JPH027749B2 - - Google Patents
Info
- Publication number
- JPH027749B2 JPH027749B2 JP7942587A JP7942587A JPH027749B2 JP H027749 B2 JPH027749 B2 JP H027749B2 JP 7942587 A JP7942587 A JP 7942587A JP 7942587 A JP7942587 A JP 7942587A JP H027749 B2 JPH027749 B2 JP H027749B2
- Authority
- JP
- Japan
- Prior art keywords
- composite material
- rotor
- molten composite
- sprue
- melting furnace
- 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
- 239000002131 composite material Substances 0.000 claims description 34
- 238000003756 stirring Methods 0.000 claims description 24
- 239000000463 material Substances 0.000 claims description 17
- 238000002844 melting Methods 0.000 claims description 15
- 230000008018 melting Effects 0.000 claims description 15
- 238000004519 manufacturing process Methods 0.000 claims description 12
- 239000002184 metal Substances 0.000 claims description 9
- 239000012779 reinforcing material Substances 0.000 claims description 9
- 239000011156 metal matrix composite Substances 0.000 claims description 8
- 239000011148 porous material Substances 0.000 claims description 6
- 239000000835 fiber Substances 0.000 claims description 5
- 239000011159 matrix material Substances 0.000 claims description 4
- 229910052755 nonmetal Inorganic materials 0.000 claims description 4
- 239000002923 metal particle Substances 0.000 claims description 3
- 239000013078 crystal Substances 0.000 description 8
- 238000004663 powder metallurgy Methods 0.000 description 8
- 238000005266 casting Methods 0.000 description 6
- 239000013528 metallic particle Substances 0.000 description 6
- 238000000034 method Methods 0.000 description 5
- 239000000956 alloy Substances 0.000 description 3
- 239000000203 mixture Substances 0.000 description 3
- 239000002245 particle Substances 0.000 description 3
- 239000002002 slurry Substances 0.000 description 3
- 229910021364 Al-Si alloy Inorganic materials 0.000 description 2
- 229910045601 alloy Inorganic materials 0.000 description 2
- 239000006185 dispersion Substances 0.000 description 2
- 239000007788 liquid Substances 0.000 description 2
- 239000000843 powder Substances 0.000 description 2
- 239000007787 solid Substances 0.000 description 2
- 238000013019 agitation Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 239000011261 inert gas Substances 0.000 description 1
- 239000011810 insulating material Substances 0.000 description 1
- 238000007712 rapid solidification Methods 0.000 description 1
- 238000011084 recovery Methods 0.000 description 1
- 239000012056 semi-solid material Substances 0.000 description 1
- 239000011345 viscous material Substances 0.000 description 1
Description
【発明の詳細な説明】
［産業上の利用分野］
本発明は、粒子分散強化または繊維強化した金
属基複合材料を連続的に製造する装置に関するも
のである。DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to an apparatus for continuously producing a particle-dispersion reinforced or fiber-reinforced metal matrix composite material.
［従来の技術］
金属基複合材料を製造するため、固液共存状態
の合金材料に対して、回転翼により機械的な回転
撹拌を加えながら非金属粒子を添加して、均質な
複合材料をつくる鋳造法は、コンポキヤスト法と
して知られている。また、急冷凝固法などで製造
した微細結晶粒粉末を非金属粉末と均質混合して
焼結させる粉末治金法がある。[Conventional technology] In order to produce metal matrix composite materials, non-metallic particles are added to alloy materials in a solid-liquid coexistence state while mechanical rotational stirring is applied using rotary blades to create homogeneous composite materials. The casting method is known as the composite casting method. There is also a powder metallurgy method in which fine crystal grain powder produced by a rapid solidification method or the like is homogeneously mixed with nonmetallic powder and sintered.
