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DE-102024210801-A1 - Nickel-iron alloy, raw part and component

DE102024210801A1DE 102024210801 A1DE102024210801 A1DE 102024210801A1DE-102024210801-A1

Abstract

The invention relates to a nickel-iron alloy and components thereof with the composition: Carbon (C) 0.01% - 0.05% Silicon (Si) 0.20% - 0.30% Manganese (Mn) 0.5% - 0.8% Cobalt (Co) up to 0.6% Chromium (Cr) 14.0% - 18.0% Nickel (Ni) 57.0% - 71.0% Titanium (Ti) 1.4% - 2.1% Aluminum (Al) 2.4% - 3.2% Boron (B) 0.002% - 0.010% Iron (Fe), optional Molybdenum (Mo) 2.7% - 3.3% Niobium (Nb): up to 0.08% Zircon (Zr) up to 0.2%.

Inventors

  • Christian Holländer
  • Christian Borgmann
  • Simon Voss
  • Dirk Kulawinski
  • Bora Kocdemir

Assignees

  • Siemens Energy Global GmbH & Co. KG

Dates

Publication Date
20260513
Application Date
20241111

Claims (13)

  1. alloy (in wt.%) comprising at least, in particular consisting of: Carbon (C) 0.01% - 0.05% in particular 0.02% - 0.04% especially 0.03% Silicon (Si) 0.20% - 0.30% in particular 0.25% Manganese (Mn) 0.5% - 0.8% in particular 0.6% Cobalt (Co) up to 0.6% Chromium (Cr) 14.0% - 18.0% in particular 15.0% - 17.0% Nickel (Ni) 57.0% - 71.0% Titanium (Ti) 1.4% - 2.1% in particular 1.6% - 1.9% Aluminum (Al) 2.4% - 3.2% in particular 2.6% - 3.0% Boron (B) 0.002% - 0.010% in particular 0.003% - 0.008% Iron (Fe), especially residual iron (Fe), optionally molybdenum (Mo) 2.7% - 3.3% in particular 3.0% Niobium (Nb): up to 0.08% especially up to 0.06% Zircon (Zr) up to 0.2%.
  2. alloy according to Claim 1 , containing no vanadium (V).
  3. alloy according to one or both of the Claims 1 or 2 , containing no tungsten (W).
  4. alloy according to one or more of the Claims 1 , 2 or 3 , containing no tantalum (Ta).
  5. alloy according to one or more of the Claims 1 , 2 , 3 or 4 , containing no zirconium (Zr).
  6. alloy according to one or more of the Claims 1 , 2 , 3 , 4 or 5 , containing no molybdenum (Mo).
  7. alloy according to one or more of the previous Claims 1 until 5 , containing molybdenum (Mo).
  8. alloy according to one or more of the Claims 1 , 2 , 3 , 4 , 5 , 6 or 7 , containing no niobium (Nb).
  9. alloy according to one or more of the previous Claims 1 until 7 , containing 0.02% - 0.06% niobium (Nb).
  10. Alloy according to one or more of the preceding claims, comprising no cobalt (Co).
  11. alloy according to one or more of the previous Claims 1 bi 9, containing 0.2% to 0.6% cobalt (Co).
  12. Alloy according to one or more of the preceding claims, comprising 59.0% to 69.0% nickel (Ni).
  13. raw part or component comprising an alloy according to one or more of the preceding claims.

