JPS6358215B2 - - Google Patents
Info
- Publication number
- JPS6358215B2 JPS6358215B2 JP55074351A JP7435180A JPS6358215B2 JP S6358215 B2 JPS6358215 B2 JP S6358215B2 JP 55074351 A JP55074351 A JP 55074351A JP 7435180 A JP7435180 A JP 7435180A JP S6358215 B2 JPS6358215 B2 JP S6358215B2
- Authority
- JP
- Japan
- Prior art keywords
- roll
- weight
- wear
- core material
- 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.)
- Expired
Links
- 239000011162 core material Substances 0.000 claims description 23
- 238000003466 welding Methods 0.000 claims description 21
- 229910052751 metal Inorganic materials 0.000 claims description 18
- 239000002184 metal Substances 0.000 claims description 18
- 150000001247 metal acetylides Chemical class 0.000 claims description 18
- 238000000034 method Methods 0.000 claims description 15
- 238000004519 manufacturing process Methods 0.000 claims description 14
- 229910000831 Steel Inorganic materials 0.000 claims description 10
- 239000002131 composite material Substances 0.000 claims description 10
- 239000010959 steel Substances 0.000 claims description 10
- 230000005496 eutectics Effects 0.000 claims description 9
- 238000005496 tempering Methods 0.000 claims description 5
- 229910000734 martensite Inorganic materials 0.000 claims description 4
- 238000010791 quenching Methods 0.000 claims description 4
- 230000000171 quenching effect Effects 0.000 claims description 4
- 229910052799 carbon Inorganic materials 0.000 description 15
- 239000011651 chromium Substances 0.000 description 15
- 229910052804 chromium Inorganic materials 0.000 description 14
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 13
- 239000000463 material Substances 0.000 description 12
- 238000005336 cracking Methods 0.000 description 10
- 238000010438 heat treatment Methods 0.000 description 10
- 238000005242 forging Methods 0.000 description 9
- 229910052742 iron Inorganic materials 0.000 description 8
- 238000005266 casting Methods 0.000 description 6
- 238000001816 cooling Methods 0.000 description 5
- 238000010586 diagram Methods 0.000 description 5
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 description 4
- 238000005096 rolling process Methods 0.000 description 4
- 230000007423 decrease Effects 0.000 description 3
- 239000002893 slag Substances 0.000 description 3
- 238000005299 abrasion Methods 0.000 description 2
- 238000005098 hot rolling Methods 0.000 description 2
- 150000002739 metals Chemical class 0.000 description 2
- 239000003921 oil Substances 0.000 description 2
- 230000035939 shock Effects 0.000 description 2
- 238000007711 solidification Methods 0.000 description 2
- 230000008023 solidification Effects 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- 206010013786 Dry skin Diseases 0.000 description 1
- 229910017082 Fe-Si Inorganic materials 0.000 description 1
- 229910017133 Fe—Si Inorganic materials 0.000 description 1
- 208000025599 Heat Stress disease Diseases 0.000 description 1
- 101100202505 Saccharomyces cerevisiae (strain ATCC 204508 / S288c) SCM4 gene Proteins 0.000 description 1
- 238000005054 agglomeration Methods 0.000 description 1
- 230000002776 aggregation Effects 0.000 description 1
- 238000005275 alloying Methods 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- WUKWITHWXAAZEY-UHFFFAOYSA-L calcium difluoride Chemical compound [F-].[F-].[Ca+2] WUKWITHWXAAZEY-UHFFFAOYSA-L 0.000 description 1
- 229910001634 calcium fluoride Inorganic materials 0.000 description 1
- 238000009750 centrifugal casting Methods 0.000 description 1
