EP0362122A1 - Method of heat-straightening steel tubes - Google Patents
Method of heat-straightening steel tubes Download PDFInfo
- Publication number
- EP0362122A1 EP0362122A1 EP89730188A EP89730188A EP0362122A1 EP 0362122 A1 EP0362122 A1 EP 0362122A1 EP 89730188 A EP89730188 A EP 89730188A EP 89730188 A EP89730188 A EP 89730188A EP 0362122 A1 EP0362122 A1 EP 0362122A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- cooling
- straightening
- pipes
- rolling stock
- accelerated
- 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.)
- Granted
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Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21D3/00—Straightening or restoring form of metal rods, metal tubes, metal profiles, or specific articles made therefrom, whether or not in combination with sheet metal parts
Definitions
- the invention relates to a method for hot straightening steel pipes according to the preamble of claim 1 and a system for performing this method.
- the cooling of steel pipes from the rolling heat or from an elevated temperature after a heat treatment measure often leads to the pipes being warped, ie to an inadequate pipe geometry (eg poor straightness, ovality).
- a hot straightening process is carried out on such warped rolling stock, which takes place at such a high temperature that the Bauschinger effect can no longer be observed.
- the temperature of the rolling stock during the straightening process is therefore usually above about 300 ° C., but below A c1 or A r1 .
- the tensile strength of the straightened good is exceeded by suitably applying mechanical stresses in the straightening cross-section, so that a defined curvature of the straightened good is set (normalization curvature).
- the desired geometry is then achieved by alternate bending and counter-bending with a decreasing bending amplitude.
- a major disadvantage of the known hot straightening process is that the rolled material undergoes a more or less uncontrolled cooling in air after the straightening process and is uneven in accordance with the geometric conditions. This leads to the fact that the "ideal geometry" achieved in the straightening machine is partially lost again.
- Even complex cooling bed constructions in which, for example the rolling stock behind the straightening machine is kept in constant rotation in order to cool down evenly, cannot remedy this defect.
- steel pipes in which wall thickness fluctuations occur due to the manufacturing process due to the circumference and / or length, lead to cooling at different locations and consequently to different degrees of shrinkage, which result in permanent deformations of the warmer zones, so that, for example, an ovality arises.
- the object of the invention is therefore to develop a generic method so that these disadvantages are largely excluded.
- an installation for carrying out this method is to be specified.
- the basic idea of the invention is to be seen in that the geometry of the rolling stock obtained during hot straightening is maintained by, as it were, freezing this state as soon as possible after it has been reached. This freezing should take place as quickly as possible, that is to say in the form of a quenching process, to a temperature at which the geometry practically no longer changes as a result of cooling voltages when cooling further.
- the necessary cooling measures e.g. nozzle ring for the supply of water, air, emulsions and / or water / air mixtures
- part of the tube length in which the desired geometry has already been achieved is therefore already cooled while a part length is still being straightened and at the same time a third part length is even being done has not entered the straightener. So cooling is not waited until the entire pipe has run out of the straightener. Rather, the targeted quenching immediately after reaching the desired geometry in the individual length elements of the tube ensures that undesirable changes in geometry due to uncontrolled cooling do not occur. It is essential that the cooling takes place as evenly as possible over the cross-section of the pipes. In the case of pipes with a non-uniform cross-sectional geometry (e.g.
- the method according to the invention makes it possible to maintain a high degree of accuracy in the geometry of the pipes after hot straightening and thus to dispense with cold messaging, and moreover has the advantage that a complex cooling bed behind the straightening machine can be dispensed with.
Abstract
Description
Die Erfindung betrifft ein Verfahren zum Warmrichten von Stahlrohren entsprechend dem Gattungsbegriff des Patentanspruchs 1 sowie eine Anlage zur Durchführung dieses Verfahrens.The invention relates to a method for hot straightening steel pipes according to the preamble of claim 1 and a system for performing this method.
