑制、更には防止でき、ロール本体と溶射被膜との密着性を従来よりも向上できる。また、溶射被膜の気孔率を規定することで、硬度の高い耐摩耗性に優れた溶射被膜を形成できる。
これにより、溶射法により製造したロールの使用範囲を、従来よりも広げることができる。
The method for manufacturing a roll according to claim 1 and 2, wherein the surface layer portion of the roll body is hardened and the hard ceramic is sprayed at a spraying speed defined on the surface thereof. It is possible to approach the hardness of the sprayed coating, to suppress and further prevent the sprayed coating from peeling from the roll body, and to improve the adhesion between the roll body and the sprayed coating. Further, by defining the porosity of the thermal spray coating, it is possible to form a thermal spray coating with high hardness and excellent wear resistance.
Thereby, the use range of the roll manufactured by the thermal spraying method can be expanded more than before.

特に、請求項2記載のロールの製造方法は、例えば、ロールの使用用途、又はロール本体の形状に応じて、ロール本体の表層部の硬化方法を選択できる。
ここで、ロール本体の表層部の硬化肉盛層による硬化は、溶射被膜の密着性を更に向上させる場合に適している。また、ロール本体の表層部の焼入れによる硬化は、例えば、ロール本体として管状部材を使用する場合のように、その厚みが薄いものに適している。
In particular, the method for producing a roll according to claim 2 can select a curing method for the surface layer portion of the roll body according to, for example, the intended use of the roll or the shape of the roll body.
Here, hardening by the hardfacing layer of the surface layer portion of the roll body is suitable for further improving the adhesion of the thermal spray coating. Moreover, hardening by hardening of the surface layer part of a roll main body is suitable for the thing whose thickness is thin like the case where a tubular member is used as a roll main body, for example.

続いて、添付した図面を参照しつつ、本発明を具体化した実施の形態につき説明し、本発明の理解に供する。
ここで、図1は本発明の一実施の形態に係るロールの製造方法の説明図、図2は硬化処理していない基材と各溶射被膜との密着性を示す説明図、図3は基材硬度と溶射被膜との密着性の関係を示す説明図、図4は各溶射方法による溶射粉末の溶射速度の説明図、図5は基材硬度と溶射装置の燃焼内圧との関係を示す説明図、図6は溶射被膜を形成した基材の転動疲労試験の結果を示す説明図、図7は各溶射方法で形成した溶射被膜の気孔率の説明図、図8は溶射被膜の硬度と溶射装置の燃焼内圧との関係を示す説明図、図9は各溶射方法で形成した溶射被膜の硬度の説明図である。
Next, embodiments of the present invention will be described with reference to the accompanying drawings for understanding of the present invention.
Here, FIG. 1 is an explanatory view of a method for manufacturing a roll according to an embodiment of the present invention, FIG. 2 is an explanatory view showing adhesion between a base material not subjected to curing treatment and each thermal spray coating, and FIG. FIG. 4 is an explanatory diagram showing the relationship between the hardness of the material and the thermal spray coating, FIG. 4 is an explanatory diagram of the thermal spraying speed of the thermal spray powder by each thermal spraying method, and FIG. 5 is an explanatory diagram showing the relationship between the substrate hardness and the combustion internal pressure of the thermal spraying device. FIG. 6, FIG. 6 is an explanatory diagram showing the results of a rolling fatigue test of a base material on which a thermal spray coating is formed, FIG. 7 is an explanatory diagram of the porosity of the thermal spray coating formed by each thermal spraying method, and FIG. FIG. 9 is an explanatory diagram showing the hardness of the thermal spray coating formed by each thermal spraying method.

図1に示すように、本発明の一実施の形態に係るロールの製造方法は、ロール本体10の表層部11を硬化させ、その表面に結合材を含む硬質セラミックスを、溶射速度800m/秒を超え1200m/秒以下で高速溶射し、気孔率が1.5体積%以下の溶射被膜12を形成して、ロール13を製造する方法である。以下、詳しく説明する。 As shown in FIG. 1, the roll manufacturing method according to an embodiment of the present invention hardens the surface layer portion 11 of the roll body 10, and hard ceramics including a binder on the surface thereof is sprayed at a spraying speed of 800 m / sec. In this method, the roll 13 is manufactured by spraying at a high speed exceeding 1200 m / sec and forming the sprayed coating 12 having a porosity of 1.5% by volume or less. This will be described in detail below.

