EP0010755B2 - Use of manganese and nickel-containing fine-grained structural steel - Google Patents
Use of manganese and nickel-containing fine-grained structural steel Download PDFInfo
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- EP0010755B2 EP0010755B2 EP79104222A EP79104222A EP0010755B2 EP 0010755 B2 EP0010755 B2 EP 0010755B2 EP 79104222 A EP79104222 A EP 79104222A EP 79104222 A EP79104222 A EP 79104222A EP 0010755 B2 EP0010755 B2 EP 0010755B2
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- steel
- nickel
- manganese
- copper
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- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 title claims abstract description 42
- 229910052759 nickel Inorganic materials 0.000 title claims abstract description 21
- 229910000746 Structural steel Inorganic materials 0.000 title claims abstract description 4
- PWHULOQIROXLJO-UHFFFAOYSA-N Manganese Chemical compound [Mn] PWHULOQIROXLJO-UHFFFAOYSA-N 0.000 title description 5
- 229910052748 manganese Inorganic materials 0.000 title description 5
- 239000011572 manganese Substances 0.000 title description 5
- 229910052802 copper Inorganic materials 0.000 claims abstract description 14
- 239000010949 copper Substances 0.000 claims abstract description 14
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 claims abstract description 13
- 229910052799 carbon Inorganic materials 0.000 claims abstract description 12
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims abstract description 11
- 239000000463 material Substances 0.000 claims abstract description 11
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims abstract description 10
- 229910052758 niobium Inorganic materials 0.000 claims abstract description 7
- 239000010955 niobium Substances 0.000 claims abstract description 7
- GUCVJGMIXFAOAE-UHFFFAOYSA-N niobium atom Chemical compound [Nb] GUCVJGMIXFAOAE-UHFFFAOYSA-N 0.000 claims abstract description 7
- 229910052742 iron Inorganic materials 0.000 claims abstract description 6
- WPBNNNQJVZRUHP-UHFFFAOYSA-L manganese(2+);methyl n-[[2-(methoxycarbonylcarbamothioylamino)phenyl]carbamothioyl]carbamate;n-[2-(sulfidocarbothioylamino)ethyl]carbamodithioate Chemical compound [Mn+2].[S-]C(=S)NCCNC([S-])=S.COC(=O)NC(=S)NC1=CC=CC=C1NC(=S)NC(=O)OC WPBNNNQJVZRUHP-UHFFFAOYSA-L 0.000 claims abstract description 6
- 229910052710 silicon Inorganic materials 0.000 claims abstract description 6
- 239000010703 silicon Substances 0.000 claims abstract description 6
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 claims abstract description 4
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 claims abstract description 4
- 229910052782 aluminium Inorganic materials 0.000 claims abstract description 4
- 239000012535 impurity Substances 0.000 claims abstract description 3
- ZAUUZASCMSWKGX-UHFFFAOYSA-N manganese nickel Chemical compound [Mn].[Ni] ZAUUZASCMSWKGX-UHFFFAOYSA-N 0.000 claims abstract description 3
- 241001062472 Stokellia anisodon Species 0.000 claims abstract 2
- 239000005864 Sulphur Substances 0.000 claims abstract 2
- 239000004411 aluminium Substances 0.000 claims abstract 2
- 230000001419 dependent effect Effects 0.000 claims abstract 2
- 229910000831 Steel Inorganic materials 0.000 claims description 38
- 239000010959 steel Substances 0.000 claims description 38
- 229910052739 hydrogen Inorganic materials 0.000 description 11
- 239000001257 hydrogen Substances 0.000 description 11
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 10
- RWSOTUBLDIXVET-UHFFFAOYSA-N Dihydrogen sulfide Chemical compound S RWSOTUBLDIXVET-UHFFFAOYSA-N 0.000 description 6
- 229910000037 hydrogen sulfide Inorganic materials 0.000 description 6
- 238000010586 diagram Methods 0.000 description 5
- 239000007789 gas Substances 0.000 description 5
- 238000010438 heat treatment Methods 0.000 description 5
- 239000007788 liquid Substances 0.000 description 4
- 229910000851 Alloy steel Inorganic materials 0.000 description 3
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 description 3
- 229910052698 phosphorus Inorganic materials 0.000 description 3
- 239000011574 phosphorus Substances 0.000 description 3
- 229910001220 stainless steel Inorganic materials 0.000 description 3
- 238000003860 storage Methods 0.000 description 3
- 230000007704 transition Effects 0.000 description 3
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 3
- VGGSQFUCUMXWEO-UHFFFAOYSA-N Ethene Chemical group C=C VGGSQFUCUMXWEO-UHFFFAOYSA-N 0.000 description 2
- 239000002253 acid Substances 0.000 description 2
- 229910045601 alloy Inorganic materials 0.000 description 2
- 239000000956 alloy Substances 0.000 description 2
- 229910001566 austenite Inorganic materials 0.000 description 2
- 238000005336 cracking Methods 0.000 description 2
- 230000003247 decreasing effect Effects 0.000 description 2
