EP0370588A1 - Method for producing high-strength seamless steel pipes - Google Patents
Method for producing high-strength seamless steel pipes Download PDFInfo
- Publication number
- EP0370588A1 EP0370588A1 EP89250030A EP89250030A EP0370588A1 EP 0370588 A1 EP0370588 A1 EP 0370588A1 EP 89250030 A EP89250030 A EP 89250030A EP 89250030 A EP89250030 A EP 89250030A EP 0370588 A1 EP0370588 A1 EP 0370588A1
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- European Patent Office
- Prior art keywords
- steel
- temperature
- tubes
- max
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Links
- 229910000831 Steel Inorganic materials 0.000 title claims abstract description 15
- 239000010959 steel Substances 0.000 title claims abstract description 15
- 238000004519 manufacturing process Methods 0.000 title abstract description 4
- 239000000203 mixture Substances 0.000 claims abstract description 3
- 238000001816 cooling Methods 0.000 claims description 14
- 238000000034 method Methods 0.000 claims description 8
- 238000005096 rolling process Methods 0.000 claims description 7
- 230000015572 biosynthetic process Effects 0.000 claims description 5
- 238000005098 hot rolling Methods 0.000 claims description 5
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 4
- 229910052804 chromium Inorganic materials 0.000 claims description 4
- 229910000859 α-Fe Inorganic materials 0.000 claims description 4
- 229910052799 carbon Inorganic materials 0.000 claims description 3
- 229910052750 molybdenum Inorganic materials 0.000 claims description 3
- 229910052802 copper Inorganic materials 0.000 claims description 2
- 239000012535 impurity Substances 0.000 claims description 2
- 229910052742 iron Inorganic materials 0.000 claims description 2
- 229910052748 manganese Inorganic materials 0.000 claims description 2
- 229910052759 nickel Inorganic materials 0.000 claims description 2
- 229910052758 niobium Inorganic materials 0.000 claims description 2
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 claims 1
- 229910052782 aluminium Inorganic materials 0.000 claims 1
- 229910052710 silicon Inorganic materials 0.000 claims 1
- 239000010703 silicon Substances 0.000 claims 1
- 238000010438 heat treatment Methods 0.000 abstract description 6
- 239000000463 material Substances 0.000 description 4
- 229910045601 alloy Inorganic materials 0.000 description 3
- 239000000956 alloy Substances 0.000 description 3
- 229910001563 bainite Inorganic materials 0.000 description 3
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 2
- 239000008186 active pharmaceutical agent Substances 0.000 description 2
- 238000005275 alloying Methods 0.000 description 2
- 238000005266 casting Methods 0.000 description 2
- 229910000734 martensite Inorganic materials 0.000 description 2
- 238000010791 quenching Methods 0.000 description 2
- 230000000171 quenching effect Effects 0.000 description 2
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 1
- 239000010949 copper Substances 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 230000018109 developmental process Effects 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000010606 normalization Methods 0.000 description 1
- 238000001953 recrystallisation Methods 0.000 description 1
- 238000005496 tempering Methods 0.000 description 1
- 229910052720 vanadium Inorganic materials 0.000 description 1
Images
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
Definitions
- the invention relates to a method for producing high-strength seamless steel tubes by hot rolling and subsequent accelerated cooling from the rolling heat.
- These pipes should be used as oilfield and line pipes and at least comply with API quality level X70.
- Seamless tubes are usually produced by hot rolling steel blocks that have been heated to around 1200 - 1250 o .
- the main forming of the rolling process takes place just below the block drawing temperature, i.e. at very high temperatures.
- the recrystallization of the structure caused by the deformation leads to strong grain growth due to these high temperatures and consequently to a corresponding deterioration in the toughness behavior of the materials. It has therefore always been considered necessary to connect a separate heat treatment in the form of a normalization or tempering treatment to the rolling process, in which a finer structure and thereby an improvement in the toughness properties is achieved by re-grain.
- Such heat treatment requires a significant amount of time and money, so it is desirable to find a way to avoid this additional treatment.
- a bainitic structure provides good toughness properties.
- this route has so far not been practical for large-scale use because the temperature control during the accelerated cooling could not take place in such a way that the bainite region was reached safely.
- the object of the invention is therefore to provide a method of the generic type with which seamless tubes with high yield strengths and high tensile strengths can be produced with good toughness properties (A v + 20 ° C > 60 J) (API quality level X70 or higher), without having to undergo additional heat treatment after rolling.
