JPS58187281A - Production of stepped bar material of sintered hard alloy - Google Patents

Abstract

PURPOSE:To produce a titled bar material having good out of roundness and cylindricity with good economy by heating the butt parts of two pieces of sintered hard alloy bar materials differing in the size of shape of section to around the eutectic temp. of said sintered hard alloy and joining the butt parts. CONSTITUTION:The respective end faces 8, 10 of bar materials 7, 9 of a sintered hard alloy having large and small diameters are butted to contact with each other. Both bar materials are beforehand ground and finished to have precision outside circumferences and the respective faces 8, 10 are ground and finished flatly and smoothly. The contact parts are locally heated by high frequency induction in a reducing atmosphere under light pressure so as to be heated to the eutectic temp. or above. Then, a melt is formed on the contact part and the contact part soften and are joined almost instantaneously while building up 11, so that the stepped bar material wherein the butt parts are joined to one body to the extent of showing no mark for the boundary is obtained. Even if the heating temp. in this stage is the eutectic temp. or below, both bar materials are joined by increasing the time and pressure.

Description

【発明の詳細な説明】 本発明は超硬ソリッド工具用の段付超硬合金棒材を経済
的に製作する方法に関するものである。一般に極く小径
の超硬工具、例えば切刃外径が１０箇以下のドリル、リ
ーマ−、エンドミル等は、超硬合金無垢の一体物の段付
丸棒から作られ、超硬ソリッド工具と総称されている。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for economically producing stepped cemented carbide bars for solid carbide tools. Generally, extremely small-diameter carbide tools, such as drills, reamers, and end mills with an outer diameter of 10 or less cutting edges, are made from a stepped round bar made of solid carbide, and are collectively called solid carbide tools. has been done.

第１図は段付丸棒材の細径部に刃付けされたドリル、第
２図は反対に太径部に刃付けされ九ドリルであって、何
れも円筒形のシャンク部を含めて全体が超硬合金から成
る超硬ソリッド工具の例である。これらの超硬ソリッド
エ臭用素材としての段付丸棒製作法は従来は比較的手数
がかかった。Figure 1 shows a drill with a blade attached to the narrow diameter part of a stepped round bar material, and Figure 2 shows a nine drill with a blade attached to the large diameter part of the stepped round bar. is an example of a solid carbide tool made of cemented carbide. Conventionally, the manufacturing method of stepped round bars for these solid carbide odor materials was relatively time-consuming.

イヒ 超硬合金は周知の通り、炭哉タングステン〔ＷＯ３や金
属コバル）［ＯＯ’１などの原料粉末の混合物を常温圧
縮して圧粉体を作ね、それを炉内で高温に加熱して、い
わゆる焼結法によって製造する。然し、前記の段付棒材
を焼結操作だけで作ることは実用的には困離であって、
その主な理由は２つある。As is well known, Ihi cemented carbide is produced by compressing a mixture of raw material powders such as carbon tungsten (WO3 and metal cobal) [OO'1] at room temperature to make a green compact, which is then heated to a high temperature in a furnace. , manufactured by the so-called sintering method. However, it is practically difficult to make the above-mentioned stepped bar only by sintering.
There are two main reasons for this.

その理由の第１は、超硬合金は焼結時の高温状態に於て
軟化していて、長物の場合には自重によって、その底面
が炉内の台座の形に倣って層性変形することである０通
常、棒材−は圧粉体を台座上に横たえて焼結するので、
その焼上りの真直度は台座の形に倣って出来上る。The first reason is that cemented carbide is softened at high temperatures during sintering, and in the case of long products, the bottom surface deforms in layers following the shape of the pedestal in the furnace due to its own weight. 0 Usually, bar material is sintered by placing the green compact on a pedestal, so
The straightness of the finished product follows the shape of the pedestal.

第２の理由は、超硬合金は焼結時に大巾な収縮を生ずる
ことである。その収縮率は当初の圧粉体に対して体積で
は約５０％、線分では約２０１に及ぶ、それ故に、焼結
前の段付圧粉体を第３図に示す様に段付合座上Ｋｌｌ然
と置いても、焼結中に２０１１ｉの線収縮率がある為に
台座との関係位置が、縦および横共にずれて、焼上りで
は第４図に示す様に棒材の細径部側の首が曲る。第３図
および第４図中の■は焼結前の段付圧粉体、■は段付台
座、■は焼上りの段付超硬棒材である。The second reason is that cemented carbide undergoes extensive shrinkage during sintering. The shrinkage rate is about 50% in volume and about 201 in line segment compared to the original green compact. Even if the bar is placed in the same position, the linear shrinkage rate of 2011i occurs during sintering, so the position relative to the pedestal will shift both vertically and horizontally, and after firing, the bar will have a small diameter as shown in Figure 4. The neck on the side is bent. In FIGS. 3 and 4, ■ is a stepped compact before sintering, ■ is a stepped pedestal, and ■ is a fired stepped cemented carbide bar.

