JPS6411086B2 - - Google Patents
Info
- Publication number
- JPS6411086B2 JPS6411086B2 JP15251983A JP15251983A JPS6411086B2 JP S6411086 B2 JPS6411086 B2 JP S6411086B2 JP 15251983 A JP15251983 A JP 15251983A JP 15251983 A JP15251983 A JP 15251983A JP S6411086 B2 JPS6411086 B2 JP S6411086B2
- Authority
- JP
- Japan
- Prior art keywords
- yield strength
- present
- temperature
- annealing
- reduction
- 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
- 238000000034 method Methods 0.000 claims description 16
- 238000004513 sizing Methods 0.000 claims description 14
- 230000008569 process Effects 0.000 claims description 10
- 238000010438 heat treatment Methods 0.000 description 20
- 238000000137 annealing Methods 0.000 description 17
- 230000009467 reduction Effects 0.000 description 17
- 239000000463 material Substances 0.000 description 15
- 230000000694 effects Effects 0.000 description 12
- 238000004519 manufacturing process Methods 0.000 description 12
- 230000007423 decrease Effects 0.000 description 11
- 238000001816 cooling Methods 0.000 description 5
- 238000003466 welding Methods 0.000 description 5
- 238000005336 cracking Methods 0.000 description 4
- 230000006872 improvement Effects 0.000 description 4
- 229910000831 Steel Inorganic materials 0.000 description 3
- 238000010586 diagram Methods 0.000 description 3
- 230000006698 induction Effects 0.000 description 3
- 239000010959 steel Substances 0.000 description 3
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 2
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 2
- 229910052799 carbon Inorganic materials 0.000 description 2
- 230000008859 change Effects 0.000 description 2
- 230000000052 comparative effect Effects 0.000 description 2
- 230000007797 corrosion Effects 0.000 description 2
- 238000005260 corrosion Methods 0.000 description 2
- 230000006866 deterioration Effects 0.000 description 2
- 229910052739 hydrogen Inorganic materials 0.000 description 2
- 239000001257 hydrogen Substances 0.000 description 2
- 238000005452 bending Methods 0.000 description 1
- 230000008901 benefit Effects 0.000 description 1
- 239000000567 combustion gas Substances 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 230000001814 effect on stress Effects 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
- C21D9/08—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for tubular bodies or pipes
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
- C21D9/50—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for welded joints
Description
【発明の詳細な説明】 本発明は電縫管の製造方法に関する。[Detailed description of the invention] The present invention relates to a method for manufacturing an electric resistance welded tube.
電縫管製造工程では、造管時におけるバウシン
ガー効果により降伏強度が低下するという問題が
あり、このような降伏強度の低下は、第１図に示
すように特に高強度（例えばAPI規格5LX―X60
程度以上）のもの程、またｔ／Ｄ（肉厚／外径）
の比較的小さい（２％前後）もの程大きい。一般
にｔ／Ｄの大きいサイズ（小径サイズ）のものに
ついては、サイジング工程で絞りがかけられるた
め、造管時に降伏強度が低下しても上記絞りによ
り強度が回復するのに対し、ｔ／Ｄの小さいサイ
ズ（大径サイズ）では座屈を生じる等の理由から
サイジング工程では絞りがほとんどかけられず、
この結果、降伏強度が低下したままで製品化され
ることになる。また管サイズによつてフインパス
やサイジングでの絞りがある程度可能だとして
も、降伏強度を回復させるような強絞りは溶接部
靭性の劣化を招く結果となる。最近は高張力電縫
管のラインパイプでも溶接部の低温衝撃特性が仕
様となつている場合が多く、したがつて上記した
絞りの度合いも自ずと限度があり、降伏強度改善
の大きな効果はあまり期待できない。近年パイプ
ラインの材質は高張力化する傾向が強く、このた
め従来では、素材のコイルとして規格値よりも降
伏強度が高いもの（X60の場合、Y.S.が５Kg／mm2
以上高いもの）を使用し、降伏強度の低下分を予
め補償しておくという対策を採ることにより高張
力電縫管の製造を可能ならしめているのが実情で
ある。また電縫管の溶接部は、溶接後行われるシ
ームアニールによりその靭性が改善されるが、続
くサイジング工程で受ける加工歪により、再びそ
の靭性が劣化してしまうという問題がある。この
