EP0308361A1 - Process for manufacturing steel pressure vessels - Google Patents

Process for manufacturing steel pressure vessels Download PDF

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Publication number
EP0308361A1
EP0308361A1 EP88730190A EP88730190A EP0308361A1 EP 0308361 A1 EP0308361 A1 EP 0308361A1 EP 88730190 A EP88730190 A EP 88730190A EP 88730190 A EP88730190 A EP 88730190A EP 0308361 A1 EP0308361 A1 EP 0308361A1
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EP
European Patent Office
Prior art keywords
steel
pressure vessels
maximum
titanium
steel pressure
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
Application number
EP88730190A
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German (de)
French (fr)
Other versions
EP0308361B1 (en
Inventor
Ingo Dr.-Ing. Von Hagen
Ekkehardt Dipl.-Ing. Schnabel
Axel Dr.Mont. Kulgemeyer
Dieter Dr.-Ing. Vespermann
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Vodafone GmbH
Original Assignee
Mannesmann AG
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Filing date
Publication date
Application filed by Mannesmann AG filed Critical Mannesmann AG
Priority to AT88730190T priority Critical patent/ATE95844T1/en
Publication of EP0308361A1 publication Critical patent/EP0308361A1/en
Application granted granted Critical
Publication of EP0308361B1 publication Critical patent/EP0308361B1/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/04—Ferrous alloys, e.g. steel alloys containing manganese
    • 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
    • C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
    • C21D1/18—Hardening; Quenching with or without subsequent tempering
    • 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
    • C21D9/0068—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for particular articles not mentioned below

Definitions

  • the invention relates to a method for producing pressure vessels from steel according to the preamble of patent claim 1.
  • tempered steels such as material 34 CrMo4 are generally used in pressure vessel construction.
  • the object of the invention is therefore to provide a method with which pressure vessels can be produced which do not have these disadvantages.
  • a reduction in the pressure vessel weight should be made possible by increased strength properties (reduction in wall thicknesses) with sufficient safety and at low costs, the material used having good welding properties and at least the following strength and toughness parameters transverse to the direction of deformation: 0.2% - proof stress over 900 N / mm2 Proof stress ratio maximum 95% Constriction at least 16% ISO V impact energy at +20 ° C over 80 J ISO V impact energy at -60 ° C over 36 J
  • the tempering steel used according to the invention can be welded without problems, ie hot-crack-free, using the customary methods.
  • it can be oil and water tempered.
  • extraordinarily good strength and toughness values result. Some of these clearly exceed the set limit values.
  • a titanium / nitrogen ratio of 3.6 to 6.5 is required to maximize the strengthening effect of boron.
  • the addition of up to 0.04% niobium can further increase the fine-grained nature and thus the toughness of the steel according to the invention
  • the proof stress ratio can increase to approximately 95% in the steel according to the invention, there is still sufficient security against disassembly of the container, because the fracture neck can be kept at least at least 16%. It is particularly important that the impact energy at -60 ° C across the deformation direction (ISO-V impact test) is over 36 J. This also makes the material suitable for use at low temperatures, such as those found under arctic conditions.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Thermal Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Physics & Mathematics (AREA)
  • Heat Treatment Of Articles (AREA)
  • Pressure Vessels And Lids Thereof (AREA)
  • Treatment Of Steel In Its Molten State (AREA)
  • Filling Or Discharging Of Gas Storage Vessels (AREA)

Abstract

To simplify the manufacture of pressure vessels and to enhance the properties thereof, a steel is proposed which has a composition of 0.15 - 0.26% of carbon 1.25 - 2.00% of manganese 0.2 - 0.5% of silicon at most 0.02% of phosphorus at most 0.005% of sulphur 0.1 - 0.5% of molybdenum 0.010 - 0.035% of titanium 0.0030 - 0.0100% of N 0.001 - 0.003% of boron 0 - 0.04% of niobium, the remainder being iron and usual impurities, the titanium content/nitrogen content ratio being adjusted to between 3.6 and 6.5. The invention also relates to a heat treatment process for the vessels manufactured from this steel.

Description

Die Erfindung betrifft ein Verfahren zur Herstellung von Druckbehältern aus Stahl gemäß dem Oberbegriff des Patent­anspruchs 1.The invention relates to a method for producing pressure vessels from steel according to the preamble of patent claim 1.