- a v + 20 ° C > 60 J API quality level X70 or higher
- temperature differences in the rolled tube of at least 100-150 K should be permissible without the required properties being called into question, and the material used should be inexpensive to produce, so it does not require large amounts of expensive alloying elements.
- the solution according to the invention essentially consists of a targeted selection of materials with narrow limits for the individual alloy elements and predetermined design rules for individual elements with one another, and a quenching treatment tailored to this material.
- a steel was found which is not only inexpensive to produce because it does not require large amounts of expensive alloying elements, but which surprisingly ensures the formation of bainite over a wide temperature interval (e.g. 150 K) of cooling (capture temperature).
- the formation of ferrite can easily be limited to uncritical values of less than 10% structure. It was found that the ratio of the elements copper and nickel to one another and the sum of the contents of Cr and Mo are extremely important for the cooling behavior with regard to achieving uniform strength and toughness values. This also applies to the narrowly limited content of carbon.
- the method according to the invention enables the production of high-strength steel pipes as oilfield and conduit pipes using an inexpensive alloy and in spite of the absence of a (costly) separate heat treatment, and by accelerated cooling from the rolling heat even on pipes that have an uneven temperature distribution, certainly a bainitic Microstructure with good toughness properties is generated over the entire pipe length. Differences in the interception temperature of up to 150 K and, depending on the setting of the alloy, also beyond do not have a critical effect on the strength and toughness properties.
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Crystallography & Structural Chemistry (AREA)
- Mechanical Engineering (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Heat Treatment Of Steel (AREA)
- Heat Treatment Of Articles (AREA)
Abstract
Description
Die Erfindung betrifft ein Verfahren zur Herstellung hochfester nahtloser Rohre aus Stahl durch Warmwalzen und anschließendes beschleunigtes Abkühlen aus der Walzhitze. Diese Rohre sollen als Ölfeld- und Leitungsrohre einsetzbar sein und mindestens der API-Gütestufe X70 entsprechen.The invention relates to a method for producing high-strength seamless steel tubes by hot rolling and subsequent accelerated cooling from the rolling heat. These pipes should be used as oilfield and line pipes and at least comply with API quality level X70.
Die Herstellung nahtloser Rohre erfolgt üblicherweise durch Warmwalzen von Stahlblöcken, die auf etwa 1200 - 1250o erwärmt wurden. Die Hauptumformung des Walzprozesses findet dicht unterhalb der Blockziehtemperatur, also bei sehr hohen Temperaturen statt. Die durch die Verformung verursachte Rekristallisation des Gefüges führt aufgrund dieser hohen Temperaturen zu einem starken Kornwachstum und infolge dessen zu einer entsprechenden Verschlechterung des Zähigkeitsverhaltens der Werkstoffe. Es ist daher bisher stets als erforderlich angesehen worden, an den Walzprozeß eine gesonderte Wärmebehandlung in Form einer Normalisierungs- oder Vergütungsbehandlung anzuschließen, bei der durch Umkörnung ein feineres Gefüge und dadurch eine Verbesserung der Zähigkeitseigenschaften erreicht wird.Seamless tubes are usually produced by hot rolling steel blocks that have been heated to around 1200 - 1250 o . The main forming of the rolling process takes place just below the block drawing temperature, i.e. at very high temperatures. The recrystallization of the structure caused by the deformation leads to strong grain growth due to these high temperatures and consequently to a corresponding deterioration in the toughness behavior of the materials. It has therefore always been considered necessary to connect a separate heat treatment in the form of a normalization or tempering treatment to the rolling process, in which a finer structure and thereby an improvement in the toughness properties is achieved by re-grain.
Eine solche Wärmebehandlung erfordert einen erheblichen Aufwand an Zeit und Kosten, so daß es wünschenswert ist, einen Weg zu finden, diese Zusatzbehandlung zu vermeiden. Grundsätzlich bietet es sich an, durch eine gezielte Abkühlung nach dem Warmwalzen im Rohr ein bainitisches Gefüge zu erzeugen, also sowohl die Ferritbildung als auch die Martensitbildung weitestgehend zu vermeiden. Ein bainitisches Gefüge liefert neben hohen Festigkeitskennwerten gute Zähigkeitseigenschaften. Dieser Weg ist jedoch bisher für einen großtechnischen Einsatz nicht praktikabel gewesen, weil die Temperaturführung während der beschleunigten Abkühlung nicht so erfolgen konnte, daß das Bainitgebiet sicher erreicht wurde.Such heat treatment requires a significant amount of time and money, so it is desirable to find a way to avoid this additional treatment. Basically, it is advisable to generate a bainitic structure in the tube by targeted cooling after hot rolling, that is, to largely avoid both ferrite formation and martensite formation. In addition to high strength values, a bainitic structure provides good toughness properties. However, this route has so far not been practical for large-scale use because the temperature control during the accelerated cooling could not take place in such a way that the bainite region was reached safely.