ようなサイジング工程で溶接部近傍が受ける加工
歪を除去し、その部分の靭性を改善させる方法と
して、サイジング後、シームアニール方式により
溶接部の熱処理を行うことも提案されているが、
この方式では溶接部近傍だけが局部加熱されるた
め、その冷却過程において熱が管周方向に急激に
奪われ溶接部が急冷されてしまい、このため溶接
部靭性改善について大きな効果は望み得ない。ま
た、上記したような局部的な熱処理では熱歪によ
る曲り等の変形を生じ易く、製品の品質低下を招
いてしまうという問題がある。 In the ERW pipe manufacturing process, there is a problem in which the yield strength decreases due to the Bauschinger effect during pipe manufacturing. X60
above), and t/D (thickness/outer diameter)
The smaller it is (around 2%), the larger it is. Generally, for pipes with a large t/D (small diameter size), a reduction is applied during the sizing process, so even if the yield strength decreases during pipe making, the strength is restored by the reduction, Due to reasons such as buckling in small sizes (large diameter sizes), almost no squeezing is applied during the sizing process.
As a result, the product is manufactured with a reduced yield strength. Furthermore, even if it is possible to reduce the weld to some extent by fine passes or sizing depending on the pipe size, strong drawing that restores the yield strength will result in deterioration of the weld toughness. Recently, low-temperature impact characteristics of welded parts are often specified in high-tension electric resistance welded line pipes, so there is a natural limit to the degree of throttling mentioned above, and the large effect of improving yield strength is not expected. Can not. In recent years, there has been a strong tendency for pipeline materials to have higher tensile strength, and for this reason, conventional coils of material with a yield strength higher than the standard value (for X60, YS is 5Kg/mm 2
In reality, it is possible to manufacture high-strength electric resistance welded pipes by taking measures to compensate for the decrease in yield strength in advance. Further, although the toughness of the welded portion of the electric resistance welded pipe is improved by seam annealing performed after welding, there is a problem in that the toughness deteriorates again due to processing strain received in the subsequent sizing process. It has been proposed that the weld be heat-treated by a seam annealing method after sizing as a method to remove the processing strain applied to the vicinity of the weld during the sizing process and improve the toughness of that area.
In this method, only the area near the weld is locally heated, so during the cooling process, heat is rapidly removed in the circumferential direction of the pipe and the weld is rapidly cooled, so that no significant effect can be expected in improving the toughness of the weld. In addition, the above-described local heat treatment tends to cause deformation such as bending due to thermal strain, resulting in a problem that the quality of the product deteriorates.
本発明はこのような事情に鑑み、ｔ／Ｄの小さ
い高張力鋼管についても、バウシンガー効果によ
る降伏強度の低下を合理的に改善でき、またその
ような降伏強度の改善とともに、サイジングによ
る溶接部靭性の低下をも改善することができる電
縫管製造方法を提供せんとするものである。 In view of these circumstances, the present invention is capable of rationally improving the decrease in yield strength due to the Bauschinger effect even for high-strength steel pipes with small t/D, and in addition to improving such yield strength, it is possible to improve the welded part due to sizing. It is an object of the present invention to provide a method for manufacturing an electric resistance welded tube that can also improve the reduction in toughness.
