JP3772202B2 - Composite work roll for cold rolling and manufacturing method thereof - Google Patents
Composite work roll for cold rolling and manufacturing method thereof Download PDFInfo
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Description
【０００１】
【発明の属する技術分野】
本発明は、鉄鋼の冷間圧延に用いられる冷間圧延用複合ワークロール及びその製造方法に関するものである。
【０００２】
【従来の技術】
従来、鉄鋼の冷間圧延用ワークロールとしては、特開昭５４−１５９３２３号公報に開示されているような５〜７％Ｃｒを含む鍛鋼が適用されてきた。これら従来の５〜７％Ｃｒ鍛鋼はオーステナイト化温度９００〜１０００℃から焼入がなされ、Ｍｓ点が２００〜３００℃程度と高く、焼入完了時点で残留オーステナイトが十分に少なく、Ｈｓ９０以上の高硬度が達成される。さらに、高硬度を安定して確保するため、残留オーステナイトをさらに分解すべく、焼入に引続き、サブゼロ処理の実施が不可欠の工程となっている。また、焼戻しは硬度を損なわないように２００℃以下の低温にて行われている。
【０００３】
【発明が解決しようとする課題】
冷間圧延において圧延中にロールのスリップや板破断が発生した場合、ロール表面が局所的に急激に過熱される現象が生ずる。従来ロールは２００℃以下の低温にて焼戻が施されており、ロール表面温度が２００℃を超えると局所的な組織変化により硬度斑の発生、場合によっては表面亀裂が発生し問題となっている。さらに、低温焼戻を適用しているため、ロール表面の圧縮残留応力が高く、亀裂が発生した場合、その進展速度が大きくスポーリングに至る可能性があった。その対策として高温焼戻が有効であることは良く知られたことである。
【０００４】
【課題を解決するための手段】
上述したような問題を解決するべく、発明者らは鋭意開発を進めた結果、本発明は、冷間圧延用ワークロールを製造するにあたり、その成分、熱処理特性を特定することにより、高温焼戻の実施を可能とし、さらに、従来は不可欠の工程であった、鍛造、サブゼロ処理を省略することにより、耐事故性に優れ、かつ安価なロールを供給することを目的とするものである。
【０００５】
その発明の要旨とするところは、
（１）鋳鋼または鍛鋼からなる芯材の周囲に連続鋳掛肉盛法にて外層を形成してなる冷間圧延用複合ワークロールであって、上記外層を重量比で、Ｃ：０．８〜１．５％、Ｓｉ：０．３〜１．５％、Ｍｎ：０．３〜１．５％、Ｃｒ：４．０〜１０．０％、Ｍｏ：１．０〜８．０％、Ｖ：０．５〜５．０％、残部がＦｅ及び不可避的不純物からなり、かつオーステナイト化温度１０００〜１１００℃におけるＭｓ点が１００℃以上２２０℃以下となるような成分で構成されることを特徴とする冷間圧延用複合ワークロール。
【０００６】
（２）重量比で、Ｃ：０．８〜１．５％、Ｓｉ：０．３〜１．５％、Ｍｎ：０．３〜１．５％、Ｃｒ：４．０〜１０．０％、Ｍｏ：１．０〜８．０％、Ｖ：０．５〜５．０％、残部がＦｅ及び不可避的不純物からなり、かつオーステナイト化温度１０００〜１１００℃におけるＭｓ点が１００℃以上２２０℃以下となる鋼を、鋳鋼または鍛鋼にて構成される芯材の周囲に連続鋳掛肉盛法にて外層として形成し、軟化焼鈍、予備調質を経て、オーステナイト化温度１０００〜１１００℃にて漸進誘導加熱・水焼入により、焼入を行い、サブゼロ処理を行うことなく４００〜６００℃の温度範囲で２回以上焼戻を行うことを特徴とする冷間圧延用複合ワークロールの製造方法にある。
【０００７】
【発明の実施の形態】
以下、本発明に係る外層の成分を限定した理由を以下に述べる。
Ｃは硬さを得るための重要な元素である。Ｃ量が０．８％未満であるとマトリックスに固溶するＣが不足し、十分なマトリックス硬さが得られなくなると同時に、高合金化が難しくなる。しかし、１．５％を超えると炭化物が粗大化し強度が低下するので上限を１．５％とした。
Ｓｉは脱酸剤として必要な元素である。その硬化を発揮するには０．３％以上必要であるが１．５％を超えると脆化するため好ましくない。