- 230000008094 contradictory effect Effects 0.000 description 1
- 238000002425 crystallisation Methods 0.000 description 1
- 230000008025 crystallization Effects 0.000 description 1
- 239000006185 dispersion Substances 0.000 description 1
- 239000007772 electrode material Substances 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 230000004907 flux Effects 0.000 description 1
- 230000004927 fusion Effects 0.000 description 1
- 238000000227 grinding Methods 0.000 description 1
- 238000007689 inspection Methods 0.000 description 1
- 239000000314 lubricant Substances 0.000 description 1
- 229910052748 manganese Inorganic materials 0.000 description 1
- 230000013011 mating Effects 0.000 description 1
- 239000011159 matrix material Substances 0.000 description 1
- 239000000155 melt Substances 0.000 description 1
- 230000008018 melting Effects 0.000 description 1
- 238000002844 melting Methods 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 229910052750 molybdenum Inorganic materials 0.000 description 1
- 229910052759 nickel Inorganic materials 0.000 description 1
- 238000001556 precipitation Methods 0.000 description 1
- 239000010723 turbine oil Substances 0.000 description 1
- 229910052720 vanadium Inorganic materials 0.000 description 1
Description
本発明は新規な複合ロールの製造法に係り、特
に肉盛ロールの製造法に関する。
一般に熱間圧延ロールには耐摩耗性、耐熱亀裂
性、強靭性という相反する性質が要求される。つ
まり、ロール材の耐摩耗性を高めるのに高炭素含
有量及び高合金元素含有量とすると耐熱亀裂性、
強靭性が低下し、逆に耐熱亀裂性、靭性を向上さ
せるためには炭素量を低くすることが必要とな
り、その結果として耐摩耗性が劣つたものとな
る。これらの性質をバランスさせるために同一材
質からなるロール材で満足させるのは困難である
ので、ロール表面に耐摩耗性、耐熱亀裂性を与
え、芯部を強靭性にする複合ロールが知られてい
る。即ちその方法として、中抜鋳造法、遠心鋳造
法、鉄板隔壁鋳造法等の鋳造法によるものと、サ
ブマージドアーク溶接肉盛法、エレクトロスラグ
溶接肉盛法等の溶接肉盛法によるものがある。し
かし、前者の鋳造法によりロールを製造した場
合、鋳造時の冷却速度には限界があり、炭化物は
個々のものが網目状に多数凝集して晶出し、その
形状も粗大である。その結果、この鋳造材は組織
的に脆弱なものとなるため、熱処理により組織を
改善し、靭性を高めているが、熱処理だけでは炭
化物を微細かつ均一に分散させることは不可能で
ある。さらに、このものはロール使用中に、炭化
物の多い部分で摩耗が少なく、炭化物の少ない部
分で摩耗が多いため、肌荒れを生ずる欠点があ
り、また、炭化物にそつて熱疲労亀裂が発生する
ため、耐熱亀裂性が劣るという問題がある。
また、サブマージドアーク溶接肉盛法によりロ
ールを製造する場合、溶着金属の成分としてとく
に炭素含有量が高くなると溶接割れが発生しやす
くなり、肉盛の厚さが大きくなると溶接割れの発
生、作業工数の増加が問題となり、さらに鋳造組
織を有するため前述の如く肌荒れ、耐熱疲労性が
低く、健全なロールが得られにくい。
エレクトロスラグ溶接肉盛法は他の溶接方法に
比較し厚く肉盛することができ、また鋳造法に比
較し、冷却速度が速いため、炭化物を微細化でき
るために、ロールの製造法として適している。し
かし、炭化物は微細ではあるが網目状に多数凝集
して晶出し、それを熱処理のみで均一に分散させ
ることは不可能である。そのため前述したように
肌荒れ及び熱疲労亀裂が生じる欠点がある。
本発明の目的は耐摩耗性のすぐれた複合ロール
の製造法を提供するにある。
本発明は、所定形状のロール芯材表面に該芯材
より耐摩耗性が大きい耐摩耗性金属を融着する複
合ロールの製造法において、前記ロール芯材とし
てC0.3〜１重量％と炭化物形成元素を含有する鋼
を用い、前記耐摩耗性金属としてC1.5〜３重量
％、Cr7〜20重量％、Ni2重量％以下、Mo2重量
％以下、V2重量％以下を含有する鋼を用い、エ
レクトロスラグ溶接にて融着した後、熱間鍛造
し、次いで焼入れ焼戻しの熱処理を行つて共晶炭
化物が基地粒内に分散したマルテンサイト組織を
有するロール表面金属組織を得ることを特徴とす
る複合ロールの製造法にある。
前記耐摩耗性金属は、熱間鍛造及び熱処理を施
すことによつて、共晶炭化物が基地粒内にほぼ均
一に分散して存在するマルテンサイト組織を有す
る。このような粒内への共晶炭化物の分散によつ
てロール全面の摩耗が防止され、著しく耐摩耗性
が向上する。さらに熱疲労に対する抵抗も向上さ
れる。
ロール芯材は芯材として必要な強度を保持する
ためにC0.3〜１重量％、必要に応じて要求される
量の炭化物形成元素を含有する鋼が用いられる。
耐摩耗性金属は芯材より耐摩耗性が高いことが
勿論であるが、特に上述の芯材に対してC1.5〜３
重量％、Cr7〜20重量％、Ni2重量％以下、Mo2
重量％以下、V2重量％以下を含有する鋼からな
るものが好適である。
芯材表面に耐摩耗性金属を融着した後に熱間鍛
造を行うことにより耐摩耗性金属中の共晶炭化物
を基地粒内にほぼ均一に分散させた組織に形成さ
せることができ、その結果、耐摩耗性の高い複合
ロールを得ることができる。
耐摩耗性金属を融着させるには肉盛溶接が好ま
しく、特にエレクトロスラグ溶接が共晶炭化物を
微細化させることから、その後の熱間鍛造を容易
に行うことができ、このことが共晶炭化物を基地
粒内により均一に分散させるのに有効ならしめて
いるものと考えられる。よつて本発明の複合ロー
ルの製造はエレクトロスラグ溶接による肉盛溶接
によるのが好適である。
エレクトロスラグその他の溶接法により肉盛ロ
ールを製造するにあたり問題となることは、芯材
の強靭性、ロール使用面の耐摩耗性、耐熱亀裂性
である。圧延効率を高めるためにはロールを小径
化しなければならない。しかしロールを小径化す
るとロールにかかる応力はそれに伴い大となるの
で、芯材の強靭化が必要となる。従つて、芯材の
炭素量が0.3重量％以下となると、かたさが低下
し傷がつきやすくなるとともに疲労強度が低下す
るため、芯材の炭素量は0.3％以上を含有する鋼
が好ましい。また、炭素量が１重量％を超えると
機械的性質が低下し大きな応力に耐えられず折損
する恐れがあるので、１％以下が好ましい。その
ため芯材の炭素量は0.3〜１重量％を含有する鋼
が好ましい。