このため本発明は、熱処理による効果に着目
し、サイジング工程後、管体を4000℃未満の温度
で低温焼鈍し、引き続きシーム部のみを400℃以
上の温度で高温焼鈍し、上記低温焼鈍による加熱
状態を利用しつつシームアニールを行うことによ
り、降伏強度の改善とともに、溶接部の急冷を防
止して溶接部靭性を適切に改善するようにしたも
のである。 For this reason, the present invention focuses on the effect of heat treatment, and after the sizing process, the tube body is low-temperature annealed at a temperature of less than 4000°C, and then only the seam portion is annealed at a high temperature of 400°C or higher. By performing seam annealing while taking advantage of the conditions, the yield strength is improved, and rapid cooling of the weld is prevented, thereby appropriately improving the weld toughness.
以下、本発明を図面を参照して説明すると、第
２図は本発明による電縫管製造方法の溶接以降の
実施状況を示しており、成形された管体Ｐはウエ
ルダー１によりシーム溶接された後、ポストアニ
ーラー２によつて溶接部が熱処理され、さらに空
冷ゾーン３及び水冷ゾーン４を通過後、サイザー
５で成形され、最終的に走行切断機６により所定
長に切断される。本発明ではこのサイザー通過
後、管体Ｐをまず加熱装置７により400℃未満の
温度で低温焼鈍するものである。この加熱装置７
としては、第３図に示すような低周波誘導加熱装
置、或は第４図に示すようなバーナ８による燃焼
ガス加熱装置等が用いられる。また、これら加熱
装置７の出側に保温ドームを設け、加熱装置容量
不足や加熱時間不足を補うようにすることができ
る。 Hereinafter, the present invention will be explained with reference to the drawings. Fig. 2 shows the implementation status after welding of the ERW pipe manufacturing method according to the present invention, and the formed pipe P is seam welded by the welder 1. Thereafter, the welded portion is heat treated by a post annealer 2, and after passing through an air cooling zone 3 and a water cooling zone 4, it is shaped by a sizer 5, and finally cut into a predetermined length by a traveling cutter 6. In the present invention, after passing through the sizer, the tube P is first annealed at a low temperature of less than 400° C. using a heating device 7. This heating device 7
For example, a low frequency induction heating device as shown in FIG. 3 or a combustion gas heating device using a burner 8 as shown in FIG. 4 is used. Furthermore, a heat insulating dome may be provided on the outlet side of the heating device 7 to compensate for insufficient heating device capacity or heating time.
上記低温焼鈍は400℃未満の温度で行われる。
400℃以上の比較的高温での焼鈍によつても降伏
強度の改善はなされるが、本発明の目的とする降
伏強度の改善効果は400℃未満の温度域で十分達
成されるものであり、400℃以上での焼鈍は加熱
用の大きなエネルギーとそのための設備的負担を
必要とし、経済性を著しく損うことになる。した
がつて焼鈍温度は400℃未満、好ましくは300℃以
下に設定される。また焼鈍による効果をある程度
期待するには、その焼鈍温度は100℃以上である
ことが好ましい。 The low temperature annealing is performed at a temperature below 400°C.
Although the yield strength can be improved by annealing at a relatively high temperature of 400°C or higher, the yield strength improvement effect aimed at by the present invention can be sufficiently achieved in a temperature range of less than 400°C. Annealing at temperatures above 0.degree. C. requires a large amount of energy for heating and a heavy burden on equipment, which significantly impairs economic efficiency. Therefore, the annealing temperature is set below 400°C, preferably below 300°C. Further, in order to expect some effect from annealing, the annealing temperature is preferably 100°C or higher.
そして、このような低温焼鈍を行うことによ
り、バウシンガー効果によつて低下した降伏強度
が大きく回復し、例えばAPI5LX―X60以上の高
張力鋼においても、大きなエネルギーを用いるこ
となく降伏強度が合理的に改善でき、ｔ／Ｄの小
さい高張力電縫管を容易に製造することができ
る。第５図は本発明による降伏強度の改善効果
（管体サイズ20″×9.52，材質×70）を示したもの
であり、400℃未満の経済的な低温焼鈍で適切な
効果が得られていることが判る。 By performing such low-temperature annealing, the yield strength decreased due to the Bauschinger effect can be greatly recovered, and even in high-strength steels such as API5LX-X60 or higher, the yield strength can be rationally increased without using large amounts of energy. It is possible to easily manufacture a high-tension electric resistance welded tube with a small t/D. Figure 5 shows the yield strength improvement effect of the present invention (tube size 20″ x 9.52, material x 70), and shows that appropriate effects are obtained with economical low-temperature annealing at less than 400°C. I understand that.
