EP0057316A1 - Ferritischer, rostfreier, korrosionsbeständiger, schweissbarer Stahl mit geringem Gehalt an Zwischengittersubstanzen und Verfahren zu seiner Herstellung - Google Patents

Ferritischer, rostfreier, korrosionsbeständiger, schweissbarer Stahl mit geringem Gehalt an Zwischengittersubstanzen und Verfahren zu seiner Herstellung Download PDF

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Publication number
EP0057316A1
EP0057316A1 EP81305667A EP81305667A EP0057316A1 EP 0057316 A1 EP0057316 A1 EP 0057316A1 EP 81305667 A EP81305667 A EP 81305667A EP 81305667 A EP81305667 A EP 81305667A EP 0057316 A1 EP0057316 A1 EP 0057316A1
Authority
EP
European Patent Office
Prior art keywords
less
stainless steel
ferritic stainless
corrosion resistant
steel
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
EP81305667A
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English (en)
French (fr)
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EP0057316B1 (de
Inventor
Thomas Humes Mccunn
Harry Edward Deverell
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.)
Allegheny Ludlum Steel Corp
Original Assignee
Allegheny Ludlum Steel Corp
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Application filed by Allegheny Ludlum Steel Corp filed Critical Allegheny Ludlum Steel Corp
Priority to AT81305667T priority Critical patent/ATE12527T1/de
Publication of EP0057316A1 publication Critical patent/EP0057316A1/de
Application granted granted Critical
Publication of EP0057316B1 publication Critical patent/EP0057316B1/de
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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
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/26—Ferrous alloys, e.g. steel alloys containing chromium with niobium or tantalum
    • 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
    • C22C38/22—Ferrous alloys, e.g. steel alloys containing chromium with molybdenum or tungsten
    • 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
    • C22C38/28—Ferrous alloys, e.g. steel alloys containing chromium with titanium or zirconium

