JP3748730B2 - Roll support equipment for continuous casting equipment - Google Patents

Description

【００２６】
以下に実施例および比較例を挙げる。
【００２７】
【実施例】
表１に示す６種類の化学成分を有する鋼を素材として、上述した焼入れ焼戻し処理を施した試験片と軌道輪、およびこの軌道輪を用いた玉軸受（表１中の実施例１〜６）を用意した。実施例１〜６に示した一部の鋼材に浸炭窒化処理を施した試験片、軌道輪および玉軸受（表１中の実施例７〜８）も用意した。
【００２８】
【比較例】
高炭素クロム軸受鋼ＳＵＪ２および本願の化学成分範囲を外れる２種類の化学成分を有する鋼を焼入れ焼戻し処理した試験片と軌道輪、およびこの軌道輪を用いた玉軸受（表１中の比較例１〜３）を用意した。ＳＵＪ２を素材としたものについては、浸炭窒化処理も施した試験片、軌道輪および玉軸受（表１中の比較例４）も用意した。
【００２９】
上記実施例および比較例の試験片、軌道輪および玉軸受のいずれかのサンプルについて、寸法安定性試験、ピーリング試験、スミアリング試験、サバン型摩耗試験および異物混入寿命試験を実施した。
各試験の概要と結果は以下の通りである。
【００３０】
（１）寸法安定性試験
３５０℃および２３０℃で焼戻し処理した軸受内輪を、それぞれ２５０℃と１５０℃で恒温保持し、内径の寸法変化率を測定した。保持時間は２５００時間とし、収縮の変化率は負の値で表示した。試験結果を表２に示す。
【００３１】
【表２】

【００３２】
実施例１〜６および比較例３の内輪は、寸法変化率が０．０１％以下であり、優れた寸法安定性を示す。浸炭窒化処理を施した実施例７、８は、これらよりもわずかに寸法変化率が大きいが、規格（０．０１５％以下）の範囲内に納まっている。比較例１は、寸法変化率は小さいが、３５０℃焼戻し、２５０℃保持の試験で収縮の寸法変化を示すため、内輪の嵌め合い応力が過多となる恐れがある。また、ＣｒとＭｏを多く含有する比較例３は膨張率が高く、規格を外れている。
【００３３】
（２）ピーリング試験
ピーリング試験は、円筒部に緩やかな曲率を有するリング状の試験片を駆動軸と、この駆動軸に平行な従動軸に取り付け、両試験片の円筒面を互いに押し当てて転動させるものである。各試験片の寸法は、直径４０ｍｍ、高さ１２ｍｍ、円筒部の曲率半径６０ｍｍであり、駆動軸側試験片の円筒面はＲmax ３μｍの粗さに研削仕上げ、従動軸側試験片の円筒面は鏡面仕上げされる。ピーリング強度は、試験終了時の従動軸側試験片円筒面のピーリング発生面積率で評価される。実施例１、７および比較例１、２について、以下の試験条件でピーリング試験を行った。なお、駆動軸側および従動軸側の両試験片は、同種のサンプルのものをペアとして用いた。
【００３４】
・試験片の最大表面粗さ：３．０μｍ（駆動軸側）、０．２μｍ（従動軸側）
・接触面圧Ｐmax ：２．３ＧＰａ
・潤滑油 ：タービン油ＶＧ４６
・駆動軸回転速度：２０００ｒｐｍ
・総回転数 ：４．８×１０⁵ 回
【００３５】
【表３】

【００３６】
試験結果を表３に示す。実施例の試験片は、いずれもピーリング発生面積率が１％程度であり、優れたピーリング強度を示す。比較例の各試験片は、実施例の３倍以上の大きなピーリング発生面積率になっている。
【００３７】
（３）スミアリング試験
スミアリング試験は、ピーリング試験と同じ装置を用いて、２つのリング状試験片を同様に転動させるものである。この試験の場合は、従動軸が一定速度で回転駆動され、駆動軸は従動軸と等速回転から徐々に増速される点が異なる。また、従動軸側試験片の円筒面が駆動軸側試験片と同じ表面粗さＲmax ３μｍに仕上げられる点も異なる。スミアリング強度は、試験片の円筒面にスミアリングが発生した時点の駆動軸と従動軸の速度比で評価される。実施例１、７および比較例１、２、４について、以下の試験条件でスミアリング試験を行った。なお、この試験においても、摺動されるペアの試験片は同種のサンプルのものとした。
【００３８】
・試験片の最大表面粗さ：３．０μｍ
・接触面圧Ｐmax ：２．１ＧＰａ
・潤滑油 ：タービン油ＶＧ４６
・駆動軸回転速度：２００ｒｐｍから１００ｒｐｍずつ増速
・従動軸回転速度：２００ｒｐｍ一定
試験結果を表３に併せて示す。実施例の試験片は、比較例１に対して、いずれも１．４倍以上の大きな速度比までスミアリングが発生しない。比較例の各試験片は、実施例の半分程度の速度差でスミアリングが発生している。
【００３９】
（４）サバン型摩耗試験
