DE2231559C3 - Use of a heat-resistant, niobium-containing fine-grain structural steel as a material for welded boiler drums and other welded pressure vessels - Google Patents
Use of a heat-resistant, niobium-containing fine-grain structural steel as a material for welded boiler drums and other welded pressure vesselsInfo
- Publication number
- DE2231559C3 DE2231559C3 DE19722231559 DE2231559A DE2231559C3 DE 2231559 C3 DE2231559 C3 DE 2231559C3 DE 19722231559 DE19722231559 DE 19722231559 DE 2231559 A DE2231559 A DE 2231559A DE 2231559 C3 DE2231559 C3 DE 2231559C3
- Authority
- DE
- Germany
- Prior art keywords
- niobium
- welded
- steel
- stress
- welding
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
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
- C22C38/12—Ferrous alloys, e.g. steel alloys containing tungsten, tantalum, molybdenum, vanadium, or niobium
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
- C21D9/50—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for welded joints
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Crystallography & Structural Chemistry (AREA)
- Heat Treatment Of Steel (AREA)
- Heat Treatment Of Articles (AREA)
- Forging (AREA)
Description
xationsversuch nach Murray erreicht man eine Standzeit von etwa 30 Minuten. Von Vorteil ist weiterhin, daß durch die Abstimmung der einzelnen Legierungsbestandteile aufeinander erreicht wird, daß die Temperatur für die Anlaßbehandlung und das Spannungsfreiglühen nach dem Schweißen übereinstimmen. Der niedrige Kohlenstoffgehalt, die Feinkörnigkeit, die Zähigkeit und auch die Widerstandsfähigkeit gegen stress-relief-cracking des Werkstoffs bewirken, daß seine Schweißeignung ausreicht, um ein Schweißen im Iediglich normalgeglühten, nicht-angelassenen Zustand zu ermöglichen. Diese beiden Eigenschaften, nämlich gleiche Temperatur für das Anlassen und das Spannungsfreiglühen und die Schweißmöglichkeit im normalgeglühten Zustand machen es möglich, das Anlassen vor dem Schweißen einzusparen und mit dem ohnehin erforderlichen Spannungsfreiglühen nach dem Schweißen zusammenzulegen. Damit wird ein ganzer Arbeitsgang eingespart und gegenüber dem Stand der Technik eine preisgünstigere Herstellung möglich. Die Schweißeignung wird dadurch optimal eingestellt, daß nur geringe Mengen von sich gegenseitig in bezug auf die Warmstreckgrenze positiv beeinflussenden Legierungselementen verwendet werden, so daß mit dem geringsten Legierungsaufwand die größtmögliche Wirkung erzielt wird.xation attempt after Murray one reaches one Standing time of about 30 minutes. Another advantage is that through the coordination of the individual alloy components that the temperature for the tempering treatment and the stress-relieving annealing is achieved match after welding. The low carbon content, the fine grain, the Toughness and also the resistance to stress-relief-cracking of the material cause its Welding suitability is sufficient for welding in every case to enable normalized, non-tempered condition. These two properties, namely the same Temperature for tempering and stress-relieving annealing and the possibility of welding in normal annealed State make it possible to save the annealing before welding and with the already necessary Put together stress-relieving annealing after welding. This becomes a whole process saved and a cheaper production possible compared to the prior art. The weldability is optimally adjusted in that only small amounts of each other with respect to the hot yield point positively influencing alloy elements are used, so that with the least Alloy expenditure the greatest possible effect is achieved.
Beim Normalglühen und Austenitisieren vor einer Vergütungsbehandlung vor allem dicker Bleche und dickwandiger Teile tritt ein häufig beobachteter Wärmebehandlungsfehler auf. Der Ac3-Punkt wurde zwar überschritten, doch die Haltezeit vor allem in der Kernzone reichte nicht aus, um eine vollständige Alpha-Gamma-Umwandlung zu erziehen. Da^ Sekundärgefüge läßt dann verschiedene Gefügeformen nebeneinander erkennen, die eine geringere Zähigkei: bewirken. Zur Vermeidung dieses Fehlers werden bei der Verwendung des Stahles im erfindungsgemäßen Sinne die Bleche und Schmiedestücke zunächst bei 90°C über Ac3 normalgeglüht, dann langsam auf etwa 20—30° C über Ac3 abgekühlt und nach Temperaturausgleich auf Raumtemperatür abgekühlt Dieses Abkühlen kann entweder an ruhender Luft oder beschleunigt, z. B. in Wasser, erfolgen. Das Anlassen und Spannungsfreiglühen der fertig zusammengeschweißten Bleche und Schmiedestücke erfolgt vorteilhaft mit einer Haltezeit, deren Dauer in Minuten etwa dem 2- bis 3fachen der Blechdicke in mm entspricht. Dabei wird auch ein zuverlässiger Abbau der Spannungen erreicht.When normalizing and austenitizing prior to tempering, especially thick sheet metal and thick-walled parts, a frequently observed heat treatment error occurs. The Ac3 point was exceeded, but the holding time, especially in the core zone, was not sufficient to bring about a complete alpha-gamma conversion. The secondary structure then reveals different structure forms side by side, which cause a lower toughness. To avoid this error, when using the steel in the sense of the invention, the sheets and forgings are initially normalized at 90 ° C above Ac 3 , then slowly cooled to about 20-30 ° C above Ac 3 and, after temperature equalization, cooled to room temperature in still air or accelerated, e.g. B. in water. The tempering and stress-relieving annealing of the completely welded sheets and forgings is advantageously carried out with a holding time, the duration of which in minutes corresponds approximately to 2 to 3 times the sheet thickness in mm. A reliable reduction in tension is also achieved in this way.
