JP3591858B2 - Carbide insert for aluminum cutting - Google Patents

Description

【００１１】
【表２】

【００１２】
【表３】

【００１３】
アルミとの反応性は鏡面ラップした各超硬試料の上にアルミの円筒状の塊を置き真空中８００℃で２時間放置後超硬ラップ面に生じた反応相の厚みで評価した。評価は下記のように４段階とした。
１：反応相の厚みが３０μｍ未満（大いに効果あり）
２：３０〜７０μｍ（効果あり）
３：７１〜１００μｍ（従来より効果あり）
４：１００μｍを越えた場合（従来と同じ）
【００１４】
切削性能はチップ形状ＴＮＧＧ３３１（内接円９．５２５ｍｍ、厚み４．７６ｍｍ、ノーズ０．４ｍｍ）を用いて切削速度３００ｍｍ切り込み２ｍｍ送り０．２ｍｍ／ＲＥＶ、アルミの旋削加工を行い、加工物の表面状態、切り粉の形状、刃先の溶着状況等から判定した工具寿命で良否を判定した。その結果を表１〜表３に併記する。
【００１５】
【発明の効果】
このように本発明の材種はアルミに対する反応性が低くアルミ加工用の切削工具として優れた特性をもつ。[0001]
[Industrial applications]
The present gun invention relates to hard tip which exhibits excellent characteristics as for aluminum machining.
[0002]
[Prior art]
In aluminum cutting, the edge of the chip is sharpened due to severe welding of the aluminum and the chip, and the surface of the chip is mirror-finished, and the surface is coated with a low coefficient of friction (TiN, TiCN, diamond, CBN, etc.). And so on. However, when the edge angle is sharpened, chipping tends to occur, and mirror-surface wraps have problems such as high manufacturing cost and difficulty in wrapping curved surfaces, and surface coating, in which film peeling is frequent and stable cutting is difficult. .
[0003]
[Problems to be solved by the invention]
As described above, carbide tips for cutting aluminum have been widely used in recent years.However, there is very little reaction with aluminum at medium and high temperatures, and toughness and strength sufficient to withstand stress concentration applied to the cutting edge during cutting. There was no carbide insert for cutting.
[0004]
[Purpose of the invention]
It is an object of the present invention to create a cemented carbide material which has very little reaction with aluminum at medium to high temperatures while maintaining sufficient toughness and strength, and to provide the cemented carbide chip for aluminum cutting.
[0005]
[Means for Solving the Problems]
The present inventors have conducted intensive studies on the reaction mechanism between aluminum and cemented carbide at medium and high temperatures, and found that damage to the cemented carbide surface is a reaction between aluminum and the metal bonding phase that is a component of the cemented carbide material. The metal binding phase is generally Co, but the reaction is extremely reduced by using a Co—Cr system containing a large amount of Cr, which is unprecedented, as well as Ni, V, TaC, NbC. It has been found that the reaction can be further reduced by adding such as appropriate. The present invention relates to a WC-based cemented carbide containing WC and a metal binder phase , wherein the metal binder phase contains Co and Cr , the amount of the metal binder phase accounts for 4 to 25% by weight of the alloy, and The amount of the binder phase is 16.7 to 36.7% , and the WC is a cemented carbide chip for aluminum cutting characterized by having an average particle size of 0.2 to 7 μm.
[0006]
[Action]
Hereinafter, the present invention will be described in more detail according to the claims. First, it is necessary that Cr be contained in an amount of 16.7 to 36.7 % by weight based on the metal binder phase. If it is less than 16.7%, the reactivity to aluminum is insufficient, and if it exceeds 36.7% , intermetallic compounds such as Co ₃ Cr and Co ₂ Cr and double carbides are formed in the production process, and the toughness is reduced. If a part of Cr is replaced by V, the reason for this is still unknown, but the welding of aluminum is reduced. In this case, if it is less than 10%, the effect of V is not clear, and if it exceeds 30%, the toughness is slightly lowered.
[0007]
Desirably, the binder phase accounts for 3 to 25% by weight of the alloy. If it is less than 3%, the toughness is reduced and the probability of breakage due to inability to withstand stress concentration increases. If it exceeds 25%, the rigidity is reduced, and it cannot be put to practical use. Substituting a part of Co for Ni improves corrosion resistance and oxidation resistance, which is practically preferable. In this case, if it is less than 10%, the effect of Ni is not clear, and if it exceeds 40%, the toughness is slightly lowered.
[0008]
The average particle size of WC is 0.2 to 7 μm, which is consistent with the gist of the present invention. If it is less than 0.2 μm, the toughness (fracture toughness value K _1C ) decreases and the probability of chipping increases. If it exceeds 7 μm, the WC carbide itself becomes a starting point of fracture, so that the toughness is also lowered, which is not desirable for practical use. Carbide is generally manufactured by sintering at a high temperature of around 1400 ° C., so that WC and other carbides dissolve in the metal binder phase, so that the metal binder phase necessarily contains small amounts of W, Ta, Nb, and the like. You. When a part of the WC is replaced with a refractory carbide, an effect corresponding to each carbide can be obtained. Substitution with TaC improves the strength at medium and high temperatures and is practically preferable. In this case, if the content is less than 3%, the effect of TaC is not clear, and if it exceeds 10%, the toughness is slightly lowered. NbC has the same effect. In this case, if it is less than 3%, the effect of NbC is not clear, and if it exceeds 10%, the toughness is slightly lowered.
[0009]
【Example】
Raw material powders such as WC, Co, and Cr were weighed at a predetermined ratio, and were wet-mixed for 72 hours in a ball mill using alcohol as a dispersant. After the completion of mixing, dry granulation was performed using spray drying. The resulting granulated powder was press-formed and vacuum-sintered while appropriately selecting a processing temperature. After sintering was completed, it was processed into a predetermined shape, and its toughness (fracture toughness value K _1C ), reactivity with aluminum, and cutting performance were investigated. Tables 1 to 3 show the composition and the like.
Tables 1 to 3 show (Cr + V) / (Co + Ni + Cr + V) as the “Cr ratio”.
[0010]
[Table 1]