しかるに、コンポキヤスト法では回転翼の回転
速度が1000rpm以下に抑えられているので、結晶
粒の均質微細化と粒子の均一分散が十分行われな
い。また、還元性雰囲気や大気中で回転翼を回転
させるので、不活性ガスや空気を巻き込みやす
く、得られた材料の機械的性質はそれほど改善さ
れない。 However, in the CompoCast method, the rotational speed of the rotor blade is suppressed to 1000 rpm or less, so homogeneous refinement of crystal grains and uniform dispersion of particles cannot be achieved sufficiently. Furthermore, since the rotor is rotated in a reducing atmosphere or the atmosphere, inert gas or air is likely to be drawn in, and the mechanical properties of the obtained material are not significantly improved.
一方、粉末治金法では、複雑な製造プロセスと
大規模な設備が不可欠であるため、必然的に材料
製造費がコスト高にならざるを得ない。 On the other hand, powder metallurgy requires complicated manufacturing processes and large-scale equipment, which inevitably leads to higher material manufacturing costs.
［発明が解決しようとする問題点］
本発明の目的は、簡単な装置により、粉末治金
で得られるような微細結晶粒と非金属粒子の均質
混合を、鋳造時にすべて同時に行うことができ、
それによつて、粉末治金材に比べて製造コストを
大幅に低下させ、またコンポキヤスト材に比べて
機械的性質のすぐれた材料を連続的に製造するこ
とができる金属基複合材料連続製造装置を得るこ
とにある。[Problems to be Solved by the Invention] An object of the present invention is to use a simple device to homogeneously mix fine crystal grains and nonmetallic particles such as those obtained by powder metallurgy, all at the same time during casting.
As a result, we have developed a continuous manufacturing device for metal matrix composite materials that can significantly reduce manufacturing costs compared to powder metallurgy materials and can continuously manufacture materials with superior mechanical properties compared to composite cast materials. It's about getting.
［問題点を解決するための手段］
上記目的を達成するための本発明の金属基複合
材料連続製造装置は、真空容器内に駆動装置によ
り低速回転駆動される撹拌翼を内挿したマトリツ
クス用金属の溶解炉を設け、この溶解炉に、溶融
した金属に対して非金属粒子あるいは繊維などの
強化材を投与する投入装置、及び混合撹拌した複
合材料溶湯を注下させる湯口を真空容器外から開
閉する湯口開閉装置を付設し、上記溶解炉の下方
に、上記湯口から複合材料溶湯が流入せしめられ
る溶融複合材料撹拌装置を配設し、この溶融複合
材料撹拌装置を、溶融複合材料を高速回転による
回転撹拌作用により飛散させる横断面が多角形状
の回転子と、この回転子を収容して飛散する溶融
複合材料を受止め、それを回収細孔から鋳型に流
下させる耐熱容器とにより構成したことを特徴と
するものである。[Means for Solving the Problems] In order to achieve the above object, the metal matrix composite material continuous manufacturing apparatus of the present invention comprises a metal matrix composite material in which a stirring blade driven to rotate at low speed by a drive device is inserted into a vacuum container. This melting furnace is equipped with a charging device that injects reinforcing materials such as non-metal particles or fibers into the molten metal, and a sprue that allows the mixed and stirred composite material molten metal to be poured into the furnace, which is opened and closed from outside the vacuum vessel. A molten composite material stirring device is provided below the melting furnace to allow the molten composite material to flow from the sprue, and the molten composite material stirring device is used to rotate the molten composite material at high speed. It is composed of a rotor with a polygonal cross section that scatters it by a rotating stirring action, and a heat-resistant container that houses this rotor, receives the scattered molten composite material, and allows it to flow down from the collection pores to the mold. This is a characteristic feature.