Das Abkühlen von Stahlrohren aus der Walzhitze oder von einer erhöhten Temperatur nach einer Wärmebehandlungsmaßnahme (z.B. Vergütung) führt häufig zum Verziehen der Rohre, d.h. zu einer unzulänglichen Rohrgeometrie (z.B. schlechte Geradheit, Ovalität). Um die durch das Walzen oder die Wärmebehandlung eingestellten mechanisch-technologischen Eigenschaften nicht zu gefährden, wird an derartig verzogenem Walzgut ein Warmrichtvorgang vorgenommen, der bei soweit erhöhter Temperatur stattfindet, daß der Bauschinger-Effekt nicht mehr beobachtet werden kann. Die Temperatur des Walzgutes liegt während des Richtvorgangs daher üblicherweise oberhalb von etwa 300oC, aber unterhalb Ac1 bzw. Ar1.The cooling of steel pipes from the rolling heat or from an elevated temperature after a heat treatment measure (eg tempering) often leads to the pipes being warped, ie to an inadequate pipe geometry (eg poor straightness, ovality). In order not to endanger the mechanical-technological properties set by the rolling or the heat treatment, a hot straightening process is carried out on such warped rolling stock, which takes place at such a high temperature that the Bauschinger effect can no longer be observed. The temperature of the rolling stock during the straightening process is therefore usually above about 300 ° C., but below A c1 or A r1 .
In einer Rollenrichtmaschine wird durch geeignetes Aufbringen mechanischer Spannungen im Richtquerschnitt die Streckgrenze des Richtgutes überschritten, so daß eine definierte Krümmung des Richtgutes eingestellt wird (Normierungskrümmung). Danach wird durch wechselweises Biegen und Gegenbiegen mit abklingender Biegeamplitude die gewünschte Geometrie erzielt.In a roller straightening machine, the tensile strength of the straightened good is exceeded by suitably applying mechanical stresses in the straightening cross-section, so that a defined curvature of the straightened good is set (normalization curvature). The desired geometry is then achieved by alternate bending and counter-bending with a decreasing bending amplitude.
Als großer Nachteil des bekannten Warmrichtverfahrens ist es anzusehen, daß das Walzgut nach dem Richtvorgang eine mehr oder weniger unkontrollierte und entsprechend den geometrischen Verhältnissen ungleichmäßige Abkühlung an Luft erfährt. Das führt nämlich dazu, daß die in der Richtmaschine erzielte "Ideal-Geometrie" teilweise wieder verlorengeht. Selbst aufwendige Kühlbettkonstruktionen, in denen z.B. das Walzgut hinter der Richtmaschine in ständiger Drehung gehalten wird, um gleichmäßig abzukühlen, vermögen diesen Mangel nicht zu beheben. So kommt es beispielsweise bei Stahlrohren, bei denen herstellungsbedingt über den Umfang und/oder die Länge Wanddickenschwankungen auftreten, zu örtlich unterschiedlich schneller Abkühlung und folglich unterschiedlich starken Schrumpfungen, die sich in bleibenden Verformungen der wärmeren Zonen auswirken, so daß z.B. eine Ovalität entsteht.A major disadvantage of the known hot straightening process is that the rolled material undergoes a more or less uncontrolled cooling in air after the straightening process and is uneven in accordance with the geometric conditions. This leads to the fact that the "ideal geometry" achieved in the straightening machine is partially lost again. Even complex cooling bed constructions, in which, for example the rolling stock behind the straightening machine is kept in constant rotation in order to cool down evenly, cannot remedy this defect. For example, steel pipes, in which wall thickness fluctuations occur due to the manufacturing process due to the circumference and / or length, lead to cooling at different locations and consequently to different degrees of shrinkage, which result in permanent deformations of the warmer zones, so that, for example, an ovality arises.
In Fällen, in denen eine hohe Maßhaltigkeit der Stahlrohre etwa für eine nachfolgende mechanische Bearbeitung (z.B. Gewindeschneiden an Ölfeldrohren) unbedingt erforderlich ist, muß daher häufig ein zusätzliches Kaltnachrichten angeschlossen werden. Dies ist jedoch nicht nur wegen des damit verbundenen Aufwandes hinsichtlich Zeit und Kosten unerwünscht, sondern kann auch die mechanisch-technologischen Eigenschaften infolge von Kaltverfestigungen negativ verändern. Darüberhinaus kann in den Verformungszonen auch die Korrosionsbeständigkeit beeinträchtigt werden.In cases where a high dimensional accuracy of the steel pipes is absolutely necessary for subsequent mechanical processing (e.g. tapping on oilfield pipes), an additional cold message must often be connected. However, this is not only undesirable because of the time and cost involved, but can also negatively change the mechanical-technological properties as a result of work hardening. In addition, the corrosion resistance can be impaired in the deformation zones.