- 238000005098 hot rolling Methods 0.000 description 2
- -1 however Substances 0.000 description 2
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 2
- 229910052717 sulfur Inorganic materials 0.000 description 2
- 239000011593 sulfur Substances 0.000 description 2
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 description 1
- QCWXUUIWCKQGHC-UHFFFAOYSA-N Zirconium Chemical compound [Zr] QCWXUUIWCKQGHC-UHFFFAOYSA-N 0.000 description 1
- 230000004888 barrier function Effects 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 230000000052 comparative effect Effects 0.000 description 1
- 150000001879 copper Chemical class 0.000 description 1
- 230000006735 deficit Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000007654 immersion Methods 0.000 description 1
- 238000005342 ion exchange Methods 0.000 description 1
- 150000002500 ions Chemical class 0.000 description 1
- 239000010410 layer Substances 0.000 description 1
- 239000003915 liquefied petroleum gas Substances 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 230000008018 melting Effects 0.000 description 1
- 238000002844 melting Methods 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 239000003921 oil Substances 0.000 description 1
- 230000035515 penetration Effects 0.000 description 1
- 239000011241 protective layer Substances 0.000 description 1
- 238000005096 rolling process Methods 0.000 description 1
- 229920006395 saturated elastomer Polymers 0.000 description 1
- 239000013535 sea water Substances 0.000 description 1
- 230000035945 sensitivity Effects 0.000 description 1
- 230000009044 synergistic interaction Effects 0.000 description 1
- 238000005496 tempering Methods 0.000 description 1
- 229910052720 vanadium Inorganic materials 0.000 description 1
- LEONUFNNVUYDNQ-UHFFFAOYSA-N vanadium atom Chemical compound [V] LEONUFNNVUYDNQ-UHFFFAOYSA-N 0.000 description 1
- 238000003466 welding Methods 0.000 description 1
- 229910052726 zirconium Inorganic materials 0.000 description 1
Images
Classifications
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- 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
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/08—Ferrous alloys, e.g. steel alloys containing nickel
-
- 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
- C22C38/12—Ferrous alloys, e.g. steel alloys containing tungsten, tantalum, molybdenum, vanadium, or niobium
Definitions
- the invention relates to the use of a manganese-nickel fine-grained structural steel with 0.04 to 0.09% carbon, 1.2 to 1.8% manganese, 0.1 to 0.4% silicon, 0.03 to 0, 08% niobium, 0.5 to 1.5% nickel, up to 0.25% aluminum, up to 0.015% sulfur and optionally 0.2 to 0.4% copper, remainder iron including impurities due to melting.
- An alloy steel of the type mentioned above is known from German Offenlegungsschrift 2407338; it contains 0.01 to 0.10% carbon, 0.5 to 2% manganese, 0.1 to 0.9% silicon, 0.001 to 0.10% niobium, 0.01 to 0.3% aluminum and 1, 4 to 3.5% nickel.
- This steel has a certain cold strength if it has been hot rolled in a controlled manner depending on the nickel content.
- hot rolling controlled as a function of the respective nickel content proves to be difficult and, in particular, complex in practice.
- the cold toughness of this steel is not sufficient to use the steel at temperatures such as that of liquid methane and, in particular, liquid ethylene.
- German Offenlegungsschrift 2461 087 that copper in a steel with 0.05 to 0.20% carbon, 0.01 to 0.8% silicon, 0.5 to 1.6% manganese, below 0 , 03% phosphorus, 0.002 to 0.02% sulfur and 0.2 to 0.8% copper, the rest iron and iron companion increases the strength, but affects the hot formability.
- the copper should increase the resistance to hydrogen or suppress the formation of hydrogen cracks, provided that the steel contains no or at most 0.6% nickel; however, this is only at the expense of hot workability.
- This steel is suitable as a material for oil or gas pipes.
- German published patent application 2157 305 is a low-alloy steel with 0.04 to 0.09% carbon, 0.1 to 0.9% silicon, 1.7 to 2.2% manganese, each with 1.0% copper or Nikkel, 0.3 to 1.5% copper and nickel and 0.01 to 0.10% niobium are known, which has a limited cold toughness with an additional vanadium content of 0.05% and a zirconium content of 0.06%. None is known about the resistance of the steel to hydrogen cracks.
- the invention is based on the object of proposing an alloy steel for use at temperatures down to -120 ° C. which can be welded, has a high yield strength at room temperature and cold toughness and resistance to hydrogen cracks and is accordingly particularly suitable as a material for welded parts, which, like pipes and containers, serve for the transport and storage of liquid gases even in the presence of hydrogen sulfide and water.