［作 用］
撹拌においてマトリツクス用金属を真空溶解
し、非金属粒子などの強化材を添加して撹拌翼の
低速回転により均一に撹拌し、十分な撹拌を行つ
た後、湯口開閉装置を操作して、湯口を開放する
ことにより、混合撹拌した複合材料溶湯を溶融複
合材料撹拌装置に流下させる。この溶融複合材料
撹拌装置においては、回転子の高速回転による撹
拌作用により溶融複合材料が飛散を繰返し、結晶
粒が微細化されると共に非金属粒子等の強化材が
均一に分散せしめられて、半固体状あるいは粘稠
状の金属基複合材料スラリーを得る。このスラリ
ーは、容器底部の細孔により回収し、インゴツト
が形成される。[Function] During stirring, the metal for the matrix is melted in vacuum, reinforcing materials such as non-metal particles are added, and the stirring blades are rotated at low speed to uniformly stir the mixture.After sufficient stirring, the sprue opening/closing device is operated. Then, by opening the sprue, the mixed and stirred composite material molten metal flows down into the molten composite material stirring device. In this molten composite material stirring device, the molten composite material is repeatedly scattered due to the stirring action caused by the high speed rotation of the rotor, making the crystal grains finer and uniformly dispersing reinforcing materials such as non-metallic particles. A solid or viscous metal matrix composite slurry is obtained. This slurry is collected through pores in the bottom of the vessel and an ingot is formed.
その結果、粉末治金で得られるような微細結晶
粒と非金属粒子の均質混合が、鋳造時にすべて同
時に行われ、しかも機械的性質のすぐれた材料が
連続的に製造される。 As a result, the homogeneous mixing of fine grains and non-metallic particles, such as those obtained in powder metallurgy, takes place all at the same time during casting, yet a material with excellent mechanical properties is produced continuously.
［実施例］
第１図及び第２図は、本発明の金属基複合材料
連続製造装置の実施例を示し、この製造装置にお
いた、真空容器１はその内部にマトリツクス用金
属の溶解炉２を備えている。[Example] FIGS. 1 and 2 show an example of the continuous manufacturing apparatus for metal matrix composite materials of the present invention. In this manufacturing apparatus, a vacuum vessel 1 has a melting furnace 2 for matrix metal inside. We are prepared.
上記溶解炉２は、周囲を断熱材３によつて囲繞
され、中心に配設したルツボ４の周囲にヒータ５
が設けられ、上面は図示しないシリンダで駆動さ
れるシヤツタ６により開閉可能に形成されてい
る。溶解炉２のルツボ４に内挿される撹拌翼８
は、その横断面が十字状をなし、外部に配置した
モータ等の駆動装置９から真空容器を通して導入
される回転軸１０の先端に固定され、駆動装置９
により1000rpm以下で低速回転駆動されるもので
ある。 The melting furnace 2 is surrounded by a heat insulating material 3, and a heater 5 is placed around a crucible 4 disposed at the center.
is provided, and the upper surface is formed to be openable and closable by a shutter 6 driven by a cylinder (not shown). Stirring blade 8 inserted into crucible 4 of melting furnace 2
has a cross-shaped cross section, and is fixed to the tip of a rotating shaft 10 introduced through a vacuum container from a drive device 9 such as a motor disposed outside.
It is driven to rotate at a low speed of 1000 rpm or less.
上記溶解炉２におけるルツボ４には、そこで溶
融した金属に対して非金属粒子あるいは繊維など
の強化材を投与する投入装置１１が付設されてい
る。この投入装置１１は、真空容器１外の強化材
用バケツト１２からルツボ４上に強化材投入管１
３を伸ばしたものである。また、上記ルツボ４の
内底には、混合撹拌した複合材料溶湯を注下させ
る湯口１５が設けられ、この湯口１５を真空容器
外から開閉する湯口開閉装置１６が付設されてい
る。この湯口開閉装置１６は、昇降モータ１７に
より湯口の開閉栓１８を昇降可能にしたものであ
る。 The crucible 4 in the melting furnace 2 is equipped with a charging device 11 for injecting reinforcing material such as non-metallic particles or fibers into the metal melted therein. This charging device 11 is configured to insert a reinforcing material charging pipe 1 onto the crucible 4 from a reinforcing material bucket 12 outside the vacuum container 1.
It is an extension of 3. Furthermore, a sprue 15 is provided at the inner bottom of the crucible 4 to allow the mixed and stirred molten composite material to be poured into the crucible, and a sprue opening/closing device 16 for opening and closing the sprue 15 from outside the vacuum container is attached. This sprue opening/closing device 16 is configured such that a sprue opening/closing plug 18 can be raised and lowered by a lifting motor 17.