Aus der DE-OS 22 62 140 ist es bekannt, Stahlhalbzeug wie Drähte, Stangen, Bleche oder Bänder, also Halbzeug mit Vollquerschnitt auf Temperaturen zwischen 149 und 480o C zu erwärmen und warm zu richten. Danach wird das Halbzeug einfach an Luft oder beschleunigt mit Hilfe von Flüssigkeit oder Druckluft abgekühlt. Die Durchführung des Richtvorgangs bei erhöhter Temperatur hat hierbei den Sinn, daß Werkstoffe, die einer Ausscheidungshärtung zugänglich sind, durch den Richtvorgang in ihren Festigkeitseigenschaften nicht beeinträchtigt werden sollen. An das Abkühlen des gerichteten Halbzeugs sind daher weder hinsichtlich des zeitlichen Abstandes zum Richtvorgang noch hinsichtlich der Kühlintensität besondere Anforderungen zu stellen. Insbesondere ergeben sich aus dieser Literaturstelle keinerlei Hinweise darauf, daß die im Richtprozeß erreichte Geometrie bei Stahlrohren durch eine gezielte Abkühlung konserviert werden könnte.From DE-OS 22 62 140 it is known to heat and straighten semi-finished steel products such as wires, rods, sheets or strips, that is to say semi-finished products with a full cross section, to temperatures between 149 and 480 ° C. Then the semi-finished product is simply cooled in air or accelerated with the help of liquid or compressed air. Carrying out the straightening process at elevated temperature has the sense that materials which are accessible for precipitation hardening should not be impaired in their strength properties by the straightening process. There are therefore no special requirements for cooling the straightened semi-finished product, either with regard to the time interval between the straightening process and with regard to the cooling intensity. In particular, there are no references from this reference insists that the geometry achieved in the straightening process for steel pipes could be preserved by targeted cooling.
Aufgabe der Erfindung ist es daher, ein gattungsgemäßes Verfahren so weiterzuentwickeln, daß diese Nachteile weitestgehend ausgeschlossen werden. Außerdem soll eine Anlage zur Durchführung dieses Verfahrens angegeben werden.The object of the invention is therefore to develop a generic method so that these disadvantages are largely excluded. In addition, an installation for carrying out this method is to be specified.
Gelöst wird diese Aufgabe hinsichtlich des Verfahrens mit den kennzelchnenden Merkmalen des Patentanspruchs 1; vorteilhafte Weiterbildungen sind in den Unteransprüchen 2 bis 6 angegeben. Eine erfindungsgemäße Anlage ist mit den Merkmalen des Patentanspruchs 7 ausgestattet und kann durch die kennzelchnenden Merkmale der Unteransprüche 8 und 9 weiter ausgestaltet werden.This object is achieved with regard to the method with the characterizing features of claim 1; Advantageous further developments are specified in subclaims 2 to 6. A system according to the invention is equipped with the features of claim 7 and can be further developed by the characterizing features of subclaims 8 and 9.