サバン型摩耗試験は、平板試験片を硬質の回転円筒の円筒面に一定時間押圧し、回転円筒との摺動で生じる平板試験片の摩耗痕の幅を測定して、体積摩耗量を算出するものである。実施例１、７および比較例１、２、４について、以下の試験条件でサバン型摩耗試験を行った。耐摩耗性は、比較例１の焼戻し温度が１８０℃のものとの体積摩耗量の比で評価した。
【００４０】
・平板試験片 ：幅５ｍｍ
・回転円筒 ：直径４０ｍｍ、幅４ｍｍ、硬さＨＲＣ６２
・押圧荷重 ：７８．４Ｎ
・接触面圧Ｐmax ：２０６ＭＰａ
・潤滑油 ：タービン油ＶＧ６８
・回転速度 ：２０００ｒｐｍ
・試験時間 ：１０分
試験結果を表３に併せて示す。実施例の試験片は、高温で焼戻しされても表面硬さが低下していないため、優れた耐摩耗性を示し、いずれも浸炭窒化処理を施された比較例４よりも体積摩耗量が少ない。
【００４１】
（４）異物混入寿命試験
実施例１、７および比較例１、２、４の玉軸受を硬質異物が混入された油浴中の回転軸に取り付け、ラジアル荷重を負荷して寿命試験を行った。この試験では、サンプル数Ｎを６とし、耐久寿命はＬ１０寿命（サンプルの９０％が破損しないで使える時間）で評価し、寿命比は比較例１の焼戻し温度が１８０℃のもののＬ１０寿命を基準値とした。
【００４２】
・玉軸受寸法 ：内径３０ｍｍ、外径６２ ｍｍ、幅１６ｍｍ
・回転速度 ：２０００ｒｐｍ
・ラジアル荷重：６．８６ｋＮ
・潤滑油 ：タービン油ＶＧ５６（２５ｃｃの油浴、油温６０℃）
・異物 ：ガスアトマイズ金属粉（粒径１００〜１８０μｍ、硬さＨＶ７００〜８００、混入量０．１ｇ／リットル）
試験結果を表３に併せて示す。実施例の玉軸受は、浸炭窒化処理なしの実施例１でも寿命比が２倍を越え、浸炭窒化処理をした実施例７は寿命比が１０倍近い長寿命になっている。
【００４３】
以上の各試験結果より、実施例のものは、優れた耐摩耗性と耐表面損傷性を有するとともに、異物混入下でも耐久寿命が長く、かつ使用中の寸法の経年変化も少ないことがわかる。
【００４４】
【発明の効果】
以上のように、この発明の連続鋳造設備のロール支持装置は、ロールを支持する転がり軸受の少なくとも軌道輪を、合金元素として質量％で、Ｃを１．０％以上で１．２％以下、Ｓｉを０．３％以上で３．０％以下、Ｎｉを０．１％以上で３．０％以下含有し、かつ、Ｖを０．０５％以上で１．０％以下、Ｍｏを０．０５％以上で０．２５％未満を単独または複合して含有する鋼材で形成し、表面硬さをロックウェル硬さＨＲＣ５８以上としたので、焼入れ焼戻し処理後の軸受の材質と表面硬さを高温下でも安定して転動疲労特性と耐摩耗性、耐表面損傷性に優れたものとし、高温環境下で使用されるロール支持装置のメインテナンス周期を長くして、連続鋳造設備の稼働率、さらには連続鋳造設備の上下工程の稼働率を高めることがきる。
【００４５】
また、合金元素として質量％で、Ｍｎを０．２％以上で１．５％以下、Ｃｒを０．３以上で５．０％以下添加することにより、前記転動疲労特性と耐摩耗性、耐表面損傷性をさらに向上させることができ、軸受の少くとも軌道輪の表層に浸炭窒化層を形成し、この浸炭窒化層の残留オーステナイト量を１０体積％以上とすることにより、表面層に高い靱性を付与して、亀裂の発生や進展を抑え、ロール支持装置のメインテナンス周期をさらに延ばすことができる。
【図面の簡単な説明】
【図１】実施形態のロール支持装置が組み込まれた連続鋳造設備の外観斜視図
【図２】ａは図１のロール支持装置の軸受部示す縦断面図、ｂはａの要部拡大断面図
【符号の説明】
１ ロール支持装置
２ 取鍋
３ タンディシュ
４ 鋳型
５ 鋳片
６ ピンチロール
７ ガイドロール
８ トーチ
９ ネック部
１０ 自動調心ころ軸受軌道
１１ ハウジング
１２、１３ シールリング
１４、１５ オイルシール
１６ 軌道
１７ 内輪
１８ 軌道
１９ 外輪
２０ ころ
２１ 保持器[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a roll support device that rotatably supports a pinch roll, a guide roll, and the like of a continuous casting facility on a housing.
[0002]
[Prior art]
