The invention relates to a turbine machine, in particular, a steam turbine, comprising an inner housing, a turbine shaft, mounted such as to rotate, characterized in that the inner housing and the turbine shaft are produced from differing materials. The turbine is made from a chrome steel with 9 to 12 wt. % of chromium and the inner housing from a chrome steel with 1 to 2 wt % of chromium.
1. A turbomachine, comprising:
a rotatably mounted turbine shaft made from a chromium steel material containing 9% to 12% by weight chromium;
an inner casing coaxial with the rotor shaft made from a chromium steel containing 1% to 2% by weight chromium and having a lower hot strength than the turbine shaft material.
2. The turbomachine as claimed in claim 1 , wherein the inner casing and the turbine shaft have regions which are configured for use at temperatures of over 550° C.
3. The turbomachine as claimed in claim 2 , wherein the turbomachine is a steam turbine.
4. The turbomachine as claimed in claim 3 , wherein the steam turbine is a high-pressure partial turbine.
5. The turbomachine as claimed in claim 3 , wherein the steam turbine is an intermediate-pressure partial turbine.
6. The turbomachine as claimed in claim 3 , wherein the steam turbine is a combined high-pressure and intermediate-pressure partial turbine.
7. The turbomachine as claimed in claim 3 , wherein the steam turbine is a combined intermediate-pressure and low-pressure partial turbine.
8. The turbomachine as claimed in claim 2 , wherein the rotor material and the inner casing material have different coefficients of thermal expansion.
9. The turbomachine as claimed in claim 2 , wherein the rotor material and the inner casing material have different rates of thermal expansion.