JPH0127819B2 - - Google Patents
Info
- Publication number
- JPH0127819B2 JPH0127819B2 JP21386181A JP21386181A JPH0127819B2 JP H0127819 B2 JPH0127819 B2 JP H0127819B2 JP 21386181 A JP21386181 A JP 21386181A JP 21386181 A JP21386181 A JP 21386181A JP H0127819 B2 JPH0127819 B2 JP H0127819B2
- Authority
- JP
- Japan
- Prior art keywords
- layer
- molten metal
- casting
- powder
- tungsten carbide
- 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
- 229910052751 metal Inorganic materials 0.000 claims description 73
- 239000002184 metal Substances 0.000 claims description 73
- 239000000843 powder Substances 0.000 claims description 42
- 238000005266 casting Methods 0.000 claims description 39
- 239000002245 particle Substances 0.000 claims description 33
- UONOETXJSWQNOL-UHFFFAOYSA-N tungsten carbide Chemical compound [W+]#[C-] UONOETXJSWQNOL-UHFFFAOYSA-N 0.000 claims description 28
- 239000010953 base metal Substances 0.000 claims description 22
- 238000000034 method Methods 0.000 claims description 20
- 229910001018 Cast iron Inorganic materials 0.000 claims description 10
- 238000009750 centrifugal casting Methods 0.000 claims description 10
- 229910001208 Crucible steel Inorganic materials 0.000 claims description 7
- 238000004519 manufacturing process Methods 0.000 claims description 6
- 230000005484 gravity Effects 0.000 description 8
- 239000000463 material Substances 0.000 description 6
- 239000000203 mixture Substances 0.000 description 5
- 230000002093 peripheral effect Effects 0.000 description 5
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 4
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 4
- 238000005299 abrasion Methods 0.000 description 4
- 230000000052 comparative effect Effects 0.000 description 4
- 229910045601 alloy Inorganic materials 0.000 description 3
- 239000000956 alloy Substances 0.000 description 3
- 230000007423 decrease Effects 0.000 description 3
- 238000005119 centrifugation Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 229910052742 iron Inorganic materials 0.000 description 2
- 238000002844 melting Methods 0.000 description 2
- 230000008018 melting Effects 0.000 description 2
- 229910052759 nickel Inorganic materials 0.000 description 2
- 238000003825 pressing Methods 0.000 description 2
- 229910000975 Carbon steel Inorganic materials 0.000 description 1
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 239000010962 carbon steel Substances 0.000 description 1
- 239000011362 coarse particle Substances 0.000 description 1
- 238000005056 compaction Methods 0.000 description 1
- 239000002131 composite material Substances 0.000 description 1
- 239000012141 concentrate Substances 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 229910052802 copper Inorganic materials 0.000 description 1
- 239000010949 copper Substances 0.000 description 1
- 239000011162 core material Substances 0.000 description 1
- 230000008021 deposition Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000009792 diffusion process Methods 0.000 description 1
- 230000004907 flux Effects 0.000 description 1
- 230000001771 impaired effect Effects 0.000 description 1
- 150000002736 metal compounds Chemical class 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 239000004576 sand Substances 0.000 description 1
- 238000004062 sedimentation Methods 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 238000003466 welding Methods 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
- B22D13/00—Centrifugal casting; Casting by using centrifugal force
- B22D13/02—Centrifugal casting; Casting by using centrifugal force of elongated solid or hollow bodies, e.g. pipes, in moulds rotating around their longitudinal axis
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Reduction Rolling/Reduction Stand/Operation Of Reduction Machine (AREA)
Description
【発明の詳細な説明】
本発明は、耐摩耗鋳物の遠心力鋳造法、特に、
鋳鉄または鋳鋼を基材金属とし、基材金属と炭化
タングステン粒子の混在する耐摩耗性にすぐれた
外層と、基材金属からなる靭性の良好な内層の２
層を有し、圧廷用ロールや搬送用ロールなどに適
した耐摩耗性と靭性を兼ね備えるロール用鋳物を
遠心力鋳造にて製造する方法に関する。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a centrifugal casting method for wear-resistant castings, particularly,
The base metal is cast iron or cast steel, and the outer layer has excellent wear resistance and has a mixture of base metal and tungsten carbide particles, and the inner layer has good toughness and is made of the base metal.
The present invention relates to a method for manufacturing roll castings by centrifugal casting, which have layers and have both abrasion resistance and toughness suitable for pressing rolls, conveying rolls, and the like.