まず、例えば、一般炭素鋼(S45Cなど)、軸受鋼、機械構造用鋼(クロムモリブデン鋼など)、又は炭素工具鋼である鋼材を、機械加工によって削り出し、直径が例えば、200mm以上1500mm以下程度のロール用素材を製造する。このロール用素材の両側又は片側には回転軸部が設けられているが、この回転軸部は、ロール胴部と共に一体的に削り出すことも、また別個に製造して取付けることも可能である。
また、ロール胴部として、前記した鋼材の成分で構成される中空のパイプを使用することも可能であり、この場合、回転軸部をパイプの両側又は片側に焼きばめして取付け、ロール用素材を製造することもできる。
First, for example, steel materials such as general carbon steel (such as S45C), bearing steel, steel for machine structure (such as chromium molybdenum steel), or carbon tool steel are machined out, and the diameter is, for example, about 200 mm to 1500 mm. The material for rolls is manufactured. A rotating shaft portion is provided on both sides or one side of the roll material, but the rotating shaft portion can be cut out integrally with the roll body portion or can be separately manufactured and attached. .
Moreover, it is also possible to use a hollow pipe composed of the above-described steel material as the roll body, and in this case, the rotary shaft is attached by shrink fitting on both sides or one side of the pipe, Can also be manufactured.

このロール用素材の表面に直接溶射被膜を形成した場合、ロール用素材の表層部と溶射被膜の硬度に大きな差があるため、溶射被膜の剥離が早期に発生し易い。ここで、図2に、ロール用素材として使用するS45Cの基材表面に硬化層を形成することなく各種溶射被膜を形成した後、その溶射被膜に鉄球を落下させ、基材表面から溶射被膜が剥離するまでの落下回数を測定した結果について示す。
図2から明らかなように、基材表面側を硬化させない場合、基材と溶射被膜との密着性が最も良好な溶射被膜(溶射粉末:WC−17Co、WC−14Cr−28Ni)でも、溶射被膜の剥離が、鉄球の落下回数6000回程度(12×500回)の少ない回数で生じている。なお、基材との密着性が最も悪い溶射被膜(溶射粉末:CrC−NiCr、WC−20Cr−7Ni)では、500回程度(1×500回)で剥離が生じている。
When the thermal spray coating is directly formed on the surface of the roll material, there is a large difference in the hardness between the surface layer portion of the roll material and the thermal spray coating, and thus the thermal spray coating is likely to peel off at an early stage. Here, in FIG. 2, after forming various sprayed coatings on the surface of the substrate of S45C used as the roll material without forming a hardened layer, iron balls are dropped on the sprayed coating, and the sprayed coating is formed from the surface of the substrate. It shows about the result of having measured the frequency | count of dropping until it peels.
As is clear from FIG. 2, even when the surface of the base material is not cured, the thermal spray coating (sprayed powder: WC-17Co, WC-14Cr-28Ni) having the best adhesion between the base material and the thermal spray coating is also used. Peeling occurs in as few times as about 6000 times (12 × 500 times). In addition, in the sprayed coating (spraying powder: CrC-NiCr, WC-20Cr-7Ni) having the worst adhesion to the base material, peeling occurs about 500 times (1 × 500 times).

そこで、まず、ロール用素材の表面側又は表層部を硬化させ、以下に示す方法で基材硬度を高める。
ロール用素材の表面側の硬化は、例えば、サブマージアーク溶接法、PTA(粉体タングステンアーク溶接)、又は粉体プラズマ溶接法により、ロール用素材の表面側に硬化肉盛層(例えば、厚みが3mm以上7.5mm以下)を形成することで行う。この硬化肉盛層の材料としては、例えば、特開平8−158019号公報に開示された高硬度肉盛溶接材料を使用できる。
なお、ロール用素材の表面側の硬化は、主として硬化肉盛層を形成して行うが、硬化層を薄くする場合には、ロール用素材の表層部を高周波焼入れすることで行うこともできる。この場合、ロール用素材としては、焼入れ可能な成分(例えば、高速度工具鋼)で構成されたものを使用する。
このように、ロール用素材の表面に硬化肉盛層を形成、又はロール用素材の表層部を焼入れしてロール本体10を製造し、その表面に溶射被膜12を形成する。
Therefore, first, the surface side or the surface layer portion of the roll material is cured, and the substrate hardness is increased by the following method.
Curing on the surface side of the roll material is performed by, for example, using a submerged arc welding method, PTA (powder tungsten arc welding), or powder plasma welding method on the surface side of the roll material on the surface side of the roll material. 3 mm or more and 7.5 mm or less). As a material for the hardfacing layer, for example, a high-hardness surfacing welding material disclosed in JP-A-8-158019 can be used.
In addition, although hardening of the surface side of the raw material for rolls is mainly performed by forming a hardfacing layer, when making a hardened layer thin, it can also be performed by induction-quenching the surface layer part of the raw material for rolls. In this case, as the roll material, a material composed of a quenchable component (for example, high-speed tool steel) is used.
In this manner, a hardfacing layer is formed on the surface of the roll material, or the surface of the roll material is quenched to manufacture the roll body 10, and the thermal spray coating 12 is formed on the surface.