- the steel is said to be resistant to liquid ethylene and to withstand temperatures down to -120 ° C.
- the solution to this problem is to use an uncontrolled hot-rolled steel of the type mentioned in the normalized state as the material for parts which come into contact with liquefied petroleum gas at temperatures down to -120 ° C. After such a heat treatment, the steel has a room temperature yield point of at least 420 Nm 2 and a transition temperature of the impact strength of 51 mm 2 transverse to the rolling direction of at least -120 ° C. and a notched impact strength of at least 280 mm 2 at room temperature.
- the steel contains 0.2 to 0.4% copper, then its crack resistance is in the presence of Traces of hydrogen sulfide particularly high. This is of considerable importance insofar as liquefied gases often contain traces of hydrogen sulfide which, when water is present at the same time, has a corrosive effect and in particular leads to hydrogen-induced cracks.
- the low carbon content of the steel results in good welding behavior on the one hand and promotes notched impact strength on the other.
- the excellent properties of the proposed steel are explained in the synergistic interaction of nikkel, niobium and manganese.
- the steel is preferably annealed normally until the core temperature is 30 to 50 ° C above the AC 3 point and then annealed for 2 to 4 minutes at 2 to 4 minutes at 550 to 650 ° C, in particular at 630 ° C, in order to improve the toughness adjust.
- FIG. 3 show the superiority of the steel to be used according to the invention (Erf.St.) with 0.61% nickel in comparison to conventional standard steels, whereby it should be noted that the steel to be used according to the invention is cross-samples, in the other cases, with one exception, are longitudinal samples.
- the comparative steels, each with an index number, are described in the following publications:
- the steels examined also each had a yield strength of at least 420 N / mm 2 and a notched impact strength of at least 280 J / cm 2 at room temperature.
- FIGS. 4 and 5 show that the crack sensitivity in the presence of hydrogen sulfide is particularly low at copper contents above about 0.02%, so that the proposed steel is particularly suitable for the transport and storage of contaminated liquid gas.
- the high resistance to cracking is due to the fact that a weak acid develops during operation under the influence of hydrogen sulfide and water.
- the resulting hydrogen ions migrate into the material and are molecularly separated at the grain boundaries. In conventional steels, this results in pressures that lead to cracking.
- part of the copper dissolves in the acid.
- the resulting ions migrate to the material surface through ion exchange and form a molecular protective layer made of copper. This copper layer acts as a barrier against further penetration of the hydrogen and explains this 4 apparent high hydrogen resistance of the steel to be used according to the invention.
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Heat Treatment Of Steel (AREA)
- Laminated Bodies (AREA)
- Catalysts (AREA)
- Filling Or Discharging Of Gas Storage Vessels (AREA)
Abstract
Description
Die Erfindung bezieht sich auf die Verwendung eines Mangan-Nickel-Feinkornbaustahls mit 0,04 bis 0,09% Kohlenstoff, 1,2 bis 1,8% Mangan, 0,1 bis 0,4% Silizium, 0,03 bis 0,08% Niob, 0,5 bis 1,5% Nickel, bis 0,25% Aluminium, bis 0,015% Schwefel und fakultativ 0,2 bis 0,4% Kupfer, Rest Eisen einschliesslich erschmelzungsbedingter Verunreinigungen.The invention relates to the use of a manganese-nickel fine-grained structural steel with 0.04 to 0.09% carbon, 1.2 to 1.8% manganese, 0.1 to 0.4% silicon, 0.03 to 0, 08% niobium, 0.5 to 1.5% nickel, up to 0.25% aluminum, up to 0.015% sulfur and optionally 0.2 to 0.4% copper, remainder iron including impurities due to melting.
Ein legierter Stahl der vorerwähnten Art ist aus der deutschen Offenlegungsschrift 2407338 bekannt; er enthält 0,01 bis 0,10% Kohlenstoff, 0,5 bis 2% Mangan, 0,1 bis 0,9% Silizium, 0,001 bis 0,10% Niob, 0,01 bis 0,3% Aluminium und 1,4 bis 3,5% Nickel. Dieser Stahl besitzt eine gewisse Kaltfestigkeit, wenn er in Abhängigkeit vom Nikkelgehalt gesteuert warmgewalzt worden ist. Ein in Abhängigkeit vom jeweiligen Nickelgehalt gesteuertes Warmwalzen erweist sich jedoch in der Praxis als schwierig und insbesondere aufwendig. Hinzu kommt, dass die Kaltzähigkeit dieses Stahls nicht ausreicht, um den Stahl bei Temperaturen zu verwenden, wie sie flüssiges Methan und insbesondere flüssiges Äthylen mit sich bringen.An alloy steel of the type mentioned above is known from German Offenlegungsschrift 2407338; it contains 0.01 to 0.10% carbon, 0.5 to 2% manganese, 0.1 to 0.9% silicon, 0.001 to 0.10% niobium, 0.01 to 0.3% aluminum and 1, 4 to 3.5% nickel. This steel has a certain cold strength if it has been hot rolled in a controlled manner depending on the nickel content. However, hot rolling controlled as a function of the respective nickel content proves to be difficult and, in particular, complex in practice. In addition, the cold toughness of this steel is not sufficient to use the steel at temperatures such as that of liquid methane and, in particular, liquid ethylene.