圧廷用ロールや搬送用ロールなどは、その胴部
表面が耐摩耗性にすぐれたものでなければなら
ず、またこれにくり返し加わる衝撃にも耐える十
分な靭性をもつことが必要である。このため、従
来、圧廷用ロールとして、遠心力鋳造にて耐摩耗
性に富む高合金からなる外層と、強靭性をもつ合
金からなる内層を形成した複合ロールが汎用さ
れ、また搬送用ロールとして、強靭性の炭素鋼々
管の外周面に耐摩耗合金を肉盛溶接したものが一
部用いられているが、これらは製造工程が煩瑣
で、コストも高い。 The surface of the body of an impression roll, conveyance roll, etc. must have excellent wear resistance, and must also have sufficient toughness to withstand repeated impacts. For this reason, conventionally, composite rolls in which an outer layer made of a highly wear-resistant high alloy and an inner layer made of a tough alloy have been formed by centrifugal force casting have been widely used as compaction rolls, and also used as conveyor rolls. Some of these are made by welding a wear-resistant alloy onto the outer circumferential surface of strong carbon steel pipes, but these require complicated manufacturing processes and are expensive.
近時、上記に代わるものとして、遠心力鋳造に
より、金属と炭化物粒子の混在する外層を形成す
ることによつて表面のみに耐摩耗性をもたせるよ
うにしたロールの鋳造法が提案されている。その
基本原理は、遠心力鋳造用モールド内に、基材金
属溶湯と、該溶湯より比重の大きい炭化物粒を鋳
込んで両者を混在させ、遠心力の作用で比重の大
きい炭化物粒を外周領域に偏在させて第１図に示
すように、モールド１内で基材金属と炭化物粒の
混在する外層（以下、「混在層」とも言う）ａと
基材金属からなる内層（以下、「金属層」とも言
う）ｂを形成し、その状態で凝固させることによ
り、該２層を有する鋳物を製造するものである。 Recently, as an alternative to the above method, a roll casting method has been proposed in which abrasion resistance is imparted only to the surface by forming an outer layer containing a mixture of metal and carbide particles by centrifugal force casting. The basic principle is that molten base metal and carbide grains with a higher specific gravity than the molten metal are mixed into a centrifugal casting mold, and the action of centrifugal force causes the carbide grains with a higher specific gravity to be cast into the outer peripheral area. As shown in FIG. 1, in the mold 1, an outer layer (hereinafter also referred to as "mixed layer") a in which base metal and carbide grains are mixed and an inner layer (hereinafter referred to as "metal layer") consisting of base metal A casting having these two layers is manufactured by forming a layer (also referred to as "b") and solidifying it in that state.
外層ａをミクロ的にみれば、第２図に示すよう
に、炭化物粒Ｐの間隙に基材金属Ｍが充填された
混在状態を呈しており、この炭化物粒Ｐの存在に
よつて外層ａに高い耐摩性が与えられる一方、内
層ｂは基材金属本来の靭性を保有する。つまり、
外層ａが耐摩耗材料として、内層ｂが靭性材料と
してそれぞれ機能するわけである。 If we look at the outer layer a microscopically, as shown in Figure 2, it exhibits a mixed state in which the base metal M is filled in the gaps between the carbide grains P, and due to the presence of the carbide grains P, the outer layer a While providing high wear resistance, the inner layer b retains the original toughness of the base metal. In other words,
The outer layer a functions as a wear-resistant material, and the inner layer b functions as a tough material.
上記鋳造は、第４図や第５図に示すように、軸
心Ｃを中心に回転する横型遠心鋳造用モールド１
と、その一端側に設置されたホツパー２を備え、
該ホツパーの先端を端板３の孔４にのぞませた遠
心鋳造装置を用いて行なわれるが、その鋳造によ
り所期の耐摩耗性をもつロールを製造するには、
金属溶湯とともに所要量の炭化物粉末がモールド
内に鋳込まれ、かつ外層（混在層）が所定の均一
な層厚に形成されることが必要である。 The above casting is carried out using a horizontal centrifugal casting mold 1 that rotates around an axis C, as shown in FIGS. 4 and 5.
and a hopper 2 installed on one end thereof,
This is carried out using a centrifugal casting machine in which the tip of the hopper is exposed to the hole 4 of the end plate 3. In order to manufacture a roll with the desired wear resistance by this casting,
It is necessary that a required amount of carbide powder is cast into the mold together with the molten metal, and that the outer layer (mixed layer) is formed to a predetermined uniform layer thickness.