上記の様に焼結だけでは段付棒材は作り難いので、今日
までは第５図に示す様に均径の円筒棒材から研削等の加
工によって細径部を削り出す方法がとられている。第５
図中の■は円筒素材の侭の大径部分、■は削り出しで作
られた細径部分、■は削り去られた部分を示す。As mentioned above, it is difficult to make stepped bars by sintering alone, so up until now, as shown in Figure 5, a method has been used in which a narrow diameter part is cut out from a cylindrical bar with a uniform diameter through processing such as grinding. There is. Fifth
In the figure, ■ indicates the large diameter part of the side of the cylindrical material, ■ indicates the small diameter part made by cutting, and ■ indicates the removed part.

本発明は旧来法とは全く発想を異にし、細径及び太径の
棒材を接合して段付棒材を作り出す方法であって、その
接合の原理を第６図によって説明する。この第６図は超
硬合金を代表するＷＯ−Ｏｏ　　系に関する成田博士創
始の金相状節回であって、次の図書から引用したもので
ある。〔コロナ社発行、榛葉久吉著１粉末冶金学′１５
４頁〕 第６図に於て、１例として図中下方の０点に示す様な［
９４１１ＷＯ＋６）Ｃｏ　）の組成を持つ超硬合金を加
熱して、破線で示す様に昇温させると、始めは〔ＷＣ＋
γ〕の２固用共存であるが、０点、即ち１２８０℃の共
晶温度に達すると０点、即共昌点に相当する〔略３５％
ＷＯ＋６５嗟Ｏｏ　）の組成を４つ融体〔δ〕相が生成
し始め、〔γ〕相が次第に消滅して、〔ＷＣ＋δ〕の２
相共存状ＩＩＫなるまで昇温は停止する。この２相共存
時に於ける、固相（ＷＯ）と滅相〔１〕の重量比には０
点を支点とする天秤のバランス関係が成立するから、各
肘の長さ０−■および＠−のに反比例する。これによっ
て計算すると融体〔δ〕の量は重量比では全体の１０１
１９１であるが、その比重け［ＷＯ）よシも小さいので
、体積比では全体の略１２−になる。上記の昇温く於て
［ＷＯ＋δ〕の２相共存が完了すると、温度は再び昇り
始め、図中のｄ線に沿ってＷＣが溶は込み融体〔δ〕の
量が増して行く。この融体〔δ〕は合金体内に局部的に
生成するのではなくて、全体的に石垣状に組立ったミク
ロンサイズの［：ＷＯ］粒間に万逼なく行渡って生成し
、合金体が柔軟化する。The present invention is completely different in concept from conventional methods, and is a method of joining small diameter and large diameter bars to create stepped bars.The principle of this joining will be explained with reference to FIG. This Figure 6 is a metal phase diagram created by Dr. Narita regarding the WO-Oo system, which is representative of cemented carbide, and is taken from the following book. [Published by Corona Publishing, written by Hisakichi Shinba 1 Powder Metallurgy '15
Page 4] In Figure 6, as an example, as shown at point 0 at the bottom of the figure, [
When a cemented carbide having a composition of 9411WO+6)Co) is heated and the temperature is raised as shown by the broken line, it initially becomes [WC+
γ], but when it reaches the 0 point, that is, the eutectic temperature of 1280°C, it immediately corresponds to the eutectic point [approximately 35%
Four molten [δ] phases begin to form, and the [γ] phase gradually disappears, and the composition of [WC+δ]
The temperature increase is stopped until the phase coexistence state IIK is reached. When these two phases coexist, the weight ratio of solid phase (WO) and dead phase [1] is 0.
Since the balance relationship of a scale with the point as the fulcrum is established, the length of each elbow is inversely proportional to 0-■ and @-. Calculating from this, the amount of melt [δ] is 101 of the total weight ratio.
191, but its specific gravity [WO] is also smaller, so the volume ratio is about 12-. When the two-phase coexistence of [WO+δ] is completed during the temperature rise described above, the temperature begins to rise again, and the amount of molten body [δ] increases along the d line in the figure as WC is injected into the melt. This melt [δ] is not generated locally within the alloy, but is generated evenly between the micron-sized [:WO] grains that are assembled like a stone wall, and is formed throughout the alloy. becomes more flexible.

