Abstract: A coated substrate is described including a substrate material, which is coated at least in part with an oxidation-resistant coating, wherein the coating consists of a wear-resistant abrasive coating layer, which contains or consists of coated abrasive particles embedded in an oxidation-resistant matrix material, wherein at least some of the abrasive particles consist of ?-Al2O3 and the abrasive particles are coated with a first particle coating layer disposed on the abrasive particles and an optional second particle coating layer disposed on the first particle coating layer, wherein the matrix material contains or consists of the compound MCrAlY, wherein M is at least one element selected from the group consisting of Ni, Co and Fe. A method for manufacturing such a coated substrate is also disclosed.

Abstract: The invention relates to a method for welding rotors for power generation having a plurality of rotor discs arranged along a rotor axis. The method includes providing forged and NDT tested rotor discs and machining the discs for weld seam preparation. The weld seam preparation has an inner narrow TIG welding gap and an adjoining outer SAW welding gap. The method further includes stapling the discs on top of each other; and checking the run-out of the stapled discs relative to each other and as a whole and, if necessary, adjusting the staple. In addition the method includes melting the root of the weld without weld filler using TIG welding; increasing the weld height by narrow gap TIG welding with parent metal weld filler to allow tilting of the rotor in horizontal position; tilting the rotor in horizontal position; finalizing the welding by filling the outer SAW welding gap using SAW welding; and checking the welds of the rotor by NDT using ultrasonic testing.

Abstract: The invention relates to a method for welding rotors for power generation such as gas turbines, steam turbines, and generators having a plurality of rotor discs arranged along a rotor axis. The method includes providing said discs with a weld seam preparation. The weld seam preparation includes a root, a first, gap-like welding section adjoining the root in radial direction, and a second, gap-like welding section adjoining the first welding section in radial direction. The method further includes melting the root by means of a first welding process; making a weld in the first welding section by means of a second welding process; and filling up the second welding section by means of a third welding process.

Abstract: A coated substrate is described including a substrate material, which is coated at least in part with an oxidation-resistant coating, wherein the coating consists of a wear-resistant abrasive coating layer, which contains or consists of coated abrasive particles embedded in an oxidation-resistant matrix material, wherein at least some of the abrasive particles consist of ?-Al2O3 and the abrasive particles are coated with a first particle coating layer disposed on the abrasive particles and an optional second particle coating layer disposed on the first particle coating layer, wherein the matrix material contains or consists of the compound MCrAlY, wherein M is at least one element selected from the group consisting of Ni, Co and Fe. A method for manufacturing such a coated substrate is also disclosed.

Abstract: The invention relates to a method for welding rotors for power generation such as gas turbines, steam turbines, and generators having a plurality of rotor discs arranged along a rotor axis. The method includes providing said discs with a weld seam preparation. The weld seam preparation includes a root, a first, gap-like welding section adjoining the root in radial direction, and a second, gap-like welding section adjoining the first welding section in radial direction. The method further includes melting the root by means of a first welding process; making a weld in the first welding section by means of a second welding process; and filling up the second welding section by means of a third welding process.

Abstract: The invention relates to a method for welding rotors for power generation having a plurality of rotor discs arranged along a rotor axis. The method includes providing forged and NDT tested rotor discs and machining the discs for weld seam preparation. The weld seam preparation has an inner narrow TIG welding gap and an adjoining outer SAW welding gap. The method further includes stapling the discs on top of each other; and checking the run-out of the stapled discs relative to each other and as a whole and, if necessary, adjusting the staple. In addition the method includes melting the root of the weld without weld filler using TIG welding; increasing the weld height by narrow gap TIG welding with parent metal weld filler to allow tilting of the rotor in horizontal position; tilting the rotor in horizontal position; finalizing the welding by filling the outer SAW welding gap using SAW welding; and checking the welds of the rotor by NDT using ultrasonic testing.