上記溶解炉２は、マトリツクス用金属を溶解し
て下方の溶融複合材料撹拌装置２０に供給するた
めの電気炉を構成するもので、この溶解炉の下方
に配設した溶融複合材料撹拌装置２０は、受湯用
ロート２１によつて回転子２３を備えた耐熱容器
２２に溶解炉２からの溶融複合材料を導くように
構成している。 The melting furnace 2 constitutes an electric furnace for melting matrix metal and supplying it to the molten composite material stirring device 20 located below.The molten composite material stirring device 20 disposed below the melting furnace is The molten composite material from the melting furnace 2 is introduced into a heat-resistant container 22 equipped with a rotor 23 through a receiving funnel 21 .
上記回転子２３は、溶融複合材料に機械的な高
速回転撹拌を加えることにより、その結晶粒を微
細化し、且つ強化材を一層均一に分散させるもの
で、前記湯口１５からほぼ中心に落下するように
供給される溶融複合材料を、その高速回転により
周囲に飛散させるため、第２図に示すように、横
断面を多角形状に形成し、回転子モータ２５によ
り高速回転する駆動軸２６に固定している。 The rotor 23 applies mechanical high-speed rotational agitation to the molten composite material to refine its crystal grains and disperse the reinforcing material more uniformly. In order to scatter the molten composite material supplied to the surrounding area by its high speed rotation, the cross section is formed into a polygonal shape and is fixed to a drive shaft 26 which is rotated at high speed by a rotor motor 25, as shown in FIG. ing.
上記回転子２３を収容する耐熱容器２２は、回
転子２３の回転に伴つて飛散する溶融複合材料を
受け止め、それを塊状集合体として下方の回収細
孔２８から鋳型２９に回収するためのものであ
る。 The heat-resistant container 22 housing the rotor 23 is for receiving the molten composite material scattered as the rotor 23 rotates and collecting it as a lumpy aggregate from the collection pore 28 below into the mold 29. be.
なお、図中、３１，３２は覗窓、３２は真空吸
引口、３４は温度制御用熱電対を示している。 In the figure, 31 and 32 are viewing windows, 32 is a vacuum suction port, and 34 is a temperature control thermocouple.
上記構成を有する装置によつて結晶粒が微細化
された合金複合材料、例えば過共晶Al−Si合金
複合材料等を製造するには、まず、真空容器１内
を真空とした後、ルツボ４で過共晶Al−Si合金
を溶解させ、投入装置１１によつて非金属粒子あ
るいは繊維などの強化材を溶融合金中に添加し
て、撹拌翼８の低速回転により均一に撹拌する。
一方、回転子２３は回転子モータ２５により1000
〜30000rpm程度の高速で回転させ、この状態で、
前記溶解炉２において撹拌翼８により十分な撹拌
混合した複合材料溶湯を、湯口開閉装置１６の操
作によつて湯口１５を開放することにより、溶融
複合材料撹拌装置２０に流下させる。 In order to manufacture an alloy composite material with refined crystal grains, such as a hypereutectic Al-Si alloy composite material, using the apparatus having the above configuration, first, the inside of the vacuum container 1 is evacuated, and then the crucible 4 is The hypereutectic Al--Si alloy is melted, and reinforcing materials such as non-metallic particles or fibers are added to the molten alloy by the charging device 11 and uniformly stirred by the slow rotation of the stirring blades 8.
On the other hand, the rotor 23 is driven by the rotor motor 25.
Rotate at a high speed of ~30000rpm, and in this state,
The molten composite material sufficiently stirred and mixed by the stirring blades 8 in the melting furnace 2 is caused to flow down into the molten composite material stirring device 20 by opening the sprue 15 by operating the sprue opening/closing device 16 .
これにより、溶融複合材料は回転中の回転子２
３上に落下し、回転子２３により微細粒子状の液
滴群となつて飛散し、耐熱容器２２の内壁に対し
て衝当を繰返す。その結果、飛散した溶融複合材
料は微細結晶粒化され、粘稠状あるいは半固体状
のものとして耐熱容器２２内を下方に伝わつて細
孔２８から鋳型２９に落下し、半固体状スラリー
の塊状複合材料として連続的に回収される。 As a result, the molten composite material is transferred to the rotating rotor 2.