ロールの圧延使用面に耐摩耗性を付与させる耐
摩耗性金属は基地粒内にかたい共晶炭化物を微細
かつ均一に分散させたものが必要である。高炭素
高クロム系の材料に析出する炭化物には、（Fe、
Cr）3C型、（Fe、Cr）7C3型、（Fe、Cr）23C6型の３
種に分類されるが、そのビツカースかたさHvは、
（Fe、Cr）3C型で1100〜2000、（Fe、Cr）7C3型で
2000〜2700、（Fe、Cr）23C6型で1400〜1800であ
る。耐摩耗性を向上させるためには、最もかたい
（Fe、Cr）7C3型の炭化物を析出させることが好ま
しい。第１図に炭素およびクロム量による炭化物
の析出形態の差違を示すが、（Fe、Cr）7C3型炭化
物を析出する範囲は図の斜線の部分である。しか
し、炭素量が1.5％未満では炭化物析出量が少な
く耐摩耗性が低下し、ロールとして十分とはいえ
ない。また、炭素量が3.0％を超えると組織は白
銑化し耐摩耗性は向上するが、耐熱性が劣化し、
熱疲労亀裂による肌荒れが発生しやすくなり使用
上問題が生じる。従つて本発明における耐摩耗性
金属の化学成分は炭素1.5〜3.0重量％、それに対
応し（Fe、Cr）7C3型炭化物を析出する範囲でク
ロム７〜20重量％が好ましい。このような高炭素
高クロム系材料は凝固時に網目状に炭化物を晶出
するため、耐摩耗性、耐熱亀裂性を向上させるに
あたり、炭化物を微細かつ均一に分散させる必要
がある。そのため本発明では凝固時に析出した大
型炭化物を熱間鍛造により分断し、微細かつ均一
に分散させるものである。これにより芯部に強靭
性をもたせかつ圧延使用面は耐摩耗性、耐熱亀裂
性にすぐれたロールを製造することが可能とな
る。また、Ni、Mo、Ｖはロールの強靭化、焼戻
し抵抗の向上をはかる目的でロールの用途に応じ
て添加することが好ましい。
実施例
芯材は直径300mmのSCM4材市販材を使用し直
径400mmの水冷モールドを用いて外層に高炭素高
クロム系材料をエレクトロスラグ溶接により肉厚
50mmに肉盛溶接した。芯材および溶着金属の化学
成分（重量％）を表に示す。
The present invention relates to a novel method for manufacturing a composite roll, and more particularly to a method for manufacturing an overlay roll. In general, hot rolling rolls are required to have contradictory properties such as wear resistance, heat cracking resistance, and toughness. In other words, if high carbon content and high alloying element content are used to improve the wear resistance of roll materials, heat cracking resistance,
Toughness decreases, and conversely, in order to improve heat cracking resistance and toughness, it is necessary to lower the carbon content, resulting in poor wear resistance. It is difficult to balance these properties with roll materials made of the same material, so composite rolls are known that provide wear resistance and heat crack resistance to the roll surface and toughness to the core. There is. That is, the methods include casting methods such as hollow casting, centrifugal casting, and steel plate bulkhead casting, and welding methods such as submerged arc welding and electroslag welding. . However, when a roll is manufactured by the former casting method, there is a limit to the cooling rate during casting, and the carbides crystallize in a network-like agglomeration of many individual carbides, resulting in a coarse shape. As a result, this cast material becomes structurally fragile, so heat treatment is used to improve the structure and increase toughness, but it is impossible to finely and uniformly disperse carbides by heat treatment alone. Furthermore, when using this roll, there is less wear in areas with a lot of carbide, and more wear in areas with less carbide, which has the disadvantage of causing rough skin, and thermal fatigue cracks occur along the carbide. There is a problem of poor heat cracking resistance. In addition, when manufacturing rolls using the submerged arc welding overlay method, weld cracks are likely to occur when the carbon content of the deposited metal becomes particularly high, and when the overlay thickness increases, weld cracks occur and the work The increase in the number of man-hours becomes a problem, and since it has a cast structure, as mentioned above, the surface becomes rough and the heat fatigue resistance is low, making it difficult to obtain a sound roll. The electroslag welding overlay method allows thicker overlays than other welding methods, and compared to casting methods, the cooling rate is faster and carbides can be made finer, making it suitable as a roll manufacturing method. There is. However, although the carbides are fine, they aggregate and crystallize