Abstract: A process for welding pipe connections for high temperature applications, particularly in power plants, including a first pipe section and a second pipe section. The first pipe section is made of a ferritic material having a first coefficient of thermal expansion. The second pipe section is made of an austenitic material having a second coefficient of thermal expansion, which is different from the first coefficient of thermal expansion. The weld joint is made of an austenitic filler material which has a third coefficient of thermal expansion which is in the range of the second coefficient of thermal expansion. The process includes axially aligning the first and second pipe sections to be connected, making an at least partially V-shaped weld joint open radially inwards, and performing an inside welding process inside the first and second pipe sections to be connected. The invention is further directed to such a pipe connection.

Abstract: A cobalt-base superalloy chemical composition is disclosed which includes, in % by weight: 25-28 W; 3-8 Al; 0.5-6 Ta; 0-3 Mo; 0.01-0.2 C; 0.01-0.1 Hf; 0.001 -0.05 B; 0.01-0.1 Si; and remainder Co and unavoidable impurities. This superalloy can be strengthened by ?? dispersions and further dispersion mechanisms. Exemplary compositions can provide good oxidation properties and improved strength values at high temperatures.

Abstract: An iron-based high-temperature alloy has the following chemical composition (values given being in % by weight): 20 Cr, 4 to 8 Al, at least one of the elements Ta and Mo with a sum of 4 to 8, 0-0.2 Zr, 0.02-0.05 B, 0.1-0.2 Y, 0-0.5 Si, remainder Fe. The alloy can be produced at low cost and is distinguished in comparison with the known prior art by outstanding oxidation resistance and good mechanical properties at high temperatures up to 1000° C.

Abstract: A turbogenerator (10) has a rotor (11) having a cylindrical rotor body (13), which at each of the two ends merges into a shaft end (14), and in a middle section has the electromagnetically active region (23) of the rotor (11), in which the rotor (11) is assembled from a plurality of rotor parts which are interconnected and arranged in series on the rotor axis (19). With such a rotor, lower losses and temperatures in the end region of the rotor, and overall a higher limit rating or a broadened output range, become possible as a result of the fact that the rotor body (13) in the active region (23) is formed of an easily magnetizable material, especially a first steel, and in that the end sections of the rotor body (13) which are located outside the active region (23) and the shaft ends (14) are formed of a material with reduced magnetizability or of a non-magnetic material, especially a second steel.

Abstract: A creep-resistant steel is characterized by the following chemical composition (values in % by weight): 9.0 to 12.0 Cr, 0.1 to 0.5 Mn, 2.3 to 3 Ni, 1.5 to 2.0 Mo, 0.1 to 0.4 V, 0.01 to 0.06 Nb, 0.08 to 0.16 C, 0.02 to 0.08 N, 0.004 to 0.012 B, 0.001 to 2 Ta, 0.001 to 0.5 La, 0.0001 to 1 Pd, maximum 0.005 P, maximum 0.005 S, maximum 0.05 Si, maximum 0.005 Sn, the remainder iron and unavoidable impurities. This steel is distinguished, as compared with commercial steels, by a greatly improved creep behavior at temperatures of 550° C. and above. Moreover, it has an improved resistance to embrittlement during long-term aging and comparatively high toughness. The steel is advantageously used as a material for gas turbine rotors which are exposed to high inlet temperatures in order to increase the efficiency of the gas turbine, but is also used for steam turbines.

Abstract: High-temperature materials, based on alloyed intermetallic NiAl, have the following chemical composition (values in % by weight): 26-30 Al, 1-6 Ta, 0.1-3 Fe, 0.1-1.5 Hf, 0.01-0.2 B, 0-1 Ti, 0.1-5 Pd, with the remainder Ni and production-related impurities. The materials have excellent properties, in particular good strength and extremely high oxidation resistance, at very high temperatures of 1300° C., for example.

Abstract: A heat treatment method for a nickel-based superalloy, in particular for the production of single-crystal components or directionally solidified components having a chemical composition permits full solution annealing at a temperature T1, the method comprising: partially solution annealing in a controlled manner at a temperature T2<T1 in a first step so as to obtain 5-10% of undissolved ?? phase in a residual eutectic; and performing a two-stage ageing treatment at respectively lower temperatures in a second step. As a function of the selected level of the partial solution annealing temperature, the proportion of the undissolved ?? phase can be adjusted in a controlled way, and the tolerance with respect to the disorientation of small-angle grain boundaries/grain boundaries can be increased.