Die Sicherheitsanforderungen an Druckbehälter, wie sie beispielsweise in den "Technische Regeln Druckgase" des Deutschen Druckbehälterausschusses (DBA) festgelegt sind, schlagen sich in gleichermaßen hohen Anforderungen an die eingesetzten Werkstoffe nieder. Bei Stahlflaschen (Prüf­druck 300 bar) wird in diesem Zusammenhang gefordert:

0,2% - Dehngrenze über 755 N/mm²
Zugfestigkeit 880 - 1030 N/mm²
ISO-V-Kerbschlagarbeit (quer) bei -20°C über 25 J Dehngrenzenverhältnis unter 90%.
The safety requirements for pressure vessels, such as those set out in the "Technical Rules for Compressed Gases" of the German Pressure Vessel Committee (DBA), are reflected in equally high requirements for the materials used. For steel bottles (test pressure 300 bar) the following is required:

0.2% proof stress over 755 N / mm²
Tensile strength 880 - 1030 N / mm²
ISO-V impact energy (crosswise) at -20 ° C over 25 J proof stress ratio under 90%.

Zur Einhaltung dieser Forderungen werden im Druckbehälter­bau im allgemeinen Vergütungsstähle wie beispielsweise Werkstoff 34 CrMo4 eingesetzt.In order to comply with these requirements, tempered steels such as material 34 CrMo4 are generally used in pressure vessel construction.

Um den Transport und die Handhabung von Druckbehältern zu verbilligen bzw. zu erleichtern, ist man bestrebt, den Druckbehälter möglichst gewichtsarm, d.h. mit geringen Wanddicken, herzustellen. Dabei sollen die Sicherheits­anforderungen jedoch voll erfüllt bleiben. Dies ist aber nur möglich, wenn die Festigkeitseigenschaften des ver­ wendeten Werkstoffs entsprechend gesteigert werden. Das aber ist bei den üblichen Vergütungsstählen unter Einhaltung der genannten Bedingungen nur in geringem Maße durchführbar.In order to make the transport and handling of pressure vessels cheaper or easier, efforts are being made to manufacture the pressure vessel as light as possible, ie with small wall thicknesses. However, the security requirements should remain fully met. But this is only possible if the strength properties of the ver used material can be increased accordingly. However, this is only feasible to a small extent with the conventional tempering steels, provided the conditions mentioned are met.

Ein weiterer Nachteil ist in der eingeschränkten Schweiß­barkeit dieser Stähle zu sehen, die durch den hohen Kohlenstoff-Gehalt von über 0,3% bedingt ist. Daneben entspricht auch die in der Regel erforderliche Öl­vergütung für solche Stähle nicht mehr den heutigen Anforderungen an moderne Fertigungsanlagen, die nach Möglichkeit eine Wasservergütung vorsehen. Schließlich weisen die für die Behälterfertigung üblicherweise verwendeten Werkstoffe Mängel hinsichtlich ihrer Kerb­schlagzähigkeit bei tiefen Temperaturen auf. Einsatz­temperaturen von unter -20 °C sind schon als proble­matisch anzusehen.Another disadvantage is the limited weldability of these steels, which is due to the high carbon content of over 0.3%. In addition, the generally required oil remuneration for such steels no longer meets today's requirements for modern production plants, which provide for water remediation if possible. Finally, the materials commonly used for container production have shortcomings in their impact strength at low temperatures. Operating temperatures of below -20 ° C are problematic.

Aufgabe der Erfindung ist es daher, ein Verfahren an­zugeben, mit dem Druckbehälter herstellbar sind, die diese Nachteile nicht aufweisen. Insbesondere soll eine Verringerung des Druckbehältergewichts durch erhöhte Festigkeitseigenschaften (Reduzierung der Wanddicken) bei ausreichender Sicherheit und unter günstigen Kosten ermöglicht werden, wobei der verwendete Werkstoff gute Schweißeigenschaften und mindestens folgende Festigkeits- und Zähigkeitskennwerte quer zur Verformungsrichtung aufweisen soll:

0,2% - Dehngrenze über 900 N/mm²
Dehngrenzenverhältnis maximal 95%
Brucheinschnürung mindestens 16%
ISO-V-Kerbschlagarbeit bei +20 °C über 80 J
ISO-V-Kerbschlagarbeit bei -60 °C über 36 J
The object of the invention is therefore to provide a method with which pressure vessels can be produced which do not have these disadvantages. In particular, a reduction in the pressure vessel weight should be made possible by increased strength properties (reduction in wall thicknesses) with sufficient safety and at low costs, the material used having good welding properties and at least the following strength and toughness parameters transverse to the direction of deformation:

