EP0142015B1 - Austenitischer Stahl - Google Patents

Austenitischer Stahl Download PDF

Info

Publication number
EP0142015B1
EP0142015B1 EP84112048A EP84112048A EP0142015B1 EP 0142015 B1 EP0142015 B1 EP 0142015B1 EP 84112048 A EP84112048 A EP 84112048A EP 84112048 A EP84112048 A EP 84112048A EP 0142015 B1 EP0142015 B1 EP 0142015B1
Authority
EP
European Patent Office
Prior art keywords
steel
steel grade
corrosion
grade according
steels
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
Application number
EP84112048A
Other languages
English (en)
French (fr)
Other versions
EP0142015A1 (de
Inventor
Jaroslav Pleva
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.)
Outokumpu Stainless AB
Original Assignee
Avesta AB
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Avesta AB filed Critical Avesta AB
Priority to AT84112048T priority Critical patent/ATE28087T1/de
Publication of EP0142015A1 publication Critical patent/EP0142015A1/de
Application granted granted Critical
Publication of EP0142015B1 publication Critical patent/EP0142015B1/de
Expired legal-status Critical Current

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
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
    • C22C38/58—Ferrous alloys, e.g. steel alloys containing chromium with nickel with more than 1.5% by weight of manganese

Definitions

  • the invention relates to an austenitic steel grade, extremely resistant especially to pitting and crevice corrosion, easily weldable and of high material strength.
  • the invention concerns also the use of the steel for products on which are made exacting demands regarding general corrosion and especially pitting and crevice corrosion, weldability, and strength.
  • the steel is developed specifically for and intended for use within the off-shore industry, e.g. in piping and tanks, and in other environments where the steel is exposed to sea water or to other chloride-containing liquids, such as in thermal power stations where sea water is used for cooling, in the bleacheries of the forest industry, in scrubbers etc.
  • Another field of application is vessels and tubes and heat exchangers for nitric acid, especially those that are cooled by sea water.
  • Piping, heat exchangers, tanks and similar equipment and apparatus are mostly made of austenitic steel with 18-21 % Ni and over 6% Mo when there, is a demand for good weldability, mechanical strength, and very high resistance to pitting and crevice corrosion.
  • the off-shore industry and other industries or plants where sea water is encountered are examples of areas where such demands are made.
  • Other fields of application are within the chemical industry, especially in the chemical bleacheries of the forest industry.
  • the alloying expenses may be reduced by the use of ferritic ELI-steels, which are also highly resistant to pitting and crevice corrosion in sea water and similar environments, provided they contain at least 25% Cr and at least 3.5% Mo.
  • ferritic ELI-steels which are also highly resistant to pitting and crevice corrosion in sea water and similar environments, provided they contain at least 25% Cr and at least 3.5% Mo.
  • a serious limitation of these materials is that they are not manufactured in thicker dimensions than about 3 mm. If the material is made thicker it becomes brittle and unweldable.
  • a primary object of the invention is to provide a steel grade which has the required combination of properties for use in welded constructions in highly corrosive environments, in spite of having a lower, rather than higher, content of expensive alloy metals than comparative conventional austenitic steels.
  • an object is to provide a steel with extremely high resistance to pitting and crevice corrosion.
  • a preferred object is to provide a steel of high resistance in other environments also, such as in HN0 3 . Typical fields of application are as indicated in the preamble.
  • a further object of the invention is to provide a steel which is easy to weld with a low energy input without any considerable loss of its corrosion resisting properties in the weld or in the heat-affected zone.
  • a preferred object is also to provide a steel with a greater mechanical strength than conventional austenitic molybdenum alloyed steels.
  • Co up to 0.5 and/or Cu up to 3.0 the balance iron and unavoidable impurities.
  • the carbon content is desirable to keep the carbon content as low as possible. Normally, the carbon content is therefore maximally 0.02%, preferably maximally 0.015%.
  • the roles of manganese and nitrogen in the steel are complex.
  • the manganese partly functions as an austenitizing agent, partly aids in dissolving nitrogen in the steel. Certain indications suggest that the manganese in this alloy directly influences the corrosion properties favourably.
  • the nitrogen works as an austenitizing agent and adds to the corrosion resistance as well.
