Nickel-iron alloy, blank and component

Abstract

The invention relates to a nickel-iron alloy and to components thereof, having the following 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), optionally molybdenum (Mo) 2.7%–3.3%, niobium (Nb) up to 0.08%, zircon (Zr) up to 0.2%.

Description

[0001] 2024PF00873

[0002] 1

[0003] Description

[0004] Nickel-iron alloy, raw part and component

[0005] The invention relates to a nickel-iron alloy, a raw part and / or component made from this alloy.

[0006] Depending on the application conditions, rotor forging discs have so far been manufactured from various forged steels.

[0007] NiCrMoV is used for compressor discs and CrMoWVNbN for turbine discs.

[0008] The choice of forging material depends on the application conditions and design requirements.

[0009] When selecting the forging material, it is always important to ensure a balance between strength and toughness in order to meet the design requirements.

[0010] The iron-based material with the highest operating temperature is currently a martensite.

[0011] There is currently no solution for higher operating temperatures.

[0012] There are considerations to switch to nickel-based discs.

[0013] Theoretically, these should allow operating temperatures greater than 923K.

[0014] However, nickel (Ni) components have the following disadvantages, which is why their use is being discussed:

[0015] - very high costs compared to a steel disc,

[0016] - longer processing times in manufacturing.

[0017] It is therefore the purpose of the invention to solve the problem mentioned above.

[0018] The problem is solved by an alloy according to claim 1, and a component or a blank according to claim 13. 2024PF00873

[0019] The dependent claims list further advantageous measures which can be combined arbitrarily to achieve further advantages.

[0020] The description only presents exemplary embodiments of the invention.

[0021] 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.

[0022] The iron-based composition is as follows (in wt. %): at least containing,

[0023] 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%, Zirconium (Zr) up to 0.2%.

[0024] In particular, the alloy consists of these elements.

[0025] Chromium (Cr) strongly promotes the formation of the sigma phase.

[0026] (Cr) is also required as an oxidation inhibitor. 2024PF00873

[0027] Cobalt (Co) improves solution annealing and contributes to solid solution hardening.

[0028] 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.

[0029] Manganese (Mn), silicon (Si), and vanadium (V) promote the formation of TCP phases and reduce the gamma prime phase. Manganese (Mn) improves oxidation resistance at high iron content.

[0030] Wolfram (W) promotes the formation of the Laves phases.

[0031] Carbon (C), boron (B) and zirconium (Zr) contribute to grain boundary strength.

[0032] The background is as follows: a) Corrosion resistance

[0033] By adjusting the chromium content to 14% to 17% by weight, the resistance to HTK2 is increased.

[0034] The background is the formation of a stable Cr2O3 layer with a sufficiently high chromium reservoir (Cr) .

[0035] At the same time, the corrosion resistance to chlorine-containing media under high-temperature corrosion conditions can preferably be increased by increasing the molybdenum (Mo) content.

[0036] 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

[0037] Increasing the chromium and molybdenum content leads to an increase in strength. This is desirable in part (2024PF00873). However, the tempering conditions must be carefully selected to ensure that the risk of notch embrittlement is low and sufficient toughness is maintained.

[0038] Preferably, a 2- or 3-stage QHT tempering treatment is used.

[0039] Advantages besides its primary use as a forged component in energy generation plants):

[0040] • Expansion of the application range of “cheap” iron-based alloys compared to “expensive nickel-based materials”.

[0041] • Faster machining of iron-based rotor components compared to nickel-based materials.

[0042] • 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.

[0043] • The application temperature can be increased, thus enabling an increase in the machine's power and performance without the need for external cooling.

[0044] Examples of the iron-based (Fe) material are (Ni66 means 66 wt.% nickel (Ni) ):

[0045] 1. Ni66, Si0.28, Mn0.70, Crl6.5, Til.9, A13.0, BO.005,

[0046] CO .04

[0047] 2. Ni68, Si0.26, Mn0.65, Crl6.2, Til.8, A12.7, BO.004,

[0048] CO.035, CoO.3

[0049] 3. Ni69, Si0.27, Mn0.75, Crl6.8, Til.9, A12.8, B0.003,

[0050] CO.038, CoO.4

[0051] 4. Ni69, Si0.25, Mn0.60, Crl6.0, Til.6, A13.0, BO.003, 2024PF00873

[0052] 5. Ni67, Si0.29, Mn0.55, Crl6.6, Til.7, A12.6, BO.006, CO.045, CoO.6

[0053] 6. Ni70, Si0.27, Mn0.65, Crl6.5, Til.9, A13.2, BO.004, CO.037, CoO.2

[0054] 7. Ni65, Si0.25, Mn0.60, Crl6.0, Til.7, A12.7, BO.003, CO.03, CoO.4, Nb0.06

[0055] 8. Ni65.5, Si0.28, Mn0.7, Cr6.3, Ti.8, A12.9, BO.005, CO.042, CoO.4

[0056] 9. Ni67.5, Si0.26, Mn0.68, Cr6.7, Ti.7, A12.8, BO.004, CO.039, CoO.5

[0057] 10. Ni66.2, Si0.27, Mn0.58, Crl6.2, To.6, A12.5, BO.006, CO.048, CoO.3

[0058] 11. Ni68.2, Si0.28, Mn0.72, Crl6.5, Til.9, A13.1, BO.003, CO.039, CoO.4

[0059] 12. Ni59, Si0.25, Mn0.60, Crl6.0, Til.9, A12.9, BO.003, CO .03

[0060] 13. Ni66.8, Si0.26, Mn0.62, Cr6.8, Ti.8, A12.7, BO.005, CO.043, CoO.4

Claims

2024PF00873 Patent claims 1. Alloy (in wt.%) comprising at least, in particular consisting of: Carbon (C) 0.01% - 0.05%, in particular 0.02% - 0.04%, most 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), in particular residual iron (Fe), optionally molybdenum (Mo) 2.7% - 3.3%, in particular 3.0%, niobium (Nb): up to 0.08%, in particular up to 0.06%, zirconium (Zr) up to 0.2%. Alloy according to claim 1, comprising no vanadium (V) .

3. Alloy according to one or both of claims 1 or 2, comprising no tungsten (W) . 2024PF00873 7 4. Alloy according to one or more of claims 1, 2 or 3, comprising no tantalum (Ta) .

5. Alloy according to one or more of claims 1, 2, 3 or 4, comprising no zirconium (Zr) .

6. Alloy according to one or more of claims 1, 2, 3, 4 or 5, comprising no molybdenum (Mo) .

7. Alloy according to one or more of the previous Claims 1 to 5, comprising molybdenum (Mo) .

8. Alloy according to one or more of claims 1, 2, 3, 4, 5, 6 or 7, containing no niobium (Nb) .

9. Alloy according to one or more of the preceding claims 1 to 7, comprising 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 preceding claims 1 to 9, comprising 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) . 2024PF00873 8 13. Raw part or component comprising an alloy according to one or more of the preceding claims.