ここで、ロール用素材の表面側又は表層部の硬化の影響について、図3を参照しながら説明する。図3は、鉄球の落下回数が1000回程度(2×500回)で剥離が生じた溶射粉末WC−12Co(図2参照)を、表面側を硬化させたS45Cの基材表面に溶射した後、形成された溶射被膜上に鉄球を落下し、基材表面から溶射被膜が剥離するまでの回数を測定した結果である。なお、基材硬度Hv180の基材は、硬化処理がなされていないものであり、一方、基材硬度Hv400〜Hv580は基材表層部の焼入れにより、Hv650及びHv900は基材表面に形成した硬化肉盛層により、それぞれ硬化処理がなされている。 Here, the influence of the hardening of the surface side or the surface layer portion of the roll material will be described with reference to FIG. In FIG. 3, the sprayed powder WC-12Co (see FIG. 2), which was peeled off when the number of drops of the iron ball was about 1000 times (2 × 500 times), was sprayed on the surface of the S45C base material whose surface was cured. Then, it is the result of having measured the number of times until an iron ball falls on the formed sprayed coating, and the sprayed coating peels from the substrate surface. In addition, the base material of the base material hardness Hv180 is not subjected to the curing treatment, while the base material hardnesses Hv400 to Hv580 are the hardened meat formed on the surface of the base material by quenching the base material surface layer portion. Each of the layers is subjected to a curing process.

図3から明らかなように、基材硬度を高めることで、ロール本体の表層部の硬度が溶射被膜の硬度(例えば、Hv1100以上1700以下程度)に近づくため、基材硬度がHv680程度に上昇するまでは、溶射被膜が剥離するまでに要する鉄球の落下回数の急激な上昇を確認できる。しかし、基材硬度がHv680程度では、基材から溶射被膜が剥離するまでの回数が、クロムめっきを施した場合の約半分程度となり、密着性は良好でない。
ここで、基材と溶射被膜の密着性を更に向上させるため、基材硬度の硬度を溶射被膜の硬度に更に近づける必要があるが、図3に示すように、基材硬度がHv700以上では、密着性の急激な低下がみられる。これは、基材に溶射粉末を吹付ける条件が適していないことに起因する。
このように、基材硬度を単に高めただけでは、溶射被膜の密着性を向上できない。
As apparent from FIG. 3, by increasing the substrate hardness, the hardness of the surface layer portion of the roll body approaches the hardness of the thermal spray coating (for example, about Hv 1100 or more and about 1700 or less), and thus the substrate hardness increases to about Hv 680 or so. Until, it is possible to confirm a rapid increase in the number of times the iron balls are dropped until the sprayed coating is peeled off. However, when the substrate hardness is about Hv680, the number of times until the sprayed coating is peeled off from the substrate is about half that when chromium plating is applied, and the adhesion is not good.
Here, in order to further improve the adhesion between the substrate and the thermal spray coating, it is necessary to make the hardness of the substrate hardness closer to the hardness of the thermal spray coating. However, as shown in FIG. There is a sharp drop in adhesion. This is because the conditions for spraying the sprayed powder onto the substrate are not suitable.
Thus, the adhesiveness of the thermal spray coating cannot be improved simply by increasing the substrate hardness.