本発明は上記の性状に着目して、超硬合金の高温接合を
企図したものである。第７図はその接合方法を示すもの
で、図中の■は超硬合金の太径棒材で■はその端面、■
は超硬合金の細径棒材で［Ｆ］はその端面であって、こ
の両方の端間■及び０を突合わせて接触させた状態であ
る。棒材■および■は予め精密に外周研削仕上し、端面
■及び０は予め平坦且平滑に研削仕上した。この接触部
分を還元雰囲気中で、軽い圧力を加え乍ら高周波誘導で
局部加熱した。温度が約１３００℃の共晶温度附近に達
した時、接触部分に融体が生成して軟化し、僅かに盛抄
上り乍ら殆んど瞬時に接合し九、これを常温まで冷却し
た後に縦断面を検鏡し九処完全に接合して、境界部を藺
めない程に一体化した。第８図は太径棒材■と細径棒材
■が完全に接合した接合段付棒材の状況を示すものであ
る０図中の■は接合部外周に僅かに残る盛抄上りである
が、段部のノツチを解消して強度上は却て有利である。The present invention focuses on the above-mentioned properties and contemplates high-temperature joining of cemented carbide. Figure 7 shows the joining method. In the figure, ■ is a large diameter bar of cemented carbide, ■ is its end surface, and ■
is a small diameter rod of cemented carbide, [F] is its end face, and the two ends (■ and 0) are brought into contact with each other. The outer peripheries of the bars (2) and (2) were precisely ground and finished, and the end faces (2) and (0) were previously ground and finished to be flat and smooth. This contact area was locally heated by high frequency induction in a reducing atmosphere while applying a light pressure. When the temperature reaches the eutectic temperature of approximately 1300°C, a molten material is generated at the contact area and softens, resulting in almost instantaneous bonding with slight melting.9 After cooling this to room temperature, After inspecting the vertical cross section, the nine parts were completely joined, and the parts were integrated so that the boundaries could not be scratched. Figure 8 shows the condition of a joined stepped bar in which a large diameter bar ■ and a small diameter bar ■ are completely joined.■ in Figure 0 is a slight shaving left on the outer periphery of the joint. However, it is actually advantageous in terms of strength by eliminating the notch in the stepped portion.

上述したのは共晶温度以上に加熱した場合であるが、共
晶温度以下の融体を生じない温度でも、時間と圧力を増
すと接合出来る。これは前記第６図の状態図からは理解
し難いが、別の超硬合金の焼結実験に於て、共晶温度以
下Ｃ）１２００℃前後から圧粉体が収縮して焼結現象が
始まることが報告されている。この事実は超硬合金は共
晶点下１００℃位でも活性化して、固相間反応によって
相互に拡散することを示すもので、前記の接合現象もそ
の性質に因るものと考えられる。この様に超硬合金の接
合に適する実用的な温度は共晶温度の上下１００℃程変
の範囲である。The above case is the case of heating above the eutectic temperature, but even at temperatures below the eutectic temperature that do not produce a melt, bonding can be achieved by increasing the time and pressure. This is difficult to understand from the phase diagram shown in Figure 6 above, but in a sintering experiment of another cemented carbide, the green compact contracted and the sintering phenomenon occurred at temperatures below the eutectic temperature of C) around 1200°C. It has been reported that it has started. This fact indicates that cemented carbide is activated even at about 100° C. below the eutectic point and diffuses into each other through solid-phase reaction, and it is thought that the above-mentioned bonding phenomenon is due to this property. As described above, the practical temperature suitable for joining cemented carbide is within a range of about 100° C. above and below the eutectic temperature.

本発明の利点の１つは経済性である。先づ段付棒の細径
部削り出しによる材料ロスが節減出来る。次に加工手数
の点から見ると、従来の複雑な段付加工法の代りに、円
筒状棒材ｔを別々に仕上げ加工してから、−挙に接合す
る単純作業であるから、加工工数は大巾に節減出来る。One of the advantages of the invention is economy. Material loss due to cutting out the small diameter part of the stepped rod can be reduced. Next, in terms of processing time, instead of the conventional complicated stepped processing method, the cylindrical bar material t is finished separately and then joined all at once, which is a simple process, so the processing time is large. You can save on width.

接合の際に太径と細径の両棒材の中心軸が精密に合致す
る様に突合わせ、且局部加熱を行なえば、接合した侭の
状態で寸法精度でも従来の加工法に遜色ない段付棒材が
得られるのである。尚本発明の接合法は丸棒よりも一聯
加工困雛な異形断面の段付棒材の加工に適用すれば更に
大きな効果が期待出来る。If the central axes of the large diameter and small diameter bars are matched precisely during joining, and local heating is applied, the dimensional accuracy of the joined state will be comparable to that of conventional processing methods. The attached bar material is obtained. It should be noted that the joining method of the present invention can be expected to have even greater effects if applied to the processing of stepped bars with irregular cross sections, which are more difficult to process in one piece than round bars.

