JPS6221042B2 - - Google Patents
Info
- Publication number
- JPS6221042B2 JPS6221042B2 JP1663882A JP1663882A JPS6221042B2 JP S6221042 B2 JPS6221042 B2 JP S6221042B2 JP 1663882 A JP1663882 A JP 1663882A JP 1663882 A JP1663882 A JP 1663882A JP S6221042 B2 JPS6221042 B2 JP S6221042B2
- Authority
- JP
- Japan
- Prior art keywords
- sintered body
- heating
- specific gravity
- melting point
- point metal
- 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
- 238000010438 heat treatment Methods 0.000 claims description 21
- 238000005245 sintering Methods 0.000 claims description 14
- 239000000843 powder Substances 0.000 claims description 13
- 238000002844 melting Methods 0.000 claims description 12
- 229910052751 metal Inorganic materials 0.000 claims description 12
- 239000002184 metal Substances 0.000 claims description 12
- 238000004519 manufacturing process Methods 0.000 claims description 9
- 230000008018 melting Effects 0.000 claims description 4
- 230000005611 electricity Effects 0.000 claims description 3
- 230000005484 gravity Effects 0.000 description 17
- 238000000034 method Methods 0.000 description 7
- 230000020169 heat generation Effects 0.000 description 6
- ZOKXTWBITQBERF-UHFFFAOYSA-N Molybdenum Chemical compound [Mo] ZOKXTWBITQBERF-UHFFFAOYSA-N 0.000 description 4
- 238000010586 diagram Methods 0.000 description 4
- 239000012535 impurity Substances 0.000 description 4
- WFKWXMTUELFFGS-UHFFFAOYSA-N tungsten Chemical compound [W] WFKWXMTUELFFGS-UHFFFAOYSA-N 0.000 description 4
- 239000007789 gas Substances 0.000 description 3
- 229910052750 molybdenum Inorganic materials 0.000 description 3
- 239000011733 molybdenum Substances 0.000 description 3
- 229910052721 tungsten Inorganic materials 0.000 description 3
- 239000010937 tungsten Substances 0.000 description 3
- 230000007423 decrease Effects 0.000 description 2
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 1
- 239000000498 cooling water Substances 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000000465 moulding Methods 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
- B22F3/00—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces
- B22F3/24—After-treatment of workpieces or articles
Landscapes
- Engineering & Computer Science (AREA)
- Manufacturing & Machinery (AREA)
- Mechanical Engineering (AREA)
- Powder Metallurgy (AREA)
Description
【発明の詳細な説明】
〔発明の技術分野〕
本発明は通電焼結を行なう高融点金属焼結体の
製造方法に関する。DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a method for producing a high-melting point metal sintered body by carrying out electrical sintering.
タングステンやモリブデンなどの高融点金属の
焼結体からなる線材などの製品を得るために、高
融点金属の焼結体を製造する場合には、通電焼結
法が多く採用されている。この通電焼結法は、高
融点金属粉で棒状をなす粉末成形体を成形し、こ
の粉末成形体の両端部に電極を夫々を取付けて、
両電極間で粉末成形体に電流を流すことにより、
成形体自身に生ずる抵抗発熱で焼結を行ない焼結
体を得るものである。
BACKGROUND ART When manufacturing a sintered body of a high-melting point metal such as tungsten or molybdenum to obtain a product such as a wire made of a sintered body of a high-melting point metal, an electric sintering method is often employed. This electrification sintering method involves molding a rod-shaped powder compact from high-melting point metal powder, attaching electrodes to both ends of the powder compact, and
By passing a current through the powder compact between both electrodes,
A sintered body is obtained by sintering using the resistance heat generated in the compact itself.
通電焼結法による焼結では、電極が高温となる
ので電極を例えば冷却水等により冷却している。
このため、電極と接触する焼結体の両端部は、電
極に冷却されて必要とする温度まで温度上昇せ
ず、焼結体の他の部分に比して充分な焼結比重
（密度）が得られない。従つて、焼結体は両端部
の密度が上がらず全体の品位が不均一となる。し
かも、焼結体の加工時に低密度の両端部が欠け落
ちて加工歩留りを低下させ、あるいは欠け落ちた
焼結体片が加工機械に詰ることがあり、このため
焼結体の両端部を切断することもある。
In sintering by the current sintering method, the electrodes reach a high temperature, so the electrodes are cooled, for example, with cooling water.
Therefore, both ends of the sintered body that come into contact with the electrodes are cooled by the electrodes and do not rise to the required temperature, and have sufficient sintering specific gravity (density) compared to other parts of the sintered body. I can't get it. Therefore, the density of the sintered body at both ends does not increase, and the overall quality becomes non-uniform. Moreover, when processing the sintered body, both ends of the sintered body may chip off, reducing the processing yield, or the pieces of the sintered body that have fallen off may clog the processing machine, so both ends of the sintered body are cut off. Sometimes I do.