Des weiteren ist es aus der deutschen Offenlegungsschrift 2461 087 bekannt, dass Kupfer bei einem Stahl mit 0,05 bis 0,20% Kohlenstoff, 0,01 bis 0,8% Silizium, 0,5 bis 1,6% Mangan, unter 0,03% Phosphor, 0,002 bis 0,02% Schwefel und 0,2 bis 0,8% Kupfer, Rest Eisen und Eisenbegleiter die Festigkeit erhöht, jedoch die Warmverformbarkeit beeinträchtigt. Ausserdem soll das Kupfer die Wasserstoffbeständigkeit erhöhen bzw. das Entstehen von Wasserstoffrissen unterdrükken, sofern der Stahl kein oder allenfalls 0,6% Nickel enthält; dies geht jedoch wiederum nur auf Kosten der Warmverarbeitbarkeit. Dieser Stahl eignet sich als Werkstoff für Erdöl- oder Erdgasrohre.Furthermore, it is known from German Offenlegungsschrift 2461 087 that copper in a steel with 0.05 to 0.20% carbon, 0.01 to 0.8% silicon, 0.5 to 1.6% manganese, below 0 , 03% phosphorus, 0.002 to 0.02% sulfur and 0.2 to 0.8% copper, the rest iron and iron companion increases the strength, but affects the hot formability. In addition, the copper should increase the resistance to hydrogen or suppress the formation of hydrogen cracks, provided that the steel contains no or at most 0.6% nickel; however, this is only at the expense of hot workability. This steel is suitable as a material for oil or gas pipes.
Aus der deutschen Offenlegungsschrift 2157 305 ist ein niedrig legierter Stahl mit 0,04 bis 0,09% Kohlenstoff, 0,1 bis 0,9% Silizium, 1,7 bis 2,2% Mangan, unter jeweils 1,0% Kupfer oder Nikkel, 0,3 bis 1,5% Kupfer und Nickel sowie 0,01 bis 0,10% Niob bekannt, der bei einem zusätzlichen Vanadiumgehalt von 0,05% und einem Zirkoniumgehalt von 0,06% eine begrenzte Kaltzähigkeit besitzt. Hinsichtlich der Beständigkeit des Stahls gegen Wasserstoffrisse ist nichts bekannt.From the German published patent application 2157 305 is a low-alloy steel with 0.04 to 0.09% carbon, 0.1 to 0.9% silicon, 1.7 to 2.2% manganese, each with 1.0% copper or Nikkel, 0.3 to 1.5% copper and nickel and 0.01 to 0.10% niobium are known, which has a limited cold toughness with an additional vanadium content of 0.05% and a zirconium content of 0.06%. Nothing is known about the resistance of the steel to hydrogen cracks.
Ähnliches gilt für einen aus der deutschen Offenlegungsschrift 2323738 bekannten Stahl mit bis 0,2% Kohlenstoff, mindestens 0,75% Mangan und mindestens 0,015% Niob, dessen mechanischen Eigenschaften jedoch von einer bestimmten Korngrösse abhängig sind. Dieser Stahl erreicht bei einem Nickelgehalt von 0,29% und einem Chromgehalt von 0,54% bei -51,1°C eine Kerbschlagzähigkeit von 51,9 J/cm2.The same applies to a steel known from German Offenlegungsschrift 2323738 with up to 0.2% carbon, at least 0.75% manganese and at least 0.015% niobium, the mechanical properties of which, however, depend on a certain grain size. With a nickel content of 0.29% and a chrome content of 0.54% at -51.1 ° C, this steel achieves a notched impact strength of 51.9 J / cm 2 .
Für den Transport und die Lagerung von Flüssiggasen sind jedoch Werkstoffe erforderlich, die bei Temperaturen bis -196°C eine ausreichende Festigkeit und Zähigkeit besitzen. Ausserdem müssen diese Werkstoffe schweissbar sein, um ein wirtschaftliches Fertigen von Rohren und Behältern zu ermöglichen.For the transport and storage of liquid gases, however, materials are required that have sufficient strength and toughness at temperatures down to -196 ° C. In addition, these materials must be weldable to enable the economical production of pipes and containers.