前述したように、電縫管製造過程における降伏
強度の低下は高強度のもの程大きい性質がある
が、このような鋼自体による傾向とは別に、管体
のｔ／Ｄが小さい程、またサイザーでの絞り量が
少ない程低下する性質があり、特にｔ／Ｄの小さ
いサイズのものでは座屈を生じ易い等の理由から
サイザーでの絞りがあまりかけられないため低下
の度合いが大きいものとなる。したがつて本発明
を適用すべき範囲は、パイプのｔ／Ｄ及び絞り量
（絞り率）という２つの要素との関係で決める必
要がある。検討の結果、ｔ／Ｄと絞り率との和の
値が降伏強度の低下量と良好な相関を有し、上記
値に基づくことにより本発明を適用すべき範囲が
適切に決定できることが判つた。第６図はX60〜
X70クラスの材質のものについてｔ／Ｄプラス絞
り率と降伏強度（Y.S.）低下との関係を調べた結
果を示したものである。これによれば、上記ｔ／
Ｄプラス絞り率の値が６％以下の範囲において降
伏強度の低下がみられ、特に５％以下の範囲でそ
の低下が大きくなつていることが判る。したがつ
て本発明はｔ／Ｄプラス絞り率の値が６％以下の
電縫管の製造工程に主として適用されることにな
る。このような電縫管は通常ｔ／D3％以下であ
る200A以上のサイズの中、大径管に相当する。
また上記のような強度低下は一般にX52クラス以
上の材質のもので問題となるものであり、通常本
発明はこのようなクラスの材質の電縫管に適用さ
れる。 As mentioned above, the lower the yield strength during the manufacturing process of ERW pipes is, the higher the strength of the steel. There is a tendency for the reduction to decrease as the amount of reduction with the sizer is reduced, and in particular, in the case of small size t/D, the degree of reduction is large because the reduction is not applied as much with the sizer for reasons such as easy buckling. . Therefore, the range to which the present invention is applied must be determined in relation to two factors: t/D of the pipe and the amount of reduction (reduction rate). As a result of the study, it was found that the value of the sum of t/D and the reduction ratio has a good correlation with the amount of decrease in yield strength, and that the range to which the present invention should be applied can be appropriately determined based on the above value. . Figure 6 shows X60~
This figure shows the results of investigating the relationship between t/D plus reduction in area and yield strength (YS) reduction for X70 class materials. According to this, the above t/
It can be seen that the yield strength decreases in the range where the value of D plus the reduction ratio is 6% or less, and the decrease is particularly large in the range of 5% or less. Therefore, the present invention is mainly applied to the manufacturing process of electric resistance welded pipes in which the value of t/D plus the reduction ratio is 6% or less. Such an electric resistance welded pipe corresponds to a large diameter pipe with a size of 200A or more, which usually has a t/D of 3% or less.
Further, the above-mentioned strength reduction is generally a problem with materials of the X52 class or higher, and the present invention is generally applied to electric resistance welded pipes made of materials of this class.
また、本発明では降伏強度の改善に伴い素材の
炭素当量を下げることができ、これによつて管体
円周溶接部の硬度を低下させ、応力腐食割れや水
素誘起割れに有効な作用を期待できる。また本発
明に附随し、曲り矯正の必要な管体に対して焼鈍
による温度が低下しないうちに矯正を施すことに
より、矯正によるバウシンガー効果の発生を適切
に除去することができる。 In addition, with the present invention, the carbon equivalent of the material can be lowered as the yield strength is improved, thereby reducing the hardness of the circumferential welded part of the tube, which is expected to have an effective effect on stress corrosion cracking and hydrogen-induced cracking. can. Further, according to the present invention, by straightening the tube body that needs to be bent before the temperature decreases due to annealing, it is possible to appropriately eliminate the Bauschinger effect caused by the straightening.
