JPH0825032B2 - Gas sealing method for welded ERW pipe - Google Patents
Gas sealing method for welded ERW pipeInfo
- Publication number
- JPH0825032B2 JPH0825032B2 JP1064726A JP6472689A JPH0825032B2 JP H0825032 B2 JPH0825032 B2 JP H0825032B2 JP 1064726 A JP1064726 A JP 1064726A JP 6472689 A JP6472689 A JP 6472689A JP H0825032 B2 JPH0825032 B2 JP H0825032B2
- Authority
- JP
- Japan
- Prior art keywords
- steel pipe
- gas
- electric resistance
- cylindrical nozzle
- resistance welded
- 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 - Fee Related
Links
- 238000007789 sealing Methods 0.000 title claims description 21
- 238000000034 method Methods 0.000 title claims description 19
- 229910000831 Steel Inorganic materials 0.000 claims description 39
- 239000010959 steel Substances 0.000 claims description 39
- 239000007789 gas Substances 0.000 claims description 27
- 239000011261 inert gas Substances 0.000 claims description 21
- 238000009826 distribution Methods 0.000 claims description 4
- 230000003111 delayed effect Effects 0.000 claims 1
- 238000003466 welding Methods 0.000 description 15
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 10
- 229910001873 dinitrogen Inorganic materials 0.000 description 10
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 6
- 239000001301 oxygen Substances 0.000 description 6
- 229910052760 oxygen Inorganic materials 0.000 description 6
- 238000002347 injection Methods 0.000 description 3
- 239000007924 injection Substances 0.000 description 3
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 2
- 230000007423 decrease Effects 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 230000003647 oxidation Effects 0.000 description 2
- 238000007254 oxidation reaction Methods 0.000 description 2
- 229910052786 argon Inorganic materials 0.000 description 1
- 238000002788 crimping Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
Landscapes
- Arc Welding In General (AREA)
- Heat Treatment Of Articles (AREA)
- Pressure Welding/Diffusion-Bonding (AREA)
Description
【発明の詳細な説明】 ［産業上の利用分野］ この発明は、電縫鋼管の溶接部が酸化されないように
ガスシールする電縫鋼管溶接部のガスシール方法に関す
る。Description: TECHNICAL FIELD The present invention relates to a gas sealing method for a welded portion of an electric resistance welded steel pipe, which performs gas sealing so that the welded portion of the electric resistance welded steel pipe is not oxidized.
［従来の技術］ 電縫鋼管は、第７図のように、成形ロール21で成形し
た素管22の突き合わせ部23を高周波溶接装置（周波数25
0KHz程度）24で加熱し、素管22を溶接機ロール25で外側
から抱え込み、溶接部26が圧着されるようにして製造し
ている。[Prior Art] As shown in FIG. 7, the electric resistance welded steel pipe has a high-frequency welding device (frequency 25) at the butting portion 23 of the raw pipe 22 formed by the forming roll 21.
It is manufactured by heating the raw tube 22 from the outside with a welding machine roll 25 and crimping the welded portion 26.
上記のような電縫鋼管の溶接工程は、従来大気中で行
なわれいる。そのため高温の溶接部近傍は鋼が酸化され
やすく、その酸化物が溶接部に巻き込まれて酸化介在物
となり、低温靭性の低下とか引張強度不足等のいわゆる
溶接欠陥の原因となっている。The welding process of the above-mentioned electric resistance welded steel pipe is conventionally performed in the atmosphere. Therefore, the steel is easily oxidized in the vicinity of the high-temperature welded portion, and the oxide is caught in the welded portion to form oxidized inclusions, which causes so-called welding defects such as low temperature low-temperature toughness and insufficient tensile strength.
このような問題に対処するため、次のような対策が試
みられている。In order to deal with such problems, the following measures have been attempted.