そこで、ロール本体10の表面に溶射被膜12を形成する条件について説明する。
溶射粉末の溶射装置として、例えば、溶射粉末の加熱用燃料として灯油及び純酸素を使用するHVOF(High Velocity Oxygen Fuel)方式の高速溶射装置14を使用する。
その溶射条件は、高速溶射装置14の火炎(フレーム)15温度が、例えば、2000℃以上3000℃以下、溶射粉末の溶射速度(吹付け速度)が800m/秒を超え1200m/秒以下(燃焼内圧は、例えば、0.7MPa以上1.0MPa以下程度)である。なお、燃焼内圧は、使用する高速溶射装置14の種類によって異なると考えられるため、ここでは、燃焼内圧と相関性を有する溶射粉末の溶射速度(燃焼内圧の上昇に伴って溶射速度も上昇)を規定している。
Therefore, conditions for forming the sprayed coating 12 on the surface of the roll body 10 will be described.
As the thermal spraying apparatus for the thermal spraying powder, for example, an HVOF (High Velocity Oxygen Fuel) type high-speed thermal spraying apparatus 14 that uses kerosene and pure oxygen as a fuel for heating the thermal spraying powder is used.
The flame spraying conditions are as follows: the flame (frame) 15 temperature of the high-speed spraying device 14 is, for example, 2000 ° C. or more and 3000 ° C. or less, and the spraying speed (spraying speed) of the sprayed powder exceeds 800 m / sec and is 1200 m / sec or less (combustion internal pressure). Is, for example, about 0.7 MPa to 1.0 MPa. In addition, since it is thought that a combustion internal pressure changes with kinds of the high-speed spraying apparatus 14 to be used, here, the spraying speed of the thermal spraying powder which has a correlation with a combustion internal pressure (a spraying speed rises with a raise of combustion internal pressure). It prescribes.

本発明で行う高速溶射の溶射速度は、図4に示すように、従来行われている溶射方法であるフレーム溶射、HEP(高出力のプラズマエネルギー溶射)、爆発溶射、HVOF−A(通常の高速溶射)、又はHVOF−B(他の高速溶射)の溶射速度(最高値が800m/秒)よりも速い。なお、溶射粉末の溶射速度を1200m/秒を超える速度に上昇させても、その効果は顕著に向上しない。
このように、溶射粉末の溶射速度を上昇させることで、図5に示すように、基材硬度をHv900まで上昇させても、基材と粉体との密着性を従来(図5の□及び△)よりも大幅に上昇(図5の○)できることを確認できた。
As shown in FIG. 4, the spraying speed of the high-speed spraying performed in the present invention is flame spraying, HEP (high-power plasma energy spraying), explosion spraying, and HVOF-A (normal high-speed spraying), which are conventionally performed spraying methods. Thermal spraying), or HVOF-B (other high-speed thermal spraying) spraying speed (maximum value is 800 m / second). Even if the spraying speed of the sprayed powder is increased to a speed exceeding 1200 m / sec, the effect is not significantly improved.
In this way, by increasing the spraying speed of the sprayed powder, as shown in FIG. 5, even when the substrate hardness is increased to Hv900, the adhesion between the substrate and the powder is conventionally increased (□ and □ in FIG. 5). It was confirmed that it can be significantly increased (◯ in FIG. 5) than (Δ).

なお、更に安定した密着性と、溶射の際の経済性を考慮すれば、溶射粉末の溶射速度の下限値を好ましくは850m/秒、更に好ましくは900m/秒とし、上限値を好ましくは1150m/秒、更に好ましくは1100m/秒とする。
このとき、ロール本体10の表層部11の硬度は、ロール本体10と溶射被膜12との密着性を向上できるHv700以上Hv1000以下(押し込み荷重:2.9N)とする。
ここで、ロール本体の表層部の硬度がHv700未満の場合、基材と溶射被膜との密着性をクロムめっきに対して十分に向上できない。一方、ロール本体の表層部の硬度を、Hv1000を超える値まで上昇させても、その効果は顕著に向上しない。
以上のことから、基材と溶射被膜との密着性を、顕著でかつ十分に向上させるには、その硬度の下限を、好ましくはHv800、更に好ましくはHv850とし、硬度の上限を、好ましくはHv950とする。
In consideration of more stable adhesion and economic efficiency at the time of thermal spraying, the lower limit value of the spraying speed of the thermal spray powder is preferably 850 m / second, more preferably 900 m / second, and the upper limit value is preferably 1150 m / second. Second, more preferably 1100 m / second.
At this time, the hardness of the surface layer portion 11 of the roll body 10 is set to Hv 700 or more and Hv 1000 or less (indentation load: 2.9 N) that can improve the adhesion between the roll body 10 and the sprayed coating 12.
Here, when the hardness of the surface layer portion of the roll body is less than Hv700, the adhesion between the base material and the sprayed coating cannot be sufficiently improved with respect to the chromium plating. On the other hand, even if the hardness of the surface layer portion of the roll body is increased to a value exceeding Hv1000, the effect is not significantly improved.
From the above, in order to significantly and sufficiently improve the adhesion between the substrate and the sprayed coating, the lower limit of the hardness is preferably Hv800, more preferably Hv850, and the upper limit of the hardness is preferably Hv950. And