本発明は通電焼結した焼結体の両端部の比重を
高めて全体に均一な品位を有する焼結体を得るこ
とができる高融点金属焼結体の製造方法を提供す
るものである。
The present invention provides a method for producing a high-melting point metal sintered body, which can increase the specific gravity of both ends of a sintered body sintered with electricity to obtain a sintered body having uniform quality throughout.
本発明の高融点金属焼結体の製造方法は、粉末
成形体を通電焼結して焼結体を形成し、この焼結
体の両端部を高周波炉の高温部で加熱してその両
端部の比重を高めるようにするものである。
The method for producing a high-melting point metal sintered body of the present invention involves sintering a powder compact by applying electricity to form a sintered body, and heating both ends of the sintered body in a high-temperature section of a high-frequency furnace. This is to increase the specific gravity of
図面は本発明の製造方法の一実施例を示してお
り、この実施例では焼結体を高周波加熱する前段
階で電気炉で加熱するものである。
The drawings show an embodiment of the manufacturing method of the present invention, in which the sintered body is heated in an electric furnace before high frequency heating.
まず、第１図で示すように高融点金属粉末すな
わちタングステン粉末またはモリブデン粉末から
なる棒状の粉末成形体１′を用意し、この粉末成
形体１′の両端部に電極２，２を夫々接続して取
付け、これら電極２，２の間に粉末成形体１′に
電流を流し、この通電により生じる抵抗発熱によ
つて粉末成形体を焼結して棒状をなす焼結体１を
得る。 First, as shown in FIG. 1, a rod-shaped powder compact 1' made of high melting point metal powder, ie, tungsten powder or molybdenum powder, is prepared, and electrodes 2, 2 are connected to both ends of this powder compact 1', respectively. A current is passed through the powder compact 1' between the electrodes 2, 2, and the powder compact is sintered by the resistance heat generated by this current flow, thereby obtaining a rod-shaped sintered compact 1.
次いで、第２図で示すように例えば複数の焼結
体１を束ねてフイードローラ３により移送し、焼
結体１を水素ガスなどの還元雰囲気を有する電気
炉４の内部を通過させる。この電気炉４では焼結
体１を低温域で加熱するもので、焼結体１をゆる
やかに昇温させて後段階での高周波加熱に対する
予備加熱の役割を有している。また、この加熱は
焼結体１に含まれる低温域で蒸発する不純物のガ
スを蒸発させて除去する。この電気炉４による加
熱に際しては焼結体１がタングステンである場合
には800℃以上、モリブデンである場合には500℃
以上の温度で夫々加熱する。 Next, as shown in FIG. 2, for example, a plurality of sintered bodies 1 are bundled and transported by a feed roller 3, and the sintered bodies 1 are passed through an electric furnace 4 having a reducing atmosphere such as hydrogen gas. This electric furnace 4 heats the sintered body 1 in a low temperature range, and has the role of slowly increasing the temperature of the sintered body 1 and preheating it for high-frequency heating in a later stage. Further, this heating evaporates and removes impurity gases contained in the sintered body 1 that evaporate in a low temperature range. When heating with this electric furnace 4, the temperature is 800°C or higher when the sintered body 1 is made of tungsten, and 500°C when it is made of molybdenum.
Heat each at the above temperature.