Definitions

  • the present invention relates to a low interstitial, corrosion resistant, weldable ferritic stainless steel with improved toughness and to a process for the manufacture thereof. More specifically, the present invention is directed to a low interstitial, corrosion resistant, weldable ferritic stainless steel with a small addition of either columbium or titanium to improve the toughness when the maximum achievable cooling rate is limited.
  • a ferritic stainless steel must have superior pitting and crevice corrosion resistance in order to be used in certain chemical environments as for example in power plants exposed to sea water, and pulp and paper process equipment.
  • Stainless steel containing 29% chromium and 4% molybdenum are highly resistant to crevice corrosion. These steels require a low level of interstitials, for example a total carbon plus nirtogen content of less than 0.025% by weight, to have good post-welding ductility and intergranular corrosion resistance.
  • Toughness is the ability of a metal to absorb energy by deforming plastically before fracturing.
  • the transition temperature is the temperature at which the fracture which occurs from the impact is 50 percent shear (ductile) and 50 percent cleavage (brittle).
  • the toughness of the 29% chromium - 4% molybdenum alloy is low compared to substantially lower chromium alloys of an equivalent carbon and nitrogen content because of the high alloy content.
  • the toughness of the 29% chromium - 4% molybdenum alloy is improved by water-quenching to speed up the cooling process instead of the slower air-cooling.
  • the water-quenching process is not poss- .ible or practical to use, so a method is needed to improve the toughness of the steel in those situations where the maximum cooling rate is limited.
  • United States Patent No. 3,807,991 teaches the addition of between 13 and 29 times the amount of nitrogen or between 0.065% and 0.363% columbium to a steel of 1% molybdenum for improved toughness and intergranular corrosion resistance in the air-cooled condition.
  • An object of the present invention is to provide a low interstitial, corrosion resistant, weldable ferritic stainless-steel with a high molybdenum content which exhibits improves toughness in heavier section thickness when the maximum achievable cooling rate is limited.
  • a further object of the present invention is to provide a low interstitial, corrosion resistant, weldable ferritic stainless steel with a high molybdenum content which exhibits improved toughness due to a small addition of either columbium or titanium.
  • this invention provides a low interstitial ferritic stainless steel which is corrosion resistant and weldable at room temperature.
  • the improvement of the present invention being an addition of a small critical amount of columbium and/or titanium to improve the toughness of the steel in situations where water quenching is impossible or impractical.
  • the present invention provides a low interstitial, corrosion resistant, weldable ferritic stainless steel with improved toughness characterized in that it consists of, by weight percent: 25.0%-35.0% chromium, 3.6%-5.6% molybdenum, less than 3% nickel, less than 2% manganese, less than 2.0% silicon, less than 0.5% aluminum, less than 0.50% copper, less than 0.050% phosphorus, less than 0.05% sulfer, less than 0.01% carbon, less than 0.02% nitrogen, the sum of the carbon and nitrogen being less than 0.025%, 0.05-050% of columbium and/or titanium, and the balance of iron.
  • the present invention further provides a process for the manufacture of ferritic stainless steel of improved toughness wherein said steel is hot rolled, annealed and cold-rolled to strip thickness, characterized in that the process comprises air-cooling from the annealing temperature before cold rolling a ferritic stainless steel consisting essentially of, by weight per cent: 25.0% - 35.0% chromium, 3.6% - 5.6% molybdenum, less than 3.0% nickel, less than 2.0% manganese, less than 2.0% silicon, less than 0.5% aluminum, less than 0.5% copper, less than 0.5% phosphorus, less than 0.05% sulfer, less than 0.01% carbon, less than 0.02% nitrogen, the sum of the carbon and nitrogen being less than 0.025%, 0.05% - 0.50% of columbium and/or titanium, and the balance iron, so as to produce a steel with a Charpy impact transition temperature of below -17.8°C (O°F) as cold-rolled to a thickness of 1.575mm(0.062 inches).
  • Chromium and molybdenum are preferably present in respective amounts of 28.5% to 30.5% and 3.75% to 4.75%.
  • Columbium and/or titanium is present preferably in the amount of 0.05% to 0.20%.
  • Manganese and silicon are each usually present in amounts of less than 1%.
  • Aluminum, copper, phosphorous, and sulfer are present usually in amounts of less than 0.1%.
  • Carbon and nitrogen are present preferably in amounts of less than 0.008% and 0.016% respectively.
  • This invention relates to a low interstitial ferritic stainless steel having a chromium content of between 25.0% and 35.0% and a molybdenum content of between 3.6% and 5.6%.
  • a small amount of columbium or titanium of between 0.05% and 0.20% is added to the steel composition to improve its toughness when the maximum achievable cooling rate is limited.
  • Ingots from four heats were vacuum-induction melted to the compositions given in Table I.
  • the ingots were conditioned, heated to a temperature of 1121°C(2050°F) and hot rolled to a strip about 3.556mm (0.140 in.) thick.
  • the hot rolled band was annealed at a temperature of 1010°C(1850°F), and water-quenched and cold rolled to a thickness of 1.575mm(0.062 in.).
  • the strip was then annealed at a temperature of 1010°C(1850°F), water-quenched and TIG welded.
  • the impact transition temperatures of the air-cooled specimens are higher than those of the water-quenched specimens it can be seen from Table II that the difference in impact transition temperatures of an air-cooled and a water-quenched 1.575mm(0.062 in.) thick steelstrip is less than 38°C (100°F). Whereas the difference in impact transition temperature for prior art compositions is 115°C(240°F).
  • the impact transition temperature of the 1.575mm (0.062 in.) steel strip of a composition according to the present invention is below -17.8°C(0°F) whereas that of prior art composition A is 54°C(130°F). It is essential that the impact transition temperature of such a steel strip be below room temperature so that the steel strip will not crack upon welding. Steels of prior art compositions had to be water-quenched before cold rolling in order to achieve the necessary toughness characteristics.
  • the composition of this invention enables us to achieve good toughness characteristics by air-cooling the steel before cold-rolling instead.
  • Corrosion tests were also performed on the 1.575mm (0.062 in.) thick strip in the as welded condition and on the base metal specimens which were heat treated at 1232 0 C (225 0 0 F) and air-cooled to simulate the heat affected zone upon welding a heavier thickness.
  • the specimens 25.4mm x 50.8mm (1 in. x 2 in.) were exposed to a boiling solution of ferritic sulfate-50% sulfuric acid for 120 hours according to ASTM A262 Practice B for intergranular corrosion testing. The corrosion rates are given in Table III.

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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)
  • Treatment Of Steel In Its Molten State (AREA)
  • Heat Treatment Of Sheet Steel (AREA)
  • Pressure Welding/Diffusion-Bonding (AREA)
  • Soft Magnetic Materials (AREA)
  • Laminated Bodies (AREA)
  • Heat Treatment Of Articles (AREA)
EP81305667A 1981-01-16 1981-12-02 Ferritischer, rostfreier, korrosionsbeständiger, schweissbarer Stahl mit geringem Gehalt an Zwischengittersubstanzen und Verfahren zu seiner Herstellung Expired EP0057316B1 (de)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT81305667T ATE12527T1 (de) 1981-01-16 1981-12-02 Ferritischer, rostfreier, korrosionsbestaendiger, schweissbarer stahl mit geringem gehalt an zwischengittersubstanzen und verfahren zu seiner herstellung.