Es ist bekannt, dass rostfreie Stähle Betriebstemperaturen bis unter -270°C gewachsen sind. Trägere der Kaltzähigkeit ist dabei insbesondere das Nickel. Der hohe Anteil teurer Legierungsbestandteile setzt der Verwendung rostfreier Stähle jedoch Grenzen, die nach preiswerteren legierten Stählen haben suchen lassen. Dies hat zur Entwicklung einer Reihe von Stählen mit etwa 9% Nickel, 0,1% Kohlenstoff, 0,80% Mangan und 0,020% Phosphor geführt, die sich durch eine im Vergleich zu den rostfreien Stählen höhere Zugfestigkeit und eine bis etwa -200°C ausreichende Kaltzähigkeit auszeichnen. Voraussetzung für die hohe Kaltzähigkeit ist jedoch ein zweistufiges Normalglühen und Anlassen, das darauf abzielt, einen ausreichenden Austenitanteil in einem ferritischen Grundgefüge einzustellen. Dem liegt die Erkenntnis zugrunde, dass sich die Zähigkeit mit zunehmendem Austenitanteil erhöht.It is known that stainless steels have grown to operating temperatures below -270 ° C. Nickel, in particular, is the carrier of the cold toughness. However, the high proportion of expensive alloy components places limits on the use of stainless steels, which led to the search for cheaper alloy steels. This has led to the development of a range of steels with approximately 9% nickel, 0.1% carbon, 0.80% manganese and 0.020% phosphorus, which is characterized by a higher tensile strength in comparison to the stainless steels and by up to approximately -200 ° C mark sufficient toughness. However, a prerequisite for the high cold toughness is a two-stage normalizing and tempering, which aims to establish a sufficient proportion of austenite in a ferritic structure. This is based on the finding that toughness increases with an increasing proportion of austenite.
Versuche haben in diesem Zusammenhang ergeben, dass sich die Kaltzähigkeit mit abnehmenden Gehalten an Kohlenstoff, Phosphor und Mangan erhöht. Des weiteren zeigte sich, dass eine stufenweise Verringerung des Nickelgehaltes auf 2,1% zu einer zunehmenden Beeinträchtigung der Kaltzähigkeit führt. So verringerten sich beispielsweise die Kerbschlagzähigkeiten normalisierter und angelassener, 8,5 bis 9,5% Nickel enthaltender Stähle von 42,5J/cmz bei -196°C, bei 3,25 bis 3,75% Nickel enthaltenen Stählen auf 25J/cm2 bei -100°C und bei 2,1 bis 2,5% Nickel enthaltenden Stählen auf 22,5j/CM2 bei -68°C. Stähle mit Nickelgehalten unter 9% gelten demnach als nicht für Tiefsttemperaturen geeignet.In this context, tests have shown that the cold toughness increases with decreasing contents of carbon, phosphorus and manganese. Furthermore, it was shown that a gradual reduction in the nickel content to 2.1% leads to an increasing impairment of the cold toughness. For example, the notched impact strengths of normalized and tempered steels containing 8.5 to 9.5% nickel were reduced from 42.5J / cmz at -196 ° C, to 3.2J to 3.75% nickel to 25J / cm 2 at -100 ° C and with 2.1 to 2.5% nickel-containing steels to 22.5j / CM2 at -68 ° C. Steels with a nickel content of less than 9% are therefore not suitable for low temperatures.
Der Erfindung liegt nun die Aufgabe zugrunde, einen legierten Stahl zur Verwendung bei Temperaturen bis -120°C vorzuschlagen, der sich schweissen lässt, eine hohe Streckgrenze bei Raumtemperatur und Kaltzähigkeit sowie Beständigkeit gegen Wasserstoffrisse besitzt und sich demgemäss insbesondere als Werkstoff für geschweisste Teile eignet, die wie Rohre und Behälter dem Transport und der Lagerung von Flüssiggasen auch bei Anwesenheit von Schwefelwasserstoff und Wasser dienen. Insbesondere soll der Stahl gegenüber flüssigem Äthylen beständig und Temperaturen bis -120°C gewachsen sein.The invention is based on the object of proposing an alloy steel for use at temperatures down to -120 ° C. which can be welded, has a high yield strength at room temperature and cold toughness and resistance to hydrogen cracks and is accordingly particularly suitable as a material for welded parts, which, like pipes and containers, serve for the transport and storage of liquid gases even in the presence of hydrogen sulfide and water. In particular, the steel is said to be resistant to liquid ethylene and to withstand temperatures down to -120 ° C.