しかるに、その鋳造法として、炭化物粉末を予
め取鍋内の金属溶湯に添加・混合しておき、これ
をホツパーからモールド内に鋳込む方法を用いた
のでは、重い炭化物粒が取鍋の底部に沈降してし
まうので、所定の混合状態で鋳込むことは不可能
である。この対策として、第４図に示すように、
ホツパー２内に注がれる金属溶湯流Ｍ上に炭化物
粒Ｐを添加しながらモールド１内に鋳込む方法も
考えられるが、溶湯の流れが緩かであると、図示
のようにホツパー内の湯道上に炭化物粒Ｐの沈積
が生じ、所定量の鋳込みを行なうことはできな
い。溶湯の流れが強ければ、上記沈積を回避する
ことは可能であるが、その反面、モールド内で遠
心力により形成されつつある混在層の炭化物粒が
溶湯の強い落下で逸散するため、第５図に示すよ
うに、溶湯の落下点近傍Ｄの混在層ａの厚さが薄
くなつてしまう。 However, if the casting method used was to add and mix carbide powder to the molten metal in the ladle in advance and then cast it into the mold from the hopper, heavy carbide grains would end up at the bottom of the ladle. It is impossible to cast in a predetermined mixed state because of settling. As a countermeasure for this, as shown in Figure 4,
It is also possible to add carbide grains P to the molten metal flow M poured into the hopper 2 while casting it into the mold 1, but if the flow of the molten metal is slow, the molten metal in the hopper will Carbide grains P are deposited on the path, making it impossible to cast a predetermined amount. If the flow of the molten metal is strong, it is possible to avoid the above-mentioned deposition, but on the other hand, the carbide grains in the mixed layer that is being formed in the mold due to centrifugal force are dissipated by the strong fall of the molten metal. As shown in the figure, the thickness of the mixed layer a near the falling point D of the molten metal becomes thin.
また、混在層ａは目的とするロールの胴部全長
に亘つて均一な層厚に形成されることが望まし
く、そのためには、モールド内に鋳込まれた炭化
物粒をモールドの長手方向に亘つてまんべんなく
分布させることが必要である。しかし、炭化物粒
は重く、しかもモールド内で遠心力が作用するた
め、鋳込み端側から他端に向かう炭化物粒の移動
は容易でなく、そのために前記第５図に示すよう
に、混在層ａの層厚が長手方向にそつて漸次減少
し、長尺体の場合には、他端側まで混在層ａを形
成することができない。 In addition, it is desirable that the mixed layer a be formed to have a uniform layer thickness over the entire length of the body of the target roll, and for that purpose, the carbide grains cast into the mold are spread over the longitudinal direction of the mold. It is necessary to distribute it evenly. However, since the carbide grains are heavy and centrifugal force acts within the mold, it is difficult for the carbide grains to move from the casting end to the other end, and as a result, as shown in FIG. The layer thickness gradually decreases along the longitudinal direction, and in the case of a long body, the mixed layer a cannot be formed all the way to the other end.
炭化物粒子として炭化タングステンを使用する
場合、該粒子は比重が極めて大きく（WCの比重
は15.7）、溶湯との比重差も大であるので、遠心
分離により炭化物粒子の濃度の高い混在層を形成
するのに有利であるが、その反面、上述のような
取鍋中やモールド内での粒子の沈積・分離とそれ
による鋳型内の粒子の不足（混在層層厚の不足）、
鋳型内の溶湯落下付近での粒子の散逸および鋳型
内の長手方向の粒子の拡散不足とそれによる混在
層厚の不均一化等が特に顕著に現れる。混在層の
層厚が不足したり、層厚が不均一であつたりする
と、耐摩耗性等所期の材料特性が得られず、構造
材料として信頼性・安定性が損なわれ、実用的価
値の欠けたものとなる。 When using tungsten carbide as carbide particles, the specific gravity of the particles is extremely large (the specific gravity of WC is 15.7) and the difference in specific gravity from the molten metal is large, so centrifugation forms a mixed layer with a high concentration of carbide particles. However, on the other hand, the above-mentioned sedimentation and separation of particles in the ladle and mold, resulting in a shortage of particles in the mold (insufficient mixed layer thickness),
Dissipation of particles in the vicinity of the molten metal falling into the mold, insufficient diffusion of particles in the longitudinal direction within the mold, and resulting non-uniformity in the thickness of the mixed layer are particularly noticeable. If the thickness of the mixed layer is insufficient or uneven, the desired material properties such as wear resistance will not be obtained, the reliability and stability of the structural material will be impaired, and the practical value will be lost. It becomes something missing.
