JPH02217106A - Graphite steel roll excellent in crack resistance - Google Patents
Graphite steel roll excellent in crack resistanceInfo
- Publication number
- JPH02217106A JPH02217106A JP3865489A JP3865489A JPH02217106A JP H02217106 A JPH02217106 A JP H02217106A JP 3865489 A JP3865489 A JP 3865489A JP 3865489 A JP3865489 A JP 3865489A JP H02217106 A JPH02217106 A JP H02217106A
- Authority
- JP
- Japan
- Prior art keywords
- graphite
- roll
- forged
- forging
- crack resistance
- 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.)
- Granted
Links
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 title claims abstract description 52
- 229910002804 graphite Inorganic materials 0.000 title claims abstract description 52
- 239000010439 graphite Substances 0.000 title claims abstract description 52
- 229910000831 Steel Inorganic materials 0.000 title claims abstract description 23
- 239000010959 steel Substances 0.000 title claims abstract description 23
- 238000005242 forging Methods 0.000 claims abstract description 17
- 239000000463 material Substances 0.000 abstract description 3
- 238000005096 rolling process Methods 0.000 description 11
- 238000000034 method Methods 0.000 description 6
- 230000000694 effects Effects 0.000 description 4
- 238000011081 inoculation Methods 0.000 description 4
- 239000000203 mixture Substances 0.000 description 4
- 238000005452 bending Methods 0.000 description 2
- 238000005266 casting Methods 0.000 description 2
- 239000011159 matrix material Substances 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- 229910052751 metal Inorganic materials 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- 229920002165 CarbonCast Polymers 0.000 description 1
- 230000005856 abnormality Effects 0.000 description 1
- 230000002411 adverse Effects 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 230000000052 comparative effect Effects 0.000 description 1
- 238000004512 die casting Methods 0.000 description 1
- 230000002401 inhibitory effect Effects 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21B—ROLLING OF METAL
- B21B27/00—Rolls, roll alloys or roll fabrication; Lubricating, cooling or heating rolls while in use
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Reduction Rolling/Reduction Stand/Operation Of Reduction Machine (AREA)
Abstract
Description
【発明の詳細な説明】
（産業上の利用分野）
本発明は、耐クラツク性に優れた黒鉛鋼ロールあるいは
ローラに関する。DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a graphite steel roll or roller with excellent crack resistance.
（従来の技術）
一般に、分塊圧延や形鋼圧延などの粗スタンドで使用さ
れるロールは、特に苛酷な圧延条件下で使用されるため
、以下の様な問題が発生する。(Prior Art) In general, rolls used in roughing stands for blooming, section rolling, etc. are used under particularly severe rolling conditions, and therefore the following problems occur.
まず、圧延時にロールに対して極めて大きな圧延荷重が
かかり、特にロール胴部に形成されたカリバー底部のコ
ーナ一部には、前記荷重が集中するため、該コーナ一部
にクラックが発生し易い。First, an extremely large rolling load is applied to the roll during rolling, and the load is particularly concentrated at a corner of the bottom of the caliber formed in the roll body, so that cracks are likely to occur at the corner.
該クラックのうち、ロール周方向に形成されたクラック
は圧延作業の進行に伴い周方向に長くかつ径方向に深く
進展するので、ロール折損事故の原因となる。また、圧
延中のロールにおいて、スリン１やかみ止まりなどの異
常が発生した場合には、圧延が一時中断するため被圧延
材の温度が低下し、これに伴って圧延荷重が増加するの
で、ロールに作用する曲げ応力が過大となりロール折損
に至る場合がある。Among these cracks, cracks formed in the circumferential direction of the roll grow longer in the circumferential direction and deeper in the radial direction as the rolling operation progresses, and thus become a cause of roll breakage accidents. In addition, if an abnormality such as sulin 1 or stoppage occurs in the roll during rolling, rolling will be temporarily interrupted and the temperature of the material to be rolled will drop, and the rolling load will increase accordingly. The bending stress acting on the roll may become excessive, leading to roll breakage.