ここで、以上の鉄球落下試験を基に、ロールとして使用する条件を疑似した転動疲労試験により、その密着性を評価した結果について、図6を参照しながら説明する。図6は、直径800mm、幅5mmの軸受鋼(SUJ2)で構成される基材表面に溶射被膜を形成し、これを接触応力250kgf/mm2 (2450MPa)で、回転速度3000rpmとし、すべり率0%で、潤滑材に水のみを使用して転動疲労試験を行った結果である。なお、比較例Aは従来使用されている市販の耐衝撃材を、比較例Bは従来の溶射方法によりWC−17Coを、実施例Aは本発明の方法を使用してWC−12Coをそれぞれ溶射した結果である。ここで、比較例Cは従来ロールとして使用しているクロムめっき(6μm)を施した結果である。
図6から明らかなように、実施例Aは、比較例A及び比較例Bと比較して、剥離するまでの転動回数を十分に向上できることを確認できた。また、本発明が目標とするクロムめっきと比較しても、略同程度の転動回数に耐え得ることを確認できた。
Here, based on the above iron ball drop test, the result of evaluating its adhesion by a rolling fatigue test simulating the conditions for use as a roll will be described with reference to FIG. FIG. 6 shows a case where a sprayed coating is formed on the surface of a base material made of bearing steel (SUJ2) having a diameter of 800 mm and a width of 5 mm, and the contact stress is 250 kgf / mm 2 (2450 MPa), the rotational speed is 3000 rpm, and the sliding rate is 0. % Is a result of a rolling fatigue test using only water as a lubricant. Comparative Example A is a conventional commercially available impact resistant material, Comparative Example B is sprayed with WC-17Co by a conventional thermal spraying method, and Example A is sprayed with WC-12Co by using the method of the present invention. It is the result. Here, Comparative Example C is the result of applying the chromium plating (6 μm) used as a conventional roll.
As is clear from FIG. 6, it was confirmed that Example A can sufficiently improve the number of rolling times until peeling as compared with Comparative Example A and Comparative Example B. Moreover, it has confirmed that it can endure substantially the same number of rolling compared with the target chromium plating of this invention.

以上のことから、表層部11を硬化させたロール本体10の表面に、WC系複合材料(硬質セラミックスの一例)であるWC系サーメットの溶射粉末を前記した条件で吹付け、膜厚が例えば、100μm以上200μm以下程度のWC系サーメットの溶射被膜12を形成し、ロール13を製造する。
このWC系サーメットは、WC(炭化タングステン)とCo系又はNi系の結合材とで構成されるものであり、例えば、WC−17Co、WC−12Co、WC−20Cr−7Ni、WC−17Cr−17Ni、WC−16Cr−19Ni、又はWC−14Cr−28Niを使用できる。なお、WC系サーメットの溶射粉末は、WCと結合材とを予め造粒し、高温で焼結させた後に粉砕して、その粒径を、例えば、10μm以上60μm以下(ここでは、15μm以上45μm以下)に調整したものである。
From the above, the sprayed powder of WC-based cermet, which is a WC-based composite material (an example of hard ceramics), is sprayed on the surface of the roll body 10 where the surface layer portion 11 is cured, and the film thickness is, for example, A WC cermet sprayed coating 12 of about 100 μm or more and 200 μm or less is formed to manufacture a roll 13.
This WC-based cermet is composed of WC (tungsten carbide) and a Co-based or Ni-based binder, for example, WC-17Co, WC-12Co, WC-20Cr-7Ni, WC-17Cr-17Ni. , WC-16Cr-19Ni, or WC-14Cr-28Ni can be used. The thermal spray powder of the WC cermet is prepared by previously granulating WC and a binder, sintering at a high temperature, and then pulverizing, and the particle size thereof is, for example, 10 μm or more and 60 μm or less (here, 15 μm or more and 45 μm). Adjusted to the following).