（１）純度99.999％以上の窒素ガスまたはアルゴンガス
を、第８図のように電縫鋼管の溶接部26、溶接電源のリ
ード部27、電極28および溶接機ロール25等溶接装置全体
を覆ったカバー29内に供給してガスシールし、酸化を防
止する。(1) Nitrogen gas or argon gas having a purity of 99.999% or more was used to cover the entire welding device such as the welded portion 26 of the electric resistance welded steel pipe, the lead portion 27 of the welding power source, the electrode 28 and the welder roll 25 as shown in FIG. It is supplied into the cover 29 and is gas-sealed to prevent oxidation.
（２）第９図のように電縫鋼管内部に窒素ガス等の不活
性ガス噴出ノズル30を配置し、この噴出ノズル30から不
活性ガスを噴出して、溶接点直前の加熱された素管の突
き合わせ部23をガスシールして、酸化を防止する。(2) As shown in FIG. 9, an inert gas jet nozzle 30 such as nitrogen gas is arranged inside the electric resistance welded steel pipe, and the inert gas is jetted from the jet nozzle 30 to heat the heated raw pipe immediately before the welding point. The butted portion 23 of is sealed with gas to prevent oxidation.
［発明が解決しようとする課題］ しかしながら、上記の方法には、次のような問題点が
あった。[Problems to be Solved by the Invention] However, the above method has the following problems.
（１）の方法は、溶接部全体を覆うため装置が大型化す
るとともに、電縫管の溶接状況を観察できないという問
題点がある。The method (1) has a problem that the apparatus is upsized because it covers the entire welded portion and the welding condition of the electric resistance welded pipe cannot be observed.
（２）の方法においては、第９図に示すように、窒素ガ
ス等の不活性ガス31を、素管22の内部から突き合わせ部
23を通して外部に噴出させる際に、外部の空気を一部突
き合わせ部23に巻き込み、ガスシール性が必ずしも万全
ではないという問題点がある。In the method (2), as shown in FIG. 9, an inert gas 31 such as nitrogen gas is abutted from the inside of the raw pipe 22 at the butted portion.
There is a problem that when the air is jetted out through the outside 23, a part of the outside air is caught in the abutting portion 23 and the gas sealing property is not always perfect.
この発明は、上述のような従来技術の問題点を解消
し、電縫鋼管の溶接部を完全にガスシールし、設備費も
嵩まず、溶接時の観察も十分にできる電縫鋼管溶接部の
ガスシール方法を提供することを目的としている。The present invention solves the problems of the prior art as described above, completely gas-seals the welded portion of the electric resistance welded steel pipe, the equipment cost does not increase, and the observation at the time of welding can be sufficiently performed. It is intended to provide a gas sealing method.
［課題を解決するための手段］ この発明に係る電縫鋼管溶接部のガスシール方法は、
電縫鋼管の溶接部近傍を電縫鋼管の内部に配備した噴射
ノズルで不活性ガスを噴出させるとともに、電縫鋼管の
外部に配備した同軸二重円筒ノズルで内円筒ノズルの流
速（Ａ）と外円筒ノズルの流速（Ｂ）の比A/Bが1.0以上
になるようにして不活性ガスを噴出させ、その流速分布
が噴出流の中心から外側へ向かって徐々に流速が遅くな
るようにしてガスシールする電縫鋼管溶接部のガスシー
ル方法である。[Means for Solving the Problem] A gas sealing method for a welded portion of an electric resistance welded steel pipe according to the present invention is
Injecting an inert gas in the vicinity of the welded part of the ERW steel pipe with an injection nozzle provided inside the ERW steel pipe, and at the same time with the flow velocity (A) of the inner cylindrical nozzle with a coaxial double cylindrical nozzle provided outside the ERW steel pipe. The inert gas is jetted so that the ratio A / B of the flow velocity (B) of the outer cylindrical nozzle is 1.0 or more, and the flow velocity distribution is gradually slowed from the center of the jet flow toward the outside. This is a gas sealing method for gas welded welded steel pipe welds.
