en sv fi en en en en ru cs da ar es sv ro el fa fr nl hu tr zh de pl fi vi ko it hbs_lat da th ja pt da da da sv de da fi en de sv da sv en da da da da da da eo da en da de eo en sv en en fr en en en en en en en es da it da en en es da en en da da en sv en en da da nl da da da it it da da da da nl pl en nl de en en en en en en en en en en en en en en en en en en en da da da da da da da en da en en en en en en en en en en en da da da da da da en fr da
9–12% Chromium Steels: Part Two :: Total Materia Article
Institutter og den akademiske verden
Deep Drawable Steels: Part One
Thermo-Mechanical Treatment (TMT) of Non-Ferrous Alloys: Part One
DataPLUS er et supplerende data modul som leverer korrosions data, materiale samlings information, materiale dimensioner og tolerancer og belægnings informationer for tusinder af metalliske og ikke-metalliske materialer.
Klik her for at se mere.
Overview of Total Materia database 12th January 2022
Total Materia har ved at give os en bestemt metode tilladt os at løse alle problemerne vi havde med søgning af alternative materialer i udlandet. Takket være Total Materia har vi udstedt virkelige "internationale" specifikationer for køb af stål i fremmede lande.
Total Materia er fortsat det eneste værktøj, der vil blive brugt til dette formål.
Bonfiglioli Industrial Gearmotors, Bologna, Italia
Vores mission er simpel;
at gøre Total Materia
til det eneste destination og
første valg for ingeniører
Prof. Dr. Viktor Pocajt, CEO
Key to Metals AG
9–12% Chromium Steels: Part Two
An overview of te development of heat-resistant ferritic-martensitic 9-12% Cr steels from te 1980s is given in this article. Te properties of several 9–12% chromium steels are described, with examples of te graphs of 100,000 h creep rupture strength of steam turbine rotor steels and piping steels.
Te steel referred to in te literature as 9Cr1Mo or P91 (no. 6) is a steel of te newer generation. It was developed under a huge American national project in te late 1970s for manufacturing pipes and vessels for a fast breeder reactor. It is tough, readily weldable and, as shown by creep tests at 593°C up to about 80,000 h, has a high creep strength at 600°C and 100,000 h of about 94 MPa.
In comparison with earlier steels it is characterized, for example, by a lower C content of only about 0.10% and a reduced Cr content of about 9%. This steel has meanwhile found wide application in all new Japanese and European power stations for te manufacture of pipes and small forgings. It is also used for te manufacture of valve chests and turbine casings.
Steel HCM 12 (no. 7) is a newly developed Japanese 12% Cr steel with 0.10% C – 1% Mo – 1% W – 0.25% V – 0.05% Nb – 0.03% N and a duplex structure of delta-ferrite and tempered martensite with improved weldability and creep strength. Te stability of te creep strength of this steel has been obtained primarily by precipitation strengthening with very fine VN precipitates and high-temperature tempering at over 800°C.
Experience with this steel has already been accumulated over a period of more than 20 years. Te steel has been extensively used for superheater tubes in chemical recovery boilers exposed to severe high-temperature corrosion attack. Te good resistance to corrosion is due to te high Cr-content of 12%.
Te Japanese rotor steels TMK 1 and TMK 2 (no. 8), developed in te 1980s, were based on te known properties of steels no. 1–6. Compared with te GE rotor steel (no. 5), te C content in particular was reduced and te sum total (C + N) was selected at around 0.17%. Based on te research work of Fujita, te Mo content was raised to 1.5% in TMK 1, whereas TMK 2 is additionally alloyed with about 1.8%W. Te Mo content is simultaneously balanced to 0.50% in keeping with Fujita’s result that te highest solution hardening was obtained with (Mo + 0.5W) = 1.5%. Both rotor steels have been used for new power stations in Japan.