Der Grundgedanke der Erfindung ist darin zu sehen, daß die beim Warmrichten erzielte Geometrie des Walzgutes beibehalten wird, indem dieser Zustand möglichst kurz nach seinem Erreichen gleichsam eingefroren wird. Dieses Einfrieren soll dabei möglichst schnell, also in Form eines Abschreckvorgangs erfolgen, und zwar bis auf eine Temperatur, bei der sich die Geometrie durch Abkühlspannungen bei weiterer Abkühlung praktisch nicht mehr ändert. Daher müssen die erforderlichen Abkühlmaßnahmen (z.B. Düsenring für die Zufuhr von Wasser, Luft, Emulsionen und/oder Wasser/Luft-Gemischen) bereits im Auslaufbereich der Richtmaschlne getroffen werden. Bei einem einzelnen Stahlrohr wird daher ein Teil der Rohrlänge, in dem die gewünschte Geometrie bereits erreicht wurde, schon gekühlt, während eine Teillänge gerade noch gerichtet wird und gleichzeitig eine dritte Teillänge noch gar nicht in die Richtmaschine eingelaufen ist. Es wird also mit der Kühlung nicht so lange gewartet, bis das gesamte Rohr aus der Richtmaschine herausgelaufen ist. Vielmehr wird durch das gezielte Abschrecken unmittelbar nach Erreichen der gewünschten Geometrie in den einzelnen Längenelementen des Rohres sichergestellt, daß unerwünschte Geometrieänderungen infolge unkontrollierter Abkühlung nicht eintreten. Wesentlich ist, daß die Abkühlung möglichst gleichmäßig uber den Querschnitt der Rohre erfolgt. Bei Rohren mit ungleichmäßiger Querschnittsgeometrie (z.B. Oelfeldrohre mit angestauchten Enden) kann es erforderlich sein, zur Erzielung einer gleichmäßigen Abkühlung die Art und/oder die Menge des pro Zeiteinheit zugeführten Kühlmittels örtlich zu verändern, d.h. an den Wärmeinhalt der jeweiligen Kühlzone des Stahlrohres anzupassen. Bereiche mit geringerer Wanddicke sind schwächer zu beaufschlagen als Bereiche mit größerer Wanddicke.The basic idea of the invention is to be seen in that the geometry of the rolling stock obtained during hot straightening is maintained by, as it were, freezing this state as soon as possible after it has been reached. This freezing should take place as quickly as possible, that is to say in the form of a quenching process, to a temperature at which the geometry practically no longer changes as a result of cooling voltages when cooling further. The necessary cooling measures (e.g. nozzle ring for the supply of water, air, emulsions and / or water / air mixtures) must therefore already be taken in the outlet area of the straightening machine. In the case of a single steel tube, part of the tube length in which the desired geometry has already been achieved is therefore already cooled while a part length is still being straightened and at the same time a third part length is even being done has not entered the straightener. So cooling is not waited until the entire pipe has run out of the straightener. Rather, the targeted quenching immediately after reaching the desired geometry in the individual length elements of the tube ensures that undesirable changes in geometry due to uncontrolled cooling do not occur. It is essential that the cooling takes place as evenly as possible over the cross-section of the pipes. In the case of pipes with a non-uniform cross-sectional geometry (e.g. oil field pipes with swaged ends), it may be necessary to locally change the type and / or the amount of coolant supplied per unit of time to achieve uniform cooling, i.e. to adapt it to the heat content of the respective cooling zone of the steel pipe. Areas with a smaller wall thickness are weaker than areas with a larger wall thickness.
Das erfindungsgemäße Verfahren ermöglicht die Beibehaltung einer hohen Genauigkeit in der Geometrie der Rohre nach dem Warmrichten und somit den Verzicht auf ein Kaltnachrichten und bringt darüberhinaus den Vorteil mit sich, daß ein aufwendiges Kühlbett hinter der Richtmaschlne entfallen kann.The method according to the invention makes it possible to maintain a high degree of accuracy in the geometry of the pipes after hot straightening and thus to dispense with cold messaging, and moreover has the advantage that a complex cooling bed behind the straightening machine can be dispensed with.
Claims (9)
dadurch gekennzeichnet,
daß die Rohre unmittelbar nach Erreichen der geforderten Geometrie beschleunigt mindestens auf eine solche Temperatur abgekühlt werden, bei der kein Verziehen durch Abkühlspannungen infolge weiterer Abkühlung mehr eintritt.1. A process for the hot straightening of steel pipes in a roll straightening machine, in which the pipes have a temperature below A r1 or A c1 and at least 300 ° C. and are cooled to room temperature after straightening,
characterized,
that the pipes are accelerated to at least such a temperature immediately after reaching the required geometry at which there is no longer any distortion due to cooling stresses as a result of further cooling.
dadurch gekennzeichnet,
daß beim Richten von Stahlrohren mit unregelmäßigem Querschnitt bzw. ungleichmäßiger Wanddicke die Kühlleistung des zur Erzielung der beschleunigten Abkühlung auf das Walzgut aufgebrachten Kühlmittels in der Weise örtlich unterschiedlich eingestellt wird, daß die Wärmeabfuhr pro Volumeneinheit über den gesamten Querschnitt der Rohre etwa gleich ist.2. The method according to claim 1,
characterized,
that when straightening steel pipes with an irregular cross-section or uneven wall thickness, the cooling capacity of the coolant applied to the rolling stock to achieve the accelerated cooling is set locally differently in such a way that the heat dissipation per unit volume is approximately the same over the entire cross-section of the pipes.