次にもう１つの利点は本発明の方法の場合、仕上った段
付棒材に真円度および円筒度の向上が期待出来ることで
ある。それは、センターレスグラインダーによる外周研
削の場合に、役付棒材では砥石軸に直角なプランジフィ
ードを与えるが、本発明の方法の様に円筒棒材を別々に
研削する場合には砥石軸に併行なスルーフィードが与え
られるので上記の精度維持に有利だからである。Another advantage is that the method of the present invention can be expected to improve the roundness and cylindricity of the finished stepped bar. When grinding the outer periphery with a centerless grinder, a plunge feed is given perpendicular to the grinding wheel axis for a service bar, but when grinding cylindrical bars separately as in the method of the present invention, a plunge feed is given perpendicular to the grinding wheel axis. This is because through feed is provided, which is advantageous in maintaining the above-mentioned accuracy.

４、図面の詳細な説明 第１図および第２図は超硬ソリッド工具の例示で多って
第１図は段付の細径部を切刃とし、太径部をシャンクと
するドリル第２図は段付の大径部を切刃とし、細径部を
シャンクとするドリル 第３図乃至第５図は役付超硬棒材製作に関する従来法の
説明図であって第３図は焼結前の段付圧粉体を段付の台
座上に載せた状態第４図は焼結後の状態であって、細径
部側の首が曲ることを示す。第５図は均径の円筒状丸棒
から研削によって削り出しで段付棒材を作る状況を示す
。4. Detailed explanation of the drawings Figures 1 and 2 are examples of solid carbide tools. The figure shows a drill in which the stepped large-diameter part is the cutting edge and the small-diameter part is the shank. FIG. 4 shows the state after sintering, in which the stepped powder compact is placed on the stepped pedestal, and shows that the neck on the narrow diameter side is bent. Fig. 5 shows a situation in which a stepped bar is made by cutting out a cylindrical round bar with a uniform diameter by grinding.

第６図乃至第８図は本発明の高温接合法に関する説明図
で第６図は高温接合の原理説明の為に引用したＮｏ　　
Ｃｏ系の金相状聾図第７図は高温接合前の状態で、太径
と細径の棒材を突合せ接触させたところ第８図は高温接
合後の状態で太径と細径が１体化して段付棒材となった
ところ 図面の浄汽（内容に変ｔなし） 矛１図 才２（！１ 手続補正書（方式） 昭和５７年８月２６日 特許庁長官　　若杉和夫　殿 １、　事件の表示　昭和５７年特許願第５７−０６９６
７２号２発ＶＳＯ名称　超硬合金の段付棒材の製造法１
補正をする者 事件との関係　　特許出願人 住所　東京都大田区中央２丁目２１番２号表　補正命令
の日付　　昭和５７年７月２７日＆　補正の対象　　図
面、第１図から第８図までの全図について。Figures 6 to 8 are explanatory diagrams related to the high temperature bonding method of the present invention, and Figure 6 is the No. 1 cited for explaining the principle of high temperature bonding.
Fig. 7 shows the condition before high-temperature bonding, when the large diameter and small diameter rods are brought into butt contact, and Fig. 8 shows the condition after high-temperature bonding, where the large diameter and small diameter are 1. When it became a stepped bar material, the drawings of Jyoki (no change in content), 1 drawing, 2 (! 1) Procedural amendment (method), August 26, 1980, Commissioner of the Patent Office, Kazuo Wakasugi, 1 , Case Description 1982 Patent Application No. 57-0696
No. 72 2-shot VSO name Production method of cemented carbide stepped bars 1
Relationship with the case of the person making the amendment Patent applicant address: 2-21-2 Chuo, Ota-ku, Tokyo Date of amendment order: July 27, 1980 & subject of amendment: Drawings, Figures 1 to 8 About the whole picture.

６　補正の内容　　別紙の通シ、図面の浄書。（内容に
変更なし）6 Contents of the amendment Attachment notice and engraving of the drawings. (No change in content)

Claims (1)

【特許請求の範囲】[Claims] 断面の太さ又は形状が相異する２種類の超硬合金棒材の
相互の端面を突合わせ接触せしめ、その接触部分を、そ
の超硬合金特有の共晶温度附近の高温にまで加熱して、
軟化した状態又は一部に融体が生成した状態に於て、両
者を接合一体化して、−個の段付の超硬合金棒材を製作
する方法。The end surfaces of two types of cemented carbide rods with different cross-sectional thicknesses or shapes are brought into butt contact, and the contact area is heated to a high temperature near the eutectic temperature unique to the cemented carbide. ,
A method of manufacturing stepped cemented carbide bars by joining and integrating both in a softened state or a state in which a molten body is partially formed.