in large numbers in the form of a network, and it is impossible to uniformly disperse them by heat treatment alone. Therefore, as mentioned above, there is a drawback that rough skin and thermal fatigue cracks occur. An object of the present invention is to provide a method for manufacturing a composite roll with excellent wear resistance. The present invention provides a method for manufacturing a composite roll in which a wear-resistant metal having higher abrasion resistance than the core material is fused to the surface of a roll core material having a predetermined shape. Using steel containing forming elements, using steel containing C1.5-3% by weight, Cr7-20% by weight, Ni2% by weight or less, Mo2% by weight or less, V2% by weight or less as the wear-resistant metal, A composite characterized in that a roll surface metal structure having a martensitic structure in which eutectic carbides are dispersed in base grains is obtained by fusion by electroslag welding, hot forging, and then heat treatment of quenching and tempering. It's in the manufacturing method of the roll. The wear-resistant metal has a martensitic structure in which eutectic carbides are almost uniformly dispersed within the base grains by hot forging and heat treatment. Such dispersion of eutectic carbides within the grains prevents wear of the entire surface of the roll, significantly improving wear resistance. Furthermore, resistance to thermal fatigue is improved. The roll core material is made of steel containing 0.3 to 1% by weight of C and, if necessary, a required amount of carbide-forming elements in order to maintain the strength required for the core material. It goes without saying that wear-resistant metals have higher wear resistance than core materials, but especially for the core materials mentioned above, C1.5 to 3
Weight%, Cr7~20wt%, Ni2wt% or less, Mo2
Preferably, the material is made of steel containing V2% by weight or less. By performing hot forging after fusing a wear-resistant metal to the surface of the core material, it is possible to form a structure in which the eutectic carbides in the wear-resistant metal are almost uniformly dispersed within the base grains. , a composite roll with high wear resistance can be obtained. Overlay welding is preferred for fusing wear-resistant metals, and electroslag welding in particular refines eutectic carbides, making subsequent hot forging easier. It is thought that this makes it effective in dispersing more uniformly within the matrix grains. Therefore, it is preferable to manufacture the composite roll of the present invention by overlay welding using electroslag welding. Problems in manufacturing overlay rolls using electroslag or other welding methods are the toughness of the core material, the wear resistance of the roll surface, and the heat cracking resistance. In order to increase rolling efficiency, the diameter of the rolls must be reduced. However, if the diameter of the roll is made smaller, the stress applied to the roll increases accordingly, so the core material needs to be made tougher. Therefore, if the carbon content of the core material is 0.3% by weight or less, the hardness decreases and the steel becomes easily scratched, and the fatigue strength decreases, so it is preferable that the core material contains a carbon content of 0.3% or more. Furthermore, if the carbon content exceeds 1% by weight, the mechanical properties will deteriorate and there is a risk that the material will not be able to withstand large stress and break, so it is preferably 1% or less. Therefore, steel containing 0.3 to 1% by weight of carbon in the core material is preferable. The wear-resistant metal that imparts wear resistance to the rolling surface of the roll must have hard eutectic carbides finely and uniformly dispersed within the base grains. Carbides precipitated in high-carbon, high-chromium materials include (Fe,