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US22556681A 1981-01-16 1981-01-16
US225566 1981-01-16

Publications (2)

Publication Number Publication Date
EP0057316A1 true EP0057316A1 (de) 1982-08-11
EP0057316B1 EP0057316B1 (de) 1985-04-03

Family

ID=22845370

Family Applications (1)

Application Number Title Priority Date Filing Date
EP81305667A Expired EP0057316B1 (de) 1981-01-16 1981-12-02 Ferritischer, rostfreier, korrosionsbeständiger, schweissbarer Stahl mit geringem Gehalt an Zwischengittersubstanzen und Verfahren zu seiner Herstellung

Country Status (10)

Country Link
EP (1) EP0057316B1 (de)
JP (1) JPS57137455A (de)
KR (1) KR880001356B1 (de)
AT (1) ATE12527T1 (de)
AU (1) AU7829481A (de)
BR (1) BR8200150A (de)
CA (1) CA1184403A (de)
DE (1) DE3169748D1 (de)
ES (1) ES8305049A1 (de)
MX (1) MX156238A (de)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2193726A (en) * 1986-07-23 1988-02-17 Jgc Corp Carbon containing compound treating apparatus with resistance to carbon deposition
EP0388283A1 (de) * 1989-03-16 1990-09-19 Ugine S.A. Rostfreier ferritischer Stahl und Verfahren zur Herstellung dieses Stahls
US5942184A (en) * 1993-10-20 1999-08-24 Sumitomo Metal Industries, Ltd. Stainless steel for high-purity gases

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4942922A (en) * 1988-10-18 1990-07-24 Crucible Materials Corporation Welded corrosion-resistant ferritic stainless steel tubing having high resistance to hydrogen embrittlement and a cathodically protected heat exchanger containing the same
JP2739531B2 (ja) * 1991-09-17 1998-04-15 日新製鋼株式会社 溶接部耐食性に優れるフェライト系ステンレス鋼

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2183715A (en) * 1938-05-21 1939-12-19 Electro Metallurg Co Corrosion resistant steel alloy
FR2158943A5 (de) * 1971-10-26 1973-06-15 Deutsche Edelstahlwerke Ag
FR2180117A1 (de) * 1972-04-14 1973-11-23 Nyby Bruk Ab
SU515825A1 (ru) * 1974-05-13 1976-05-30 Предприятие П/Я В-2120 Ферритна сталь
FR2377457A1 (fr) * 1977-01-14 1978-08-11 Thyssen Edelstahlwerke Ag Acier ferritique au chrome-nickel-molybdene resistant a la corrosion

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4331474A (en) * 1980-09-24 1982-05-25 Armco Inc. Ferritic stainless steel having toughness and weldability

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2183715A (en) * 1938-05-21 1939-12-19 Electro Metallurg Co Corrosion resistant steel alloy
FR2158943A5 (de) * 1971-10-26 1973-06-15 Deutsche Edelstahlwerke Ag
FR2180117A1 (de) * 1972-04-14 1973-11-23 Nyby Bruk Ab
SU515825A1 (ru) * 1974-05-13 1976-05-30 Предприятие П/Я В-2120 Ферритна сталь
FR2377457A1 (fr) * 1977-01-14 1978-08-11 Thyssen Edelstahlwerke Ag Acier ferritique au chrome-nickel-molybdene resistant a la corrosion

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2193726A (en) * 1986-07-23 1988-02-17 Jgc Corp Carbon containing compound treating apparatus with resistance to carbon deposition
GB2193726B (en) * 1986-07-23 1991-05-22 Jgc Corp Carbon containing compound treating apparatus with resistance to carbon deposition
EP0388283A1 (de) * 1989-03-16 1990-09-19 Ugine S.A. Rostfreier ferritischer Stahl und Verfahren zur Herstellung dieses Stahls
WO1990010723A1 (fr) * 1989-03-16 1990-09-20 Ugine, Aciers De Chatillon Et Gueugnon Acier inoxydable ferritique et procede pour l'elaboration d'un tel acier
FR2644478A1 (de) * 1989-03-16 1990-09-21 Ugine Aciers
US5230752A (en) * 1989-03-16 1993-07-27 Ugine, Aciers De Chatillon Et Gueugnon Ferritic stainless steel and process for producing such a steel
US5942184A (en) * 1993-10-20 1999-08-24 Sumitomo Metal Industries, Ltd. Stainless steel for high-purity gases

Also Published As

Publication number Publication date
DE3169748D1 (en) 1985-05-09
ES508364A0 (es) 1983-03-16
ATE12527T1 (de) 1985-04-15
CA1184403A (en) 1985-03-26
ES8305049A1 (es) 1983-03-16
KR880001356B1 (ko) 1988-07-28
MX156238A (es) 1988-07-27
BR8200150A (pt) 1982-11-03
AU7829481A (en) 1982-07-22
JPS57137455A (en) 1982-08-25
EP0057316B1 (de) 1985-04-03
KR830007871A (ko) 1983-11-07

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