Dies liegt daran, daß die einzelnen Stahlrohre unvermeidbar am Ende der letzten Walzstufe stets nicht nur untereinander unterschiedliche Temperaturen aufweisen; es bestehen auch erhebliche Temperaturdifferenzen über die Rohrlänge und sogar über den Rohrumfang. Diese Temperaturdifferenzen betragen typischerweise bis zu 100oC und lassen sich am Ende der beschleunigten Abkühlung in nahezu unveränderter Größe auf dem Rohr wiederfinden. Es kann also praktisch keine fixe Abkühltemperatur angestrebt werden. Das aber bedeutet, daß durch die Abkühlung nur in einzelnen Zonen des Rohres das Bainitgebiet in der gewünschten Weise erreicht wird, während in anderen Zonen Ferrit (durch zu langsame bzw. nicht ausreichend tiefe Abkühlung) oder Martensit (durch zu tiefe Abkühlung) entsteht. Insgesamt weisen solche Rohre örtlich außerordentlich stark abweichende Zähigkeits- und Festigkeitseigenschaften auf und sind für die vorgesehene Verwendung nicht geeignet.This is because the individual steel tubes inevitably do not only have different temperatures at the end of the last rolling stage; there are also significant temperature differences across the length of the pipe and even over the pipe circumference. These temperature differences are typically up to 100 o C and can be found on the pipe in almost unchanged size at the end of the accelerated cooling. So practically no fixed cooling temperature can be aimed for. However, this means that the bainite area is reached in the desired manner by cooling only in individual zones of the tube, while ferrite (due to cooling that is too slow or not sufficiently deep) or martensite (due to cooling too deep) is produced in other zones. Overall, such pipes have extremely different toughness and strength properties and are not suitable for the intended use.
Aufgabe der Erfindung ist es daher, ein Verfahren der gattungsgemäßen Art anzugeben, mit dem nahtlose Rohre mit hohen Streckgrenzen und hohen Zugfestigkeiten bei gleichzeitig guten Zähigkeitseigenschaften (Av+20°C > 60 J) (API-Gütestufe X70 oder höher) herstellbar sind, ohne daß diese nach dem Walzen einer zusätzlichen Wärmebehandlung unterzogen werden müssen. Dabei sollen Temperaturunterschiede im gewalzten Rohr von mindestens 100 - 150 K zulässig sein, ohne daß die geforderten Eigenschaften in Frage gestellt werden, und der verwendete Werkstoff soll preiswert herstellbar sein, also keine größeren Mengen an teuren Legierungselementen erfordern.The object of the invention is therefore to provide a method of the generic type with which seamless tubes with high yield strengths and high tensile strengths can be produced with good toughness properties (A v + 20 ° C > 60 J) (API quality level X70 or higher), without having to undergo additional heat treatment after rolling. At the same time, temperature differences in the rolled tube of at least 100-150 K should be permissible without the required properties being called into question, and the material used should be inexpensive to produce, so it does not require large amounts of expensive alloying elements.
Gelöst wird diese Aufgabe erfindungsgemäß durch ein Verfahren mit den Merkmalen des Patentanspruchs 1; vorteilhafte Weiterbildungen dieses Verfahrens sind in den Unteransprüchen 2 und 3 angegeben.This object is achieved according to the invention by a method having the features of patent claim 1; Advantageous developments of this method are specified in subclaims 2 and 3.