Most slabs and bloom slabs, such as steel plates and steel bars, are manufactured with continuous casting equipment. Also, in the field of non-ferrous metals such as aluminum, continuous casting equipment may be used for the production of slabs. Many of the continuous casting equipment for slabs and blooms are of vertical type, curved type, or vertical curved type that combines these, and some non-ferrous metal and deformed parts are cast horizontally. Things are also used.
[0003]
FIG. 1 shows a vertical bending type as an embodiment of the present invention as an example of a continuous casting facility. This continuous casting equipment is for producing a slab for a steel plate. Molten steel placed in a ladle 2 is cast into a mold 4 through a tundish 3 and is primarily cooled in the mold 4 to form a surface layer portion. The solidified slab 5 is drawn vertically below the mold 4 by the pinch roll 6. The slab 5 pulled out by the pinch roll 6 is sandwiched between a large number of guide rolls 7 and guided in a curved shape. After being secondarily cooled by a spray (not shown) disposed between the rolls, the whole is solidified. Then, it is cut into a predetermined length by a torch 8 disposed at the exit of the curved portion.
[0004]
The pinch rolls and guide rolls differ depending on the type of continuous casting equipment, but these rolls are rotatably supported on the housing by rolling bearings and are driven to rotate at a low speed according to the casting speed. As a rolling bearing, a double row roller bearing is often used. Such a roll support device is subjected to a high load in a poor environment where the heat from the slab is placed in a high temperature environment and foreign matter such as scales peeled off from the slab, cooling water and its water vapor scatter. . The rolling bearings of these roll support devices are made by quenching high carbon chrome bearing steel SUJ2, and these bearings are tempered at a temperature higher than their operating temperature in order to prevent dimensional changes when the temperature rises. Has been processed.