Abstract: High-temperature materials, based on alloyed intermetallic NiAl, have the following chemical composition (values in % by weight): 26-30 Al, 1-6 Ta, 0.1-3 Fe, 0.1-1.5 Hf, 0.01-0.2 B, 0-1 Ti, 0.1-5 Pd, with the remainder Ni and production-related impurities. The materials have excellent properties, in particular good strength and extremely high oxidation resistance, at very high temperatures of 1300° C., for example.

Abstract: A turbogenerator (10) has a rotor (11) having a cylindrical rotor body (13), which at each of the two ends merges into a shaft end (14), and in a middle section has the electromagnetically active region (23) of the rotor (11), in which the rotor (11) is assembled from a plurality of rotor parts which are interconnected and arranged in series on the rotor axis (19). With such a rotor, lower losses and temperatures in the end region of the rotor, and overall a higher limit rating or a broadened output range, become possible as a result of the fact that the rotor body (13) in the active region (23) is formed of an easily magnetizable material, especially a first steel, and in that the end sections of the rotor body (13) which are located outside the active region (23) and the shaft ends (14) are formed of a material with reduced magnetizability or of a non-magnetic material, especially a second steel.

Abstract: A maraging heat-treatment steel includes 8.5 to 9.5% by weight of Cr, 0.15 to 0.25% by weight of Mn, 2 to 2.7% by weight of Ni, 0.5 to 2.5% by weight of Mo, 0.4 to 0.8% by weight of V, 0.001 to 0.15% by weight of Si, 0.06 to 0.1% by weight of C, 0.11 to 0.15% by weight of N, 0.02 to 0.04% by weight of Nb, maximum 0.007% by weight of P, maximum 0.005% by weight of S, maximum 0.01% by weight of Al, iron and standard impurities, wherein a weight ratio of vanadium to nitrogen V/N is in a range between 4.3 and 5.5.

Abstract: A cobalt-base superalloy chemical composition is disclosed which includes, in % by weight: 25-28 W; 3-8 Al; 0.5-6 Ta; 0-3 Mo; 0.01-0.2 C; 0.01-0.1 Hf; 0.001-0.05 B; 0.01-0.1 Si; and remainder Co and unavoidable impurities. This superalloy can be strengthened by ?? dispersions and further dispersion mechanisms. Exemplary compositions can provide good oxidation properties and improved strength values at high temperatures.

Abstract: A creep-resistant steel is characterized by the following chemical composition (values in % by weight): 9.0 to 12.0 Cr, 0.1 to 0.5 Mn, 2.3 to 3 Ni, 1.5 to 2.0 Mo, 0.1 to 0.4 V, 0.01 to 0.06 Nb, 0.08 to 0.16 C, 0.02 to 0.08 N, 0.004 to 0.012 B, 0.001 to 2 Ta, 0.001 to 0.5 La, 0.0001 to 1 Pd, maximum 0.005 P, maximum 0.005 S, maximum 0.05 Si, maximum 0.005 Sn, the remainder iron and unavoidable impurities. This steel is distinguished, as compared with commercial steels, by a greatly improved creep behavior at temperatures of 550° C. and above. Moreover, it has an improved resistance to embrittlement during long-term aging and comparatively high toughness. The steel is advantageously used as a material for gas turbine rotors which are exposed to high inlet temperatures in order to increase the efficiency of the gas turbine, but is also used for steam turbines.

Abstract: The disclosure relates to a creep-resistant steel which having a chemical composition (values in % by weight) of: about 0.10 to 0.15 C, 8 to 13 Cr, 0.1 to 0.5 Mn, 2 to 3 Ni; at least one or both elements from the group Mo, W in a range in each case of about 0.5 to 2.0 or, if both elements are present, a maximum total of about 3.0; about 0.02 to 0.2 Nb, 0.05 to 2 Ta, 0.1 to 0.4 V, 0.005 to 2 Pd, 0.02 to 0.08 N, 0.03 to 0.15 Si; and about 80 to 120 ppm B, maximum about 100 ppm Al, maximum about 150 ppm P, maximum about 250 ppm As, maximum about 120 ppm Sn, maximum about 30 ppm Sb, maximum 50 ppm S, a remainder of the composition being iron and impurities.