【０００８】
ＭｎもＳｉ同様、脱酸剤として必要な元素である。その効果を発揮するには０．３％以上必要であるが１．５％を超えると脆化するため好ましくない。
ＣｒはＣと結合しやすくＭ7 Ｃ3 系炭化物を構成し、耐摩耗性を確保する上で必要な元素であるが少ないと十分な耐摩耗性が確保できず、一方多すぎると炭化物が粗大化しネット状に発達する傾向があり靱性が低下する。その最適な範囲は４％以上１０％以下である。
【０００９】
Ｍｏは硬質の炭化物が得られ、また高温で焼戻を行う場合、その二次硬化に強く寄与する元素である。１％未満の場合、炭化物としての析出が不十分である。しかし、８％を超えるとネット状の粗大な炭化物となるため、その適切な範囲を１％以上８％以下とした。 Ｖは硬度の極めて高いＭＣ系炭化物を形成するため最も強く耐摩耗性に寄与する元素である。しかし、０．５％未満であるとその効果は小さく、５％を超えると研削性が阻害されるため、その範囲を０．５％以上５％以下とした。
【００１０】
本発明においては、以下に説明するようにオーステナイト化温度１０００〜１１００℃におけるＭｓ点が１００℃以上２２０℃以下であることが重要であり、そのためには上記成分範囲に中でさらにＭｓ点が上記温度範囲に入るよう各々の成分の添加量組合せ及び調整が必要である。
なお、本発明のロールの焼入方法としては漸進誘導加熱・水焼入の採用が望ましく、焼入におけるロール表面の冷却速度としては２００℃／分以上、さらに望ましくは５００℃／分以上の冷却速度を確保することが望ましい。
【００１１】
本発明の焼入条件および成分系ではＭｓ点が低いため、残留オーステナイトが多量に残留し、焼入時の硬さはＨｓ７０〜８０程度にすぎない。従来ならば、ここで焼戻実施前にサブゼロ処理が実施され、焼入硬さがＨｓ９０となるよう調整が行われる。しかし本発明においては、このようなサブゼロ処理の実施は不要である。なお、Ｍｓ点が１００℃を下回ると残留オーステナイトがあまりに多量に残留し安定化するため、高温焼戻で二次硬化を得ることが困難となり、Ｈｓ９０以上の高硬度を確保するためには、サブゼロ処理の実施が不可欠となり、本発明の目的の１つに反する。一方、Ｍｓ点が２２０℃を超えると、焼入時でＨｓ９０以上の高硬度が得られるものの、５００℃以上の高温焼戻を行った場合、残留オーステナイトが少なすぎるため、二次硬化が得られず、硬さはむしろ低下することになる。
【００１２】
次に、本発明に係る冷間圧延用複合ワークロールの製造法について説明する。
本発明に係る成分範囲は従来ロールに比べ、焼入性改善のため、高Ｃ、高合金の成分設計となっており、鋳造法としては連続鋳掛肉盛法が望ましい。従来のＥＳＲ（エレクトロ スラグ リメルティング）法により鋳造した一体型ロールの場合、鍛造が必要であり、また、高Ｃ、高合金の成分設計とした場合軸の靱性確保の点で問題がある。従って、靱性のある素材を芯材として用いることのできる複合ロールとすることが望ましい。複合ロールの製造法としては、他に特公平７−６８５８８号公報に開示されているＥＳＲ法にて芯材の外周に外層材を溶着させる方法が提案されている。本発明においてはＭｓ点を限られた温度範囲に入るよう調整するため、外層材の成分管理は厳しく行う必要がある。ＥＳＲ法の場合、溶着時の芯材の溶け込み量の制御が難しく、成分誤差が大きいという難点がある。本発明においては、芯材の溶け込み量の制御の容易な連続鋳掛肉盛法の適用が望ましい。
【００１３】
図１は本発明に係る連続鋳掛肉盛法を説明する概略図である。この図１に示すように、連続鋳掛肉盛法とは、垂直に立てられた芯材１の周囲に水冷モールド７を設け、その間隙に外層２からなる溶湯９を加熱コイル６により加熱しつつ導入し、芯材１を断続的に下方に引抜きながら順次凝固、芯材１への溶着を進め、複合ロールを鋳造するものである。この方法によれば、引抜き速度の調整により芯材溶け込み量の制御が容易にできるものである。鋳造後、直ちに軟化焼鈍を行い、所定の形状、寸法に粗削後、予備調質を経て漸進誘導加熱・水焼入により焼入が施される。なお、４は予熱コイル、５は耐火枠、７は水冷モールド、８はノズルである。
【００１４】