なお、本実施の形態で形成する溶射被膜12の気孔率は、1.5体積%以下となっている。この気孔率は、基材(50mm×60mm×3mm)に対して溶射を行い、厚み150μm以上200μm以下の溶射被膜を形成し、これを精密カッターを用いて切断して樹脂埋めした後、研磨(1μmダイヤモンドペーストを使用)して、光学顕微鏡(倍率200倍)で溶射被膜の切断面を写真撮影して画像解析し、全面積中に占める気孔部分(例えば、黒色)の面積を算出することで得られる値である。
図7に示すように、本発明の方法で形成した溶射被膜の気孔率(0.5体積%)は、前記爆発溶射と同等ではあるが、プラズマ溶射又は前記HVOF−Bで形成した溶射被膜の気孔率よりも、大幅に小さい。
このように、溶射被膜12の気孔率を小さくすることで、溶射被膜12の硬度を上昇できる。
Note that the porosity of the thermal spray coating 12 formed in the present embodiment is 1.5% by volume or less. This porosity is sprayed on a base material (50 mm × 60 mm × 3 mm) to form a sprayed coating having a thickness of 150 μm or more and 200 μm or less, and this is cut with a precision cutter and filled with resin, followed by polishing ( 1 μm diamond paste is used), the cut surface of the sprayed coating is photographed with an optical microscope (200 × magnification), image analysis is performed, and the area of pores (for example, black) occupying the entire area is calculated. This is the value obtained.
As shown in FIG. 7, the porosity (0.5% by volume) of the sprayed coating formed by the method of the present invention is equivalent to that of the above-mentioned explosive spraying, but the plasma sprayed coating or the sprayed coating formed of the above HVOF-B. It is much smaller than the porosity.
Thus, the hardness of the thermal spray coating 12 can be increased by reducing the porosity of the thermal spray coating 12.

また、図8に、本発明の方法と前記HVOF−Aでそれぞれ形成した溶射被膜の硬度(押し込み荷重:2.9N)を測定した結果について示す。
図8に示すように、いずれの方法においても、燃焼内圧の上昇、即ち溶射速度の上昇に伴って溶射被膜の硬度が上昇する傾向がみられる。
更に、図9に、本発明(燃焼内圧0.85MPa)の方法と、前記したフレーム溶射、HEP、爆発溶射、HVOF−A、又はHVOF−Bで、それぞれ形成した溶射被膜の硬度(押し込み荷重:2.9N)を測定した結果について示す。
図9に示すように、本発明の方法を使用することで、他の方法よりも溶射被膜の硬度を向上できる傾向があることを確認できた。
Moreover, in FIG. 8, it shows about the result of having measured the hardness (indentation load: 2.9N) of the sprayed coating each formed by the method of this invention and the said HVOF-A.
As shown in FIG. 8, in any of the methods, there is a tendency that the hardness of the thermal spray coating increases as the combustion internal pressure increases, that is, the spraying speed increases.
Further, FIG. 9 shows the hardness (indentation load: each of the thermal spray coatings formed by the method of the present invention (combustion internal pressure 0.85 MPa) and the above-described flame spraying, HEP, explosion spraying, HVOF-A, or HVOF-B. It shows about the result of having measured 2.9N).
As shown in FIG. 9, it was confirmed that by using the method of the present invention, the hardness of the sprayed coating tends to be improved as compared with other methods.

従って、溶射速度を調整し、溶射被膜の気孔率を1.5体積%以下にすることで、溶射被膜12の硬度を上昇できるが、更に硬度を向上させるには、溶射被膜の気孔率を1.3体積%以下にすることが好ましく、更には1.0体積%以下にすることが好ましい。
一方、気孔率を小さくするに伴って、溶射被膜の硬度を上昇できるため、気孔率の下限値については規定していないが、実際に製造する溶射被膜は、少なくとも0.1体積%、又は0.2体積%、更には0.3体積%の気孔率を含んでいる。
これにより、溶射法によってロール本体10と溶射被膜12との密着性を従来よりも向上させ、耐摩耗性に優れ、しかも長寿命化を図ることが可能なロール13を提供できる。なお、ロール13は、必要に応じて研磨処理が施される。
Accordingly, the hardness of the sprayed coating 12 can be increased by adjusting the spraying speed and setting the porosity of the sprayed coating to 1.5 volume% or less. However, in order to further improve the hardness, the porosity of the sprayed coating is set to 1. It is preferable to make it 3 volume% or less, and it is further preferable to make it 1.0 volume% or less.
On the other hand, since the hardness of the thermal spray coating can be increased as the porosity is decreased, the lower limit value of the porosity is not specified, but the thermal spray coating actually produced is at least 0.1% by volume, or 0%. It contains a porosity of .2% by volume and even 0.3% by volume.
Thereby, the adhesiveness of the roll main body 10 and the sprayed coating 12 can be improved by the thermal spraying method compared with the past, and it can provide the roll 13 which is excellent in abrasion resistance, and can achieve lifetime improvement. The roll 13 is subjected to a polishing process as necessary.