0.2% - proof stress over 900 N / mm²
Proof stress ratio maximum 95%
Constriction at least 16%
ISO V impact energy at +20 ° C over 80 J
ISO V impact energy at -60 ° C over 36 J

Gelöst wird diese Aufgabe durch ein Verfahren mit den kennzeichnenden Merkmalen des Patentanspruchs 1. Zur weiteren Verbesserung der Durchhärtbarkeit der Druckbehälter (insbesondere bei Wanddicken über 30 mm) wird dem verwendeten Stahl vorteilhaft entsprechend Patentanspruch 2 Chrom bis maximal 0,3% zugesetzt.This object is achieved by a method with the characterizing features of claim 1. To further improve the hardenability of the pressure vessels (in particular for wall thicknesses above 30 mm), chromium is advantageously added to the steel used in accordance with claim 2 to a maximum of 0.3%.

Der erfindungsgemäß verwendete Vergütungsstahl ist trotz des relativ hohen Kohlenstoffanteils von bis zu 0,25% in der vorgegebenen Legierungszusammensetzung nach den üblichen Verfahren problemlos, d.h. heißrißfrei schweißbar. Darüberhinaus kann er sowohl öl- als auch wasservergütet werden. In Kombination mit der Misch­kristallverfestigung und der Verbesserung der Durch­härtbarkeit durch Bor ergeben sich außerordentlich gute Festigkeits- und Zähigkeitskennwerte. Diese über­schreiten die gesetzten Grenzwerte zum Teil deutlich. Um die festigkeitssteigernde Wirkung des Bors maximal ausnutzen zu können, ist ein Titan/Stickstoff-Verhältnis von 3,6 bis 6,5 erforderlich. Durch Zusatz von bis zu 0,04% Niob kann die Feinkörnigkeit und damit die Zähig­keit des erfindungsgemäßen Stahls noch weiter gesteigert werden.Wenngleich sich das Dehngrenzenverhältnis bei dem erfindungsgemäßen Stahl auf etwa 95% erhöhen kann, so ist dennoch eine ausreichende Sicherheit gegen ein Zerlegen des Behälters vorhanden, weil die Bruchein­schnürung auf jeden Fall auf Werten von mindestens 16% gehalten werden kann. Besonders wesentlich ist, daß die Kerbschlagarbeit bei -60 °C quer zur Verformungs­richtung (ISO-V-Kerbschlagproben) über 36 J liegt. Dies macht den Werkstoff auch für eine Anwendung bei tiefen Temperaturen, wie sie unter arktischen Bedin­gungen herrschen, verwendbar.Despite the relatively high carbon content of up to 0.25% in the specified alloy composition, the tempering steel used according to the invention can be welded without problems, ie hot-crack-free, using the customary methods. In addition, it can be oil and water tempered. In combination with the solid solution strengthening and the improvement of the hardenability by boron, extraordinarily good strength and toughness values result. Some of these clearly exceed the set limit values. A titanium / nitrogen ratio of 3.6 to 6.5 is required to maximize the strengthening effect of boron. The addition of up to 0.04% niobium can further increase the fine-grained nature and thus the toughness of the steel according to the invention Although the proof stress ratio can increase to approximately 95% in the steel according to the invention, there is still sufficient security against disassembly of the container, because the fracture neck can be kept at least at least 16%. It is particularly important that the impact energy at -60 ° C across the deformation direction (ISO-V impact test) is over 36 J. This also makes the material suitable for use at low temperatures, such as those found under arctic conditions.

Die besondere Eignung des erfindungsgemäßen Stahl für den Bau von Druckbehältern wird durch die beiden nachfol­genden Beispiele weiter verdeutlicht.The particular suitability of the steel according to the invention for the construction of pressure vessels is further illustrated by the two examples below.