本発明は、上記問題点を解決したものであり、
鋳鉄または鋳鋼を基材金属とし、基材金属と50〜
80％（体積）の炭化タングステン粒子からなる混
在層と、その内側の基材金属からなる金属層との
二層構造を有するロール用耐摩耗鋳物の製造方法
であつて、軸心を中心に回転する円形断面を有す
る横型遠心力鋳造用モールド内に基材金属溶湯を
鋳込み、遠心力にて形成される層厚10mm以上の溶
湯層に、炭化タングステン粉末を、該溶湯層の長
手方向に亘つて均一に添加し、溶湯層中を遠心移
行させることにより溶湯層の外周部に炭化タング
ステン粒子と基材金属とが混在する層を長手方向
の全長に亘つて所望の層厚に形成するようにした
耐摩耗性鋳物の鋳造法を提供する。 The present invention solves the above problems,
Cast iron or cast steel is the base metal, and the base metal and the
A method for manufacturing a wear-resistant casting for rolls having a two-layer structure of a mixed layer consisting of 80% (volume) tungsten carbide particles and a metal layer consisting of a base metal inside the mixed layer, which rotates around its axis. The base metal molten metal is cast into a horizontal centrifugal casting mold with a circular cross section, and tungsten carbide powder is applied to the molten metal layer with a thickness of 10 mm or more formed by centrifugal force in the longitudinal direction of the molten metal layer. By uniformly adding tungsten carbide particles and moving them centrifugally through the molten metal layer, a layer in which tungsten carbide particles and base metal are mixed is formed at the outer periphery of the molten metal layer to a desired layer thickness over the entire length in the longitudinal direction. A method for casting wear-resistant castings is provided.
第３図に本発明による鋳造要領の具体例を示
す。図中、５は炭化タングステン粉末の添加装置
である。まず、ホツパー２にて端板３の孔４より
モールド１へ鋳鉄または鋳鋼の鉄系金属溶湯の鋳
込みを開始する。鋳込まれた溶湯は遠心力により
モールドの内周面に沿う溶湯層６を形成する。溶
湯層６が適当な層厚になつた時点で、ホツパーと
反対側の端板３′の孔４′よりモールド内に挿入さ
れた炭化タングステン粉末添加装置５にて、溶湯
層６の長手方向にそつてほゞ均等に粉末を落下さ
せる。溶湯層６の表面に落下した粉末は、遠心力
によつて溶湯層を通つて外周面側に到達し、混在
層ａを形成する。その状態でモールドの回転を続
行しつつ凝固させることにより混在層ａと金属層
ｂを有する鋳物を得る。 FIG. 3 shows a specific example of the casting procedure according to the present invention. In the figure, 5 is a device for adding tungsten carbide powder. First, the hopper 2 starts pouring a molten iron-based metal such as cast iron or cast steel into the mold 1 through the hole 4 of the end plate 3. The poured molten metal forms a molten metal layer 6 along the inner peripheral surface of the mold due to centrifugal force. When the molten metal layer 6 reaches an appropriate thickness, the tungsten carbide powder adding device 5 inserted into the mold through the hole 4' in the end plate 3' on the opposite side of the hopper is used to add tungsten carbide powder in the longitudinal direction of the molten metal layer 6. Then, let the powder fall almost evenly. The powder that has fallen onto the surface of the molten metal layer 6 passes through the molten metal layer and reaches the outer peripheral surface side due to centrifugal force, forming a mixed layer a. In this state, the mold is solidified while continuing to rotate, thereby obtaining a casting having a mixed layer a and a metal layer b.
上記のように、本発明方法では、混在層ａを形
成するための炭化タングステン粉末が金属溶湯流
とは別の経路で、金属層の長手方向に亘つて添加
されるから、得られる鋳物の混在層は、前記のよ
うに不均一となることがなく、長手方向に亘つて
添加された量に応じた所望の層厚に形成される。
長手方向の添加量を均等にすれば、混在層の層厚
も均一になることは言うまでもない。むろん、前
記のようにホツパー２からの金属溶湯の流れを強
くする必要はないから、溶湯落下点近傍の混在
層々厚が局部的に薄くなることもない。 As described above, in the method of the present invention, the tungsten carbide powder for forming the mixed layer a is added along the longitudinal direction of the metal layer through a route different from the molten metal flow, so that the mixed layer a is mixed in the resulting casting. The layer is not non-uniform as described above, and is formed in the desired layer thickness in the longitudinal direction depending on the amount added.
Needless to say, if the amount added in the longitudinal direction is made uniform, the thickness of the mixed layer will also be made uniform. Of course, since there is no need to strengthen the flow of the molten metal from the hopper 2 as described above, the thickness of the mixed layers near the molten metal falling point does not become locally thin.