Die Lösung dieser Aufgabe besteht darin, als Werkstoff für Teile, die wie Rohre und Behälter mit Flüssiggas bei Temperaturen bis -120°C in Berührung kommen, einen nicht gesteuert warmgewalzten Stahl der eingangs erwähnten Art im normalgeglühten Zustand zu verwenden. Nach einer derartigen Wärmebehandlung besitzt der Stahl eine Raumtemperatur-Streckgrenze von mindestens 420 Njmm2 und eine Übergangstemperatur der Kerbschlagzähigkeit von 51 Jjcm2 quer zur Walzrichtung von mindestens -120°C sowie eine Kerbschlagzähigkeit von mindestens 280 Jjcm2 bei Raumtemperatur.The solution to this problem is to use an uncontrolled hot-rolled steel of the type mentioned in the normalized state as the material for parts which come into contact with liquefied petroleum gas at temperatures down to -120 ° C. After such a heat treatment, the steel has a room temperature yield point of at least 420 Nm 2 and a transition temperature of the impact strength of 51 mm 2 transverse to the rolling direction of at least -120 ° C. and a notched impact strength of at least 280 mm 2 at room temperature.
Enthält der Stahl 0,2 bis 0,4% Kupfer, dann ist seine Rissbeständigkeit in Anwesenheit von Schwefelwasserstoffspuren besonders hoch. Dem kommt insofern eine erhebliche Bedeutung zu, als Flüssiggase häufig Spuren von Schwefelwasserstoff enthalten, der bei gleichzeitiger Anwesenheit von Wasser korrodierend wirkt und insbesondere zu wasserstoffinduzierten Rissen führt.If the steel contains 0.2 to 0.4% copper, then its crack resistance is in the presence of Traces of hydrogen sulfide particularly high. This is of considerable importance insofar as liquefied gases often contain traces of hydrogen sulfide which, when water is present at the same time, has a corrosive effect and in particular leads to hydrogen-induced cracks.
Der geringe Kohlenstoffgehalt des Stahls bedingt einerseits ein gutes Schweissverhalten und fördert andererseits die Kerbschlagzähigkeit. Insgesamt finden die ausgezeichneten Eigenschaften des vorgeschlagenen Stahls ihre Erklärung in dem synergistischen Zusammenwirken von Nikkel, Niob und Mangan.The low carbon content of the steel results in good welding behavior on the one hand and promotes notched impact strength on the other. Overall, the excellent properties of the proposed steel are explained in the synergistic interaction of nikkel, niobium and manganese.
Der Stahl wird vorzugsweise so lange normalgeglüht, bis die Kerntemperatur 30 bis 50°C über dem AC3-Punkt liegt und anschliessend je 2 Millimeter Materialdicke zwei bis vier Minuten bei 550 bis 650°C, insbesondere bei 630°C angelassen, um die Kaltzähigkeit einzustellen.The steel is preferably annealed normally until the core temperature is 30 to 50 ° C above the AC 3 point and then annealed for 2 to 4 minutes at 2 to 4 minutes at 550 to 650 ° C, in particular at 630 ° C, in order to improve the toughness adjust.
Die Erfindung wird nachfolgend anhand von in den Figuren dargestellten Diagrammen und von Ausführungsbeispielen des näheren erläutert. In der Zeichnung zeigen:
Proben der Versuchsstähle wurden den aus den Diagrammen ersichtlichen Wärmebehandlungen unterworfen sowie hinsichtlich ihrer Kerbschlagzähigkeit und Kaltzähigkeit untersucht. Die Ergebnisse sind aus den Diagrammen der Fig. 1 und 2 ersichtlich und zeigen, dass sowohl die Kerbschlagzähigkeit bei Raumtemperatur als auch die Übergangstemperatur im Bereich von 0,5 bis 1,5% Nickel unabhängig von der jeweiligen Wärmebehandlung ein Optimum durchlaufen, ohne dass es dazu besonderer Massnahmen bedarf. Das ist insofern überraschend, als nach herkömmlicher Auffassung ein abnehmender Nickelgehalt mit einer Verringerung der Kalt- und Kerbschlagzähigkeit einhergeht, sofern nicht besondere Massnahmen wie ein gesteuertes Warmwalzen angewandt werden, um die Kaltzähigkeit einzustellen.Samples of the test steels were subjected to the heat treatments shown in the diagrams and examined with regard to their impact strength and cold toughness. The results can be seen from the diagrams of FIGS. 1 and 2 and show that both the notched impact strength at room temperature and the transition temperature in the range from 0.5 to 1.5% nickel go through an optimum regardless of the respective heat treatment, without it this requires special measures. This is surprising in that, according to the conventional view, a decreasing nickel content is accompanied by a reduction in the cold and notched impact strength, unless special measures such as controlled hot rolling are used to adjust the cold toughness.