Die erfindungsgemäße Lösung besteht im wesentlichen aus einer gezielten Werkstoffauswahl mit enggesetzten Grenzen für die einzelnen Legierungselemente und vorgegebenen Bemessungsregeln für einzelne Elemente untereinander sowie einer auf diesen Werkstoff abgestimmten Abschreckbehandlung. Es konnte ein Stahl gefunden werden, der nicht nur preiswert herstellbar ist, weil er keine größeren Mengen teurer Legierungselemente erfordert, sondern der überraschenderweise über ein breites Temperaturintervall (z.B. 150 K) der Abkühlung (Abfangtemperatur) die Bildung von Bainit gewährleistet. Die Entstehung von Ferrit kann problemlos auf unkritische Werte von unter 10 % Gefügeanteil beschränkt werden. Es wurde festgestellt, daß dem Verhältnis der Elemente Kupfer und Nickel untereinander sowie der Summe der Gehalte an Cr und Mo für das Abkühlverhalten hinsichtlich der Erzielung gleichmäßiger Festigkeits- und Zähigkeitswerte eine außerordentliche Bedeutung zukommt. Dies gilt ebenfalls für den engbegrenzten Gehalt an Kohlenstoff. Bei Einhaltung der vorgegebenen Analyse erhält man einen Stahl, der hinsichtlich der Endtemperatur der Abschreckbehandlung in einem breiten Temperaturintervall praktisch gleichmäßig gute Werte liefert. Dabei ist es gleichgültig, in welchem Zustand die Einsatzblöcke vorliegen (z.B. Gußblöcke, Rundstrangguß, gerundeter Vierkantstrangguß, gewalzter Rundstahl).The solution according to the invention essentially consists of a targeted selection of materials with narrow limits for the individual alloy elements and predetermined design rules for individual elements with one another, and a quenching treatment tailored to this material. A steel was found which is not only inexpensive to produce because it does not require large amounts of expensive alloying elements, but which surprisingly ensures the formation of bainite over a wide temperature interval (e.g. 150 K) of cooling (capture temperature). The formation of ferrite can easily be limited to uncritical values of less than 10% structure. It was found that the ratio of the elements copper and nickel to one another and the sum of the contents of Cr and Mo are extremely important for the cooling behavior with regard to achieving uniform strength and toughness values. This also applies to the narrowly limited content of carbon. If the given analysis is followed, a steel is obtained which delivers practically uniformly good values with regard to the final temperature of the quenching treatment over a wide temperature range. It does not matter what condition the insert blocks are in (e.g. cast blocks, round casting, rounded square casting, rolled round steel).
Die Wirksamkeit des erfindungsgemäßen Verfahrens wird anhand der für ein Ausführungsbeispiel in den Figuren 1 und 2 dargestellten Werte der Zugfestigkeit Rm und der Streckgrenze Rt0,5 bzw. der Kerbschlagarbeit Av+20°C in Abhängigkeit von der Abfangtemperatur der beschleunigten Abkühlung deutlich erkennbar. Die ermittelten Werte beziehen sich auf einen Stahl mit folgender Zusammensetzung:
0,09 % C
1,5 % Mn
0,25 % Cr
0,06 % V
0,04 % Nb
0,016 % P
0,003 % S
Rest Eisen und übliche VerunreinigungenThe effectiveness of the method according to the invention can be clearly seen on the basis of the values of the tensile strength R m and the yield strength R t0.5 or the notched impact energy A v + 20 ° C. for an exemplary embodiment shown in FIGS. 1 and 2, depending on the interception temperature of the accelerated cooling . The values determined relate to a steel with the following composition:
0.09% C
1.5% Mn
0.25% Cr
0.06% V
0.04% Nb
0.016% P
0.003% S
Balance iron and usual impurities
Wie aus Figur 1 hervorgeht, liegen die Meßwerte der Streckgrenze und der Zugfestigkeit in einem Abfangtemperaturbereich von 350 - 520oC nahezu auf gleichbleibendem Niveau. Die Streckgrenzenverhältnisse Rt0,5/Rm liegen durchweg unter 80 %. Trotz des groben Ausgangsgefüges liefert der Stahl mit der erfindungsgemäßen Abkühlbehandlung gute Kerbschlagarbeitswerte (Figur 2). Im Intervall der Abfangtemperatur von 350 - 520oC beträgt diese bei einer Prüftemperatur von +20oC stets deutlich mehr als 60 J.As is apparent from Figure 1, the measured values of yield strength and tensile strength are in a Abfangtemperaturbereich 350-520 o C almost at the same level. The yield point ratios R t0.5 / R m are consistently below 80%. Despite the rough starting structure, the steel with the cooling treatment according to the invention provides good impact energy values (FIG. 2). In the interval of the interception temperature of 350 - 520 o C, this is always significantly more than 60 J at a test temperature of +20 o C
Das erfindungsgemäße Verfahren ermöglicht unter Verwendung einer preiswerten Legierung und trotz Verzichts auf eine (kostenaufwendige) gesonderte Wärmebehandlung die Herstellung hochfester Stahlrohre als Ölfeld- und Leitungsrohre, wobei durch beschleunigte Abkühlung aus der Walzhitze auch an solchen Rohren, die eine ungleichmäßige Temperaturverteilung aufweisen, sicher ein bainitisches Gefüge mit guten Zähigkeitseigenschaften über die gesamte Rohrlänge erzeugt wird. Unterschiede in der Abfangtemperatur von bis zu 150 K und je nach Einstellung der Legierung auch darüber hinaus wirken sich dabei nicht kritisch auf die Festigkeits- und Zähigkeitseigenschaften aus.The method according to the invention enables the production of high-strength steel pipes as oilfield and conduit pipes using an inexpensive alloy and in spite of the absence of a (costly) separate heat treatment, and by accelerated cooling from the rolling heat even on pipes that have an uneven temperature distribution, certainly a bainitic Microstructure with good toughness properties is generated over the entire pipe length. Differences in the interception temperature of up to 150 K and, depending on the setting of the alloy, also beyond do not have a critical effect on the strength and toughness properties.