次いで、電気炉４による加熱を終了した後に、
焼結体１はフイードローラ３により移送して高周
波炉５に搬送する。そして、焼結体１の端部を高
周波炉５の内部の温度が高い部分に位置させて加
熱する。すなわち、高周波炉５はその高温部で焼
結体１の端部を加熱し、焼結体１の両端部の焼結
密度を他の部分と同等に増大させるためのもので
ある。また、この加熱は焼結体１に含まれる高温
域で蒸発する不純物のガスを蒸発させて除去す
る。この高周波加熱では焼結体１がタングステン
である場合には2500〜3000℃で、モリブデンの場
合には1800〜2200℃で加熱する。高周波炉５によ
る加熱について説明を加える。高周波炉５に設け
られたコイル６における発熱温度分布は、第３図
のＡ線で示すようにコイル６の中央部から両端部
にかけて発熱温度が徐々に低下するカーブを描く
特性を有している。一方、焼結体１の両端部は第
３図のＢ線で示すように端末に向うに従い比重す
なわち密度が低下するようにカーブを描く密度分
布を有している。そこで、高周波炉５のコイル６
の発熱温度分布と、このコイル６内を通過する焼
結体１の両端部の比重分布とを対比してみると、
夫々の分布のカーブが逆となる関係になる。従つ
て、焼結体１を搬送して焼結体１の比重が低い一
方の端部（搬送方向前端部）をコイル６の発熱温
度が最も高い部分に対応する位置に停止させ、コ
イル６の発熱温度が最も高い部分で焼結体１の一
方の端部を加熱する。これにより焼結体１の一方
の端部の比重が大幅に増大する。次いで、焼結体
１を搬送して焼結体１の比重が低い他方の端部
（搬送方向後端部）をコイル６の発熱温度が最も
高い部分に対応する位置で停止させ、コイル６の
発熱温度が最も高い部分で焼結体１の他方の端部
を加熱する。これにより焼結体１の他方の端部の
比重が大幅に増大する。このため、焼結体１の両
端部は図示Ｂ線の破線部分で示すように焼結体１
の他の部分と略同等の大きさになり、焼結体１は
全体にわたり略均一な比重を有することになる。
また、高周波炉５による加熱の前段階で電気炉４
により焼結体１を予備加熱してある程度温度上昇
してあるので、焼結体１を高周波炉５により必要
とする温度まで容易且つ迅速に加熱できる。一般
に高周波炉は焼結体１の抵抗の小さな低温域での
加熱効率が悪く温度上昇が遅い欠点があるので、
焼結体１を予備加熱することは高周波加熱におけ
る加熱効率および作業スピードの点で効果的であ
る。さらに、電気炉４による加熱および高周波炉
５による加熱において夫々焼結体１に含まれる不
純物のガスを除去してあるので、焼結体１におけ
る不純物の含有量も少なく且つ均一である。 Next, after finishing the heating in the electric furnace 4,
The sintered body 1 is transferred by a feed roller 3 to a high frequency furnace 5. Then, the end of the sintered body 1 is placed in a high-temperature part of the high-frequency furnace 5 and heated. That is, the high-frequency furnace 5 is used to heat the ends of the sintered body 1 in its high-temperature part, thereby increasing the sintering density at both ends of the sintered body 1 to the same level as the other parts. Further, this heating evaporates and removes impurity gases contained in the sintered body 1 that evaporate in a high temperature range. In this high-frequency heating, when the sintered body 1 is tungsten, it is heated at 2500 to 3000°C, and when it is molybdenum, it is heated at 1800 to 2200°C. An explanation will be added regarding heating by the high frequency furnace 5. The heat generation temperature distribution in the coil 6 provided in the high frequency furnace 5 has a characteristic that the heat generation temperature draws a curve that gradually decreases from the center to both ends of the coil 6, as shown by line A in FIG. . On the other hand, both ends of the sintered body 1 have a density distribution that draws a curve such that the specific gravity, or density, decreases toward the ends, as shown by line B in FIG. Therefore, the coil 6 of the high frequency furnace 5
Comparing the heat generation temperature distribution and the specific gravity distribution at both ends of the sintered body 1 passing through the coil 6, we find that
The relationship is such that the respective distribution curves are opposite. Therefore, the sintered body 1 is transported, and one end of the sintered body 1 having a low specific gravity (the front end in the transport direction) is stopped at a position corresponding to the part where the heat generation temperature of the coil 6 is highest. One end of the sintered body 1 is heated at the part where the exothermic temperature is highest. As a result, the specific gravity of one end of the sintered body 1 increases significantly. Next, the sintered body 1 is transported, and the other end of the sintered body 1 having a lower specific gravity (the rear end in the transport direction) is stopped at a position corresponding to the part where the heat generation temperature of the coil 6 is highest. The other end of the sintered body 1 is heated at the portion where the exothermic temperature is highest. As a result, the specific gravity of the other end of the sintered body 1 increases significantly. Therefore, both ends of the sintered body 1 are connected to the sintered body 1 as shown by the broken line portion of line B in the figure.
The sintered body 1 has a substantially uniform specific gravity throughout.
In addition, the electric furnace 4 is heated before heating by the high frequency furnace 5.
Since the sintered body 1 has been preheated and the temperature has risen to some extent, the sintered body 1 can be easily and quickly heated to the required temperature by the high frequency furnace 5. In general, high frequency furnaces have the disadvantage of poor heating efficiency and slow temperature rise in the low temperature range where the resistance of the sintered body 1 is low.
Preheating the sintered body 1 is effective in terms of heating efficiency and work speed in high-frequency heating. Further, since the impurity gas contained in the sintered body 1 is removed during heating by the electric furnace 4 and heating by the high frequency furnace 5, the content of impurities in the sintered body 1 is small and uniform.