[0005]
[Problems to be solved by the invention]
As described above, since the rolling bearing of the roll support device of the continuous casting equipment is used at a high load and a low speed under a high temperature environment, it is difficult to form an oil film of lubricating grease, and the grease is washed away by intrusion of cooling water or the like. As a result, wear on the raceway surface and surface damage such as peeling and smearing may occur. In some cases, a foreign object such as a scale bites into the raceway surface. For this reason, there are cases where the raceway surface is rough due to such wear or surface damage, and the maintenance cycle of the roll support device is short.
[0006]
Normally, continuous casting equipment is operated continuously day and night, and the period of periodic repairs is determined by adjusting the upper steelmaking process and the lower rolling process. Therefore, continuous casting equipment is used for maintenance of roll support equipment. Stopping irregularly not only lowers the operating rate of the continuous casting equipment, but also affects the operating rate of the steel making process and rolling process. In recent years, the ratio of direct rolling, in which continuous cast slabs are rolled without reheating, and hot charged rolling, in which continuous cast slabs are charged into a reheating furnace while hot, has increased. The impact of the stop on the rolling process is even greater.
[0007]
Then, the subject of this invention is providing the roll support apparatus of the continuous casting installation with a long maintenance cycle.
[0008]
[Means for Solving the Problems]
In order to solve the above problems, the present invention is a roll supporting device for a continuous casting facility for rotatably supported by a rolling bearing the roll housing, at least bearing ring of the bearing, by mass% as an alloying element, C 1.0% or more and 1.2% or less, Si 0.3% or more and 3.0% or less , Ni 0.1% or more and 3.0% or less , and V 0.05 % % Or more and 1.0% or less, Mo is 0.05% or more and less than 0.25% is formed of a steel material alone or in combination, and the surface hardness is set to Rockwell hardness HRC58 or more. Adopted.
[0009]
The alloy element of the steel material that forms at least the bearing ring of the bearing contains Si in an amount of 0.3 to 3.0% because Si suppresses softening in a high temperature region and improves the heat resistance of the rolling bearing. This is because there is an action to do. If it is less than 0.3%, the effect cannot be obtained, and the heat resistance is improved as the amount of Si is increased. However, if the content exceeds 3.0%, the effect is saturated and hot. Since workability and machinability deteriorate, the upper limit was limited to 3.0%.
[0010]
The reason why Ni is contained in an amount of 0.1 to 3.0%, V is 0.05 to 1.0%, and Mo is less than 0.05 to 0.25% alone or in combination is as follows.
[0011]
Ni dissolves in steel and strengthens the matrix. In particular, when the bearing is used at high temperatures, it suppresses changes in the structure during the rolling fatigue process and reduces the hardness at high temperatures. Suppress. Therefore, Ni has an effect of improving rolling fatigue characteristics, wear resistance, and surface damage resistance in a high temperature environment. Ni also has the effect of improving the corrosion resistance. In order to acquire these effects, since it is necessary to contain Ni 0.1% or more, the minimum in the case of adding was made into 0.1%. However, if Ni is contained in excess of 3.0%, a large amount of retained austenite is generated during the quenching process, and a predetermined hardness cannot be obtained, and the cost of the steel material becomes expensive. Limited to 0%.
[0012]
V binds to carbon to precipitate fine carbides, refines crystal grains to improve strength and toughness, suppresses softening during high-temperature tempering treatment, and further suppresses softening in a high-temperature region. Therefore, like Ni described above, V has an effect of improving rolling fatigue characteristics, wear resistance, and surface damage resistance under a high temperature environment. In order to obtain this effect, the lower limit of the V content is set to 0.05%. The reason why the upper limit is limited to 1.0% is that if V is contained in a large amount exceeding 1.0%, machinability and hot workability are lowered.