モールド内の溶湯層６への粉末の添加時期は任
意であるが、例えば、溶湯層の層厚が約10mm以上
になつた時点で添加するのが好ましい。搬送ロー
ルのような中空鋳物を目的とするときは、溶湯の
所定の全長が鋳込まれたのちに添加してもよい。
また、圧廷用ロールの鋳造においては、粉末の添
加後に、後工程として芯材を鋳込み中実体とすれ
ばよい。このように、溶湯の鋳込み途中、または
完了後に粉末を添加すれば、粉末と金属がよく混
り合い、前記第２図に示すように粉末粒子の間隙
に金属が十充填された良好な混在状態が得られ
る。 Although the timing of adding the powder to the molten metal layer 6 in the mold is arbitrary, it is preferable to add the powder when the thickness of the molten metal layer reaches approximately 10 mm or more, for example. When the purpose is a hollow casting such as a conveyor roll, it may be added after a predetermined full length of the molten metal has been cast.
In addition, in casting an impression roll, after adding the powder, a core material may be cast as a subsequent step to form a solid body. In this way, if the powder is added during or after the molten metal is poured, the powder and metal will mix well, creating a good mixed state in which the gaps between the powder particles are fully filled with metal, as shown in Figure 2 above. is obtained.
なお、粉末の添加により溶湯層が降温・粘稠化
して該粉末の遠心分離が妨げられるような場合に
は、予め粉末を、例えば400〜600℃に加熱して用
いるのも好ましい一法である。 In addition, in the case where the temperature of the molten metal layer decreases and becomes viscous due to the addition of the powder, which impedes centrifugation of the powder, it is also a preferable method to heat the powder in advance to, for example, 400 to 600°C. .
本発明において基材金属として鋳鉄または鋳鋼
を用いるのは、ロール類等の構造材料として必要
な強度・靭性等の機械的性質を確保するためであ
る。これらの鉄系金属溶湯は、炭化タングステン
粒子との濡れ性も良いので、鋳型内における溶湯
への粒子の取り込み、混じり合いが容易に行われ
る点で有利である。 The reason why cast iron or cast steel is used as the base metal in the present invention is to ensure mechanical properties such as strength and toughness required as a structural material for rolls and the like. These iron-based metal molten metals have good wettability with tungsten carbide particles, so they are advantageous in that the particles can be easily taken into and mixed with the molten metal in the mold.
また、硬質炭化物として炭化タングステンを使
用するのは、極めて硬質で（WCの硬度Hv：約
2086）、ロール類の表面の耐摩耗性の向上に著効
を有すること、高融点（WCの融点：約2776℃）
で、鋳鉄や鋳鋼の溶湯中で溶解しにくいこと、溶
湯との比重差が大きく、遠心分離により粒子濃度
差が50℃（体積）以上と、粒子が緻密に混在する
混在層を形成するのに有利であること、等によ
る。 In addition, the use of tungsten carbide as a hard carbide is extremely hard (WC hardness Hv: approx.
2086), has a remarkable effect on improving the abrasion resistance of the surface of rolls, and has a high melting point (WC melting point: approximately 2776℃)
However, it is difficult to dissolve in the molten metal of cast iron or cast steel, and there is a large difference in specific gravity with the molten metal, and when centrifuged, the particle concentration difference is 50℃ (volume) or more, forming a mixed layer in which particles are densely mixed. By virtue of being advantageous, etc.
上記粉末は、あまり粒径が小さいと、混在層中
への集中が困難となるので、比較的粗粒のものが
好ましい。粉末粒子表面には、酸化防止のため
に、例えばニツケル系、銅系などのめつきが施こ
されることもあり、あるいは溶融フラツクスを浸
潤させておくことも有用である。 If the particle size of the above powder is too small, it will be difficult to concentrate in the mixed layer, so it is preferable that the powder has relatively coarse particles. The surfaces of the powder particles may be plated with, for example, nickel or copper to prevent oxidation, or it is also useful to infiltrate them with molten flux.
混在層ａの耐摩耗性は、炭化タングステン粒子
の濃度が高い程、向上する。混在層中の粒子濃度
は遠心力を強めることにより高くすることができ
る。しかし、粒子濃度が余り高くなると、強度・
靭性が低くなる。ロール類等の構造材料としての
耐摩耗性と強度・靭性の両面を考慮すると、混在
層中の炭化タングステン粒子濃度は50〜80％（体
積）が好ましい。 The wear resistance of the mixed layer a improves as the concentration of tungsten carbide particles increases. The particle concentration in the mixed layer can be increased by increasing the centrifugal force. However, if the particle concentration becomes too high, the strength and
Toughness decreases. Considering both wear resistance and strength/toughness as a structural material for rolls, etc., the concentration of tungsten carbide particles in the mixed layer is preferably 50 to 80% (by volume).