［作用］ この発明に係る電縫鋼管溶接部のガスシール方法は、
電縫鋼管の溶接部近傍を電縫鋼管の内部に配備した噴射
ノズルで不活性ガスを噴出させるとともに、電縫鋼管の
外部に配備した同軸二重円筒ノズルで内円筒ノズルの流
速（Ａ）と外円筒ノズルの流速（Ｂ）の比A/Bが1.0以上
になるようにして不活性ガスを噴出させているので、同
軸二重円筒ノズルからの不活性ガスの噴出流が、噴出流
の中心から外側へ向って徐々に流速が遅くなる流速分布
となり、空気の電縫鋼管突き合わせ部への巻き込みがな
く、ガスシール性が向上する。[Operation] The gas sealing method for the welded portion of the electric resistance welded steel pipe according to the present invention is
Injecting an inert gas in the vicinity of the welded part of the ERW steel pipe with an injection nozzle provided inside the ERW steel pipe, and at the same time with the flow velocity (A) of the inner cylindrical nozzle with a coaxial double cylindrical nozzle provided outside the ERW steel pipe. Since the inert gas is jetted so that the ratio A / B of the flow velocity (B) of the outer cylindrical nozzle is 1.0 or more, the jet flow of the inert gas from the coaxial double cylindrical nozzle is the center of the jet flow. The flow velocity distribution is such that the flow velocity gradually decreases from the outside to the outside, air is not entrained in the welded portion of the electric resistance welded steel pipe, and the gas sealability is improved.
［実施例］ 本発明の１実施例の電縫鋼管溶接部のガスシール方法
を、第１図〜第６図により説明する。第１図は、この電
縫鋼管溶接部のガスシール方法を示す説明図である。電
縫鋼管１は、その素管２の突き合わせ部3,3が、高周波
電極によりその電極接点4,4で誘導加熱され、高温の状
態になった後、サイドロール５で素管２を抱え込むよう
にして、突き合わせ部3,3を圧着させて製造される。こ
の時圧着される前の突き合わせ部3,3は、高温のため空
気に触れると酸化され、鋼の酸化物が溶接部６に巻き込
まれてしまう。そこでこの電縫鋼管溶接部のガスシール
方法においては、窒素ガスの配管７をサイドロール５の
前方からサイドロール方向に向けて、素管２の内部に差
し込み、その先端に設けた噴出ノズル８から窒素ガスを
素管２の突き合わせ部3,3に向けて噴出している。また
素管２の上方にも窒素ガスの配管９を配管し、その先端
に設けた同軸二重円筒ノズル10から電極接点4,4および
サイドロール５方向に向けて窒素ガスを噴出している。
したがって、電縫鋼管１の溶接部近傍は、電縫鋼管１の
内外からガスシールされた状態になっている。[Embodiment] A gas sealing method for welded portions of an electric resistance welded steel pipe according to an embodiment of the present invention will be described with reference to FIGS. 1 to 6. FIG. 1 is an explanatory view showing a gas sealing method for the welded portion of the electric resistance welded steel pipe. As for the electric resistance welded steel pipe 1, the butted portions 3, 3 of the raw pipe 2 are induction-heated by the high frequency electrodes at the electrode contacts 4, 4 and become high temperature, and then the raw pipe 2 is held by the side rolls 5. Then, the butted portions 3, 3 are pressure-bonded to each other to be manufactured. At this time, the butted portions 3, 3 before being crimped are oxidized when they come into contact with air due to the high temperature, and the oxide of steel is caught in the welded portion 6. Therefore, in the gas sealing method for the welded portion of the electric resistance welded steel pipe, the nitrogen gas pipe 7 is inserted into the raw pipe 2 from the front side of the side roll 5 toward the side roll direction, and the jet nozzle 8 provided at the tip thereof is used. Nitrogen gas is jetted toward the butted portions 3, 3 of the base pipe 2. A nitrogen gas pipe 9 is also provided above the raw pipe 2, and nitrogen gas is jetted from the coaxial double cylindrical nozzle 10 provided at the tip thereof toward the electrode contacts 4, 4 and the side rolls 5.
Therefore, the vicinity of the welded portion of the electric resistance welded steel pipe 1 is gas-sealed from the inside and outside of the electric resistance welded steel pipe 1.