加熱装置７（低周波誘導加熱装置等）により
400℃以下の温度で低温焼鈍された管体Ｐは、第
２図及び第７図に示されるように直ちに溶接部加
熱装置９（高周波誘導加熱装置等）により、靭性
改善を目的として溶接部のみが400℃以上の温度
で高温焼鈍される。ここで本発明では、溶接部の
局部加熱前に、既に低温焼鈍によつて管周方向が
均一に加熱されているため、溶接部加熱後の冷却
速度が低く抑えられるものであり、これによりサ
イジング工程で受ける加工歪による靭性の劣化を
適切に改善することができる。なおこの高温焼鈍
の下限温度を400℃としたのは、400℃未満では溶
接部の靭性改善が十分でないからである。また、
溶接部の焼鈍温度の上限については、溶接部の組
織の粗大化を防止するため1000℃以下とすること
が望ましい。 By heating device 7 (low frequency induction heating device, etc.)
The pipe P that has been low-temperature annealed at a temperature of 400°C or lower is immediately heated by a welding part heating device 9 (such as a high-frequency induction heating device) as shown in FIGS. 2 and 7 to improve the toughness of the welded part. is annealed at a high temperature of 400℃ or higher. Here, in the present invention, the circumferential direction of the tube is already uniformly heated by low-temperature annealing before the local heating of the weld zone, so the cooling rate after heating the weld zone can be suppressed to a low level. It is possible to appropriately improve the deterioration of toughness due to processing strain received in the process. The lower limit temperature of this high-temperature annealing was set at 400°C because the toughness of the welded part is not sufficiently improved below 400°C. Also,
The upper limit of the annealing temperature of the weld is preferably 1000°C or less in order to prevent the structure of the weld from becoming coarse.
第８図はこのような本発明法により製造された
電縫管（X70クラス）の溶接部衝撃特性を比較材
（溶接→シームアニール→サイジングによるもの）
のそれとともに示したもので、20″×6.35サイズ
の供試材の溶接部衝撃特性（試験片10×5.0mm）
をそれぞれ示したものである。これによれば、本
発明材ではサイジングしたままの比較材に較べ衝
撃特性が大幅に改善されていることが判る。 Figure 8 shows the impact characteristics of the welded part of the electric resistance welded pipe (X70 class) manufactured by the method of the present invention compared to the material (welding → seam annealing → sizing).
The impact characteristics of the welded part of the 20" x 6.35 size test material (test piece 10 x 5.0 mm) are shown together with that of
are shown respectively. According to this, it can be seen that the impact properties of the material of the present invention are significantly improved compared to the comparative material that has been sized.
以上述べた本発明によれば、ｔ／Ｄの小さい高
張力電縫管についても、造管時におけるバウシン
ガー効果による降伏強度の低下を経済的且つ合理
的に改善でき、このため素材として規格値よりも
高い強度のものを使用したり、或はフインパスや
サイジングでの強絞りを行つたりすることなくラ
インパイプ用等の高張力電縫管を簡単且つ経済的
に製造することができる。また上記降伏強度の改
善により、素材の炭素当量そのものが下げられる
ため、管体円周溶接部の硬度を低下させ応力腐食
割れや水素誘起割れに有効な作用を期待できると
いう効果がある。さらにこのような降伏強度の改
善とともに、サイジングによる溶接部靭性の低下
が適切に改善された電縫管を簡単且つ経済的に製
造することができるものである。 According to the present invention described above, it is possible to economically and rationally improve the decrease in yield strength due to the Bauschinger effect during pipe manufacturing even for high-tension electric resistance welded pipes with a small t/D, and therefore the standard value as a material can be improved. It is possible to easily and economically manufacture high-tensile resistance welded pipes for line pipes, etc., without using materials with higher strength than those of the present invention, or without performing strong drawing during fin passes or sizing. Furthermore, since the carbon equivalent of the material itself is lowered due to the improvement in yield strength, the hardness of the circumferential welded portion of the tube is reduced, which is expected to be effective against stress corrosion cracking and hydrogen-induced cracking. Furthermore, it is possible to easily and economically manufacture an electric resistance welded pipe in which the reduction in welded part toughness due to sizing is appropriately improved in addition to such improvement in yield strength.