Aus den Figuren des Bildes 3 ergibt sich die Überlegenheit des erfindungsgemäss zu verwendenden Stahls (Erf.St.) mit 0,61% Nickel im Vergleich zu herkömmlichen Normstählen, wobei zu beachten ist, dass es sich bei dem erfindungsgemäss zu verwendenden Stahl um Querproben, in den anderen Fällen, mit einer Ausnahme, um Längsproben handelt. Die jeweils mit einer Kennziffer versehenen Vergleichsstähle sind in den folgenden Druckschriften beschreiben:The figures in FIG. 3 show the superiority of the steel to be used according to the invention (Erf.St.) with 0.61% nickel in comparison to conventional standard steels, whereby it should be noted that the steel to be used according to the invention is cross-samples, in the other cases, with one exception, are longitudinal samples. The comparative steels, each with an index number, are described in the following publications:
- Fig. 1 die Abhängigkeit der Raumtemperatur-Kerbschlagzähigkeit vom Nickelgehalt und der Art der Wärmebehandlung.Fig. 1 shows the dependence of the room temperature notched impact strength on the nickel content and the type of heat treatment.
- Fig. die Abhängigkeit der Übergangstemperatur vom Nickelgehalt und der Wärmebehandlung,The dependence of the transition temperature on the nickel content and the heat treatment,
- Fig. die Abhängigkeit der Kerbschlagzähigkeit und des Verformungsbruchs eines unter die Erfindung fallenden Stahls im Vergleich zu bekannten Stählen von der Prüftemperatur,FIG. 1 shows the dependence of the notched impact strength and the deformation fracture of a steel covered by the invention in comparison to known steels on the test temperature,
- Fig. 4 den Gehalt an gelöstem Wasserstoff in Abhängigkeit vom Kupfergehalt nach einem 96stündigen Tauchen in ein mit Schwefelwasserstoff gesättigtes Seewasser und4 shows the content of dissolved hydrogen as a function of the copper content after a 96-hour immersion in sea water saturated with hydrogen sulfide and
- Fig. die Länge der wasserstoffinduzierten Risse in Abhängigkeit vom Wasserstoffgehalt.Fig. The length of the hydrogen-induced cracks depending on the hydrogen content.
Die den Diagrammen der Fig. 1 und 2 zugrundeliegenden Versuche wurden an den Stählen 1 bis 5 der aus der nachfolgenden Tabelle ersichtlichen Zusammensetzung durchgeführt. Von den angegebenen fallen die Stähle 2 und 3 unter die Erfindung.
- 2. Hoesch-Berichte 1/72, Seiten 5-20
- 3. Jasper H.K. Achtelik, «Kaltzähe Stähle», Nikkelinformationsbüro, 1964.
- 2. Hoesch reports 1/72, pages 5-20
- 3. Jasper HK Achtelik, “Cold-tough steels”, Nikkel information office, 1964.
Die untersuchten Stähle besassen zudem jeweils bei Raumtemperatur eine Streckgrenze von mindestens 420 N/mm2 und eine Kerbschlagzähigkeit von mindestens 280 J/cm2.The steels examined also each had a yield strength of at least 420 N / mm 2 and a notched impact strength of at least 280 J / cm 2 at room temperature.
Des weiteren zeigen die Diagramme der Fig. 4 und 5, dass die Rissempfindlichkeit in Anwesenheit von Schwefelwasserstoff bei Kupfergehalten über etwa 0,02% besonders gering ist, so dass sich der vorgeschlagene Stahl insbesondere auch zum Transport und zur Lagerung von verunreinigtem Flüssiggas eignet. Die hohe Rissbeständigkeit erklärt sich daraus, dass im Betrieb unter dem Einfluss von Schwefelwasserstoff und Wasser eine schwache Säure entsteht. Die dabei entstehenden Wasserstoffionen wandern in den Werkstoff und scheiden sich molekular an den Korngrenzen ab. Daraus resultieren bei herkömmlichen Stählen zu einer Rissbildung führende Drücke. Bei dem erfindungsgemäss zu verwendenden Stahl löst sich hingegen ein Teil des Kupfers in der Säure. Die dabei entstehenden Ionen wandern durch Ionenaustausch an die Werkstoffoberfläche und bilden dort eine molekulare Schutzschicht aus Kupfer. Diese Kupferschicht wirkt als Sperrschicht gegen ein weiteres Eindringen des Wasserstoffs und erklärt die aus Fig. 4 ersichtliche hohe Wasserstoffbeständigkeit des erfindungsgemäss zu verwendenden Stahls.Furthermore, the diagrams in FIGS. 4 and 5 show that the crack sensitivity in the presence of hydrogen sulfide is particularly low at copper contents above about 0.02%, so that the proposed steel is particularly suitable for the transport and storage of contaminated liquid gas. The high resistance to cracking is due to the fact that a weak acid develops during operation under the influence of hydrogen sulfide and water. The resulting hydrogen ions migrate into the material and are molecularly separated at the grain boundaries. In conventional steels, this results in pressures that lead to cracking. In the steel to be used according to the invention, on the other hand, part of the copper dissolves in the acid. The resulting ions migrate to the material surface through ion exchange and form a molecular protective layer made of copper. This copper layer acts as a barrier against further penetration of the hydrogen and explains this 4 apparent high hydrogen resistance of the steel to be used according to the invention.