このガスシール方法は、上述のように特別なシールカ
バーを使用することなく、電縫鋼管の溶接部をガスシー
ルすることができ、電縫鋼管の溶接部に酸化物が巻き込
まれるのを防止している。This gas sealing method can gas seal the welded portion of the electric resistance welded steel pipe without using a special seal cover as described above, and prevents oxides from being caught in the welded portion of the electric resistance welded steel pipe. ing.
第２図は、同軸二重円筒ノズル10を模式的に表した説
明図である。ガスの流路は、内円筒11の内部12と、内円
筒11と外円筒13で構成される空間14とに別れる。そし
て、内円筒11の内部12を流れる不活性ガスの流速は、内
円筒11と外円筒13で構成される空間14を流れる不活性ガ
スの流速よりも速くなるようにしている。なお内円筒11
の内部12に整流板15を設け、不活性ガスの流れが乱流と
ならないようにしている。このように構成しているの
は、単なる円筒ノズルでは、不活性ガスの流れと周囲の
空気との流れとの間に流速の大きな差があるので、不活
性ガスの流れの中に空気を巻き込み、この空気が前記素
管２の突き合わせ部3,3に触れて、突き合わせ部3,3を酸
化させるからである。この同軸二重円筒ノズル10の場合
には、ノズルの中心から外側に向けて徐々に流速が遅く
なる流速分布となっているので、単なる円筒ノズルと異
なり、空気を巻き込むことはない。FIG. 2 is an explanatory view schematically showing the coaxial double cylindrical nozzle 10. The gas flow passage is divided into an inside 12 of the inner cylinder 11 and a space 14 constituted by the inner cylinder 11 and the outer cylinder 13. The flow velocity of the inert gas flowing through the inside 12 of the inner cylinder 11 is set to be higher than the flow velocity of the inert gas flowing through the space 14 formed by the inner cylinder 11 and the outer cylinder 13. The inner cylinder 11
A rectifying plate 15 is provided in the interior 12 so that the flow of the inert gas does not become a turbulent flow. In this configuration, in a simple cylindrical nozzle, there is a large difference in the flow velocity between the flow of the inert gas and the flow of the surrounding air, so air is entrained in the flow of the inert gas. This is because the air touches the butted portions 3,3 of the raw tube 2 and oxidizes the butted portions 3,3. In the case of the coaxial double cylindrical nozzle 10, since the flow velocity distribution is such that the flow velocity gradually decreases from the center of the nozzle toward the outside, unlike the simple cylindrical nozzle, air is not entrained.
第３図は、同軸二重円筒ノズル10がいかに周辺の空気
を巻き込まないかを示すグラフであり、ノズル先端から
の距離と酸素濃度との関係を単管円筒ノズルと比較して
示している。この図から明らかなように、同軸二重円筒
ノズル10は、ノズル先端から150mm離れた位置において
も、酸素濃度は10ppmと単管円筒ノズルの1000ppmに比較
して100分の１であり、いかに空気を巻き込まないかが
理解できる。FIG. 3 is a graph showing how the coaxial double-cylindrical nozzle 10 does not entrain the surrounding air, and shows the relationship between the distance from the nozzle tip and the oxygen concentration in comparison with the single-tube cylindrical nozzle. As is clear from this figure, the coaxial double cylindrical nozzle 10 has an oxygen concentration of 10 ppm even at a position 150 mm away from the nozzle tip, which is 1/100 of 1000 ppm of the single pipe cylindrical nozzle. You can understand if you are not involved.