上述の様な問題解決のため、通常、強靭性、耐クラツク
性が良好な黒鉛鋼ロールが使用されている。黒鉛鋼ロー
ルは、組織中に晶出した球状または塊状の黒鉛が、ロー
ルに加えられた衝撃荷重を吸収すると共にクラックの進
展緩和を図ることができるので、優れた耐折損性を有し
ている。To solve the above-mentioned problems, graphite steel rolls, which have good toughness and crack resistance, are usually used. Graphite steel rolls have excellent breakage resistance because the spherical or lump-like graphite crystallized in the structure can absorb the impact load applied to the roll and alleviate the propagation of cracks. .
（発明が解決しようとする課題）
上述の様に、黒鉛鋼ロールは、耐折損性が比較的良好な
のであるが、その効果はいまだ十分満足できるものでは
なく、特に既述の様な、カリハー底部などにクラックが
発生し易いロールにおいては問題となり易い。(Problems to be Solved by the Invention) As mentioned above, graphite steel rolls have relatively good breakage resistance, but the effect is still not fully satisfactory, especially when the This can easily become a problem in rolls where cracks are likely to occur.
本発明は上述の問題点に鑑みてなされたもので、ロール
の耐クラック性を向上すると共に、強靭性も向上させる
ことによって折損事故の発生しにくい黒鉛鋼ロールを提
供することを目的としている。The present invention was made in view of the above-mentioned problems, and an object of the present invention is to provide a graphite steel roll that is less prone to breakage accidents by improving the crack resistance of the roll and also improving the toughness.
（課題を解決するための手段）
上記目的を達成するためになされた本発明は、鍛造によ
り黒鉛がロールの軸方向に沿って延伸された黒鉛鋼ロー
ルであって、該ロール胴部における前記黒鉛は、主とし
てその短径ｄと長さｌの比ｆｉ／ｄが３以上であること
を発明の構成としている。(Means for Solving the Problems) The present invention, which has been made to achieve the above object, provides a graphite steel roll in which graphite is stretched along the axial direction of the roll by forging, wherein the graphite in the body of the roll is The main feature of the invention is that the ratio fi/d of the minor axis d to the length l is 3 or more.
（作 用）
本発明の黒鉛鋼ロールは、鋳造素材を鍛造成形したので
、黒鉛鋼の組織中に晶出している球状または塊状の黒鉛
を、前記鍛造加工によって、被鍛造材の主変形方向（す
なわち該ロールの軸方向）に沿って細長く延伸させるこ
とができた。(Function) Since the graphite steel roll of the present invention is formed by forging a cast material, the spherical or lumpy graphite crystallized in the structure of the graphite steel is removed in the main deformation direction ( In other words, the film could be stretched into a thin strip along the axial direction of the roll.
このため、ロール周方向に沿って発生したクラックは、
上記の軸方向に沿って延伸された黒鉛と極めて交差し易
く、該黒鉛との交差によって、クラックの進展が効果的
に阻止される。従って、周方向にクラックが発生しても
、前記黒鉛と早期に交差することによって、前記クラッ
クを微小なりランクのまま止めることかできる。For this reason, cracks that occur along the circumferential direction of the roll are
It is extremely easy to intersect with the graphite stretched along the above-mentioned axial direction, and the propagation of cracks is effectively prevented by intersecting with the graphite. Therefore, even if a crack occurs in the circumferential direction, by intersecting the graphite at an early stage, the crack can be stopped in a small size.
尚、本発明のロールでは、既述のロール周方向だけでな
く、ロール軸方向にもクラックが発生ずるが、該軸方向
のクラックはロール折損に対して無害であるため、本発
明のロールの耐クラツク性、耐折損性に悪影響を及ばず
ことはない。In addition, in the roll of the present invention, cracks occur not only in the circumferential direction of the roll as described above but also in the axial direction of the roll, but since cracks in the axial direction are harmless to roll breakage, the roll of the present invention This will not adversely affect crack resistance and breakage resistance.
