Martensitic steel having a Z-phase, powder and component

Abstract

An alloy which includes at least the following (in % by weight): carbon (C): 0.15%-0.25%; silicon (Si): 0.0%-0.08%; manganese (Mn): 0.03%-0.20%; chromium (Cr): 9.5%-10.5%; molybdenum (Mo): 0.4%-1.0%; tungsten (W): 1.6%-2.4%; cobalt (Co): 2.5%-3.5%; nickel (Ni): 0.0%-0.40%; boron (B): 0.003%-0.02%; nitrogen (N): 0.0%-0.40%; titanium (Ti): 0.02%-0.10%; vanadium (V): 0.10%-0.30%; niobium (Nb): 0.02%-0.08%; copper (Cu): 1.20%-2.10%; and aluminum (Al): 0.003%-0.06%, in particular 0.005%-0.04%; the remainder being iron (Fe).

Claims

1. An alloy consisting essentially of (in % by weight): carbon (C): 0.15%-0.25%, silicon (Si): 0.0%-0.08%, manganese (Mn): 0.03%-0.20%, chromium (Cr): 9.5%-10.5%, molybdenum (Mo): 0.4%-1.0%, tungsten (W): 1.6%-2.4%, cobalt (Co): 2.5%-3.5%, nickel (Ni): 0.0%-0.40%, boron (B): 0.003%-0.02%, nitrogen (N): 0.0%-0.40%, titanium (Ti): 0.02%-0.10%, vanadium (V): 0.10%-0.30%, niobium (Nb): 0.02%-0.08%, copper (Cu): 1.20%-2.10%, aluminum (Al): 0.003%-0.06%, balance iron (Fe), wherein the alloy is configured as a rotor disk and can withstand temperatures up to 873 K.

2. The alloy as claimed in claim 1 consisting essentially of 0.2% by weight of carbon (C).

3. The alloy as claimed in claim 1 consisting essentially of 0.06% by weight of silicon (Si).

4. The alloy as claimed in claim 1 consisting essentially of 0.1% by weight of manganese (Mn).

5. The alloy as claimed in claim 1 consisting essentially of 10.00% by weight of chromium (Cr).

6. The alloy as claimed in claim 1 consisting essentially of 0.7% by weight of molybdenum (Mo).

7. The alloy as claimed in claim 1 consisting essentially of 2.0% by weight of tungsten (W).

8. The alloy as claimed in claim 1 consisting essentially of 3.0% by weight of cobalt (Co).

9. The alloy as claimed in claim 1 consisting essentially of 0.0% by weight of nickel (Ni) except for contamination level.

10. The alloy as claimed in claim 1 consisting essentially of 0.010% by weight of boron (B).

11. The alloy as claimed in claim 1 consisting essentially of 0.0% by weight of nitrogen (N) except for contamination level.

12. The alloy as claimed in claim 1 consisting essentially of 0.05% by weight of titanium (Ti).

13. The alloy as claimed in claim 1 consisting essentially of 0.20% by weight of vanadium (V).

14. The alloy as claimed in claim 1 consisting essentially of 0.05% by weight of niobium (Nb).

15. The alloy as claimed in claim 1 consisting essentially of 1.75% by weight of copper (Cu).

16. The alloy as claimed in claim 1 consisting essentially of 0.02% by weight of aluminum (Al).

17. An alloy consisting of (in % by weight): carbon (C): 0.19%-0.21%, silicon (Si): 0.0%-0.06%, manganese (Mn): 0.05%-0.15%, chromium (Cr): 9.8%-10.2%, molybdenum (Mo): 0.6%-0.8%, tungsten (W): 1.9%-2.1%, cobalt (Co): 2.8%-3.2%, nickel (Ni): 0.0%-0.20%, boron (B): 0.006%-0.01%, nitrogen (N): 0.0%-0.20%, titanium (Ti): 0.04%-0.08%, vanadium (V): 0.15%-0.25%, niobium (Nb): 0.04%-0.06%, copper (Cu): 1.65%-1.85%, aluminum (Al): 0.005%-0.04%, Balance iron (Fe), wherein the alloy is a martensitic steel rotor disk that withstands temperatures up to 873 K.