Description

The invention relates to a nickel-iron alloy, a raw part and/or component made from this alloy. Depending on the application conditions, rotor forging discs have so far been manufactured from various forged steels. NiCrMoV is used for compressor discs and CrMoWVNbN for turbine discs. The choice of forging material depends on the application conditions and design requirements. When selecting the forging material, it is always important to ensure a balance between strength and toughness in order to meet the design requirements. The iron-based material with the highest operating temperature is currently a martensite. There is currently no solution for higher operating temperatures. There are considerations to switch to nickel-based discs. Theoretically, these should allow operating temperatures greater than 923K. However, nickel (Ni) components have the following disadvantages, which is why their use is being discussed: - very high costs compared to a steel disc, - longer processing times in manufacturing. It is therefore the purpose of the invention to solve the problem mentioned above. The problem is solved by an alloy according to claim 1, as well as a component or a blank according to claim 13. The dependent claims list further advantageous measures which can be combined arbitrarily to achieve further advantages. The description only presents exemplary embodiments of the invention. The validation of an austenitic steel demonstrated its suitability for higher operating temperatures. The chemistry and heat treatment are generally sufficient to withstand the challenges of a forged component used in power generation plants at temperatures above 873 K. The iron-based composition is as follows (in wt.%): at least showing, Carbon (C) 0.01% - 0.05% Silicon (Si) 0.20% - 0.30% Manganese (Mn) 0.5% - 0.8% Cobalt (Co) up to 0.6% Chromium (Cr) 14.0% - 18.0% Nickel (Ni) 57.0% - 71.0% Titanium (Ti) 1.4% - 2.1% Aluminum (Al) 2.4% - 3.2% Boron (B) 0.002% - 0.010% Iron (Fe), optional Molybdenum (Mo), Niobium (Nb): 2.7% - 3.3%, down to 0.08% Zircon (Zr) up to 0.2%. In particular, the alloy consists of these elements. Chromium (Cr) strongly promotes the formation of the sigma phase. Chromium (Cr) is also required as an oxidation inhibitor. Cobalt (Co) improves solution annealing and contributes to solid solution hardening. Molybdenum (Mo) promotes the formation of Laves and TCP phases. Molybdenum (Mo) can also improve oxidation properties and contributes to the solid solution hardening of the austenite phase. Manganese (Mn), silicon (Si), and vanadium (V) promote the formation of TCP phases and reduce the gamma prime phase. Manganese (Mn) improves oxidation resistance in high iron concentrations. Wolfram (W) promotes the formation of the Laves phases. Carbon (C), boron (B) and zirconium (Zr) contribute to grain boundary strength. The background is as follows: a) Corrosion resistance By adjusting the chromium content to 14% to 17% by weight, resistance to HTK2 is increased. The underlying principle is the formation of a stable Cr₂O₃layer with a sufficiently high chromium reservoir (Cr). Simultaneously, increasing the molybdenum (Mo) content can preferably enhance corrosion resistance to chlorine-containing media under high-temperature corrosion conditions. The effect of molybdenum (Mo) and chromium (Cr) is not limited to high-temperature applications alone, but would also provide increased corrosion protection for marine applications. b) Notch embrittlement Increasing the chromium and molybdenum content leads to an increase in strength. This is desirable on the one hand. On the other hand, the choice of tempering conditions must be carefully considered to ensure that the risk of notch embrittlement is low and sufficient toughness is maintained. Preferably, a 2- or 3-stage QHT tempering treatment is used. Advantages besides its primary use as a forged component in energy generation plants): • Expansion of the application range of “cheap” iron-based alloys compared to “expensive nickel-based materials”. • Faster machining of iron-based rotor components compared to nickel-based materials. • Experience gained from the design, manufacturing, and production of high-alloy iron-based alloys can largely be applied. This is particularly helpful for all probabilistic approaches. • The application temperature can be increased, thus enabling an increase in the machine's power and performance without the need for external cooling. Examples of the iron-based (Fe) material are (Ni66 means 66 wt.% nickel (Ni)): 1. Ni66, Si0.28, Mn0.70, Cr16.5, Ti1.9, Al3.0, B0.005, C0.04 2. Ni68, Si0.26, Mn0.65, Cr16.2, Ti1.8, Al2.7, B0.004, C0.035, Co0.3 3. Ni69, Si0.27, Mn0.75, Cr16.8, Ti1.9, Al2.8, B0.003, C0.038, Co0.4 4. Ni69, Si0.25, Mn0.60, Cr16.0, Ti1.6, Al3.0, B0.003, C0.03 5. Ni67, Si0.29, Mn0.55, Cr16.6, Ti1.7, Al2.6, B0.006, C0.045, Co0.6 6. Ni70, Si0.27, Mn0.65, Cr16.5, Ti1.9, Al3.2, B0.004, C0.037, Co0.2 7. Ni65, Si0.25, Mn0.60, Cr16.0, Ti1.7, Al