そして、上記延伸された黒鉛の形状は、主としてその短
径ｄと長さ！の比Ｎ／ｄを３以上に形成する。３未満で
は前記の軸方向に沿って形成された黒鉛のクラック進展
阻止効果が十分でないからである。もっとも、本発明で
は黒鉛の延伸を鍛造加工によって行なうので、ロール胴
部における変形が大きくなると、鍛造成形コストも大と
なるだけでなく、過大な変形に伴い被鍛造部材（インゴ
ット）に割れなどが発生し易くなるので、前記Ｃ／ｄは
１０以下にとどめるのが望ましい。The shape of the drawn graphite is mainly determined by its short axis d and length! The ratio N/d is set to 3 or more. This is because if it is less than 3, the graphite formed along the axial direction will not have a sufficient effect of inhibiting the growth of cracks. However, in the present invention, graphite is drawn by forging, so if the deformation in the roll body becomes large, not only will the forging cost increase, but the forged member (ingot) may be cracked due to excessive deformation. Since this is likely to occur, it is desirable to keep the C/d to 10 or less.
尚、組織中にはＮ／ｄが３未満の小さい黒鉛も不可避的
に存在するが、Ｎ／ｄが３以上のものが主として（面積
率で７０％程度以上）存在していればよい。Although small graphites with an N/d of less than 3 are inevitably present in the structure, it is sufficient that graphite with an N/d of 3 or more is mainly present (approximately 70% or more in terms of area ratio).
また、前記鍛造加工による黒鉛の延伸と共に、被鍛造部
材の基地組織も、主変形方向（軸方向）に沿って鍛造繊
維状組織が形成されるため、該方向における機械的性質
が顕著に向上する。このため、本発明のロールは、上述
の黒鉛の作用に加え、基地組織も強化されるので、耐ク
ラック性および強靭性が共に向上された優れた性質を有
する。In addition, as the graphite is stretched by the forging process, a forged fibrous structure is formed in the base structure of the forged member along the main deformation direction (axial direction), so the mechanical properties in this direction are significantly improved. . Therefore, in addition to the above-mentioned effect of graphite, the roll of the present invention has excellent properties such as improved crack resistance and toughness because the base structure is also strengthened.
（実施例）
まず、本発明で使用する黒鉛鋼について説明する。黒鉛
鋼は、通常、Ｃ含有量が０．５ｗｔ％以上の高炭素鋳鋼
のなかでも、特にＣおよびＳｉ含有量が高い過共析組織
を有しており、鋳造時の接種によって、黒鉛を晶出させ
たものである。該黒鉛鋼は、既述のように耐摩耗性およ
び強靭性に優れている。(Example) First, graphite steel used in the present invention will be explained. Among high-carbon cast steels with a C content of 0.5 wt% or more, graphite steel usually has a hypereutectoid structure with particularly high C and Si contents, and graphite is crystallized by inoculation during casting. This is what I let out. As mentioned above, the graphite steel has excellent wear resistance and toughness.
本発明に適用される黒鉛鋼の好適な化学組成として、た
とえば、下記に示す組成（単位、重量％）を例示するこ
とができる。As a suitable chemical composition of graphite steel applied to the present invention, the following composition (unit, weight %) can be exemplified.