Claims (3)
0,08 - 0,13 % C
1,40 - 1,90 % Mn
0 - 0,50 % Cr
0 - 0,50 % Mo
0 - 0,70 % Ni
0 - 0,40 % Cu
0,04 - 0,13 % V
max. 0,020 % P
max. 0,010 % S
Rest Eisen und übliche Verunreinigungen,
wobei die Summe der Gehalte an Cr und Mo im Bereich 0,20 bis 0,70 % liegt und das Mengenverhältnis Cu/Ni bei Vorhandensein beider Elemente auf maximal 1 beschränkt ist.
0.08 - 0.13% C
1.40 - 1.90% Mn
0 - 0.50% Cr
0 - 0.50% Mo
0 - 0.70% Ni
0-0.40% Cu
0.04 - 0.13% V
Max. 0.020% P
Max. 0.010% S
Remainder iron and usual impurities,
where the sum of the Cr and Mo contents is in the range 0.20 to 0.70% and the Cu / Ni ratio is limited to a maximum of 1 if both elements are present.
dadurch gekennzeichnet,
daß dem Stahl maximal 0,04 % Nb zugesetzt wird.2. The method according to claim 1,
characterized,
that a maximum of 0.04% Nb is added to the steel.
dadurch gekennzeichnet,
daß dem Stahl maximal 0,04 % Ti zugesetzt wird.3. The method according to claim 1 or 2,
characterized,
that a maximum of 0.04% Ti is added to the steel.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| AT89250030T ATE89869T1 (en) | 1988-09-16 | 1989-09-07 | PROCESS FOR MANUFACTURING HIGH-STRENGTH SEAMLESS STEEL PIPES. |
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE3832014 | 1988-09-16 | ||
| DE3832014A DE3832014C2 (en) | 1988-09-16 | 1988-09-16 | Process for the production of high-strength seamless steel tubes |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| EP0370588A1 true EP0370588A1 (en) | 1990-05-30 |
| EP0370588B1 EP0370588B1 (en) | 1993-05-26 |
Family
ID=6363380
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| EP89250030A Expired - Lifetime EP0370588B1 (en) | 1988-09-16 | 1989-09-07 | Method for producing high-strength seamless steel pipes |
Country Status (5)
| Country | Link |
|---|---|
| US (1) | US5019180A (en) |
| EP (1) | EP0370588B1 (en) |
| JP (1) | JPH02115318A (en) |
| AT (1) | ATE89869T1 (en) |
| DE (2) | DE3832014C2 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0526330A1 (en) * | 1991-07-30 | 1993-02-03 | Ascometal | Process for making thinwalled tubes, steel for making these tubes and so produced tubes for bicycle frames |
Families Citing this family (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2711163B2 (en) * | 1990-01-12 | 1998-02-10 | 新日本製鐵株式会社 | Method for producing high corrosion resistant low alloy linepipe steel with excellent corrosion resistance |
| AT902U1 (en) * | 1995-08-28 | 1996-07-25 | Plansee Ag | METHOD FOR PRODUCING SEAMLESS TUBES |
| US20020011284A1 (en) * | 1997-01-15 | 2002-01-31 | Von Hagen Ingo | Method for making seamless tubing with a stable elastic limit at high application temperatures |
| DE102008011856A1 (en) * | 2008-02-28 | 2009-09-10 | V&M Deutschland Gmbh | High strength low alloy steel for seamless tubes with excellent weldability and corrosion resistance |
| CN101829679B (en) * | 2009-03-09 | 2013-09-04 | 鞍钢股份有限公司 | Production method for improving impact toughness of hot-rolled oil well pipe coupling material |
| CN103627887B (en) * | 2013-08-28 | 2015-06-03 | 内蒙古北方重工业集团有限公司 | Thermal processing method for eliminating carbide precipitation of low-carbon low-alloy heat-resisting steel |
| CN106676391A (en) * | 2016-12-12 | 2017-05-17 | 中国长江三峡集团公司 | Main shaft forge piece of large-sized water-turbine generator set |