Abstract: An iron-based high-temperature alloy has the following chemical composition (values given being in % by weight): 20 Cr, 4 to 8 Al, at least one of the elements Ta and Mo with a sum of 4 to 8, 0-0.2 Zr, 0.02-0.05 B, 0.1-0.2 Y, 0-0.5 Si, remainder Fe. The alloy can be produced at low cost and is distinguished in comparison with the known prior art by outstanding oxidation resistance and good mechanical properties at high temperatures up to 1000° C.

Abstract: A heat treatment method for a nickel-based superalloy, in particular for the production of single-crystal components or directionally solidified components having a chemical composition permits full solution annealing at a temperature T1, the method comprising: partially solution annealing in a controlled manner at a temperature T2<T1 in a first step so as to obtain 5-10% of undissolved ?? phase in a residual eutectic; and performing a two-stage ageing treatment at respectively lower temperatures in a second step. As a function of the selected level of the partial solution annealing temperature, the proportion of the undissolved ?? phase can be adjusted in a controlled way, and the tolerance with respect to the disorientation of small-angle grain boundaries/grain boundaries can be increased.

Abstract: A maraging heat-treatment steel includes 8.5 to 9.5% by weight of Cr, 0.15 to 0.25% by weight of Mn, 2 to 2.7% by weight of Ni, 0.5 to 2.5% by weight of Mo, 0.4 to 0.8% by weight of V, 0.001 to 0.15% by weight of Si, 0.06 to 0.1% by weight of C, 0.11 to 0.15% by weight of N, 0.02 to 0.04% by weight of Nb, maximum 0.007% by weight of P, maximum 0.005% by weight of S, maximum 0.01% by weight of Al, iron and standard impurities, wherein a weight ratio of vanadium to nitrogen V/N is in a range between 4.3 and 5.5.

Abstract: The invention discloses an intermetallic material consisting of the following composition by weight percent: 10% Al, 22% Cr, 36% Co, 0.2% Y, 0.2% Hf, 2% Ta, 3% Fe, remainder Ni and inevitable impurities. The invention also describes its use as a layer protecting against high temperatures and at locations of thermal turbomachines which are subject to friction or vibration.

Abstract: The invention relates to a hybrid blade (1) for thermal turbomachines, having an airfoil (2) made of a metallic material of a certain density, and having a blade root (3). It is characterized in that the blade root (3), compared with the airfoil (2), is made of a different metallic material having a lower density, and in that the airfoil (20) is connected to the blade root (3) in a positive-locking manner. The blade in this case is advantageously a compressor blade, in particular a high-pressure compressor blade, in which the airfoil (2) is made of a stainless CrNi steel and the blade root (3) is made of a high-temperature titanium alloy or an intermetallic gamma titanium aluminide alloy or an intermetallic orthorhombic titanium aluminide alloy.

Abstract: The invention discloses an intermetallic material consisting of the following composition by weight percent: 10% Al, 22% Cr, 36% Co, 0.2% Y, 0.2% Hf, 2% Ta, 3% Fe, remainder Ni and inevitable impurities. The invention also describes its use as a layer protecting against high temperatures and at locations of thermal turbomachines which are subject to friction or vibration.

Abstract: The invention relates to a hybrid blade (1) for thermal turbomachines, having an airfoil (2) made of a metallic material of a certain density, and having a blade root (3). It is characterized in that the blade root (3), compared with the airfoil (2), is made of a different metallic material having a lower density, and in that the airfoil (20) is connected to the blade root (3) in a positive-locking manner. The blade in this case is advantageously a compressor blade, in particular a high-pressure compressor blade, in which the airfoil (2) is made of a stainless CrNi steel and the blade root (3) is made of a high-temperature titanium alloy or an intermetallic gamma titanium aluminide alloy or an intermetallic orthorhombic titanium aluminide alloy.