Rotor steels nos. 9 and 10 are primarily te result of research work performed in te 1980s under te European cooperation program COST 501. Steel no. 9 is a 9%CrMoVNb steel which is additionally alloyed with about 0.01% boron. It is an onward development of te TAF steel for large components with reduced contents of Cr, Nb and B and with an increase in V.
Creep tests with specimens from a 900 mm diameter pilot rotor, which have so far reached about 100,000 h, indicate a probable creep rupture strength of about 120 MPa at 100,000 h and 600°C. Creep tests up to 94,000 h with specimens from a 600 mm diameter pilot rotor with a similar composition confirm this value. A larger pilot rotor with a diameter of about 1200 mm is under investigation.
Te creep strength of te steel X12CrMoWVNbN10-1-1 (steel no. 10) containing 0.06%N instead of 0.01%B and only 1% Mo instead of 1.5% Mo and, in addition, 0.8% W, is about 20% lower, see Figure 3. So far, te longest test period is about 100,000 h.
This rotor steel has primarily been used for te new advanced European steam power plants. This steel type has also successfully been applied for many valve chests and turbine casings in te new plants.
Te pipe steel, E 911, developed under COST 501, features a somewhat comparable chemical composition. Te Cr content was reduced to roughly 9%. Te Ni content is also distinctly lower since because of te lower Cr content there is no risk of te occurrence of delta-ferrite. Based on results up to roughly 100,000 h, te creep rupture strength of this steel is estimated to be 98 MPa at 600°C and 100,000 h.
Figure 3: 100,000 h creep rupture strength of steam turbine rotor steels as a function of test temperature.
Steel no. 11 is also based on te research work of Fujita. It is a 9% Cr pipe steel specifically alloyed with 0.10% C – 1.8% W – 0.5% Mo – 0.2% V – 0.06% Nb – 0.05% N and about 0.003%B and tempered at about 750°C. It was developed in te second half of te 1980s under te designation NF 616 (P92). Based on creep tests up to about 100,000 h, te creep rupture strength is estimated to be 113 MPa at 600°C and 100,000 h.
A similar pipe steel HCM 12A (P122), steel no. 12, has also been developed in Japan alloyed with a higher Cr content of 11% in order to improve oxidation resistance. About 1% copper has been added to reduce te tendency to delta ferrite formation caused by te higher Cr-content.
Te newest evaluation of te available results of long term creep tests led to an estimated creep rupture strength of 101MPa at 600°C and 100,000 h. Figure 4 compares te 100,000 h creep rupture strength versus te temperature for te new pipe steels. In addition to te pipe steel P91, all three pipe steels (E 911, NF 616 and HCM 12A) are in successful use for te new advanced steam power plants.
Figure 4: 100,000h creep rupture strength of steam plant piping steels as a function of test temperature.
Skriv en sætning for at søge efter:
Denne artikel tilhører en serie af artikler. Du kan klikke på linkene nedenfor for at læse mere om dette emne.
9–12% Chromium Steels: Part One
Finding creep data in te Total Materia database
Total Materia Extended Range includes te largest database of creep data for thousands of metal alloys, heat treatments and loading conditions.
Yield stress and creep rupture strength at different temperatures are displayed along with te calculation of Larsen-Miller parameter and te remaining life of te component.
Enter te material of interest into te quick search field. You can optionally narrow your search by specifying te country/standard of choice in te designated field and then click Search.
Total Materia After clicking te material from te resulting list, a list of subgroups derived from standard specifications appears.
Because Total Materia Extended Range creep properties are neutral to standard specifications, you can review creep data by clicking te appropriate link for any of te subgroups.
Yield stress and creep rupture strength data is given in a tabular format.
You can also enter your own temperatures and stress values to manipulate te data to show te Larson-Miller Parameter for theoretical conditions of your choice.
Simply enter your desired conditions and click calculate.
For you’re a chance to take a test drive of te Total Materia database, we invite you to join a community of over 150,000 registered users through te Total Materia Free Demo.
© 2022 Key to Metals AG. Alle Rettigheder Forbeholdes