本発明では最適なＭｓ点の設定と焼戻し温度の組合せにより高硬度で、かつ耐事故性に優れた冷間圧延用複合ワークロールを提供するものである。本発明ではオーステナイト化温度１０００〜１１００℃の高温域から焼入が行われる。オーステナイト化温度が１１００℃を超えると晶出炭化物が固溶してしまうため好ましくない。また、１０００℃を下回るとＭｓ点が高くなり、残留オーステナイトが不足するため、本発明の目的である高温焼戻の適用が困難となる。焼入後の焼戻は４００℃以上の高温で行わなければならない。焼戻温度が４００℃より低いと二次硬化作用が得られない。逆に、焼戻温度が６００℃より高いとかえって硬さが低下することになる。望ましくは５００〜５５０℃の温度範囲で２回以上行うとよい。
【００１５】
【実施例】
（実施例１）
表１に示す各成分にてサンプル材を溶製し、８５０℃×１０時間の軟化焼鈍を行い、１０００℃×１０時間の拡散処理、次いで７００℃×１０時間の焼戻を行った後、サイズ径３×１０ｍｍの試験片を作製した。各成分につき５〜６本の試験片を作製し、それぞれ全自動変態膨張測定装置を用いて温度１０５０℃に１０分間保定の後、−２００℃／分の冷却速度にて室温まで冷却した。その後、４００〜６００℃の温度範囲で温度条件を変えながら２〜３回焼戻処理を行い、ビッカース硬さを測定した。表１に全自動変態膨張測定装置にて測定された各成分のオーステナイト化温度１０５０℃におけるＭｓ点および焼戻処理において得られた最高硬さをショア硬さに換算した値を示す。
【００１６】
【表１】
表１から明らかなように、本発明にかかる成分範囲に属し、かつ、オーステナイト化温度範囲１０００〜１１００℃での高温焼戻によりＭｓ点が１００〜２２０℃の温度範囲にある本発明例Ｎｏ１〜Ｎｏ５の全てにおいてはサブゼロ処理を行うことなく、４００〜６００℃での高温焼戻の実施によりＨｓ９０以上の高硬度がいずれも確保されている。これに対して、比較例Ｎｏ６においては、Ｃ，Ｓｉ，Ｍｎ，Ｃｒ，Ｍｏ，Ｖの成分は、本発明の成分範囲には属するものの、オーステナイト化温度１０００〜１１００℃におけるＭｓ点が１００℃未満であるため、残留オーステナイトが多く生成し、その結果５００〜６００℃の高温焼戻を行っても二次硬化が得られなかった。
【００１８】
比較例Ｎｏ７においては、成分は本発明の成分範囲に属するものの、オーステナイト化温度１０００〜１１００℃におけるＭｓ点が２２０℃を超えているため、４００〜６００℃での高温焼戻において、硬度低下によりＨｓ９０以上の硬度を得ることができなかった。比較例Ｎｏ８，Ｎｏ９においては、オーステナイト化温度１０００〜１１００℃におけるＭｓ点が２２０℃を超えているため、比較例Ｎｏ７と同じく、Ｈｓ９０以上の硬度が得られなかった。なお、比較例Ｎｏ８の場合、Ｃ量が０．８％を下回っているため、合金量を調整してもＭｓ点を本発明の温度範囲に調整することはできない。
【００１９】
また、比較例Ｎｏ９の場合、Ｃ量が１．５％を超えており、合金量を本発明の成分範囲の上限に調整してもＭｓ点を本発明の温度範囲を満足させることはできない。本発明の成分範囲を超えて合金を添加するとＭｓ点を下げることは可能であるが、炭化物の粗大化するためロール材料としては適さない。
なお、Ｃ，Ｓｉ，Ｍｎ，Ｃｒ，Ｍｏ，Ｖの各々の成分量が本発明工程の範囲内の溶湯であっても、Ｍｓ点が２２０℃より高くなった場合には、例えばＣ０．８〜１．５％の範囲内でＣ量を上げる、あるいは合金量を減らすことにより成分調整すると良い。また、逆にＭｓ点が１００℃より低い場合には、その逆の調整をすると良い。
【００２０】
（実施例２）
表２に示す成分を有する外層材を径４５０ｍｍ、長さ３５００ｍｍの芯材ＳＣＭ４４０に厚さ７０ｍｍで１７００ｍｍ長さ連続鋳掛肉盛法により鋳造し、ロール用素材を作製した。なお、この成分のオーステナイト化温度１０５０℃におけるＭｓ点は予じめ別途作製した試験片を用いて全自動変態膨張測定装置にて測定したところ１２０℃であった。鋳造後直ちに軟化焼鈍を行い、粗削後、調質処理として１０００℃にオーステナイト化後、焼入し７００℃にて焼戻を行った。焼入前加工実施後、表面温度１１００℃にて漸進誘導加熱・水焼入により焼入を行った。室温まで冷却後、５３０℃にて２回焼戻を行った。その結果、硬さＨｓ９３を有するロールを製造することができた。このロールを最終仕上げ加工の後、冷間圧延タンデムミルにて使用に供したところ、板破断に遭遇しても硬度斑や表面亀裂が発生することなく、優れた耐事故性を有することが確認された。