Ｃ： １．０〜１．８％、
Ｓｉ：１．０〜２．０％、
Ｍｎ ： ０．４〜１．０％、
Ｎｉ：１．０％以上、
残部実質的にＦｅ
上記のような組成の溶湯に接種して、あるいは、鋳造後
に熱処理して、基地組織中に黒鉛が晶出した黒鉛鋼を形
成する。この際、晶出した黒鉛の形状は球状または塊状
である。尚、接種する場合には、接種によるＳｉの増加
分を考慮して、溶湯の３１含有量を上記Ｓｉ含有量より
低値に調整しておく。C: 1.0 to 1.8%, Si: 1.0 to 2.0%, Mn: 0.4 to 1.0%, Ni: 1.0% or more, balance substantially Fe as above Graphite steel in which graphite crystallizes in the matrix structure is formed by inoculating molten metal with the same composition or by heat-treating it after casting. At this time, the shape of the crystallized graphite is spherical or lumpy. In addition, when inoculating, the 31 content of the molten metal is adjusted to a value lower than the above Si content in consideration of the increase in Si due to inoculation.
上述のようにして溶製された黒鉛鋼から成るインゴット
を、鍛造加工することによって、前記球状または塊状の
黒鉛を基地と共に軸方向に沿って延伸させると同時に、
該鍛造加工によって、所定の形状のロールに成形する。By forging an ingot made of graphite steel melted as described above, the spherical or lumpy graphite is stretched along the axial direction together with the base,
The forging process forms a roll into a predetermined shape.
以下に具体的製造例について述べる。A specific manufacturing example will be described below.
Ｃｒ ： ０．１ −１．０
Ｍｏ ： ０．１ 〜１．０
Ｐ：０．０５％未満
Ｓ：０．０４％未満
〈実施例Ａ〉
■ 第１表に示す化学組成（単位、重量％）の黒鉛鋼か
ら成るインゴットを製作した。尚、前記インゴットは接
種によって組織中に黒鉛を晶出させており、表中Ｓｉ含
有量は接種後の値である。Cr: 0.1 -1.0 Mo: 0.1 - 1.0 P: less than 0.05% S: less than 0.04% <Example A> ■ Chemical composition shown in Table 1 (unit, weight %) ) made of graphite steel. Note that graphite is crystallized in the tissue of the ingot by inoculation, and the Si content in the table is the value after inoculation.
第１表
（注）残部実質的にＦｅ
■ ■で製作したインゴットを、鍛造温度１１５０〜９
００°Ｃで鍛造成形して鍛造後寸法が、胴径５８７ｍｍ
φ、胴長１８５０ｍｍｊ２ （軸受部：径３１５ ｍｍ
φ、長さ５００ｍｍ ｌ ）のロールを得た。Table 1 (Note) An ingot made of substantially Fe ■ ■ was forged at a temperature of 1150 to 9
Forged at 00°C and has a body diameter of 587mm after forging.
φ, body length 1850mmj2 (bearing part: diameter 315mm
A roll having a diameter of φ and a length of 500 mm l was obtained.
このとき、ロール胴部における鍛錬成形比は２．５Ｓ〜
３．６８であり、軸受部におけるそれは８．５Ｓ〜１２
．５ Ｓであった。At this time, the forging forming ratio in the roll body is 2.5S~
3.68, and that at the bearing part is 8.5S~12
．． It was 5S.
■ 上記で得た鍛造ロールに８４０’Ｃで１０時間、さ
らに、６ｏｏ’ｃで１０時間熱処理を施した。(2) The forged roll obtained above was heat treated at 840'C for 10 hours and then at 60'C for 10 hours.
■ 上記処理後、ロールの胴部は表面から１００ｍｍの
カリバー底相当部、軸受部は表面から２５ｍｍの位置か
ら試料を採取した。(2) After the above treatment, samples were taken from the body of the roll at a position corresponding to the caliber bottom 100 mm from the surface, and from the bearing at a position 25 mm from the surface.