Cr) 3 C type, (Fe, Cr) 7 C 3 type, (Fe, Cr) 23 C 6 type 3
Although it is classified as a species, its bitcurs hardness Hv is
(Fe, Cr) 1100-2000 for 3 C type, (Fe, Cr) 7 C 3 type
2000-2700, (Fe, Cr) 23C 6 type is 1400-1800. In order to improve wear resistance, it is preferable to precipitate the hardest (Fe, Cr) 7 C 3 type carbide. FIG. 1 shows the difference in the precipitation form of carbides depending on the amount of carbon and chromium, and the range where (Fe, Cr) 7 C 3 type carbides are precipitated is the shaded area in the figure. However, if the carbon content is less than 1.5%, the amount of carbide precipitated is small and the wear resistance is reduced, making it unsatisfactory as a roll. Additionally, if the carbon content exceeds 3.0%, the structure becomes white and wear resistance improves, but heat resistance deteriorates.
Skin roughness due to thermal fatigue cracks is likely to occur, causing problems in use. Therefore, the chemical composition of the wear-resistant metal in the present invention is preferably 1.5 to 3.0% by weight of carbon and 7 to 20% by weight of chromium, so long as the corresponding (Fe, Cr) 7 C 3 type carbide is precipitated. Since such high-carbon, high-chromium materials crystallize carbides in a network shape during solidification, it is necessary to disperse the carbides finely and uniformly in order to improve wear resistance and heat cracking resistance. Therefore, in the present invention, large carbides precipitated during solidification are divided by hot forging and dispersed finely and uniformly. This makes it possible to manufacture a roll whose core has toughness and whose rolling surface has excellent wear resistance and heat crack resistance. Further, Ni, Mo, and V are preferably added depending on the purpose of the roll for the purpose of toughening the roll and improving the tempering resistance. Example: The core material is a commercially available SCM4 material with a diameter of 300 mm, and the outer layer is made of a high carbon, high chromium material by electroslag welding using a water-cooled mold with a diameter of 400 mm.
Welded overlay to 50mm. The chemical components (wt%) of the core material and weld metal are shown in the table.
【表】
エレクトロスラグ溶接は、肉盛溶接部の割れを
防止するため芯材を200〜300℃に予熱し、溶接電
流を0.6〜1A／mm2とし、フラツクスにCaF274％、
NaF24％、Mn1％、Fe−Si1％を使用して、行つ
た。
第２図はエレクトロスラグ肉盛溶接よる複合ロ
ールを製造する装置の構成図である。ロール芯材
１の表面に管状電極材２を用い、溶接機３によつ
て溶接する。アークが発生するとスラグ８が溶融
するとともに、溶融金属７が形成され、芯材１の
表面に溶接肉盛が形成される。溶融金属７はスト
ツパ９によつて溶け落ちが防止される。スラグは
厚さ50〜60mmに常時調整される。
肉盛後の鋼塊表面から予備実験を行うために肉
盛部分の試料を採取し、これを1100℃近傍で鍛錬
比2.0に熱間鍛造した。鍛造後、油焼入れ及び焼
戻しの熱処理を行つた。
第３図は肉盛溶接したままのａ及び熱間鍛造し
たものｂの断面の400倍の顕微鏡写真である。図
に示すように、肉盛溶接したままのものは粒界に
網目状に凝集して共晶炭化物が晶出しているのに
対し、鍛造したものは共晶炭化物が粒内に分散し
て粒状に晶出していることがわかる。基地はマル
テンサイト組織である。
第４図は、西原式摩耗試験結果を示す線図であ
る。摩耗試験はタービン油を潤滑材に用い、相手
材にJISのSKH9材を用い、摩耗減量を測定した
ものである。試料は外径30mm、内径16mm、厚さ８
mmである。図に示す如く、本発明の鍛造したもの
は肉盛溶接したままのものに比らべ耐摩耗性がす
ぐれていることがわかる。
第５図は熱衝撃試験における亀裂発生までの回
数を示すグラフである。熱衝撃試験は600℃まで
約７秒で高周波加熱によつて加熱し、引き続いて
水冷する加熱冷却のくり返しによつて行つたもの
である。試料は直径20mm、厚さ50mmである。図に
示す如く、本発明の鍛造したものは肉盛溶接した
ままのものにくらべ亀裂発生までのくり返し数が
約1.5倍すぐれていることが分る。
以上の如く、肉盛溶接した後鍛造したものはす