第４図は、本発明の電縫鋼管溶接部のガスシール方法
の効果を示すグラフであり、溶接点からの距離と酸素濃
度との関係を電縫鋼管の内部のみをガスシールした場合
と比較して示している。この図から明らかなように、内
部のみをガスシールした場合が溶接点から100mmの位置
（ノズルからの不活性ガス噴射位置）の近傍のみがガス
シール性が高いのに対して、本発明の電縫鋼管溶接部の
ガスシール方法においては、溶接点から200mmまでのす
べての範囲において、すなわち不活性ガス噴射位置の前
後100mmのすべての位置において、100ppm以下の酸素濃
度に納まっており、優れたガスシール性を示している。
この理由は、電縫鋼管の素管の突き合わせ部において、
管内部からの窒素ガス等の不活性ガスの流れを、管外部
の同軸二重円筒ノズルからの高純度不活性ガスの流れが
前記素管の突き合わせ部に押さえ付け、この突き合わせ
部に不活性ガスの付着流を形成させ、大気の巻き込みが
なくなるからである。FIG. 4 is a graph showing the effect of the gas sealing method of the welded portion of the electric resistance welded steel pipe of the present invention, comparing the relationship between the distance from the welding point and the oxygen concentration with the case where only the inside of the electric resistance welded steel pipe is gas sealed. Is shown. As is clear from this figure, when only the inside is gas-sealed, the gas-sealing property is high only in the vicinity of the position 100 mm from the welding point (the position where the inert gas is injected from the nozzle). In the gas sealing method for sewn steel pipe welds, the oxygen concentration of 100 ppm or less is contained in the entire range from the welding point to 200 mm, that is, in all positions 100 mm before and after the inert gas injection position, which is an excellent gas. Shows sealing properties.
The reason for this is that in the butting part of the element pipe of ERW steel pipe,
The flow of an inert gas such as nitrogen gas from the inside of the pipe is suppressed by the flow of the high-purity inert gas from the coaxial double cylindrical nozzle outside the pipe at the abutting portion of the raw pipe, and the inert gas is passed to this abutting portion. This is because the adhering flow is formed and the entrainment of the atmosphere is eliminated.
第５図は、第６図のように同軸二重円筒ノズル10を、
ノズル先端10aから溶接点16までの水平方向距離Ｌを100
mm、高さＨを50mmになるように、またノズル10の水平面
との傾き角度Ａを60度となるようにして配置して、不活
性ガスを噴射した時の溶接点からの距離と酸素濃度との
関係を示したものである。第５図から明らかなように、
ほとんどの位置において酸素濃度は100ppm以下になって
おり、ガスシール性が優れていることが分かる。FIG. 5 shows the coaxial double cylindrical nozzle 10 as shown in FIG.
The horizontal distance L from the nozzle tip 10a to the welding point 16 is 100
mm, the height H is 50 mm, and the inclination angle A of the nozzle 10 with respect to the horizontal plane is 60 degrees, and the distance from the welding point and the oxygen concentration when the inert gas is injected It shows the relationship with. As is clear from FIG.
It can be seen that the oxygen concentration is 100 ppm or less at most positions and that the gas sealability is excellent.
なお、本発明は上記実施例に限定されるものではな
く、本発明の目的を達成し得る範囲内で任意に設計変更
することができる。The present invention is not limited to the above-mentioned embodiment, and the design can be arbitrarily changed within the range in which the object of the present invention can be achieved.
［発明の効果］ 本発明により、電縫鋼管溶接部近傍のガスシールがシ
ールカバー無しに行なえ、溶接部への酸化介在物の巻き
込みを防止することができる。[Effect of the Invention] According to the present invention, gas sealing in the vicinity of the welded portion of the electric resistance welded steel pipe can be performed without a seal cover, and the inclusion of oxidized inclusions in the welded portion can be prevented.