[0013]
Mo improves the hardenability of the steel, prevents temper embrittlement, and further suppresses softening at high temperatures. Therefore, Mo also has the effect of improving rolling fatigue characteristics, wear resistance, and surface damage resistance in a high temperature environment. In order to obtain this effect, the lower limit of the Mo content is set to 0.05%. If the Mo content is 0.25% or more, the machinability decreases and the steel material cost also increases, so the upper limit was limited to less than 0.25%.
[0014]
Even if the bearing is subjected to tempering treatment at a high temperature due to the action of each alloy element described above, the surface hardness is set to Rockwell hardness HRC58 or more to ensure excellent rolling fatigue characteristics. The wear resistance and surface damage resistance can be improved, the durability life of the bearing can be extended, and the maintenance cycle of the roll support device can be extended.
[0015]
By adding mass% as an alloying element to the steel material, Mn is 0.2% or more and 1.5% or less, and Cr is 0.3 or more and 5.0% or less. Abrasion and surface damage resistance can be further improved.
[0016]
That is, both Mn and Cr improve the hardenability of the steel material, Mn dissolves in the steel and strengthens the steel, and Cr forms carbides and strengthens the steel. The reason why the lower limit of the Mn content is 0.2% and the lower limit of the Cr content is 0.3% is to obtain these effects. In addition, the upper limit of the Mn content is limited to 1.5% in order to avoid a decrease in machinability, and the upper limit of the Cr content is limited to 5.0% in order to generate large carbides. This is to prevent embrittlement due to the above.
[0017]
By forming a carbonitriding layer on at least the surface layer of the bearing ring of the bearing and making the amount of retained austenite of the carbonitriding layer 10 volume% or more, the surface layer of the bearing ring is imparted with high toughness and cracks are generated. And the progress can be suppressed, and the durability life of the bearing can be further extended.
[0018]
That is, when the nitrogen content of the surface layer is increased by carbonitriding, the Ms point (martensite transformation start temperature) of the surface layer is lowered, and when this is quenched, a large amount of untransformed austenite remains in the surface layer. Residual austenite has high toughness and work-hardening properties and functions to suppress the occurrence and development of cracks. Also, the surface layer with a lower Ms point starts martensite transformation later than the inside, and the amount of transformation is less than the inside, so that a compressive residual stress is formed in the surface layer and the fatigue strength of the surface layer is improved. To do. The reason why the amount of retained austenite in the carbonitrided layer is set to 10% by volume or more is to obtain these effects. On the other hand, since the amount of retained austenite is reduced due to high temperature tempering, the dimensional change due to decomposition of retained austenite during use can be suppressed.
[0019]
A double row roller bearing can be adopted as the rolling bearing device.
[0020]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows a continuous casting facility using the roll support apparatus 1 of the present invention. As described above, this continuous casting equipment is for producing a slab for a steel plate. Molten steel placed in a ladle 2 is cast into a mold 4 through a tundish 3, and the surface layer portion is solidified in the mold 4. The cast slab 5 is pulled out vertically below the mold 4 by the pinch roll 6. The slab 5 pulled out by the pinch roll 6 is sandwiched between a large number of guide rolls 7 and guided in a curved shape. After being cooled and sprayed, the whole is solidified, and then the torch 8 disposed at the exit of the curved portion Cut to length. In addition, although illustration is abbreviate | omitted, each guide roll 7 is also rotatably supported by the roll support apparatus of another housing.
[0021]
As shown in FIG. 2A, the roll support device 1 rotatably supports a neck portion 9 of a pinch roll 6 on a housing 11 with a double-row self-aligning roller bearing 10. Both sides are sealed by seal rings 12 and 13 and oil seals 14 and 15, respectively. As shown in an enlarged view in FIG. 2B, the self-aligning roller bearing 10 is provided between an inner ring 17 having a double row raceway 16 on an outer peripheral surface and an outer ring 19 having a spherical raceway 18 on an inner peripheral surface. A double-row barrel-shaped roller 20 is rotatably held by a cage 21, an outer ring 19 is fitted to the inner peripheral surface of the housing 11, and an inner ring 17 is sealed to the neck portion 9 of the pinch roll 6. The axial direction is fixed by the rings 12 and 13.