[0011]
[Table 2]

[0012]
[Table 3]

[0013]
The reactivity with aluminum was evaluated by placing a cylindrical lump of aluminum on each mirror-wrapped cemented carbide sample, leaving it at 800 ° C. in a vacuum for 2 hours, and then evaluating the thickness of the reaction phase formed on the cemented carbide wrap surface. The evaluation was made in four stages as follows.
1: The thickness of the reaction phase is less than 30 μm (very effective)
2: 30 to 70 µm (with effect)
3: 71 to 100 μm (more effective than before)
4: When exceeding 100 μm (same as before)
[0014]
The cutting performance is as follows: Using a tip shape TNGG331 (inscribed circle 9.525 mm, thickness 4.76 mm, nose 0.4 mm), cutting speed 300 mm, cutting depth 2 mm, feed 0.2 mm / REV, aluminum turning, and the surface of the workpiece Pass / fail was determined based on the tool life determined from the state, the shape of the cutting powder, the welding state of the cutting edge, and the like. The results are also shown in Tables 1 to 3 .
[0015]
【The invention's effect】
As described above, the grade of the present invention has low reactivity to aluminum and has excellent characteristics as a cutting tool for aluminum processing.

Claims (5)

In a WC-based cemented carbide containing WC and a metal binder phase , the metal binder phase contains Co and Cr , the amount of the metal binder phase occupies 4 to 25% by weight of the alloy, and Cr is the amount of the metal binder phase. 16.7-36.7 % , wherein the WC has an average particle size of 0.2-7 μm. 2. The cemented carbide chip for aluminum cutting according to claim 1, wherein 10-40% of the Co amount is replaced with Ni. 2. The cemented carbide tip for aluminum cutting according to claim 1, wherein 10 to 30% of the amount of Cr is replaced by V. 2. The cemented carbide chip for aluminum cutting according to claim 1, wherein 3 to 10% of the WC amount is replaced with TaC. 2. The cemented carbide chip for aluminum cutting according to claim 1, wherein 3 to 10% of the WC amount is replaced with NbC.