第１図は前記胴部採取試料の、ロール軸方向に対して平
行な断面の金属組織写真を、また、第２図は前記方向に
対して垂直な断面の金属組織写真をそれぞれ示したもの
である。両図より、鍛造加工によって、球状または塊状
の黒鉛が、基地組織の変形と共に、ロール軸方向、すな
わち、鍛造加工における主変形方向に沿って延伸されて
いることが認められる。また、該延伸された黒鉛は、主
としてロール軸方向に沿って短径ｄと長さ乏との比ｆｆ
ｉ／ｄが３以上の種々の細長い形状に形成されており、
これら長・短の多数の黒鉛が、延伸方向に沿って、組織
中に混在しているのが認められる。Figure 1 shows a photo of the metallographic structure of a cross section parallel to the roll axis direction of the sample collected from the trunk, and Figure 2 shows a photo of the metallographic structure of a cross section perpendicular to the direction. be. From both figures, it is recognized that the spherical or lumpy graphite is stretched along the roll axis direction, that is, the main deformation direction in the forging process, along with the deformation of the base structure due to the forging process. In addition, the drawn graphite mainly has a ratio of short axis d to length ff along the roll axis direction.
It is formed into various elongated shapes with i/d of 3 or more,
It is observed that a large number of these long and short graphites are mixed in the structure along the drawing direction.
■ 一方、上記各試料の軸方向の機械的性質について測
定した。測定結果を第２表に示す。(2) On the other hand, the axial mechanical properties of each of the above samples were measured. The measurement results are shown in Table 2.
尚、比較例として、従来通りの金型鋳造法で製作した黒
鉛鋼ロールから採取した胴部試料の軸方向の測定値を示
した。As a comparative example, the measured values in the axial direction of a body sample taken from a graphite steel roll produced by a conventional die casting method are shown.
第２表より、鍛造加工に伴いロール軸方向に形成された
鍛造繊維状組織の形成によって、鍛造成形ロールに比べ
て機械的性質の向」−が認められた。すなわち、ロール
胴部において、引張り強さが約２３％、耐力が約２４％
、伸びが約３０％。From Table 2, it was observed that the mechanical properties were improved compared to the forged formed roll due to the formation of a forged fibrous structure formed in the axial direction of the roll during the forging process. That is, in the roll body, the tensile strength is approximately 23% and the yield strength is approximately 24%.
, the elongation is about 30%.
曲げ強さが約２７％、たわみが約２９％１ シャルピー
衝撃値が約１２７％向上した。また、ロール軸受部につ
いても胴部と同様ないしそれ以上の機械的性質の向上が
認められた。Bending strength improved by about 27%, deflection by about 29%1, and Charpy impact value by about 127%. Furthermore, it was observed that the mechanical properties of the roll bearing portion were improved to the same extent or even higher than those of the body portion.
上述の様に、黒鉛の延伸と共に基地組織も強化されたの
で、耐クラック性が向上し、耐折損性も向上させること
ができた。As mentioned above, as the graphite was drawn, the matrix structure was also strengthened, so that the crack resistance and breakage resistance were improved.
〈実施例Ｂ〉
上述の製造実施例と同様の組成の黒鉛鋼から成るインゴ
ットから、同様の操作により、胴径５６０ｍｍφ、胴長
１８５０＋＋ｕ＋＋ｊ２のボックスカリバー（Ｈ：６０
伽、 Ｂ ： １５０岨）が形成されたロールを製作
し、三重式鋼片圧延機の粗スタンドに設置して圧延に供
した。その結果、一定量圧延後、再使用のためロール表
面を改削する際、従来の鋳造成形したロールでは、クラ
ックが深く形成されているため、上記改削後でも除去さ
れずに残留するクラックが多数あるのに対し、本実施例
のロールではクラックが大きく進展することがないため
、除去されずに残留したクラックは皆無であった。現在
２回目の改削を行ったうえで、使用中であるが、該２回
目の改削においても、周方向のクラックは全て除去する
ことができ、極めて良好な結果を得ている。<Example B> A box caliber (H: 60
A roll having a diameter of 150 cm was manufactured, and was placed in a roughing stand of a triple billet rolling mill and subjected to rolling. As a result, when the roll surface is modified for reuse after rolling a certain amount, cracks are formed deep in conventional cast-formed rolls, so cracks that remain are not removed even after the modification. In contrast, in the roll of this example, the cracks did not develop significantly, so there were no cracks that remained without being removed. It is currently in use after being revised for the second time, and even in the second revision, all the cracks in the circumferential direction were able to be removed, and very good results have been obtained.