[0022]
The inner ring 17 and the outer ring 19 are made of steel having chemical components shown in the following Table 1 as an example, heated to 840 ° C. to 860 ° C., quenched into a salt bath, and tempered at 350 ° C. . In some examples, heating before quenching was performed in a carburizing atmosphere to which ammonia gas was added, and carbonitriding was also performed. For the carbonitrided one, the tempering temperature was 230 ° C.
[0023]
The inner ring 17 and the outer ring 19 of the self-aligning roller bearing 10 of the above-described embodiment are both subjected to a carbonitriding process, as a result of inspection by sample extraction, both having a surface hardness of Rockwell hardness HRC58 or higher. The amount of retained austenite in the carbonitrided layer was 10% by volume or more.
[0024]
The above-described embodiments have shown the pinch roll support device of the vertical bending type continuous casting equipment. However, the roll support device of the present invention can be used in various types of continuous casting equipment including the non-ferrous metal field. It can be used for supporting a roll or the like.
[0025]
[Table 1]

[0026]
Examples and comparative examples are given below.
[0027]
【Example】
Using steels having six kinds of chemical components shown in Table 1 as raw materials, the test pieces and race rings subjected to the quenching and tempering treatment described above, and ball bearings using the race rings (Examples 1 to 6 in Table 1) Prepared. Test pieces, bearing rings and ball bearings (Examples 7 to 8 in Table 1) obtained by subjecting some of the steel materials shown in Examples 1 to 6 to carbonitriding were also prepared.
[0028]
[Comparative example]
High carbon chrome bearing steel SUJ2 and test pieces and race rings that were quenched and tempered of steels having two types of chemical components that deviate from the chemical component range of the present application, and ball bearings using the race rings (Comparative Example 1 in Table 1) ~ 3) were prepared. For those using SUJ2 as a raw material, a test piece, bearing ring and ball bearing (Comparative Example 4 in Table 1) which were also carbonitrided were also prepared.
[0029]
A dimensional stability test, a peeling test, a smearing test, a savan-type wear test, and a foreign matter contamination life test were performed on any of the samples of the test pieces, race rings and ball bearings of the above-mentioned examples and comparative examples.
The outline and results of each test are as follows.
[0030]
(1) Dimensional stability test The bearing inner rings tempered at 350 ° C and 230 ° C were kept at a constant temperature at 250 ° C and 150 ° C, respectively, and the dimensional change rate of the inner diameter was measured. The holding time was 2500 hours, and the rate of contraction change was displayed as a negative value. The test results are shown in Table 2.
[0031]
[Table 2]

[0032]
The inner rings of Examples 1 to 6 and Comparative Example 3 have a dimensional change rate of 0.01% or less and exhibit excellent dimensional stability. In Examples 7 and 8 subjected to the carbonitriding process, the dimensional change rate is slightly larger than these, but is within the range of the standard (0.015% or less). In Comparative Example 1, although the dimensional change rate is small, the dimensional change of shrinkage is shown in the test of tempering at 350 ° C. and holding at 250 ° C., so there is a possibility that the fitting stress of the inner ring becomes excessive. Further, Comparative Example 3 containing a large amount of Cr and Mo has a high expansion coefficient and is out of specification.
[0033]
(2) Peeling test In the peeling test, a ring-shaped test piece having a gentle curvature is attached to a cylindrical portion on a drive shaft and a driven shaft parallel to the drive shaft, and the cylindrical surfaces of both test pieces are pressed against each other for rolling. It is something to move. Each test piece has a diameter of 40 mm, a height of 12 mm, and a cylindrical portion with a radius of curvature of 60 mm. The cylindrical surface of the drive shaft side test piece is ground to a roughness of Rmax 3 μm, and the cylindrical surface of the driven shaft side test piece is Mirror finish. The peeling strength is evaluated by the peeling generation area ratio of the cylindrical surface of the driven shaft side test piece at the end of the test. For Examples 1 and 7 and Comparative Examples 1 and 2, a peeling test was performed under the following test conditions. In addition, the sample of the same kind was used as a pair for both the test pieces on the drive shaft side and the driven shaft side.