The liquid drops onto the heat-resistant container 22 and is scattered as a group of fine droplets by the rotor 23, repeatedly hitting the inner wall of the heat-resistant container 22. As a result, the scattered molten composite material becomes fine crystal grains, travels downward in the heat-resistant container 22 as a viscous or semi-solid material, and falls into the mold 29 through the pores 28, forming lumps of semi-solid slurry. Continuously collected as composite material.
その結果、粉末治金で得られるような微細結晶
粒と非金属粒子の均質混合が、鋳造時にすべて同
時に行われ、しかも機械的性質のすぐれた材料が
連続的に製造される。 As a result, the homogeneous mixing of fine grains and non-metallic particles, such as those obtained in powder metallurgy, takes place all at the same time during casting, yet a material with excellent mechanical properties is produced continuously.
［発明の効果］
以上に詳述した本発明の連続製造装置によれ
ば、粉末治金で得られるような微細結晶粒と非金
属粒子あるいは繊維の均質混合を、鋳造時にすべ
て同時に行うことができるので、粉末治金材に比
べて製造コストを大幅に低下させ、またコンポキ
ヤスト材に比べて機械的性質のすぐれた材料を連
続的に製造することができる。[Effects of the Invention] According to the continuous manufacturing apparatus of the present invention detailed above, it is possible to homogeneously mix fine crystal grains and nonmetal particles or fibers, such as those obtained by powder metallurgy, all at the same time during casting. Therefore, manufacturing costs can be significantly lowered compared to powder metallurgy materials, and materials with superior mechanical properties compared to composite cast materials can be manufactured continuously.
第１図は本発明の実施例の正面断面図、第２図
はその側断面図である。
１……真空容器、２……溶解炉、８……撹拌
翼、９……駆動装置、１１……投入装置、１５…
…湯口、１６……湯口開閉装置、２０……溶融複
合材料撹拌装置、２２……耐熱容器、２３……回
転子、２８……回収細孔、２９……鋳型。
FIG. 1 is a front sectional view of an embodiment of the present invention, and FIG. 2 is a side sectional view thereof. DESCRIPTION OF SYMBOLS 1... Vacuum container, 2... Melting furnace, 8... Stirring blade, 9... Drive device, 11... Feeding device, 15...
...gate, 16...gate opening/closing device, 20...molten composite material stirring device, 22...heat-resistant container, 23...rotor, 28...recovery pore, 29...mold.
Claims (1)
れる撹拌翼を内挿したマトリツクス用金属の溶解
炉を設け、この溶解炉に、溶融した金属に対して
非金属粒子あるいは繊維などの強化材を投与する
投入装置、及び混合撹拌した複合材料溶湯を注下
させる湯口を真空容器外から開閉する湯口開閉装
置を付設し、上記溶解炉の下方に、上記湯口から
複合材料溶湯が流入せしめられる溶融複合材料撹
拌装置を配設し、この溶融複合材料撹拌装置を、
溶融複合材料を高速回転による回転撹拌作用によ
り飛散させる横断面が多角形状の回転子と、その
回転子を収容して飛散する溶融複合材料を受止
め、それを回収細孔から鋳型に流下させる耐熱容
器とにより構成したことを特徴とする金属基複合
材料の連続製造装置。1. A melting furnace for matrix metal is provided in a vacuum container with stirring blades driven by a drive device to rotate at low speed, and reinforcing materials such as non-metal particles or fibers are injected into the melting furnace into the melted metal. and a sprue opening/closing device for opening and closing the sprue from outside the vacuum container into which the mixed and stirred molten composite material is poured, and the molten composite material is made to flow into the lower part of the melting furnace from the sprue. A stirring device is installed, and this molten composite material stirring device is
A rotor with a polygonal cross section that scatters the molten composite material through the rotational stirring action of high-speed rotation, and a heat-resistant rotor that accommodates the rotor and receives the scattered molten composite material and allows it to flow through the collection pores into the mold. 1. A continuous manufacturing apparatus for a metal matrix composite material, characterized in that it is comprised of a container.