【００２１】
【表２】
【発明の効果】
以上述べたように、本発明によれば耐事故性に優れ、かつ安価な冷間圧延用複合ワークロールを得ることができる極めて優れた効果を奏するものである。
【図面の簡単な説明】
【図１】本発明に係る連続鋳掛肉盛法を説明する概略図である。
【符号の説明】
１ 芯材
２ 外層
４ 予熱コイル
５ 耐火枠
６ 加熱コイル
７ 水冷モールド
８ ノズル
９ 溶湯[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a composite work roll for cold rolling used for cold rolling of steel and a method for producing the same.
[0002]
[Prior art]
Conventionally, forged steel containing 5 to 7% Cr as disclosed in JP-A-54-159323 has been applied as a work roll for cold rolling of steel. These conventional 5 to 7% Cr forged steels are quenched from an austenitizing temperature of 900 to 1000 ° C., the Ms point is as high as about 200 to 300 ° C., the retained austenite is sufficiently small at the time of completion of quenching, and Hs 90 or more is high. Hardness is achieved. Furthermore, in order to stably secure high hardness, it is indispensable to perform sub-zero treatment following quenching in order to further decompose retained austenite. Moreover, tempering is performed at a low temperature of 200 ° C. or less so as not to impair the hardness.
[0003]
[Problems to be solved by the invention]
When roll slip or plate breakage occurs during rolling in cold rolling, a phenomenon occurs in which the roll surface is locally rapidly heated. Conventional rolls are tempered at a low temperature of 200 ° C. or lower, and when the roll surface temperature exceeds 200 ° C., hardness irregularities are generated due to local structural changes, and surface cracks may occur in some cases. Yes. Furthermore, since low temperature tempering is applied, the compressive residual stress on the roll surface is high, and when cracks occur, the rate of progress is large, which may lead to spalling. It is well known that high temperature tempering is effective as a countermeasure.