前記炭化タングステン粉末添加装置５は、例え
ば長尺の樋状体７が支持棒８にてモールド内に挿
入されるようになつており、該樋状体に粉末を充
填して、予めモールド１内に設置しておくか、も
しくは溶湯の鋳込み開始後に挿入し、所定の時期
に反転させて該粉末を溶湯層６の表面に落下させ
るか、あるいは樋状体をモールド内の軸方向に移
動させつつ、その先端から粉末を落下させるよう
にしてもよい。要するに添加装置の形態、添加要
領は、溶湯層の長手方向に亘つて所要量の粉末を
添加し得るならば、どのようなものであつてもよ
い。 The tungsten carbide powder adding device 5 is configured such that, for example, a long gutter-like body 7 is inserted into the mold with a support rod 8, and the gutter-like body is filled with powder and added to the mold 1 in advance. Alternatively, the powder may be placed in the mold after the molten metal has started pouring, and turned over at a predetermined time to cause the powder to fall onto the surface of the molten metal layer 6, or the gutter-shaped body may be moved in the axial direction within the mold. , the powder may fall from its tip. In short, the shape of the addition device and the manner of addition may be of any type as long as the required amount of powder can be added over the longitudinal direction of the molten metal layer.
次に本発明方法の実施例、および比較例につい
て説明する。 Next, examples of the method of the present invention and comparative examples will be described.
実施例１、２および比較例
第３図に示す遠心鋳造装置（モールドは、CO2
型による砂型モールド使用）において、基材金属
としてニハード系鋳鉄を用い、その溶湯をホツパ
ー２にてモールド内に鋳込むとともに、炭化タン
グステン粉末を添加装置５にて溶湯層の長手方向
に亘つて添加することにより中空円筒状鋳物（管
体）を鋳造し、冷却後、その鋳造管を縦割りして
外周部の混在層形成状況を観察した（実施例１お
よび２）。また、比較例として、第６図に示す遠
心鋳造装置にて、炭化タングステン粉末をホツパ
ー２の溶湯流に連続添加する方法により鋳造管を
製造し、同様の観察を行なつた。なお、いづれの
場合も、炭化タングステン粉末は表面にニツケル
めつきを施しており、かつ予め500℃に加熱して
使用した。また、鋳造時の遠心力はモールド内周
面で65Gである。Examples 1 and 2 and Comparative Example The centrifugal casting apparatus shown in Fig. 3 (the mold was
In the process (using a sand mold), nihard cast iron is used as the base metal, and the molten metal is cast into the mold using the hopper 2, and tungsten carbide powder is added to the molten metal layer in the longitudinal direction using the adding device 5. A hollow cylindrical casting (tubular body) was cast by this method, and after cooling, the cast tube was vertically divided to observe the formation of a mixed layer on the outer periphery (Examples 1 and 2). Further, as a comparative example, a cast tube was manufactured by a method of continuously adding tungsten carbide powder to the molten metal flow in the hopper 2 using the centrifugal casting apparatus shown in FIG. 6, and similar observations were made. In each case, the tungsten carbide powder had a nickel plated surface and was heated to 500°C before use. Furthermore, the centrifugal force during casting is 65G on the inner peripheral surface of the mold.
モールド寸法： 内径（鋳物外径に相当）：220mm、長さ：400mm。Mold dimensions: Inner diameter (equivalent to casting outer diameter): 220mm, length: 400mm.
ニハード系鋳鉄
目標成分：C3.29％、Si0.75％、Mn0.65％、
Ni4.4％、Cr1.57％、Mo0.41％。Nihard cast iron Target composition: C3.29%, Si0.75%, Mn0.65%,
Ni4.4%, Cr1.57%, Mo0.41%.
溶湯比重：7.0
鋳込み量：45.7Kg
炭化タングステン（WC）粉末
比重：15.7
中心粒度：200μ
添加量：7.7Kg
実施例 １
〔〕 鋳込み条件
(i) 溶湯鋳込み温度：150℃
(ii) 溶湯の鋳込所要時間（鋳込み開始から終了
までの経過時間）：42秒
(iii) WC粉末添加開始時期：溶湯鋳込み終了
（溶湯重厚：約27mm）の１秒後
(iv) WC粉末添加所要時間（添加開始から終了
までの経過時間）：２秒
〔〕 鋳造管断面状況
上記条件で得られた鋳造管のWC粉末と鋳鉄
からなる外周部の混在層における炭化タングス
テン粒子濃度は60％（体積）であり、その層厚
は、長手方向全長にわたりほゞ３mm（最大層厚
3.2mm、最小層厚2.5mm）と、工業的に満足すべ
き均一性を有している。 Molten metal specific gravity: 7.0 Casting amount: 45.7Kg Tungsten carbide (WC) powder Specific gravity: 15.7 Center particle size: 200μ Addition amount: 7.7Kg Example 1 [] Casting conditions (i) Molten metal pouring temperature: 150℃ (ii) Molten metal pouring Required time (elapsed time from start to end of pouring): 42 seconds (iii) Time to start adding WC powder: 1 second after the end of molten metal pouring (molten metal thickness: approx. 27 mm) (iv) Time required to add WC powder (elapsed time from start of addition) Elapsed time until completion): 2 seconds [] Cast pipe cross-sectional condition The tungsten carbide particle concentration in the mixed layer on the outer periphery consisting of WC powder and cast iron of the cast pipe obtained under the above conditions was 60% (volume); The layer thickness is approximately 3 mm (maximum layer thickness) over the entire length in the longitudinal direction.