第１図は電縫管のｔ／Ｄと成形による降伏強度
の変化量との関係を示すものである。第２図は本
発明の実施状況を部分的に示す説明図である。第
３図及び第４図はそれぞれ本発明における管体加
熱状況の一例を示す説明図である。第５図はサイ
ジング工程後の管体焼鈍温度とコイル時に較べて
の降伏強度低下量との関係を示すものである。第
６図は管体ｔ／Ｄとサイジング工程度における絞
り率との和の値と成形による降伏強度の変化量と
の関係を示すものである。第７図は本発明におけ
る管体加熱状況の一例を示す説明図である。第８
図は本発明によつて製造された電縫管の溶接部衝
撃特性を比較材それとともに示したものである。
図において、７′は加熱装置、９は溶接部加熱
装置である。
FIG. 1 shows the relationship between t/D of an electric resistance welded pipe and the amount of change in yield strength due to forming. FIG. 2 is an explanatory diagram partially showing the state of implementation of the present invention. FIG. 3 and FIG. 4 are explanatory diagrams each showing an example of the tubular body heating situation in the present invention. FIG. 5 shows the relationship between the annealing temperature of the tube after the sizing process and the amount of decrease in yield strength compared to when coiling. FIG. 6 shows the relationship between the sum of the tube body t/D and the reduction rate in the sizing process and the amount of change in yield strength due to forming. FIG. 7 is an explanatory diagram showing an example of a tubular body heating situation in the present invention. 8th
The figure shows the impact characteristics of the welded part of the electric resistance welded pipe manufactured according to the present invention together with that of a comparative material. In the figure, 7' is a heating device, and 9 is a welding part heating device.
Claims (1)
で低温焼鈍し、引き続きシーム部のみを400℃以
上の温度で高温焼鈍する電縫管の製造方法。1. After the sizing process, the tube body is annealed at a low temperature of less than 400°C, and only the seam portion is subsequently annealed at a high temperature of 400°C or more.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP15251983A JPS6046321A (en) | 1983-08-23 | 1983-08-23 | Manufacture of seam welded pipe |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP15251983A JPS6046321A (en) | 1983-08-23 | 1983-08-23 | Manufacture of seam welded pipe |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS6046321A JPS6046321A (en) | 1985-03-13 |
| JPS6411086B2 true JPS6411086B2 (en) | 1989-02-23 |
Family
ID=15542213
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP15251983A Granted JPS6046321A (en) | 1983-08-23 | 1983-08-23 | Manufacture of seam welded pipe |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS6046321A (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS624830A (en) * | 1985-06-28 | 1987-01-10 | Nippon Kokan Kk <Nkk> | Heat treatment of large diameter weld steel pipe |
| EP1204772B1 (en) * | 1999-05-10 | 2007-07-25 | EUROPIPE GmbH | Method for producing welded steel pipes with a high degree of strength, ductility and deformability |
| US7461874B2 (en) * | 2006-08-30 | 2008-12-09 | Shape Corporation | Selectively annealed bumper beam |
| CN103128162B (en) * | 2013-03-18 | 2014-11-05 | 辽宁工程技术大学 | Metal detonator tube shell hot stamping stretching method |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5515532A (en) * | 1978-07-18 | 1980-02-02 | Nippon Telegr & Teleph Corp <Ntt> | Character input system |
-
1983
- 1983-08-23 JP JP15251983A patent/JPS6046321A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS6046321A (en) | 1985-03-13 |
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