[0004]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, the inventors have intensively developed, and as a result, the present invention has been designed to identify high temperature tempering by specifying its components and heat treatment characteristics when manufacturing a cold rolling work roll. In addition, by omitting forging and sub-zero treatment, which have been indispensable steps in the past, it is intended to supply rolls that are excellent in accident resistance and inexpensive.
[0005]
The gist of the invention is that
(1) A cold rolled composite work roll in which an outer layer is formed by a continuous casting overlay method around a core material made of cast steel or forged steel, and the outer layer is in a weight ratio of C: 0.8 to 1.5%, Si: 0.3-1.5%, Mn: 0.3-1.5%, Cr: 4.0-10.0%, Mo: 1.0-8.0%, V : 0.5 to 5.0%, the balance is composed of Fe and inevitable impurities, and is composed of components such that the Ms point at an austenitizing temperature of 1000 to 1100 ° C is 100 ° C to 220 ° C. A composite work roll for cold rolling.
[0006]
( 2 ) By weight ratio, C: 0.8 to 1.5%, Si: 0.3 to 1.5%, Mn: 0.3 to 1.5%, Cr: 4.0 to 10.0% , Mo: 1.0 to 8.0%, V: 0.5 to 5.0%, the balance is Fe and inevitable impurities, and the Ms point at an austenitizing temperature of 1000 to 1100 ° C is 100 ° C to 220 ° C. The following steel is formed as an outer layer around the core composed of cast steel or forged steel as an outer layer by the continuous casting overlaying method, undergoes soft annealing and preliminary tempering, and gradually proceeds at an austenitizing temperature of 1000 to 1100 ° C. A method for producing a composite work roll for cold rolling characterized by performing quenching by induction heating and water quenching and performing tempering twice or more in a temperature range of 400 to 600 ° C. without performing sub-zero treatment. There is .
[0007]
DETAILED DESCRIPTION OF THE INVENTION
The reason why the components of the outer layer according to the present invention are limited will be described below.
C is an important element for obtaining hardness. If the amount of C is less than 0.8%, the amount of C dissolved in the matrix is insufficient, and sufficient matrix hardness cannot be obtained, and at the same time, high alloying becomes difficult. However, if it exceeds 1.5%, the carbides become coarse and the strength decreases, so the upper limit was made 1.5%.
Si is an element necessary as a deoxidizer. In order to exhibit the hardening, 0.3% or more is necessary. However, if it exceeds 1.5%, it is not preferable because it becomes brittle.
[0008]
Mn is also an element necessary as a deoxidizing agent like Si. In order to exhibit the effect, 0.3% or more is necessary, but exceeding 1.5% is not preferable because it becomes brittle.
Cr is easy to bond with C and constitutes an M 7 C 3 type carbide. It is an element necessary for ensuring wear resistance, but if it is too small, sufficient wear resistance cannot be ensured. Tend to develop into a net shape and toughness decreases. The optimal range is 4% or more and 10% or less.
[0009]
Mo is an element that provides a hard carbide and contributes strongly to the secondary hardening when tempering is performed at a high temperature. When it is less than 1%, precipitation as carbide is insufficient. However, if it exceeds 8%, it becomes a net-like coarse carbide, so the appropriate range was made 1% to 8%. V is an element that contributes most strongly to wear resistance because it forms MC-based carbides with extremely high hardness. However, if it is less than 0.5%, the effect is small, and if it exceeds 5%, the grindability is hindered, so the range was made 0.5% to 5%.
[ 0010 ]
In the present invention, it is important that the Ms point at an austenitizing temperature of 1000 to 1100 ° C. is 100 ° C. or higher and 220 ° C. or lower as described below. It is necessary to combine and adjust the addition amount of each component so as to fall within the temperature range.