dadurch gekennzeichnet,
daß das Abkühlen mit mindestens 30 K/s erfolgt.3. The method according to claim 1 or 2,
characterized,
that the cooling takes place with at least 30 K / s.
dadurch gekennzeichnet,
daß das Abkühlen mit mindestens 100 K/s erfolgt.4. The method according to claim 1 or 2,
characterized,
that the cooling takes place with at least 100 K / s.
dadurch gekennzeichnet,
daß die örtlich unterschiedlichen Kühlleistungen durch entsprechende Steuerung der spezifischen Kühlmittelmenge eingestellt werden.5. The method according to any one of claims 1 to 4,
characterized,
that the locally different cooling capacities are set by appropriate control of the specific amount of coolant.
dadurch gekennzeichnet,
daß die örtlich unterschiedlichen Kühlleistungen durch Beaufschlagung der Rohre mit örtlich unterschiedlichen Kühlmedien, insbesondere mit Wasser, Wasser/Luft-Gemisch, Emulsion oder Druckluft eingestellt werden.6. The method according to any one of claims 1 to 5,
characterized,
that the locally different cooling capacities are set by subjecting the pipes to locally different cooling media, in particular water, water / air mixture, emulsion or compressed air.
dadurch gekennzeichnet,
daß am Auslauf der Rollenrichtmaschine eine Vorrichtung für die Zuführung eines Kühlmittels zur beschleunigten Abkühlung des Walzgutes angeordnet ist.7. Plant for carrying out the method according to claim 1 with a roller straightening machine and optionally an upstream heating device for the pipes,
characterized,
that a device for supplying a coolant for accelerated cooling of the rolling stock is arranged at the outlet of the roller straightening machine.
dadurch gekennzeichnet,
daß die Abkühlvorrichtung als System von ringförmig angeordneten Düsen ausgebildet ist.8. Plant according to claim 7 for straightening, in particular, rotationally symmetrical rolling stock,
characterized,
that the cooling device is designed as a system of annularly arranged nozzles.
dadurch gekennzeichnet,
daß die Durchflußleistung der Düsen abschnittsweise oder einzeln regelbar ist.9. The device according to claim 8,
characterized,
that the flow rate of the nozzles can be regulated in sections or individually.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| AT89730188T ATE87515T1 (en) | 1988-09-27 | 1989-08-16 | PROCESS FOR HOT STRAIGHTENING OF STEEL PIPES. |
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE3833163 | 1988-09-27 | ||
| DE3833163 | 1988-09-27 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| EP0362122A1 true EP0362122A1 (en) | 1990-04-04 |
| EP0362122B1 EP0362122B1 (en) | 1993-03-31 |
Family
ID=6364031
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| EP89730188A Expired - Lifetime EP0362122B1 (en) | 1988-09-27 | 1989-08-16 | Method of heat-straightening steel tubes |
Country Status (4)
| Country | Link |
|---|---|
| EP (1) | EP0362122B1 (en) |
| AT (1) | ATE87515T1 (en) |
| DE (1) | DE58903947D1 (en) |
| ES (1) | ES2039933T3 (en) |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0967027A2 (en) * | 1998-06-27 | 1999-12-29 | Sms Schloemann-Siemag Aktiengesellschaft | Method for straightening steel sections while at the same time minimising the internal stress |
| DE19828785A1 (en) * | 1998-06-27 | 1999-12-30 | Schloemann Siemag Ag | Process for straightening profile steel |
| KR100878735B1 (en) * | 2006-07-12 | 2009-01-14 | 닛토덴코 가부시키가이샤 | Polarizing plate with optical compensation layer, method of producing the same, and liquid crystal panel, liquid crystal display, and image display including the same |
| CN104668316A (en) * | 2015-02-25 | 2015-06-03 | 成都易态科技有限公司 | Method and device for out-of-furnace straightening of sintered blank |