ぐれた耐摩耗性及び耐衝撃性が得られる見通しが
得られたので、上述したと同じ温度で得られた肉
盛ロールを自由鍛造により鍛錬比2.0になるよう
に熱間鍛造した。鍛造した後、950℃で焼ならし
を行い、次いで880℃で焼なまし処理した後、油
焼入れ及び焼戻しの熱処理を行つた。次いで、表
面研削及び検査を行い、熱間圧延用ロールに用い
た結果、その耐摩耗性が顕著にすぐれ、従来の単
なる肉盛のままのものに比らべ格段に長寿命であ
つた。
以上、本発明のロールは従来のロールに比らべ
耐摩耗性及び耐熱亀裂性がすぐれ、圧延効率が格
段にすぐれていた。[Table] In electroslag welding, the core material is preheated to 200 to 300℃ to prevent cracks in the overlay weld, the welding current is 0.6 to 1A/ mm2 , and the flux is 74 % CaF2.
This was done using 24% NaF, 1% Mn, and 1% Fe-Si. FIG. 2 is a configuration diagram of an apparatus for manufacturing a composite roll by electroslag overlay welding. A tubular electrode material 2 is used on the surface of the roll core material 1 and welded by a welding machine 3. When the arc is generated, the slag 8 melts, molten metal 7 is formed, and weld overlay is formed on the surface of the core material 1. The molten metal 7 is prevented from melting through by the stopper 9. The slag is constantly adjusted to a thickness of 50 to 60 mm. A sample of the overlaid part was taken from the surface of the steel ingot after overlaying for preliminary experiments, and this was hot forged at around 1100℃ to a forging ratio of 2.0. After forging, heat treatment of oil quenching and tempering was performed. Figure 3 is a 400x microscopic photograph of the cross-section of a as-welded specimen (a) and a hot-forged specimen (b). As shown in the figure, in the as-welded product, eutectic carbide aggregates in a network shape at grain boundaries and crystallizes, whereas in the forged product, eutectic carbide is dispersed within the grains, forming a granular shape. It can be seen that crystallization occurs. The base is a martensitic structure. FIG. 4 is a diagram showing the results of the Nishihara type abrasion test. The wear test used turbine oil as the lubricant and JIS SKH9 material as the mating material, and measured the wear loss. The sample has an outer diameter of 30 mm, an inner diameter of 16 mm, and a thickness of 8 mm.
mm. As shown in the figure, it can be seen that the forged parts of the present invention have better wear resistance than those which have been overlay welded. FIG. 5 is a graph showing the number of times until cracking occurs in a thermal shock test. Thermal shock tests were conducted by heating to 600°C for about 7 seconds using high-frequency heating, followed by water cooling, and repeated heating and cooling. The sample has a diameter of 20 mm and a thickness of 50 mm. As shown in the figure, it can be seen that the forged product of the present invention is about 1.5 times better in the number of cycles until cracking occurs than the as-welded product. As mentioned above, it is expected that products forged after overlay welding will have excellent wear resistance and impact resistance. Therefore, the overlay roll obtained at the same temperature as mentioned above was free forged and the forging ratio was increased. Hot forged to 2.0. After forging, it was normalized at 950°C, then annealed at 880°C, and then subjected to heat treatment of oil quenching and tempering. Next, surface grinding and inspection were carried out, and when the roll was used in a hot rolling roll, it was found to have significantly superior wear resistance and to have a much longer lifespan than conventional rolls with just overlay. As described above, the roll of the present invention had better wear resistance and heat cracking resistance than conventional rolls, and had much better rolling efficiency.