As the quenching method of the roll of the present invention, it is desirable to employ progressive induction heating / water quenching, and the cooling rate of the roll surface during quenching is 200 ° C./min or more, more preferably 500 ° C./min or more. It is desirable to ensure speed.
[ 0011 ]
Since the Ms point is low in the quenching conditions and the component system of the present invention, a large amount of retained austenite remains, and the hardness during quenching is only about Hs 70-80. Conventionally, the sub-zero treatment is performed here before the tempering, and the quenching hardness is adjusted to Hs90. However, in the present invention, it is not necessary to perform such sub-zero processing. If the Ms point is lower than 100 ° C., too much retained austenite remains and stabilizes, so that it is difficult to obtain secondary hardening by high-temperature tempering. In order to ensure a high hardness of Hs90 or more, subzero Implementation of the process becomes indispensable and is contrary to one of the objects of the present invention. On the other hand, when the Ms point exceeds 220 ° C., high hardness of Hs90 or higher can be obtained at the time of quenching, but when high temperature tempering of 500 ° C. or higher is performed, residual austenite is too small, and secondary hardening is obtained. Rather, the hardness will rather decrease.
[ 0012 ]
Next, the manufacturing method of the composite work roll for cold rolling which concerns on this invention is demonstrated.
The component range according to the present invention is a high-C, high-alloy component design for improving hardenability compared to conventional rolls, and the continuous casting overlay method is desirable as the casting method. In the case of an integral roll cast by the conventional ESR (electro slag remelting) method, forging is necessary, and when a high C, high alloy component design is used, there is a problem in securing the toughness of the shaft. Therefore, it is desirable to use a composite roll that can use a tough material as a core material. As another method for producing a composite roll, a method in which an outer layer material is welded to the outer periphery of a core material by the ESR method disclosed in Japanese Patent Publication No. 7-68588 has been proposed. In the present invention, since the Ms point is adjusted so as to fall within a limited temperature range, it is necessary to strictly manage the components of the outer layer material. In the case of the ESR method, it is difficult to control the penetration amount of the core material at the time of welding, and there is a problem that the component error is large. In the present invention, it is desirable to apply a continuous casting overlay method that allows easy control of the amount of core material penetration.
[ 0013 ]
FIG. 1 is a schematic diagram for explaining the continuous casting overlay method according to the present invention. As shown in FIG. 1, the continuous casting overlay method is a method in which a
[ 0014 ]
In the present invention, a composite work roll for cold rolling having high hardness and excellent accident resistance is provided by a combination of an optimal Ms point setting and a tempering temperature. In the present invention, quenching is performed from a high temperature range of austenitizing temperature 1000-1100 ° C. When the austenitizing temperature exceeds 1100 ° C., the crystallized carbide is dissolved, which is not preferable. On the other hand, when the temperature is lower than 1000 ° C., the Ms point becomes high and the retained austenite becomes insufficient. Tempering after quenching must be performed at a high temperature of 400 ° C or higher. If the tempering temperature is lower than 400 ° C., the secondary curing action cannot be obtained. Conversely, when the tempering temperature is higher than 600 ° C., the hardness is rather lowered. Desirably, it may be performed twice or more in a temperature range of 500 to 550 ° C.
[ 0015 ]
【Example】
Example 1
Sample materials were melted with the components shown in Table 1, softened and annealed at 850 ° C. for 10 hours, subjected to diffusion treatment at 1000 ° C. for 10 hours, and then tempered at 700 ° C. for 10 hours. A test piece having a diameter of 3 × 10 mm was produced. Five to six test pieces were prepared for each component, and each sample was held at a temperature of 1050 ° C. for 10 minutes using a fully automatic transformation expansion measuring device, and then cooled to room temperature at a cooling rate of −200 ° C./min. Then, tempering was performed 2 to 3 times while changing the temperature condition in the temperature range of 400 to 600 ° C., and the Vickers hardness was measured. Table 1 shows values obtained by converting the Ms point of each component measured by a fully automatic transformation expansion measuring device at an austenitizing temperature of 1050 ° C. and the maximum hardness obtained in the tempering process into Shore hardness.