[0034]
・ Maximum surface roughness of test piece: 3.0 μm (drive shaft side), 0.2 μm (driven shaft side)
Contact surface pressure Pmax: 2.3 GPa
・ Lubricant: Turbine oil VG46
・ Drive shaft rotation speed: 2000rpm
・ Total number of revolutions: 4.8 × 10 ⁵ times [0035]
[Table 3]

[0036]
The test results are shown in Table 3. The test pieces of the examples all have a peeling generation area ratio of about 1% and exhibit excellent peeling strength. Each test piece of the comparative example has a large peeling area ratio that is three times or more that of the example.
[0037]
(3) Smearing test The smearing test rolls two ring-shaped test pieces in the same manner using the same apparatus as the peeling test. In this test, the driven shaft is rotationally driven at a constant speed, and the driving shaft is different from the driven shaft in that the speed is gradually increased from constant speed rotation. Another difference is that the cylindrical surface of the driven shaft side test piece is finished to the same surface roughness Rmax 3 μm as the drive shaft side test piece. The smearing strength is evaluated by the speed ratio between the drive shaft and the driven shaft when smearing occurs on the cylindrical surface of the test piece. For Examples 1 and 7 and Comparative Examples 1, 2, and 4, smearing tests were performed under the following test conditions. In this test as well, the pair of specimens to be slid was of the same type.
[0038]
・ Maximum surface roughness of specimen: 3.0 μm
・ Contact pressure Pmax: 2.1 GPa
・ Lubricant: Turbine oil VG46
-Drive shaft rotational speed: Increased by 200 rpm from 200 rpm-Driven shaft rotational speed: 200 rpm constant Test results are also shown in Table 3. In the test pieces of Examples, smearing does not occur up to a large speed ratio of 1.4 times or more compared to Comparative Example 1. Each test piece of the comparative example is smeared with a speed difference of about half that of the example.
[0039]
(4) Sabang-type wear test The Sabang-type wear test is a method in which a flat test piece is pressed against the cylindrical surface of a hard rotating cylinder for a certain period of time, and the width of the wear mark on the flat test piece generated by sliding with the rotating cylinder is measured. The volume wear amount is calculated. For Examples 1 and 7 and Comparative Examples 1, 2, and 4, a Saban-type wear test was performed under the following test conditions. The abrasion resistance was evaluated by the ratio of the volume wear amount with that of Comparative Example 1 having a tempering temperature of 180 ° C.
[0040]
・ Flat plate test piece: Width 5mm
・ Rotating cylinder: diameter 40mm, width 4mm, hardness HRC62
・ Pressure load: 78.4N
Contact surface pressure Pmax: 206 MPa
・ Lubricant: Turbine oil VG68
・ Rotation speed: 2000rpm
Test time: 10 minutes test results are also shown in Table 3. The test pieces of the examples show excellent wear resistance because the surface hardness does not decrease even when tempered at a high temperature, and each of them has a smaller volume wear amount than the comparative example 4 subjected to carbonitriding treatment. .
[0041]
(4) Foreign matter mixing life test The ball bearings of Examples 1 and 7 and Comparative Examples 1, 2, and 4 were attached to a rotating shaft in an oil bath mixed with hard foreign matter, and a life test was performed by applying a radial load. . In this test, the number of samples N was 6, and the durability life was evaluated as L10 life (time in which 90% of the sample can be used without being damaged), and the life ratio was based on the L10 life when the tempering temperature of Comparative Example 1 was 180 ° C. Value.