  • a required amount of nickel is added in addition to manganese and nitrogen.
  • a synergistic effect of molybdenum and nitrogen as regards resistance to pitting and crevice corrosion is also attained with the steel according to the invention. In other words, the nitrogen strengthens the favourable effect of the molybdenum.
  • Chromium is a fundamental element for resistance to general corrosion and also enhances the resistance to other types of corrosion.
  • a preferred characteristic of the steel according to the invention is that the chromium equivalent (according to Shaeffler) is at least 24, and the nickel equivalent is at least 25, the ratio of the chromium equivalent to the nickel equivalent being no more than 0.9, preferably no more than 0.8.
  • the steel is non-stabilized, which means that it does not contain any significant, intentional additions of niobium, tantalum, titanium or zirconium.
  • the total amount of these elements must not exceed 0.1%. Higher amounts would have a too detrimental effect upon the corrosion resistance, because these elements readily combine not only with carbon but also with nitrogen present in the steel to form nitrides, such that the effective nitrogen content would be reduced.
  • a preferred composition of the steel according to the invention is the following: optionally Co up to 0.5 and/or Cu up to 3.0 the balance iron and unavoidable impurities.
  • the total amount of Nb+Ta+Ti+Zr shall not exceed 0.1 %. More preferably the carbon content is 0.015% at the maximum.
  • copper may be included up to no more than 3%.
  • the possible effects of including copper in the steel according to the invention has not been subject to investigation, however. It is conceivable that it may improve corrosion resistance in strong acids.
  • the copper content should be limited to a max. of 0.5%.
  • Copper at concentrations less than 0.5% may be found in secondary metal or traces of process metallurgy additions.
  • cobalt This is an expensive element. Wilful additions of this element should therefore be avoided.
  • Cobalt also has the drawback of becoming radioactive when subjected to radiation, which makes cobalt alloyed material impermissible for such parts of nuclear power stations as are exposed to radiation. The cobalt content therefore should be restricted to a max. of 0.5%.
  • traces of elements added for process metallurgy reasons may be mentioned aluminium and calcium. Niobium, vanadium and titanium should not be present at levels exceeding those of impurities.
  • each steel sample made and investigated is presented in Table 1, group 1.
  • Steels Nos. 1-15 were manufactured as melts with a weight of 2 kg. Of these, those with a totally austenitic structure (after rolling and solution heating) were subjected to further investigations, especially regarding their corrosion properties. In order to evaluate the initial investigations, a melt of 50 kg was then manufactured, steel No. 16.
  • Groups 2 and 3 of Table 1 present data for commercially available steels tested, as well as figures from the literature concerning other steels, see the reference list on pp. 2-3.
  • the B charges (steels Nos. 1-15) were forged to 30 mm square section and rolled to strips of 3 mm thickness and then solution heated (1100°C/1 h/H 2 0). No notable problems of poor hot state ductility were encountered.
  • Steel No. 3 were not nearly as resistant as steel No. 6 and ended up somewhat below the result of steel No. 20, in spite of having equal content of chromium and nickel and a molybdenum content only 1.5 and a nitrogen content only 0.21% lower than that of steel No. 6.
  • the samples were of the steel grade No. 16 according to the invention and the comparison materials 24 and 25. All samples had been ground and pickled in 10% HN03+1% HF, 10 min at 60°C, prior to exposure.
  • Steel No. 16 had the lowest weight loss in g/M2 and the lowest pit depth while steel No. 25 had the highest weight loss and greatest pit depth.
  • the exposure confirmed the laboratory data presented above on the 2 kg samples of steel No. 6.
  • the corrosion test carried out in the laboratory of the corrosion properties of steel No. 16 are summarized in Table 5.
  • the steel was MIG welded with an electrode of the type Avesta P12. Especially noteworthy is that there were no corrosion attacks, neither in the weld nor in the heat affected zone. There were no problems associated with the welding itself.
  • the steel could be welded with a very low heat input, 0.235 kJ/mm.
  • the weld was of a high quality smooth, without spatter or pores.
  • the quench annealed hot rolled plate showed the following mechanical properties:

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Heat Treatment Of Steel (AREA)
  • Golf Clubs (AREA)
  • Dowels (AREA)
  • Powder Metallurgy (AREA)

Claims (10)