Der Erfindungsgegenstand gibt die Möglichkeit, durch die Kombination einer bestimmten Analyse mit einer einfachen Wärmebehandlung das Problem »stress-relief-cracking« zu überwinden. Hierbei ergeben sich bei einer höheren Normalglühtemperatur von 990° C bessere Kerbschlagzähigkeitswerte als bei einer Normalglühtemperatur von 930° C.The subject matter of the invention gives the possibility, by combining a certain analysis with to overcome the problem of "stress-relief-cracking" with a simple heat treatment. Result here At a higher normalizing temperature of 990 ° C, better notched impact strength values than with a Normal annealing temperature of 930 ° C.
•Κ• Κ
Claims (2)
keit beim Spannungsfreiglühen nach dem Schweißen für 0,10—0,50% Si
geschweißte Kesseltrommeln und andere geschweißte 1,00—1,60% Mn
Druckbehälter. " 45 max. 0,025% P
Es ist der Vorschlag bekannt, derartigen Stählen zur max. 0,025% S
Verfeinerung des Primär- und Sekundär-Gefüges Niob 0,60—1,20% Ni
in der Größenordnung von 0,03 bis 0,06% zuzugeben. 0,20—0,40% Cr
Niobgehalte in dieser Größenordnung sollen eine we- 0,20—0,40% Mo
sentliche Verbesserung der Zähigkeit und eine Erhö- 50 0,005—0,015% Nb
hung der Warmstreckgrenze bewirken. So wird in der Rest Eisen und übliche Verunreinigungen
DE-AS 12 63 051 ein Verfahren zur WärmebehandlungThe invention relates to the use of a heat-resistant, niobium-containing fine-grain structural steel with heat-resistant, niobium-containing fine-grain structural steel as a material with improved toughness and insensitivity to cracks - a maximum of 0.16% C
Stress relief annealing after welding for 0.10-0.50% Si
welded boiler drums and other welded 1.00-1.60% Mn
Pressure vessel. "45 max. 0.025% P
The proposal is known to use such steels to a maximum of 0.025% S
Refinement of the primary and secondary structure Niobium 0.60-1.20% Ni
to be added in the order of magnitude of 0.03 to 0.06%. 0.20-0.40% Cr
Niobium contents in this order of magnitude should be 0.20-0.40% Mo
substantial improvement in toughness and an increase in 50 0.005-0.015% Nb
increase the hot yield strength. So in the rest there will be iron and usual impurities
DE-AS 12 63 051 a method for heat treatment
Priority Applications (4)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DE19722231559 DE2231559C3 (en) | 1972-06-28 | 1972-06-28 | Use of a heat-resistant, niobium-containing fine-grain structural steel as a material for welded boiler drums and other welded pressure vessels |
JP7134473A JPS5410921B2 (en) | 1972-06-28 | 1973-06-26 | |
FR7323693A FR2190932A1 (en) | 1972-06-28 | 1973-06-28 | Niobium-contg steel - resistant to stress relief cracking and suitable for welded press tank pts |
SE7309162A SE409215B (en) | 1972-06-28 | 1973-06-28 | JOINT WELDED FOREMAL AND METHOD AND MEANS TO PRODUCE THIS |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DE19722231559 DE2231559C3 (en) | 1972-06-28 | 1972-06-28 | Use of a heat-resistant, niobium-containing fine-grain structural steel as a material for welded boiler drums and other welded pressure vessels |
Publications (3)
Publication Number | Publication Date |
---|---|
DE2231559A1 DE2231559A1 (en) | 1974-01-10 |
DE2231559B2 DE2231559B2 (en) | 1977-12-29 |
DE2231559C3 true DE2231559C3 (en) | 1986-07-10 |
Family
ID=5849019
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
DE19722231559 Expired DE2231559C3 (en) | 1972-06-28 | 1972-06-28 | Use of a heat-resistant, niobium-containing fine-grain structural steel as a material for welded boiler drums and other welded pressure vessels |
Country Status (4)
Country | Link |
---|---|
JP (1) | JPS5410921B2 (en) |
DE (1) | DE2231559C3 (en) |
FR (1) | FR2190932A1 (en) |
SE (1) | SE409215B (en) |
Family Cites Families (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB1084231A (en) * | 1900-01-01 | |||
GB497011A (en) * | 1936-06-24 | 1938-12-09 | Electro Metallurg Co | Steels |
DE1236051B (en) * | 1962-11-02 | 1967-03-09 | Rowenta Metallwarenfab Gmbh | Moment on switch |
PL79948B1 (en) * | 1968-01-31 | 1975-08-30 | Mitsubishi Jukogyo Kabushiki Kaisha | |
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 |
-
1972
- 1972-06-28 DE DE19722231559 patent/DE2231559C3/en not_active Expired
-
1973
- 1973-06-26 JP JP7134473A patent/JPS5410921B2/ja not_active Expired
- 1973-06-28 FR FR7323693A patent/FR2190932A1/en active Granted
- 1973-06-28 SE SE7309162A patent/SE409215B/en unknown
Also Published As
Publication number | Publication date |
---|---|
FR2190932B1 (en) | 1976-10-01 |
FR2190932A1 (en) | 1974-02-01 |
DE2231559B2 (en) | 1977-12-29 |
SE409215B (en) | 1979-08-06 |
DE2231559A1 (en) | 1974-01-10 |
JPS5410921B2 (en) | 1979-05-10 |
JPS4952712A (en) | 1974-05-22 |
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Legal Events
Date | Code | Title | Description |
---|---|---|---|
C3 | Grant after two publication steps (3rd publication) | ||
8339 | Ceased/non-payment of the annual fee |