[0042]
Ball bearing dimensions: 30 mm inner diameter, 62 mm outer diameter, 16 mm width
・ Rotation speed: 2000rpm
・ Radial load: 6.86kN
Lubricating oil: Turbine oil VG56 (25 cc oil bath, oil temperature 60 ° C.)
Foreign matter: gas atomized metal powder (particle size 100 to 180 μm, hardness HV 700 to 800, mixing amount 0.1 g / liter)
The test results are also shown in Table 3. The ball bearing of the example has a life ratio exceeding twice even in Example 1 without the carbonitriding treatment, and the life ratio of Example 7 with the carbonitriding treatment is nearly 10 times longer.
[0043]
From the above test results, it can be seen that the examples have excellent wear resistance and surface damage resistance, have a long durability life even under the presence of foreign matter, and have little aging change in dimensions during use.
[0044]
【The invention's effect】
As described above, the roll support device of the continuous casting equipment according to the present invention includes at least a bearing ring of a rolling bearing that supports the roll in mass% as an alloy element, and C is 1.0% or more and 1.2% or less, Si is 0.3% or more and 3.0% or less , Ni is 0.1% or more and 3.0% or less , V is 0.05% or more and 1.0% or less, and Mo is 0.00%. It is made of steel material containing 05% or more and less than 0.25% alone or in combination, and the surface hardness is set to Rockwell hardness HRC58 or more, so the material and surface hardness of the bearing after quenching and tempering treatment are high temperature The rolling fatigue characteristics, wear resistance, and surface damage resistance are stable even under high conditions, the maintenance cycle of roll support equipment used in high temperature environments is lengthened, the operation rate of continuous casting equipment, Can increase the operating rate of the upper and lower processes of continuous casting equipment
[0045]
Further, by adding mass% as an alloy element, Mn is 0.2% or more and 1.5% or less, and Cr is 0.3 or more and 5.0% or less, the rolling fatigue characteristics and wear resistance, The surface damage resistance can be further improved, and a carbonitriding layer is formed on the surface layer of at least the bearing ring of the bearing, and the amount of retained austenite of the carbonitriding layer is 10% by volume or more. It is possible to impart toughness, suppress the occurrence and development of cracks, and further extend the maintenance cycle of the roll support device.
[Brief description of the drawings]
FIG. 1 is an external perspective view of a continuous casting facility in which a roll support device of an embodiment is incorporated. FIG. 2a is a longitudinal sectional view showing a bearing portion of the roll support device of FIG. [Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Roll support apparatus 2 Ladle 3 Tundish 4 Mold 5 Slab 6 Pinch roll 7 Guide roll 8 Torch 9 Neck part 10 Self-aligning roller bearing track 11 Housing 12, 13 Seal ring 14, 15 Oil seal 16 Track 17 Inner ring 18 Track 19 Outer ring 20 Roller 21 Cage

Claims (4)

In a roll support device of a continuous casting facility that rotatably supports a roll by a rolling bearing on a housing, at least the bearing ring of the bearing is mass% as an alloy element, and C is 1.0% or more and 1.2% or less, Si is 0.3% or more and 3.0% or less , Ni is 0.1% or more and 3.0% or less , V is 0.05% or more and 1.0% or less, and Mo is 0.00%. A roll support device for continuous casting equipment, characterized in that it is formed of a steel material containing not less than 05% and less than 0.25% alone or in combination, and the surface hardness is not less than Rockwell hardness HRC58. 2. The continuous casting equipment according to claim 1, wherein the steel material is added by mass% as an alloy element, Mn is 0.2% or more and 1.5% or less, and Cr is 0.3% or more and 5.0% or less. Roll support device. The roll support device for a continuous casting facility according to claim 1 or 2, wherein a carbonitriding layer is formed on at least a surface layer of the bearing ring of the bearing, and a residual austenite amount of the carbonitriding layer is 10% by volume or more. The roll support device for continuous casting equipment according to any one of claims 1 to 3, wherein the rolling bearing is a double row roller bearing.

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