1. Stahlsorte des austenitischen Typs, die insbesondere gegen Lochfraß und Spaltkorrosion extrem widerstandsfähig, leicht schweißbar und von hoher Materialfestigkeit ist, dadurch gekennzeichnet, daß sie die folgende chemische Zusammensetzung in Gew.-% hat:
Figure imgb0013
gegebenenfalls Co bis zu 0,5 und/oder Cu bis zu 3,0 Rest Eisen und unvermeidbare Verunreinigungen.
2. Stahlsorte nach Anspruch 1, dadurch gekennzeichnet, daß ihr sogenannter PRE-Wert (=%Cr+3,3x%Mo+16x%N) zumindest 41, vorzugsweise von 41 bis 45 beträgt.
3. Stahlsorte nach Anspruch 1, dadurch gekennzeichnet, daß sie 14-17 Ni enthält.
4. Stahlsorte nach Anspruch 1, dadurch gekennzeichnet, daß sie 9-11 Mn enthält.
5. Stahlsorte nach Anspruch 1, dadurch gekennzeichnet, daß sie 18-23 Cr enthält.
6. Stahlsorte nach Anspruch 1, dadurch gekennzeichnet, daß sie 4-8 Mo enthält.
7. Stahlsorte nach Anspruch 1, dadurch gekennzeichnet, daß sie 0,3-0,48 enthält.
8. Stahlsorte nach einem der Ansprüche 1-7, dadurch gekennzeichnet, daß sie nicht mehr als 0,02 C und eine Gesamtmenge von nicht mehr als 0,1% an Niobium, Tantal, Titan und Zirkon enthält.
9. Stahlsorte nach einem der vorhergehenden Ansprüche, dadurch gekennzeichnet, daß ihr Cr-Äquivalent (=%Cr+%Mo+1,5x%Si+O,5x%Nb) zumindest 24, daß ihr Ni-Äquivalent (=%Ni+O,5x%Mn+30 (%C+%N)) zumindest 25, und daß der Quotient Cr-Äqu./Ni-Äqu. weniger als oder gleich 0,9, vorzugsweise weniger als oder gleich 0,8 ist.
10. Stahlsorte nach einem der Ansprüche 1-9, dadurch gekennzeichnet, daß sie die folgende Zusammensetzung hat:
Figure imgb0014
gegebenenfalls Co bis zu 0,5 und/oder Cu bis zu 3,0 Rest Eisen und unvermeidbare Verunreinigungen.
EP84112048A 1983-10-21 1984-10-08 Austenitischer Stahl Expired EP0142015B1 (de)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT84112048T ATE28087T1 (de) 1983-10-21 1984-10-08 Austenitischer stahl.

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
SE8305795A SE441455B (sv) 1983-10-21 1983-10-21 Stal av austenitisk typ
SE8305795 1983-10-21

Publications (2)

Publication Number Publication Date
EP0142015A1 EP0142015A1 (de) 1985-05-22
EP0142015B1 true EP0142015B1 (de) 1987-07-01

Family

ID=20352991

Family Applications (1)

Application Number Title Priority Date Filing Date
EP84112048A Expired EP0142015B1 (de) 1983-10-21 1984-10-08 Austenitischer Stahl

Country Status (4)

Country Link
EP (1) EP0142015B1 (de)
AT (1) ATE28087T1 (de)
DE (1) DE3464504D1 (de)
SE (1) SE441455B (de)

Families Citing this family (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4560408A (en) * 1983-06-10 1985-12-24 Santrade Limited Method of using chromium-nickel-manganese-iron alloy with austenitic structure in sulphurous environment at high temperature
EP0342574A1 (de) * 1988-05-17 1989-11-23 Thyssen Edelstahlwerke AG Korrosionsbeständiger austenitischer Stahl
JPH0699781B2 (ja) * 1989-08-11 1994-12-07 株式会社日立製作所 耐中性子照射脆化に優れたオーステナイト鋼及びその用途
SE465373B (sv) * 1990-01-15 1991-09-02 Avesta Ab Austenitiskt rostfritt staal
FR2705689B1 (fr) * 1993-05-28 1995-08-25 Creusot Loire Acier inoxydable austénitique à haute résistance à la corrosion par les milieux chlorurés et sulfuriques et utilisations.
JP2004043845A (ja) * 2002-07-09 2004-02-12 Nippon Steel Corp 流体部品
JP2004043844A (ja) * 2002-07-09 2004-02-12 Nippon Steel Corp 流体部品
JP2005281855A (ja) * 2004-03-04 2005-10-13 Daido Steel Co Ltd 耐熱オーステナイト系ステンレス鋼及びその製造方法
CN103703158B (zh) 2011-05-26 2016-06-08 新加坡商·联合管线亚太有限公司 奥氏体不锈钢

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1205289B (de) * 1964-05-27 1965-11-18 Phoenix Rheinrohr Ag Verwendung einer austenitischen Stahllegierung als Werkstoff fuer geschweisste Bauteile, die dem Angriff von Seewasser und/oder Meeres-atmosphaere ausgesetzt sind
FR1466926A (fr) * 1966-02-03 1967-01-20 Suedwestfalen Ag Stahlwerke éléments de construction en acier austénitique
BE757048A (fr) * 1969-10-09 1971-03-16 Boehler & Co Ag Geb Applications d'un acier entierement austenique dans des conditions corrodantes
JPS5424364B2 (de) * 1973-05-04 1979-08-21
US3912503A (en) * 1973-05-14 1975-10-14 Armco Steel Corp Galling resistant austenitic stainless steel