3.2mm, minimum layer thickness 2.5mm), which has industrially satisfactory uniformity.
実施例 ２
〔〕 鋳込み条件
(i) 溶湯鋳込み温度：1550℃
(ii) 溶湯の鋳込み所要時間：40秒
(iii) WC粉末添加開始時期：溶湯鋳込み開始か
ら29秒後（この時点で、全溶湯量の約3/4が
鋳込まれており、モールド内での溶湯層厚は
約19mmである）。Example 2 [] Casting conditions (i) Molten metal pouring temperature: 1550°C (ii) Time required for pouring the molten metal: 40 seconds (iii) WC powder addition start time: 29 seconds after the start of molten metal pouring (at this point, all the molten metal Approximately 3/4 of the amount is cast, and the molten metal layer thickness within the mold is approximately 19 mm).
(iv) WC粉末添加所要時間：２秒
〔〕 鋳造管断面状況
得られた鋳造管の外周部混在層の炭化タング
ステン濃度は60％（体積）であり、その層厚
は、長手方向全長にわたり、ほゞ３mm（最大層
厚3.2mm、最小層厚2.4mm）と、工業的に均一で
ある。 (iv) Required time for adding WC powder: 2 seconds [] Cross-sectional condition of cast pipe The tungsten carbide concentration of the mixed layer on the outer periphery of the obtained cast pipe was 60% (volume), and the layer thickness was 60% (volume) over the entire length in the longitudinal direction. It is approximately 3 mm (maximum layer thickness 3.2 mm, minimum layer thickness 2.4 mm), which is industrially uniform.
なお、混在層の組織を第７図に示す（倍率50
倍）。WC粒子が緻密、かつ均一に分散し、該
粒子間に十分基材金属が充填された良好な組織
を有することが判る。 The structure of the mixed layer is shown in Figure 7 (magnification: 50
times). It can be seen that the WC particles are densely and uniformly dispersed, and have a good structure in which the base metal is sufficiently filled between the particles.
比較例
〔〕 鋳込み条件
(i) 溶湯の鋳込み温度：1540℃
(ii) 溶湯鋳込み所要時間：40秒
(iii) WC粉末添加開始時期：溶湯の鋳込み開始
の１秒後
(iv) WC粉末添加所要時間：31秒
〔〕 鋳込み結果と鋳造管断面状況
鋳込終了後、ホツパー２の湯道上に、WC粉
末約0.6Kgが残留していた。また、鋳造管断面
の混在層ａは第６図に示すように不均一（図
中、イ：3.5mm、ロ：1.5mm、ハ：3.5mm）で、鋳
込み側の溶湯落下点の近傍の層厚が薄く、しか
もWC粉末は他端側まで到達せず、該他端付近
では混在層が存在しない。Comparative example [] Pouring conditions (i) Molten metal pouring temperature: 1540℃ (ii) Molten metal pouring time: 40 seconds (iii) WC powder addition start time: 1 second after starting molten metal pouring (iv) WC powder addition required Time: 31 seconds [] Casting results and cross-sectional condition of the cast pipe After casting, approximately 0.6 kg of WC powder remained on the runner of hopper 2. In addition, the mixed layer a in the cross section of the casting pipe is non-uniform as shown in Figure 6 (A: 3.5 mm, B: 1.5 mm, C: 3.5 mm in the figure), and the layer near the molten metal falling point on the casting side is uneven. The thickness is thin, and the WC powder does not reach the other end, and there is no mixed layer near the other end.