| CN113996888A (en) * | 2021-11-24 | 2022-02-01 | 中冶陕压重工设备有限公司 | Welding repair method for machining deformation of support roller bearing seat |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE888401C (en) * | 1943-07-20 | 1953-08-31 | Administration Sequestre Des R | Process for straightening workpieces |
| DE914862C (en) * | 1942-12-29 | 1954-08-09 | Hohenlimburger Walzwerke Ag | Continuous process and device for hardening, tempering and bending profile bars |
| GB748357A (en) * | 1953-06-01 | 1956-05-02 | Somerset Wire Company Ltd | Improvements in the manufacture of wire and the like |
| GB1038359A (en) * | 1964-05-27 | 1966-08-10 | Drever Co | Roller pressure quench system |
| DE2262140A1 (en) * | 1972-12-19 | 1974-06-20 | Lasalle Steel Co | Deforming steels - without reducing their strength |
-
1989
- 1989-08-16 AT AT89730188T patent/ATE87515T1/en not_active IP Right Cessation
- 1989-08-16 DE DE8989730188T patent/DE58903947D1/en not_active Expired - Fee Related
- 1989-08-16 ES ES198989730188T patent/ES2039933T3/en not_active Expired - Lifetime
- 1989-08-16 EP EP89730188A patent/EP0362122B1/en not_active Expired - Lifetime
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE914862C (en) * | 1942-12-29 | 1954-08-09 | Hohenlimburger Walzwerke Ag | Continuous process and device for hardening, tempering and bending profile bars |
| DE888401C (en) * | 1943-07-20 | 1953-08-31 | Administration Sequestre Des R | Process for straightening workpieces |
| GB748357A (en) * | 1953-06-01 | 1956-05-02 | Somerset Wire Company Ltd | Improvements in the manufacture of wire and the like |
| GB1038359A (en) * | 1964-05-27 | 1966-08-10 | Drever Co | Roller pressure quench system |
| DE2262140A1 (en) * | 1972-12-19 | 1974-06-20 | Lasalle Steel Co | Deforming steels - without reducing their strength |
Non-Patent Citations (1)
| Title |
|---|
| PATENT ABSTRACTS OF JAPAN, Band 8, Nr. 50 (M-281)[1487], 7. März 1987; & JP-A-58 202 915 (SUMITOMO KINZOKU KOGYO K.K.) 26-11-1983 * |
Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0967027A2 (en) * | 1998-06-27 | 1999-12-29 | Sms Schloemann-Siemag Aktiengesellschaft | Method for straightening steel sections while at the same time minimising the internal stress |
| DE19828785A1 (en) * | 1998-06-27 | 1999-12-30 | Schloemann Siemag Ag | Process for straightening profile steel |
| EP0967026A3 (en) * | 1998-06-27 | 2000-07-05 | SMS Demag AG | Method for straightening steel sections |
| EP0967027A3 (en) * | 1998-06-27 | 2000-07-05 | SMS Demag AG | Method for straightening steel sections while at the same time minimising the internal stress |
| DE19828785C2 (en) * | 1998-06-27 | 2000-08-03 | Sms Demag Ag | Process for straightening rolled section steel |
| KR100878735B1 (en) * | 2006-07-12 | 2009-01-14 | 닛토덴코 가부시키가이샤 | Polarizing plate with optical compensation layer, method of producing the same, and liquid crystal panel, liquid crystal display, and image display including the same |
| US7557883B2 (en) | 2006-07-12 | 2009-07-07 | Nitto Denko Corporation | Polarizing plate with optical compensation layer, method of producing the same, and liquid crystal panel, liquid crystal display, and image display including the same |
| CN104668316A (en) * | 2015-02-25 | 2015-06-03 | 成都易态科技有限公司 | Method and device for out-of-furnace straightening of sintered blank |
| CN113996888A (en) * | 2021-11-24 | 2022-02-01 | 中冶陕压重工设备有限公司 | Welding repair method for machining deformation of support roller bearing seat |
Also Published As
| Publication number | Publication date |
|---|---|
| DE58903947D1 (en) | 1993-05-06 |
| ES2039933T3 (en) | 1993-10-01 |
| EP0362122B1 (en) | 1993-03-31 |
| ATE87515T1 (en) | 1993-04-15 |
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