（発明の効果）
本発明では、黒鉛鋼から成るロールの組織中の黒鉛がロ
ール軸方向に沿って、該黒鉛のｌ／ｄが設定値以上とな
るように延伸されているため、ロールの周方向に発生し
たクラックは、大きく進展する前に延伸された黒鉛と交
差して、その進展が緩和されるので、クラックの周方向
への進展は早期のうちに阻止される。(Effects of the Invention) In the present invention, the graphite in the structure of the roll made of graphite steel is stretched along the roll axis direction so that l/d of the graphite is equal to or higher than a set value. Cracks that occur in the circumferential direction intersect with the stretched graphite and slow their progress before they progress significantly, so that the cracks' progress in the circumferential direction is stopped at an early stage.
一方、上記鍛造成形によって、ロールの基地組織も軸方
向に沿って強化され、同方向における機械的強度が顕著
に向上する。On the other hand, by the forging, the base structure of the roll is also strengthened along the axial direction, and the mechanical strength in the same direction is significantly improved.
従って、本発明のロールは、ロール周方向に発生したク
ラックの進展が早期に阻止されるうえ、機械的強度も高
いので、耐クラツク性に極めて優れており、クラックの
進展によるロール折損事故の発生が少なく、耐折損性の
優れた信頼性の極めて高いロールである。Therefore, the roll of the present invention prevents the propagation of cracks generated in the circumferential direction of the roll at an early stage, and has high mechanical strength, so it has extremely excellent crack resistance and prevents roll breakage accidents due to propagation of cracks. This is an extremely reliable roll with low breakage resistance and excellent breakage resistance.
第１図は本実施例に係るロール胴部の軸方向に平行な断
面の金属組織写真（倍率５０倍）、第２１図は第１回の
方向に垂直な断面の金属組織写真（倍率５０倍）である
。Fig. 1 is a photograph of the metallographic structure of a cross section parallel to the axial direction of the roll body according to this example (magnification: 50x), and Fig. 21 is a photo of the metallographic structure of a cross section perpendicular to the first direction (magnification: 50x). ).
Claims (1)
れた黒鉛鋼ロールであって、該ロール胴部における前記
黒鉛は、主としてその短径ｄと長さｌの比ｌ／ｄが３以
上であることを特徴とする耐クラック性に優れた黒鉛鋼
ロール。(1) A graphite steel roll in which graphite is stretched along the axial direction of the roll by forging, and the graphite in the roll body mainly has a ratio l/d of its minor axis d to length l of 3 or more. A graphite steel roll with excellent crack resistance.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1038654A JP2750142B2 (en) | 1989-02-18 | 1989-02-18 | Graphite steel roll with excellent crack resistance |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1038654A JP2750142B2 (en) | 1989-02-18 | 1989-02-18 | Graphite steel roll with excellent crack resistance |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH02217106A true JPH02217106A (en) | 1990-08-29 |
| JP2750142B2 JP2750142B2 (en) | 1998-05-13 |
Family
ID=12531244
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP1038654A Expired - Lifetime JP2750142B2 (en) | 1989-02-18 | 1989-02-18 | Graphite steel roll with excellent crack resistance |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2750142B2 (en) |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS58387A (en) * | 1981-06-24 | 1983-01-05 | Hitachi Ltd | Production of composite roll |
-
1989
- 1989-02-18 JP JP1038654A patent/JP2750142B2/en not_active Expired - Lifetime
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS58387A (en) * | 1981-06-24 | 1983-01-05 | Hitachi Ltd | Production of composite roll |
Also Published As
| Publication number | Publication date |
|---|---|
| JP2750142B2 (en) | 1998-05-13 |
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