Beispiel 1:Example 1:

Für eine Flasche (Wanddicke 4 mm) aus einem Stahl mit der Zusammensetzung:

0,24 % C
1,4 % Mn
0,28 % Si
0,013 % P
0,0018 % S
0,29 % Mo
0,023 % Ti
0,0020 % B
0,0037 % N

ergaben sich nach der erfindungsgemäßen Vergütungs­behandlung (15 min bei 870 °C, Abschrecken im Ölbad; 30 min bei 600 °C, Abkühlen an Luft) folgende Eigenschaften:

0,2 % - Dehngrenze 903 N/mm²
Zugfestigkeit 950 N/mm²
Dehngrenzenverhältnis 95%
Brucheinschnürung 20%
ISO-V-Kerbschlagarbeit bei +20 °C (quer) 133 J
ISO-V-Kerbschlagarbeit bei -60 °C (quer) 58 J.For a bottle (wall thickness 4 mm) made of steel with the composition:

0.24% C
1.4% Mn
0.28% Si
0.013% P
0.0018% S
0.29% Mo
0.023% Ti
0.0020% B
0.0037% N

After the heat treatment according to the invention (15 minutes at 870 ° C., quenching in an oil bath; 30 minutes at 600 ° C., cooling in air), the following properties resulted:

0.2% - yield strength 903 N / mm²
Tensile strength 950 N / mm²
Proof ratio 95%
Constriction 20%
ISO-V impact energy at +20 ° C (transverse) 133 J
ISO-V impact energy at -60 ° C (transverse) 58 J.

Beispiel 2:Example 2:

Für einen Serienbehälter (6 mm Wanddicke) aus einem Stahl mit der Zusammensetzung:

0,2 % C
1,74 % Mn
0,3 % Si
0,013 % P
0,0014 %S
0,30 % Mo
0,021 % Ti
0,0022 % B
0,0048 % N

ergaben sich nach der erfindungsgemäßen Vergütungs­behandlung (15 Min bei 880 °C, Abschrecken im Wasser­bad; 30 min bei 500 °C, Abkühlen an Luft) folgende Eigenschaften:

0,2 % - Dehngrenze 992 N/mm²
Zugfestigkeit 1042 N/mm²
Dehngrenzenverhältnis 95%
Brucheinschnürung 17%
ISO-V-Kerbschlagarbeit bei +20 °C (quer) 114 J
ISO-V-Kerbschlagarbeit bei -60 °C (quer) 40 J.For a series container (6 mm wall thickness) made of steel with the composition:

0.2% C
1.74% Mn
0.3% Si
0.013% P
0.0014% S
0.30% Mo
0.021% Ti
0.0022% B
0.0048% N

After the heat treatment according to the invention (15 minutes at 880 ° C., quenching in a water bath; 30 minutes at 500 ° C., cooling in air), the following properties resulted:

0.2% proof stress 992 N / mm²
Tensile strength 1042 N / mm²
Proof ratio 95%
Fracture reduction 17%
ISO-V impact energy at +20 ° C (transverse) 114 J
ISO-V impact energy at -60 ° C (transverse) 40 J.

Claims (2)

1. Verfahren zur Herstellung von Druckbehältern aus Stahl durch Warm- und/oder Kaltformgebung und an­schließendes Härten und Anlassen, dadurch gekenn­zeichnet, daß ein Stahl mit der Zusammensetzung
0,15 - 0,26 % Kohlenstoff
1,25 - 2,00 % Mangan
0,2 - 0,5 % Silizium
maximal 0,02 % Phosphor
maximal 0,005 % Schwefel
o,1 - 0,5 % Molybdän
0,010 - 0,035 % Titan
0,0030 - 0,0100 % N
0,001 - 0,003 % Bor
0 - 0,04 %Niob
Rest Eisen und übliche Verunreinigungen

verwendet wird, wobei das Verhältnis des Titange­haltes zum Stickstoffgehalt zwischen 3,6 und 6,5 eingestellt wird, daß die Druckbehälter zum Härten auf 30-50 K oberhalb Ac₃ erwärmt und anschließend mit einer Geschwindigkeit von 15-40 K/s auf unter 100°C abgekühlt werden und daß das Anlassen bei Temperaturen von mindestens 500 °C bis maximal 50 K unterhalb Ac₁ und einer Haltezeit von mindestens 5 min durchgeführt wird.1. A process for the production of steel pressure vessels by hot and / or cold forming and subsequent hardening and tempering, characterized in that a steel with the composition
0.15-0.26% carbon
1.25 - 2.00% manganese
0.2-0.5% silicon
maximum 0.02% phosphorus
maximum 0.005% sulfur
0.1-0.5% molybdenum
0.010 - 0.035% titanium
0.0030 - 0.0100% N
0.001 - 0.003% boron
0-0.04% niobium
Balance iron and usual impurities