Also Published As

Publication number Publication date
DE3464504D1 (en) 1987-08-06
EP0142015A1 (de) 1985-05-22
SE8305795D0 (sv) 1983-10-21
ATE28087T1 (de) 1987-07-15
SE441455B (sv) 1985-10-07
SE8305795L (sv) 1985-04-22

Similar Documents

Publication Publication Date Title
EP0156778B1 (de) Rostfreier ferritisch-austenitischer Stahl
CA2165817C (en) Ferritic-austenitic stainless steel and use of the steel
EP2773785B1 (de) Duplexedelstahl
JP7059357B2 (ja) 二相ステンレスクラッド鋼板およびその製造方法
US5286310A (en) Low nickel, copper containing chromium-nickel-manganese-copper-nitrogen austenitic stainless steel
US20100000636A1 (en) Duplex stainless steel
EP3575427B1 (de) Zweiphasiger edelstahlarmierter stahl und verfahren zur herstellung davon
GB1565419A (en) Stainless steel welded articles
CA1214667A (en) Duplex alloy
EP0142015B1 (de) Austenitischer Stahl
EP0438992B1 (de) Austenitischer rostfreier Stahl
US3957544A (en) Ferritic stainless steels
EP0458606B1 (de) Palladium enthaltender austenitischer Stahl zur Verwendung in Gegenwart von konzentrierter Schwefelsäure auf hoher Temperatur
US4765957A (en) Alloy resistant to seawater and other corrosive fluids
US4832765A (en) Duplex alloy
GB1564243A (en) Austenitic stainless steel
JPS6358214B2 (de)
US20210292876A1 (en) Austenitic Heat Resistant Alloy and Welded Joint Including the Same
JP4465066B2 (ja) フェライト・オーステナイト二相系ステンレス鋼用溶接材料
US4050928A (en) Corrosion-resistant matrix-strengthened alloy
RU2222633C2 (ru) Сталь ферритная коррозионно-стойкая
US3672876A (en) Ductile corrosion-resistant ferrous alloys containing chromium
JPH08134593A (ja) 耐海水腐食性と耐硫化水素腐食性に優れた高強度オーステナイト合金
JPS61136662A (ja) 耐応力腐食割れ性にすぐれたオ−ステナイト系ステンレス鋼
JPH02115350A (ja) 耐海水腐食性に優れたステンレス鋼

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

AK Designated contracting states

Designated state(s): AT BE CH DE FR GB IT LI LU NL SE

17P Request for examination filed

Effective date: 19851015

17Q First examination report despatched

Effective date: 19860827

GRAA (expected) grant

Free format text: ORIGINAL CODE: 0009210

RAP1 Party data changed (applicant data changed or rights of an application transferred)

Owner name: AVESTA AKTIEBOLAG

AK Designated contracting states

Kind code of ref document: B1

Designated state(s): AT BE CH DE FR GB IT LI LU NL SE

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: NL

Effective date: 19870701

Ref country code: LI

Effective date: 19870701

Ref country code: IT

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT;WARNING: LAPSES OF ITALIAN PATENTS WITH EFFECTIVE DATE BEFORE 2007 MAY HAVE OCCURRED AT ANY TIME BEFORE 2007. THE CORRECT EFFECTIVE DATE MAY BE DIFFERENT FROM THE ONE RECORDED.

Effective date: 19870701

Ref country code: CH

Effective date: 19870701

Ref country code: BE

Effective date: 19870701

Ref country code: AT

Effective date: 19870701

REF Corresponds to:

Ref document number: 28087

Country of ref document: AT

Date of ref document: 19870715

Kind code of ref document: T

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: SE

Effective date: 19870731

REF Corresponds to:

Ref document number: 3464504

Country of ref document: DE

Date of ref document: 19870806

ET Fr: translation filed
REG Reference to a national code

Ref country code: CH

Ref legal event code: PL

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: LU

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 19871031

NLV1 Nl: lapsed or annulled due to failure to fulfill the requirements of art. 29p and 29m of the patents act
PLBE No opposition filed within time limit

Free format text: ORIGINAL CODE: 0009261

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: NO OPPOSITION FILED WITHIN TIME LIMIT

26N No opposition filed
PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: GB

Payment date: 19910927

Year of fee payment: 8

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: FR

Payment date: 19911007

Year of fee payment: 8

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: DE

Payment date: 19911031

Year of fee payment: 8

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: GB

Effective date: 19921008

GBPC Gb: european patent ceased through non-payment of renewal fee

Effective date: 19921008

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: FR

Effective date: 19930630

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: DE

Effective date: 19930701

REG Reference to a national code

Ref country code: FR

Ref legal event code: ST