18. Te An alloy consisting of (in % by weight): carbon (C): 0.20%, silicon (Si): 0.06%, manganese (Mn): 0.10%, chromium (Cr): 10%, molybdenum (Mo): 0.7%, tungsten (W): 2.0%, cobalt (Co): 3.0%, nickel (Ni): 0.0%, boron (B): 0.010%, nitrogen (N): 0.0%, titanium (Ti): 0.05%, vanadium (V): 0.20%, niobium (Nb): 0.05%, copper (Cu): 1.75%, aluminum (Al): 0.02%, balance iron (Fe), wherein the alloy is a martensitic steel having a Z phase alloy.

Description

DETAILED DESCRIPTION OF INVENTION

(1) The alloy composition of martensitic steels has hitherto been restricted by the formation of the Z phase within the time over which the component is utilized.

(2) The alloy of the invention comprises at least (in % by weight): carbon (C): 0.15%-0.25%, preferably 0.19%-0.21%, silicon (Si): 0.0%-0.08%, preferably 0.0%-0.06%, manganese (Mn): 0.03%-0.20%, preferably 0.05%-0.15%, chromium (Cr): 9.5%-10.5%, preferably 9.8%-10.2%, molybdenum (Mo): 0.4%-1.0%, preferably 0.6%-0.8%, tungsten (W): 1.6%-2.4%, preferably 1.9%-2.1%, cobalt (Co): 2.5%-3.5%, preferably 2.8%-3.2%, nickel (Ni): 0.0%-0.40%, preferably 0.0%-0.20%, boron (B): 0.003%-0.02%, preferably 0.006%-0.01%, nitrogen (N): 0.0%-0.40%, preferably 0.0%-0.20%, titanium (Ti): 0.02%-0.10%, preferably 0.04%-0.08%, vanadium (V): 0.10%-0.30%, preferably 0.15%-0.25%, niobium (Nb): 0.02%-0.08%, preferably 0.04%-0.06%, copper (Cu): 1.20%-2.10%, preferably 1.65%-1.85%, aluminum (Al): 0.003%-0.06%, in particular 0.005%-0.04%, balance iron (Fe), in particular consisting of these elements.

(3) New concepts enable the limit to be shifted: a) shifting of the formation of the Z-phase towards 200 000 hours, b) formation of the Z-phase before commencement of the time over which the later GT forged component is utilized.

(4) As a consequence, the mechanical properties no longer change over the time of utilization as a result of the formation of the Z-phase. Instead, the characteristic values due to the formation of the Z-phase are much more constant. Design of the components is possible.

(5) An advantageous embodiment is (in % by weight): carbon (C): 0.20%, silicon (Si): 0.06%, manganese (Mn): 0.10%, chromium (Cr): 10%, molybdenum (Mo): 0.7%, tungsten (W): 2.0%, cobalt (Co): 3.0%, nickel (Ni): 0.0%, boron (B): 0.010%, nitrogen (N): 0.0%, titanium (Ti): 0.05%, vanadium (V): 0.20%, niobium (Nb): 0.05%, copper (Cu): 1.75%, aluminum (Al): 0.02%, balance iron (Fe).

(6) Apart from the use as forged disk in a gas turbine, further uses are conceivable, for example gas turbine compressor blades, steam turbine blade or as steam turbine forged part.

(7) The advantages are: —expansion of the use range of “inexpensive” iron-based alloys compared to “expensive nickel-based materials”, —faster workability of the rotor components based on iron (9%-11% of Cr) compared to nickel-based materials, —experience from the construction, finishing and production of the high-alloy iron-based alloys can largely be carried over; this helps, for example, in all probabilistic approaches (e.g. fracture mechanics =>minimized risk), —use temperature can be increased and therefore makes power and performance increases for the machine possible without external cooling being necessary.