[ 0016 ]
[Table 1]
As is apparent from Table 1, the present invention examples No1 belong to the component range according to the present invention and have an Ms point in the temperature range of 100 to 220 ° C by high temperature tempering in the austenitizing temperature range of 1000 to 1100 ° C. In all of No. 5 , high hardness of Hs90 or higher is ensured by performing high temperature tempering at 400 to 600 ° C. without performing sub-zero treatment. On the other hand, in Comparative Example No. 6 , although the components of C, Si, Mn, Cr, Mo, and V belong to the component range of the present invention, the Ms point at the austenitizing temperature of 1000 to 1100 ° C. is less than 100 ° C. Therefore, a lot of retained austenite was generated, and as a result, secondary curing could not be obtained even when tempering at 500 to 600 ° C. was performed.
[ 0018 ]
In comparative example No7 , although a component belongs to the component range of this invention, since the Ms point in austenitizing temperature 1000-1100 degreeC exceeds 220 degreeC, in high temperature tempering at 400-600 degreeC, by hardness reduction A hardness of Hs90 or higher could not be obtained. In Comparative Examples No. 8 and No. 9 , since the Ms point at the austenitizing temperature of 1000 to 1100 ° C. exceeded 220 ° C., the hardness of Hs90 or higher was not obtained as in Comparative Example No. 7 . In the case of comparative example No8 , since the C amount is less than 0.8%, the Ms point cannot be adjusted to the temperature range of the present invention even if the alloy amount is adjusted.
[ 0019 ]
In the case of Comparative Example No. 9 , the C amount exceeds 1.5%, and even if the alloy amount is adjusted to the upper limit of the component range of the present invention, the Ms point cannot satisfy the temperature range of the present invention. If an alloy is added exceeding the component range of the present invention, it is possible to lower the Ms point, but it is not suitable as a roll material because of coarsening of carbides.
In addition, even if each component amount of C, Si, Mn, Cr, Mo, and V is a molten metal within the range of the process of the present invention, when the Ms point is higher than 220 ° C., for example, C0.8 to It is preferable to adjust the components by increasing the C content within the range of 1.5% or decreasing the alloy content. On the contrary, when the Ms point is lower than 100 ° C., the reverse adjustment may be performed.
[ 0020 ]
(Example 2)
An outer layer material having the components shown in Table 2 was cast on a core material SCM440 having a diameter of 450 mm and a length of 3500 mm by a continuous casting overlay method having a thickness of 70 mm and a length of 1700 mm to produce a roll material. The Ms point of this component at an austenitizing temperature of 1050 ° C. was 120 ° C. when measured with a fully automatic transformation expansion measuring device using a test piece separately prepared in advance. Immediately after casting, soft annealing was performed, and after rough cutting, as a tempering treatment, austenitized to 1000 ° C., quenched, and tempered at 700 ° C. After the pre-quenching processing, quenching was performed by progressive induction heating and water quenching at a surface temperature of 1100 ° C. After cooling to room temperature, tempering was performed twice at 530 ° C. As a result, a roll having a hardness Hs93 could be manufactured. When this roll was used in a cold-rolled tandem mill after final finishing, it was confirmed that it had excellent accident resistance without causing hardness spots or surface cracks even when it encountered a plate break. It was.
[ 0021 ]
[Table 2]
【The invention's effect】
As described above, according to the present invention, it is possible to obtain a cold work composite work roll for cold rolling that is excellent in accident resistance and has an extremely excellent effect.