第１図は炭素量とクロム量の変化による炭化物
形成形態を示す線図、第２図はエレクトロスラグ
溶接による肉盛ロールを製造する構成図、第３図
は断面の顕微鏡写真、第４図は回転数と摩耗量と
の関係を示す線図、第５図は亀裂発生までの回数
を示すグラフである。
１……ロール芯材、２……電極、３……溶接
機、４……水冷治具、６……熱電対、７……溶融
金属、８……スラグ、１０……増幅器、１１……
直流モータ、１２……マニプレータ。
Figure 1 is a diagram showing the form of carbide formation due to changes in the amount of carbon and chromium, Figure 2 is a block diagram of manufacturing a build-up roll by electroslag welding, Figure 3 is a microscopic photograph of a cross section, and Figure 4 is A diagram showing the relationship between the rotational speed and the amount of wear, and FIG. 5 is a graph showing the number of times until cracking occurs. 1... Roll core material, 2... Electrode, 3... Welding machine, 4... Water cooling jig, 6... Thermocouple, 7... Molten metal, 8... Slag, 10... Amplifier, 11...
DC motor, 12...manipulator.
Claims (1)
耗性が大きい耐摩耗性金属を融着する複合ロール
の製造法において、前記ロール芯材としてC0.3〜
１重量％と炭化物形成元素とを含有する鋼を用
い、前記耐摩耗性金属としてC1.5〜３重量％、
Cr7〜20重量％、Ni2重量％以下、Mo2重量％以
下、V2重量％以下を含有する鋼を用い、エレク
トロスラグ溶接にて融着した後、熱間鍛造し、次
いで焼入れ焼戻しの熱処理を行つて共晶炭化物が
基地粒内に分散したマルテンサイト組織を有する
ロール表面金属組織を得ることを特徴とする複合
ロールの製造法。1. In a method for manufacturing a composite roll in which a wear-resistant metal having higher wear resistance than the core material is fused to the surface of a roll core material of a predetermined shape, the roll core material is C0.3~
Using steel containing 1% by weight and a carbide-forming element, 1.5 to 3% by weight of C as the wear-resistant metal,
Steel containing 7 to 20% by weight of Cr, 2% by weight or less of Ni, 2% by weight or less of Mo, and 2% by weight or less of V is used, and after being fused by electroslag welding, it is hot forged, and then heat treated by quenching and tempering. A method for manufacturing a composite roll, characterized by obtaining a roll surface metal structure having a martensitic structure in which eutectic carbides are dispersed within base grains.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP7435180A JPS572862A (en) | 1980-06-04 | 1980-06-04 | Composite roll and its manufacture |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP7435180A JPS572862A (en) | 1980-06-04 | 1980-06-04 | Composite roll and its manufacture |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS572862A JPS572862A (en) | 1982-01-08 |
| JPS6358215B2 true JPS6358215B2 (en) | 1988-11-15 |
Family
ID=13544611
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP7435180A Granted JPS572862A (en) | 1980-06-04 | 1980-06-04 | Composite roll and its manufacture |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS572862A (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS58167007A (en) * | 1982-03-26 | 1983-10-03 | Hitachi Ltd | High strength, high abrasion resistance, and high toughness roll, and its manufacture |
| JPS61238407A (en) * | 1985-04-15 | 1986-10-23 | Hitachi Ltd | Compound roll and its production |
| JPH0768588B2 (en) * | 1989-06-26 | 1995-07-26 | 株式会社日立製作所 | Method for manufacturing metal rolling rolls |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5212612A (en) * | 1975-07-21 | 1977-01-31 | Nippon Steel Corp | Wear resistant tool steel |
| JPS5380350A (en) * | 1976-12-27 | 1978-07-15 | Hitachi Metals Ltd | Preparation of roll for hot rolling |
-
1980
- 1980-06-04 JP JP7435180A patent/JPS572862A/en active Granted
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5212612A (en) * | 1975-07-21 | 1977-01-31 | Nippon Steel Corp | Wear resistant tool steel |
| JPS5380350A (en) * | 1976-12-27 | 1978-07-15 | Hitachi Metals Ltd | Preparation of roll for hot rolling |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS572862A (en) | 1982-01-08 |
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