次に、本発明の作用効果を確認するために行った実施例について説明する。
基材と溶射被膜との密着性の評価は、前記した転動疲労試験の接触応力を110kgf/mm2 (980MPa)又は250kgf/mm2 (2450MPa)とし、基材から溶射被膜が剥離するまでの転動回数を測定することで行った。ここで、基材として軸受鋼(SUJ2)を使用し、溶射装置としてHVOF方式の高速溶射装置を使用した。なお、実施例1〜5に使用した高速溶射装置は、溶射粉末の溶射速度を1000m/秒にするものであり、従来例1に使用した高速溶射装置(HVOF−B)は、溶射粉末の溶射速度を500m/秒にするものである。
この試験条件と試験結果を表1に示す。
Next, examples carried out for confirming the effects of the present invention will be described.
The evaluation of the adhesion between the base material and the thermal spray coating is performed until the contact stress in the rolling fatigue test is 110 kgf / mm 2 (980 MPa) or 250 kgf / mm 2 (2450 MPa), and the thermal spray coating is peeled off from the base material. This was done by measuring the number of rolling. Here, bearing steel (SUJ2) was used as the base material, and an HVOF type high-speed spraying device was used as the spraying device. In addition, the high-speed thermal spraying apparatus used in Examples 1 to 5 sets the thermal spraying speed of the thermal spray powder to 1000 m / second, and the high-speed thermal spraying apparatus (HVOF-B) used in Conventional Example 1 is thermal spraying of the thermal spraying powder. The speed is set to 500 m / sec.
Table 1 shows the test conditions and test results.

Figure 0004639317
Figure 0004639317

まず、転動疲労試験の接触応力を低い方の値(110kgf/mm2 )に設定した従来例1と実施例1及び2について説明する。
従来例1のように、実施例1及び2と比較して溶射被膜の気孔率が高い場合、溶射被膜の硬度が低くなり、その結果、基材から溶射被膜が剥離するまでの転動回数が大幅に低下する傾向があることを確認できた。
一方、実施例1及び2のように、溶射被膜の気孔率が1.3体積%以下であれば、基材と溶射被膜との密着性を良好にできる傾向があることを確認できた。
First, Conventional Example 1 and Examples 1 and 2 in which the contact stress in the rolling fatigue test is set to a lower value (110 kgf / mm 2 ) will be described.
As in Conventional Example 1, when the porosity of the sprayed coating is high compared to Examples 1 and 2, the hardness of the sprayed coating is reduced, and as a result, the number of rolling times until the sprayed coating is peeled off from the substrate is reduced. It was confirmed that there was a tendency to decrease significantly.
On the other hand, as in Examples 1 and 2, it was confirmed that when the porosity of the sprayed coating was 1.3% by volume or less, the adhesion between the substrate and the sprayed coating tends to be good.

次に、転動疲労試験の接触応力を高い方の値(250kgf/mm2 )に設定した実施例3〜5について説明する。
実施例3〜5に示すように、基材に肉盛溶接を行ってその硬度を高め、溶射被膜の気孔率を0.61体積%以下にすることで、基材と溶射被膜との密着性を良好にできる傾向があることを確認できた。
Next, Examples 3 to 5 in which the contact stress in the rolling fatigue test is set to a higher value (250 kgf / mm 2 ) will be described.
As shown in Examples 3 to 5, the adhesion between the base material and the thermal spray coating is achieved by performing overlay welding on the base material to increase its hardness and setting the porosity of the thermal spray coating to 0.61% by volume or less. It was confirmed that there is a tendency to improve.