以上のように、本発明方法によれば、外周部に
炭化タングステン粒子と鋳鉄または鋳鋼からなる
混在層が長手方向の全長に亘つて所望の層厚に形
成された鋳物を製造することができ、その混在層
によつて確実かつ安定した耐摩耗性を保証するこ
とができる。むろん、混在層の内側の金属層によ
つて良好な靭性をも具備する。従つて、圧廷用ロ
ールや搬送用ロールなどの各種ロール類として用
いれば、表面の摩耗、衝撃によく耐え、すぐれた
耐久性が得られる。また、ロール類に限らず、要
するに耐摩耗性と靭性の要求される各種装置、機
械の部材として用い同様の効果を得ることができ
る。 As described above, according to the method of the present invention, it is possible to manufacture a casting in which a mixed layer of tungsten carbide particles and cast iron or cast steel is formed in the outer peripheral portion to a desired layer thickness over the entire length in the longitudinal direction, The mixed layer ensures reliable and stable wear resistance. Of course, the metal layer inside the mixed layer also provides good toughness. Therefore, when used as various rolls such as pressing rolls and conveying rolls, they can withstand surface abrasion and impact well and have excellent durability. Moreover, the same effect can be obtained not only in rolls but also in various devices and machine members that require wear resistance and toughness.
第１図はモールド内の鋳物の２層構造を示す断
面説明図、第２図は鋳物の２層構造のミクロ的組
織を模式的に示す断面説明図、第３図〔〕は本
発明方法の実施要領の具体例を示す断面説明図、
〔〕はそのＡ−Ａ断面図、第４図および第５図
は従来の鋳造法による鋳込状況を示す断面説明
図、第６図は実施例関係の鋳物断面説明図、第７
図は本発明方法で得られた鋳物の組織を示す図面
代用写真（倍率50）である。
１：モールド、２：ホツパー、５：金属化合物
粉末添加装置、６：溶湯層、ａ：外層（混在層）、
ｂ：内層（金属層）、Ｍ：基材金属、Ｐ：硬質粒
子（炭化タングステン粒子）。
Fig. 1 is an explanatory cross-sectional view showing the two-layer structure of the casting in the mold, Fig. 2 is an explanatory cross-sectional view schematically showing the microstructure of the two-layer structure of the casting, and Fig. 3 [ ] is an explanatory cross-sectional view showing the two-layer structure of the casting. A cross-sectional explanatory diagram showing a specific example of the implementation procedure,
[ ] is a sectional view taken along the line A-A, FIGS. 4 and 5 are cross-sectional explanatory views showing the state of casting by the conventional casting method, FIG. 6 is an explanatory cross-sectional view of castings related to examples, and
The figure is a photograph (magnification: 50) showing the structure of a casting obtained by the method of the present invention. 1: mold, 2: hopper, 5: metal compound powder addition device, 6: molten metal layer, a: outer layer (mixed layer),
b: inner layer (metal layer), M: base metal, P: hard particles (tungsten carbide particles).
Claims (1)
50〜80％（体積）の炭化タングステン粒子からな
る混在層と、基材金属からなる金属層との二層構
造を有するロール用耐摩耗鋳物の製造方法であつ
て、軸心を中心に回転する円形断面を有する横型
遠心力鋳造用モールド内に基材金属溶湯を鋳込
み、遠心力にて形成される層厚10mm以上の溶湯層
に、炭化タングステン粉末を、該溶湯層の長手方
向に亘つて均一に添加し、溶湯層中を遠心移行さ
せることにより溶湯層の外周部に炭化タングステ
ン粒子と基材金属とが混在する層を長手方向に亘
つて均一な層厚に形成し凝固させることを特徴と
する耐摩耗鋳物の遠心力鋳造法。1 Cast iron or cast steel is the base metal, and the base metal
A method for manufacturing a wear-resistant casting for rolls having a two-layer structure of a mixed layer consisting of 50 to 80% (volume) tungsten carbide particles and a metal layer consisting of a base metal, which rotates around its axis. The base metal molten metal is cast into a horizontal centrifugal casting mold with a circular cross section, and tungsten carbide powder is uniformly applied to the molten metal layer with a thickness of 10 mm or more formed by centrifugal force over the longitudinal direction of the molten metal layer. By adding tungsten carbide particles to the molten metal layer and centrifugally transferring it through the molten metal layer, a layer in which tungsten carbide particles and base metal are mixed is formed on the outer periphery of the molten metal layer to a uniform thickness in the longitudinal direction and solidified. Centrifugal casting method for wear-resistant castings.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP21386181A JPS58116969A (en) | 1981-12-30 | 1981-12-30 | Centrifugal casting method for abrasion resistance casting |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP21386181A JPS58116969A (en) | 1981-12-30 | 1981-12-30 | Centrifugal casting method for abrasion resistance casting |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS58116969A JPS58116969A (en) | 1983-07-12 |
| JPH0127819B2 true JPH0127819B2 (en) | 1989-05-31 |
Family
ID=16646229
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP21386181A Granted JPS58116969A (en) | 1981-12-30 | 1981-12-30 | Centrifugal casting method for abrasion resistance casting |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS58116969A (en) |
-
1981
- 1981-12-30 JP JP21386181A patent/JPS58116969A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS58116969A (en) | 1983-07-12 |
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