[Brief description of the drawings]
FIG. 1 is a schematic view for explaining a continuous cast overlay method according to the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1
Claims (2)
Ｃ：０．８〜１．５％、
Ｓｉ：０．３〜１．５％、
Ｍｎ：０．３〜１．５％、
Ｃｒ：４．０〜１０．０％、
Ｍｏ：１．０〜８．０％、
Ｖ：０．５〜５．０％、
残部がＦｅ及び不可避的不純物からなり、かつオーステナイト化温度１０００〜１１００℃におけるＭｓ点が１００℃以上２２０℃以下となるような成分で構成されることを特徴とする冷間圧延用複合ワークロール。A composite work roll for cold rolling in which an outer layer is formed by a continuous casting overlay method around a core material made of cast steel or forged steel, and the outer layer is in a weight ratio,
C: 0.8 to 1.5%
Si: 0.3 to 1.5%,
Mn: 0.3 to 1.5%,
Cr: 4.0 to 10.0%,
Mo: 1.0-8.0%,
V: 0.5-5.0%
A composite work roll for cold rolling, characterized in that the balance is made of Fe and inevitable impurities, and the Ms point at an austenitizing temperature of 1000 to 1100 ° C is 100 ° C to 220 ° C.
Ｃ：０．８〜１．５％、
Ｓｉ：０．３〜１．５％、
Ｍｎ：０．３〜１．５％、
Ｃｒ：４．０〜１０．０％、
Ｍｏ：１．０〜８．０％、
Ｖ：０．５〜５．０％、
残部がＦｅ及び不可避的不純物からなり、かつオーステナイト化温度１０００〜１１００℃におけるＭｓ点が１００℃以上２２０℃以下となる鋼を、鋳鋼または鍛鋼にて構成される芯材の周囲に連続鋳掛肉盛法にて外層として形成し、軟化焼鈍、予備調質を経て、オーステナイト化温度１０００〜１１００℃にて漸進誘導加熱・水焼入により、焼入を行い、サブゼロ処理を行うことなく４００〜６００℃の温度範囲で２回以上焼戻を行うことを特徴とする冷間圧延用複合ワークロールの製造方法。 By weight,
C: 0.8 to 1.5%
Si: 0.3 to 1.5%,
Mn: 0.3 to 1.5%,
Cr: 4.0 to 10.0%,
Mo: 1.0-8.0%,
V: 0.5-5.0%
Continuous cast overlaying around the core composed of cast steel or forged steel, with the balance being Fe and unavoidable impurities and having an Ms point of 100 ° C. to 220 ° C. at an austenitizing temperature of 1000 to 1100 ° C. It is formed as an outer layer by the method, undergoes soft annealing, preliminary tempering, quenching by progressive induction heating / water quenching at an austenitizing temperature of 1000-1100 ° C., and 400-600 ° C. without sub-zero treatment A method for producing a composite work roll for cold rolling, characterized in that tempering is performed twice or more in the temperature range .
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
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| JP09366098A JP3772202B2 (en) | 1998-04-06 | 1998-04-06 | Composite work roll for cold rolling and manufacturing method thereof |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP09366098A JP3772202B2 (en) | 1998-04-06 | 1998-04-06 | Composite work roll for cold rolling and manufacturing method thereof |
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| Publication Number | Publication Date |
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| JPH11285710A JPH11285710A (en) | 1999-10-19 |
| JP3772202B2 true JP3772202B2 (en) | 2006-05-10 |
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Families Citing this family (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1301815C (en) * | 2005-06-01 | 2007-02-28 | 东北大学 | Electromagnetic continuous casting method of composite roller and its casting equipment |
| SE0600841L (en) * | 2006-04-13 | 2007-10-14 | Uddeholm Tooling Ab | Cold Work |
| KR101672915B1 (en) * | 2015-01-07 | 2016-11-08 | 주식회사 광성텍 | Composite roll manufactured by drawing process and manufacturing method of the same |
| CN105239012B (en) * | 2015-10-15 | 2018-05-18 | 中钢集团邢台机械轧辊有限公司 | Semi high speed steel cold-rolling working roll and manufacturing method with highly resistance accident performance |
| CN114367538A (en) * | 2021-12-23 | 2022-04-19 | 中钢集团邢台机械轧辊有限公司 | Working roll of temper mill and manufacturing method thereof |
| CN115074625B (en) * | 2022-06-23 | 2023-05-09 | 宝钢轧辊科技有限责任公司 | Intermediate roll of Sendzimir mill and manufacturing method thereof |
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1998
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