以上、本発明を、一実施の形態を参照して説明してきたが、本発明は何ら上記した実施の形態に記載の構成に限定されるものではなく、特許請求の範囲に記載されている事項の範囲内で考えられるその他の実施の形態や変形例も含むものである。例えば、前記したそれぞれの実施の形態や変形例の一部又は全部を組合せて本発明のロールの製造方法を構成する場合も本発明の権利範囲に含まれる。
また、前記実施の形態においては、硬質セラミックスとしてWCを使用する場合について説明したが、例えば、WmCn(mとnはそれぞれ整数)を使用することも、またCr32、NbC、VC、MoC、又はTiCを使用することも可能である。
As described above, the present invention has been described with reference to one embodiment. However, the present invention is not limited to the configuration described in the above embodiment, and is described in the claims. Other embodiments and modifications conceivable within the scope of the above are also included. For example, a case where the roll manufacturing method of the present invention is configured by combining a part or all of the above-described embodiments and modifications is also included in the scope of the right of the present invention.
Further, in the above embodiment has described the case of using WC as hard ceramics, for example, possible to use WmCn (m and n each is an integer) are also Cr 3 C 2, NbC, VC , MoC It is also possible to use TiC.

本発明の一実施の形態に係るロールの製造方法の説明図である。It is explanatory drawing of the manufacturing method of the roll which concerns on one embodiment of this invention. 硬化処理していない基材と各溶射被膜との密着性を示す説明図である。It is explanatory drawing which shows the adhesiveness of the base material which is not hardening-processed, and each thermal spray coating. 基材硬度と溶射被膜との密着性の関係を示す説明図である。It is explanatory drawing which shows the relationship of adhesiveness of a base-material hardness and a sprayed coating. 各溶射方法による溶射粉末の溶射速度の説明図である。It is explanatory drawing of the thermal spraying speed of the thermal spraying powder by each thermal spraying method. 基材硬度と溶射装置の燃焼内圧との関係を示す説明図である。It is explanatory drawing which shows the relationship between base-material hardness and the combustion internal pressure of a thermal spraying apparatus. 溶射被膜を形成した基材の転動疲労試験の結果を示す説明図である。It is explanatory drawing which shows the result of the rolling fatigue test of the base material in which the sprayed coating was formed. 各溶射方法で形成した溶射被膜の気孔率の説明図である。It is explanatory drawing of the porosity of the sprayed coating formed by each thermal spraying method. 溶射被膜の硬度と溶射装置の燃焼内圧との関係を示す説明図である。It is explanatory drawing which shows the relationship between the hardness of a thermal spray coating, and the combustion internal pressure of a thermal spraying apparatus. 各溶射方法で形成した溶射被膜の硬度の説明図である。It is explanatory drawing of the hardness of the sprayed coating formed by each thermal spraying method.

符号の説明Explanation of symbols

10:ロール本体、11:表層部、12:溶射被膜、13:ロール、14:高速溶射装置、15:火炎 10: Roll body, 11: Surface layer part, 12: Spray coating, 13: Roll, 14: High-speed spraying device, 15: Flame

Claims (2)

ロール本体の表層部をHv700以上Hv950以下に硬化させ、その表面に、WC系複合材料からなって結合材を含む硬質セラミックスを、造粒して10μm以上60μm以下とした溶射粉末の溶射速度が800m/秒を超え1200m/秒以下でかつ火炎温度が2000℃以上3000℃以下で高速溶射し、気孔率が0.1体積%以上1体積%以下の溶射被膜を形成することを特徴とするロールの製造方法。 The surface layer portion of the roll body is cured to Hv 700 or more and Hv 950 or less, and a hard ceramic including a binder made of a WC-based composite material is granulated on the surface thereof, and the spraying speed of the sprayed powder is 10 μm or more and 60 μm or less is 800 m. Of a roll characterized by forming a sprayed coating having a porosity of 0.1% by volume or more and 1% by volume or less by high-speed thermal spraying at a flame temperature of 2000 ° C. or higher and 3000 ° C. or lower and exceeding 1200 / second and 1200 m / s or less. Production method. 請求項1記載のロールの製造方法において、前記ロール本体の表層部は、硬化肉盛層の形成又は焼入れにより硬化させることを特徴とするロールの製造方法。 The method for manufacturing a roll according to claim 1, wherein the surface layer portion of the roll body is cured by forming a hardened layer or quenching.
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