第１図は本発明の１実施例の電縫鋼管溶接部のガスシー
ル方法を示す説明図、第２図は同軸二重円筒ノズル10を
模式的に表した説明図、第３図，第４図，第５図は同軸
二重円筒ノズルの効果を示すグラフ図、第６図は同軸二
重円筒ノズルの配置状況を示す説明図、第７図は電縫鋼
管の製造工程を示す説明図、第８図および第９図は従来
のガスシール技術を示す説明図である。 １…電縫鋼管、２…電縫鋼管の素管、３…素管の突き合
わせ部、４…電極接点、５…サイドロール、６…溶接
部、７…窒素ガス配管、８…噴出ノズル、９…窒素ガス
配管、10…同軸二重円筒ノズル、11…内円筒、13…外円
筒、15…整流板。FIG. 1 is an explanatory view showing a gas sealing method for a welded portion of an electric resistance welded steel pipe of an embodiment of the present invention, and FIG. 2 is an explanatory view schematically showing a coaxial double cylindrical nozzle 10, FIGS. 3, 4 Fig. 5 is a graph showing the effect of the coaxial double cylindrical nozzle, Fig. 6 is an explanatory diagram showing the arrangement of the coaxial double cylindrical nozzle, and Fig. 7 is an explanatory diagram showing the manufacturing process of the electric resistance welded steel pipe. 8 and 9 are explanatory views showing a conventional gas sealing technique. DESCRIPTION OF SYMBOLS 1 ... ERW steel pipe, 2 ... ERW steel pipe base pipe, 3 ... Base pipe butting part, 4 ... Electrode contact, 5 ... Side roll, 6 ... Welding part, 7 ... Nitrogen gas piping, 8 ... Jet nozzle, 9 … Nitrogen gas piping, 10… Coaxial double cylindrical nozzle, 11… Inner cylinder, 13… Outer cylinder, 15… Rectangular plate.
───────────────────────────────────────────────────── フロントページの続き (56)参考文献 特公 昭52−22945（ＪＰ，Ｂ２) 特公 昭56−26518（ＪＰ，Ｂ２) 実公 昭59−27981（ＪＰ，Ｙ２) ─────────────────────────────────────────────────── ─── Continuation of the front page (56) References Japanese Patent Publication No. 52-22945 (JP, B2) Japanese Publication No. 56-26518 (JP, B2) Actual Publication No. 59-27981 (JP, Y2)
Claims (1)
配備した噴射ノズルで不活性ガスを噴出させるととも
に、電縫鋼管の外部に配備した同軸二重円筒ノズルで内
円筒ノズルの流速（Ａ）と外円筒ノズルの流速（Ｂ）の
比A/Bが1.0以上になるようにして不活性ガスを噴出さ
せ、その流速分布が噴出流の中心から外側へ向かって徐
々に流速が遅くなるようにしてガスシールすることを特
徴とする電縫鋼管溶接部のガスシール方法。1. An injecting nozzle disposed near the welded portion of an electric resistance welded steel pipe to eject an inert gas, and an coaxial double cylindrical nozzle disposed outside the electric resistance welded steel pipe serves as an inner cylindrical nozzle. The inert gas is ejected so that the ratio A / B between the flow velocity (A) and the flow velocity (B) of the outer cylindrical nozzle is 1.0 or more, and the flow velocity distribution gradually increases from the center of the jet flow to the outside. A gas sealing method for a welded portion of an electric resistance welded steel pipe, characterized in that the gas sealing is performed so as to be delayed.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1064726A JPH0825032B2 (en) | 1989-03-16 | 1989-03-16 | Gas sealing method for welded ERW pipe |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1064726A JPH0825032B2 (en) | 1989-03-16 | 1989-03-16 | Gas sealing method for welded ERW pipe |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH02241676A JPH02241676A (en) | 1990-09-26 |
| JPH0825032B2 true JPH0825032B2 (en) | 1996-03-13 |
Family
ID=13266442
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP1064726A Expired - Fee Related JPH0825032B2 (en) | 1989-03-16 | 1989-03-16 | Gas sealing method for welded ERW pipe |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0825032B2 (en) |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5222945A (en) * | 1975-08-14 | 1977-02-21 | Mitsubishi Electric Corp | Device for detecting the flat of a wheel |
| JPS5626518A (en) * | 1979-08-10 | 1981-03-14 | Koichi Iitani | Operation of bag filter having multiple chambers |
| JPS5927981U (en) * | 1982-08-13 | 1984-02-21 | 本田技研工業株式会社 | Handle locking device |
-
1989
- 1989-03-16 JP JP1064726A patent/JPH0825032B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH02241676A (en) | 1990-09-26 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| LAPS | Cancellation because of no payment of annual fees |