| CN106591720A (en) * | 2016-12-12 | 2017-04-26 | 中国长江三峡集团公司 | Large water-turbine generator set spindle forged piece |
| CN109001106B (en) * | 2018-06-05 | 2022-04-22 | 长江三峡技术经济发展有限公司 | Method for effectively checking impact absorption energy of high-strength hot-rolled magnetic yoke steel plate of hydraulic generator |
| CN113249553B (en) * | 2021-06-25 | 2021-11-05 | 宁波威乐新材料科技有限公司 | Quenching method and hot forming process of steel and steel workpiece |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| AT193914B (en) * | 1954-06-02 | 1957-12-10 | Oesterr Alpine Montan | Steel for reinforcement in construction |
| FR1566594A (en) * | 1968-03-22 | 1969-05-09 | ||
| CH507373A (en) * | 1968-01-31 | 1971-05-15 | Mitsubishi Heavy Ind Ltd | Process for the production of a high tensile strength weldable steel |
| DE2649019B2 (en) * | 1976-06-14 | 1979-10-25 | Nippon Steel Corp., Tokio | Method of making seamless tubes |
| EP0092629A1 (en) * | 1982-04-22 | 1983-11-02 | Ugine Savoie | Process for the manufacture of rods and tubes from steels with great mechanical properties |
| GB2137539A (en) * | 1983-03-28 | 1984-10-10 | Mannesmann Ag | Manufacturing seamless steel pipe |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5397922A (en) * | 1977-02-08 | 1978-08-26 | Nippon Kokan Kk <Nkk> | Manufacture of non-refined high tensile steel |
-
1988
- 1988-09-16 DE DE3832014A patent/DE3832014C2/en not_active Expired - Fee Related
-
1989
- 1989-09-07 DE DE8989250030T patent/DE58904493D1/en not_active Expired - Fee Related
- 1989-09-07 EP EP89250030A patent/EP0370588B1/en not_active Expired - Lifetime
- 1989-09-07 AT AT89250030T patent/ATE89869T1/en not_active IP Right Cessation
- 1989-09-11 JP JP1235473A patent/JPH02115318A/en active Pending
-
1990
- 1990-02-07 US US07/477,047 patent/US5019180A/en not_active Expired - Fee Related
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| AT193914B (en) * | 1954-06-02 | 1957-12-10 | Oesterr Alpine Montan | Steel for reinforcement in construction |
| CH507373A (en) * | 1968-01-31 | 1971-05-15 | Mitsubishi Heavy Ind Ltd | Process for the production of a high tensile strength weldable steel |
| FR1566594A (en) * | 1968-03-22 | 1969-05-09 | ||
| DE2649019B2 (en) * | 1976-06-14 | 1979-10-25 | Nippon Steel Corp., Tokio | Method of making seamless tubes |
| EP0092629A1 (en) * | 1982-04-22 | 1983-11-02 | Ugine Savoie | Process for the manufacture of rods and tubes from steels with great mechanical properties |
| GB2137539A (en) * | 1983-03-28 | 1984-10-10 | Mannesmann Ag | Manufacturing seamless steel pipe |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0526330A1 (en) * | 1991-07-30 | 1993-02-03 | Ascometal | Process for making thinwalled tubes, steel for making these tubes and so produced tubes for bicycle frames |
| FR2679924A1 (en) * | 1991-07-30 | 1993-02-05 | Ascometal Sa | PROCESS FOR MANUFACTURING A THIN-WALL STEEL TUBE, STEEL FOR PRODUCING THE TUBE AND TUBE FOR A CYCLE FRAME OBTAINED |
Also Published As
| Publication number | Publication date |
|---|---|
| ATE89869T1 (en) | 1993-06-15 |
| DE58904493D1 (en) | 1993-07-01 |
| US5019180A (en) | 1991-05-28 |
| JPH02115318A (en) | 1990-04-27 |
| EP0370588B1 (en) | 1993-05-26 |
| DE3832014A1 (en) | 1990-03-22 |
| DE3832014C2 (en) | 1994-11-24 |
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