is used, the ratio of the titanium content to the nitrogen content being set between 3.6 and 6.5, that the pressure vessel is heated to 30-50 K above Ac₃ for hardening and then at a rate of 15-40 K / s to below 100 ° C are cooled and that the tempering is carried out at temperatures of at least 500 ° C to a maximum of 50 K below Ac₁ and a holding time of at least 5 min. 2. Verfahren nach Anspruch 1,
dadurch gekennzeichnet, daß der verwendete Stahl zusätzlich maximal 0,3% Chrom enthält.2. The method according to claim 1,
characterized in that the steel used additionally contains a maximum of 0.3% chromium.
EP88730190A 1987-09-16 1988-08-23 Process for manufacturing steel pressure vessels Expired - Lifetime EP0308361B1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT88730190T ATE95844T1 (en) 1987-09-16 1988-08-23 PROCESS FOR MANUFACTURING STEEL PRESSURE TANKS.

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE3731481 1987-09-16
DE19873731481 DE3731481A1 (en) 1987-09-16 1987-09-16 METHOD FOR THE PRODUCTION OF STEEL PRESSURE TANKS

Publications (2)

Publication Number Publication Date
EP0308361A1 true EP0308361A1 (en) 1989-03-22
EP0308361B1 EP0308361B1 (en) 1993-10-13

Family

ID=6336365

Family Applications (1)

Application Number Title Priority Date Filing Date
EP88730190A Expired - Lifetime EP0308361B1 (en) 1987-09-16 1988-08-23 Process for manufacturing steel pressure vessels

Country Status (3)

Country Link
EP (1) EP0308361B1 (en)
AT (1) ATE95844T1 (en)
DE (2) DE3731481A1 (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
NL1013099C2 (en) * 1999-09-20 2001-03-21 Matthijs De Jong Pressurized tank for liquefied gas, especially for gas tankers, comprises a steel material with specific silicon, chromium, copper, molybdenum and nickel contents

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1083466A (en) * 1963-12-05 1967-09-13 Ishikawajima Harima Heavy Ind Method of manufacturing steel with improved mechanical properties
FR2287519A1 (en) * 1974-10-07 1976-05-07 Kobe Steel Ltd Weldable structural steel - which is resistant to embrittlement in the heat affected zone

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DD79594A (en) *
JPS52152814A (en) * 1976-06-14 1977-12-19 Nippon Steel Corp Thermo-mechanical treatment of seamless steel pipe
JPS62196326A (en) * 1986-02-24 1987-08-29 Sumitomo Metal Ind Ltd Manufacture of high-strength steel excellent in surface toughness

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1083466A (en) * 1963-12-05 1967-09-13 Ishikawajima Harima Heavy Ind Method of manufacturing steel with improved mechanical properties
FR2287519A1 (en) * 1974-10-07 1976-05-07 Kobe Steel Ltd Weldable structural steel - which is resistant to embrittlement in the heat affected zone

Non-Patent Citations (3)

* Cited by examiner, † Cited by third party
Title
METAL SCIENCE AND HEAT TREATMENT, Band 27, Nr. 9-10, September/Oktober 1985, Seiten 646-649, Plenum Publishing Corp., New York, US; T.A. BEILINOVA et al.: "Quenching of tanks in "water-air" medium" *
PATENT ABSTRACTS OF JAPAN, Band 12, Nr. 50 (C-476)[2897], 16. Februar 1988; & JP-A-62 196 326 (SUMITOMO METAL IND. LTD) 29-08-1987 *
PATENT ABSTRACTS OF JAPAN, Band 8, Nr. 225 (C-247)[1662], 16. Oktober 1984; & JP-A-59 110 725 (KAWASAKI SEITETSU K.K.) 26-06-1984 *

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
NL1013099C2 (en) * 1999-09-20 2001-03-21 Matthijs De Jong Pressurized tank for liquefied gas, especially for gas tankers, comprises a steel material with specific silicon, chromium, copper, molybdenum and nickel contents

Also Published As

Publication number Publication date
DE3731481A1 (en) 1989-04-06
DE3884900D1 (en) 1993-11-18
EP0308361B1 (en) 1993-10-13
ATE95844T1 (en) 1993-10-15

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