Priority Applications (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP7942587A JPS63242462A (en) | 1987-03-30 | 1987-03-30 | Apparatus for continuously producing metal base composite material |
| US07/175,217 US4865808A (en) | 1987-03-30 | 1988-03-30 | Method for making hypereutetic Al-Si alloy composite materials |
| US07/352,878 US4917359A (en) | 1987-03-30 | 1989-05-17 | Apparatus for making hypereutectic Al-Si alloy composite materials |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP7942587A JPS63242462A (en) | 1987-03-30 | 1987-03-30 | Apparatus for continuously producing metal base composite material |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS63242462A JPS63242462A (en) | 1988-10-07 |
| JPH027749B2 true JPH027749B2 (en) | 1990-02-20 |
Family
ID=13689512
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP7942587A Granted JPS63242462A (en) | 1987-03-30 | 1987-03-30 | Apparatus for continuously producing metal base composite material |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS63242462A (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5267601A (en) * | 1988-11-10 | 1993-12-07 | Lanxide Technology Company, Lp | Method for forming a metal matrix composite body by an outside-in spontaneous infiltration process, and products produced thereby |
| US5329983A (en) * | 1991-10-08 | 1994-07-19 | Arnold J. Cook | Sealed chamber die castings of metal matrix components |
| US5524699A (en) * | 1994-02-03 | 1996-06-11 | Pcc Composites, Inc. | Continuous metal matrix composite casting |
| CN109848397A (en) * | 2019-04-18 | 2019-06-07 | 杭州圣檀服饰有限公司 | A kind of magnetic head manufacturing device |
-
1987
- 1987-03-30 JP JP7942587A patent/JPS63242462A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS63242462A (en) | 1988-10-07 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US6491423B1 (en) | Apparatus for mixing particles into a liquid medium | |
| US4865808A (en) | Method for making hypereutetic Al-Si alloy composite materials | |
| US4743428A (en) | Method for agitating metals and producing alloys | |
| KR20000048914A (en) | Apparatus and method for semi-solid material production | |
| JPH02500201A (en) | Composite manufacturing method | |
| US6106588A (en) | Preparation of metal matrix composites under atmospheric pressure | |
| KR910006069B1 (en) | Method for manufacture of cast articles of fiber-reinforced aluminium composite | |
| CN100491553C (en) | Technique of preparing grain reinforced aluminum base composite material and special equipment thereof | |
| JPH027749B2 (en) | ||
| JPH0431009B2 (en) | ||
| KR101117460B1 (en) | A manufacturing method of composite metal powder using the gas atomization | |
| JPS6122018B2 (en) | ||
| JP2701298B2 (en) | Method and apparatus for continuous production of metal matrix composite materials | |
| US4605438A (en) | Apparatus and method for forming a wear-resistant metal composition | |
| JPS61119632A (en) | Manufacture of high ductility material | |
| JPH0114298B2 (en) | ||
| CN115298501A (en) | Apparatus and method for preparing metal matrix composites | |
| JPH0622531Y2 (en) | Continuous production equipment for metal matrix composites | |
| JPH044382B2 (en) | ||
| JPH06108178A (en) | Apparatus for production of composite material | |
| CN215998698U (en) | Bottom casting device for preparing particle reinforced aluminum matrix composite | |
| JPS6280203A (en) | Apparatus for continuous production of superplastic alloy material | |
| Ichikawa et al. | Refinement of microstructures and improvement of mechanical properties in intermetallic TiAl alloys by rheocasting | |
| KR20000048913A (en) | Apparatus and method for integrated semi-solid material production and casting | |
| CA1292615C (en) | Method and apparatus for agitating metals and producing alloys |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |
|
| R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |
|
| R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |
|
| EXPY | Cancellation because of completion of term | ||
| FPAY | Renewal fee payment (prs date is renewal date of database) |
Year of fee payment: 18 Free format text: PAYMENT UNTIL: 20080220 |