このようにして焼結体１を高周波炉５により加
熱し、焼結体１の両端部の比重を高めて全体を均
一な比重とすることができる。 In this way, the sintered body 1 can be heated by the high frequency furnace 5 to increase the specific gravity at both ends of the sintered body 1, thereby making the entire body uniform in specific gravity.
そして、この焼結体１を線材などの製品の加工
工程に供給する。この場合、焼結体１は両端部が
他の部分と同等の比重を有しているので、焼結体
端部が欠落して加工歩留りを低下させたり、欠落
した焼結体片が加工機械に詰りを生じることを防
止できる。 This sintered body 1 is then supplied to a processing process for products such as wire rods. In this case, both ends of the sintered body 1 have the same specific gravity as other parts, so the ends of the sintered body may be missing, reducing the processing yield, or the missing sintered body pieces may be removed by the processing machine. can prevent clogging.
なお、本発明の製造方法では前述した実施例で
示したように高周波加熱の前段階で予備加熱する
ことが好ましいが、これに限らず焼結体を直接高
周波加熱しても良く、この場合にも焼結体の両端
部の比重を高めることができる。 In addition, in the manufacturing method of the present invention, as shown in the above-mentioned embodiment, it is preferable to perform preheating before high-frequency heating, but the sintered body may be directly high-frequency heated, and in this case, It is also possible to increase the specific gravity at both ends of the sintered body.
本発明の高融点金属焼結体の製造方法は以上説
明したように、粉末成形体を通電焼結して得られ
た焼結体の両端部を高周波炉の高温部で加熱する
ことにより、通電焼結では不充分であつた焼結体
の両端部の比重（密度）を高めることができ、焼
結体の比重を全体にわたり均一にすることができ
る。従つて、通電焼結法により焼結されたもので
ありながら、全体に均一な品位を有する高融点金
属焼結体を得ることができる。
As explained above, the method for producing a high melting point metal sintered body of the present invention is to heat both ends of the sintered body obtained by energizing sintering of a powder compact in the high temperature section of a high frequency furnace. The specific gravity (density) of both ends of the sintered body, which was insufficient by sintering, can be increased, and the specific gravity of the sintered body can be made uniform throughout. Therefore, it is possible to obtain a high melting point metal sintered body having uniform quality throughout, even though it is sintered by the current sintering method.
第１図および第２図は夫々本発明方法の一実施
例を示すもので、第１図は通電焼結工程を示す説
明図、第２図は焼結体加熱工程を示す説明図、第
３図は高周波加熱の発熱温度分布と焼結体端部の
比重分布との関係を示す線図である。
１…焼結体、１′…粉末成形体、２…電極、４
…電気炉、５…高周波炉、６…コイル。
Figures 1 and 2 each show an embodiment of the method of the present invention, with Figure 1 being an explanatory diagram showing the energizing sintering process, Figure 2 being an explanatory diagram showing the sintered body heating process, and Figure 3 being an explanatory diagram showing the sintered body heating process. The figure is a diagram showing the relationship between the heat generation temperature distribution of high-frequency heating and the specific gravity distribution at the end of the sintered body. 1... Sintered body, 1'... Powder compact, 2... Electrode, 4
...Electric furnace, 5...High frequency furnace, 6...Coil.
Claims (1)
焼結し、次いで得られた焼結体の端部を高周波炉
の高温部で加熱することを特徴とする高融点金属
焼結体の製造方法。 ２ 高周波炉による加熱の前に還元雰囲気中で予
備加熱を施こす特許請求の範囲第１項に記載の高
融点金属焼結体の製造方法。[Claims] 1. A high-melting point metal characterized by sintering a rod-shaped powder compact made of a high-melting point metal by applying electricity, and then heating the end portion of the obtained sintered body in a high-temperature section of a high-frequency furnace. A method for producing a sintered body. 2. The method for producing a high melting point metal sintered body according to claim 1, wherein preheating is performed in a reducing atmosphere before heating in a high frequency furnace.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1663882A JPS58133304A (en) | 1982-02-04 | 1982-02-04 | Preparation of high melting point metal sintered body |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1663882A JPS58133304A (en) | 1982-02-04 | 1982-02-04 | Preparation of high melting point metal sintered body |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS58133304A JPS58133304A (en) | 1983-08-09 |
| JPS6221042B2 true JPS6221042B2 (en) | 1987-05-11 |
Family
ID=11921897
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP1663882A Granted JPS58133304A (en) | 1982-02-04 | 1982-02-04 | Preparation of high melting point metal sintered body |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS58133304A (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS60114504A (en) * | 1983-11-24 | 1985-06-21 | Toshiba Corp | Tungsten sintered body |
-
1982
- 1982-02-04 JP JP1663882A patent/JPS58133304A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS58133304A (en) | 1983-08-09 |
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