Claims (4)
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
AT79104222T ATE4228T1 (en) | 1978-11-02 | 1979-10-31 | USE OF MANGANESE NICKEL FINE GRAIN STEEL. |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DE2847506 | 1978-11-02 | ||
DE2847506A DE2847506C2 (en) | 1978-11-02 | 1978-11-02 | Use of a low-temperature manganese-nickel fine-grain structural steel |
Publications (3)
Publication Number | Publication Date |
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EP0010755A1 EP0010755A1 (en) | 1980-05-14 |
EP0010755B1 EP0010755B1 (en) | 1983-07-20 |
EP0010755B2 true EP0010755B2 (en) | 1986-08-06 |
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ID=6053669
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Application Number | Title | Priority Date | Filing Date |
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EP79104222A Expired EP0010755B2 (en) | 1978-11-02 | 1979-10-31 | Use of manganese and nickel-containing fine-grained structural steel |
Country Status (5)
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EP (1) | EP0010755B2 (en) |
AT (1) | ATE4228T1 (en) |
CA (1) | CA1149647A (en) |
DE (1) | DE2847506C2 (en) |
NO (1) | NO151506C (en) |
Families Citing this family (2)
Publication number | Priority date | Publication date | Assignee | Title |
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EP0262281B1 (en) * | 1986-09-25 | 1989-05-10 | MANNESMANN Aktiengesellschaft | Process for the production of tubes for use at temperatures up to minus 40 degrees celsius |
HU205393B (en) * | 1988-06-22 | 1992-04-28 | Gyoergy Vizi | Process for producing corner element of steel container from hot rolled steel plate |
Family Cites Families (11)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB974028A (en) * | 1963-02-13 | 1964-11-04 | South Durham Steel & Iron Comp | Improvements in and relating to low alloy steels |
DE1758507B1 (en) * | 1968-06-15 | 1970-12-10 | Thyssen Roehrenwerke Ag | Use of high-strength manganese-alloyed fine-grain structural steel as a material for welded objects with good low-temperature properties |
US3619302A (en) * | 1968-11-18 | 1971-11-09 | Yawata Iron & Steel Co | Method of heat-treating low temperature tough steel |
DE2039910B2 (en) * | 1970-08-11 | 1973-08-02 | Nippon Steel Corp , Tokio | HEAT TREATMENT PROCESS FOR A STEEL |
JPS5215523B1 (en) * | 1970-11-18 | 1977-04-30 | ||
CA966702A (en) * | 1972-05-12 | 1975-04-29 | Reginald N. Shaughnessy | Method for the production of high strength notch tough steel |
US3834949A (en) * | 1973-02-14 | 1974-09-10 | Inland Steel Co | Hot rolled flat steel article for cryogenic service and method for producing same |
JPS5411774B2 (en) * | 1973-02-15 | 1979-05-17 | ||
GB1436846A (en) * | 1973-03-16 | 1976-05-26 | Int Nickel Ltd | Steels |
DE2461087A1 (en) * | 1973-12-28 | 1975-07-03 | Sumitomo Metal Ind | HYDROGEN RESISTANT STEEL FOR PIPING PIPES |
US4138278A (en) * | 1976-08-27 | 1979-02-06 | Nippon Steel Corporation | Method for producing a steel sheet having remarkably excellent toughness at low temperatures |
-
1978
- 1978-11-02 DE DE2847506A patent/DE2847506C2/en not_active Expired
-
1979
- 1979-10-31 EP EP79104222A patent/EP0010755B2/en not_active Expired
- 1979-10-31 AT AT79104222T patent/ATE4228T1/en not_active IP Right Cessation
- 1979-11-01 NO NO793516A patent/NO151506C/en unknown
- 1979-11-02 CA CA000339072A patent/CA1149647A/en not_active Expired
Also Published As
Publication number | Publication date |
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NO793516L (en) | 1980-05-05 |
ATE4228T1 (en) | 1983-08-15 |
DE2847506A1 (en) | 1980-05-14 |
EP0010755B1 (en) | 1983-07-20 |
CA1149647A (en) | 1983-07-12 |
NO151506B (en) | 1985-01-07 |
DE2847506C2 (en) | 1986-04-17 |
EP0010755A1 (en) | 1980-05-14 |
NO151506C (en) | 1985-04-24 |
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