Abstract: An alumina-forming, high temperature creep resistant alloy is composed essentially of, in terms of weight percent: up to 10 Fe, 3.3 to 4.6 Al, 6 to 22 Cr, 0.68 to 0.74 Mn, 5.2 to 6.6 Mo, 0.4 to 1.2 Ti, up to 0.1 Hf, 0.005 to 0.05 La, 0.4 to 0.6 W, 0.1 to 0.35 C, up to 0.002 B, 0.001 to 0.02 N, balance Ni.

Abstract: A tubular article can be formed from high temperature steam oxidation resistant and high temperature creep resistant alloy steel. The steel can include a chemical composition that include Fe, C, Si, Mn, Ni, Cr, Cu, Ti, Nb, Mo, and N, and optionally other elements. The steel alloy can include 0.06 to 0.15 wt % C, 0.1 to 0.5 wt % Si, 0.2 to 0.6 wt %, 0.05 to 0.4 wt % Ni, 4.5 to 6.0 wt % Cr, 1.0 to 2.0 wt % Cu, 0.04 to 0.08 wt % Ti, 0.01 to 0.06 wt % Nb, 0.45 to 1.2 wt % Mo, and 0.008 to 0.05 wt % N, up to 0.01 wt % of optional element Al, up to 0.01 wt % of optional element Zr, up to 3.0 wt % of optional element Co, up to 0.07 wt % of optional element V, up to 3.0 wt % of optional element W, up to 0.015 wt % of optional element P, up to 0.003 wt % of optional element S, up to 0.1 wt % of optional element Ca, up to 0.1 wt % of optional element Ta, up to 0.1 wt % of optional element Mg, up to 0.1 wt % of optional element Se, up to 0.1 wt % of optional element Te, up to 0.1 wt % of optional element B, up to 0.

Abstract: An essentially Fe- and Co-free alloy is composed essentially of, in terms of weight percent: 6.0 to 7.5 Cr, 0 to 0.15 Al, 0.5 to 0.85 Mn, 11 to 19.5 Mo, 0.03 to 4.5 Ta, 0.01 to 9 W, 0.03 to 0.08 C, 0 to 1 Re, 0 to 1 Ru, 0 to 0.001 B, 0.0005 to 0.005 N, balance Ni, the alloy being characterized by, at 850° C., a yield strength of at least 25 Ksi, a tensile strength of at least 38 Ksi, a creep rupture life at 12 Ksi of at least 25 hours, and a corrosion rate, expressed in weight loss [g/(cm2 sec)]10?11 during a 1000 hour immersion in liquid FLiNaK at 850° C., in the range of 3 to 10.

Abstract: A method of in-situ reconditioning a heat exchanger includes the steps of: providing an in-service heat exchanger comprising a precipitate-strengthened alloy wherein at least one mechanical property of the heat exchanger is degraded by coarsening of the precipitate, the in-service heat exchanger containing a molten salt working heat exchange fluid; deactivating the heat exchanger from service in-situ; in a solution-annealing step, in-situ heating the heat exchanger and molten salt working heat exchange fluid contained therein to a temperature and for a time period sufficient to dissolve the coarsened precipitate; in a quenching step, flowing the molten salt working heat-exchange fluid through the heat exchanger in-situ to cool the alloy and retain a supersaturated solid solution while preventing formation of large precipitates; and in an aging step, further varying the temperature of the flowing molten salt working heat-exchange fluid to re-precipitate the dissolved precipitate.

Abstract: An Fe—Ni—Cr alloy is composed essentially of, in terms of wt. %: 2.4 to 3.7 Al, up to 1.05 Co, 14.8 to 15.9 Cr, 25 to 36 Fe, up to 1.2 Hf, up to 4 Mn, up to 0.6 Mo, up to 2.2 Nb, up to 1.05 Ta, 1.9 to 3.6 Ti, up to 0.08 W, up to 0.03 Zr, 0.18 to 0.27 C, up to 0.0015 N, balance Ni, wherein, in terms of atomic percent: 8.5?Al+Ti+Zr+Hf+Ta?11.5, 0.53?Al÷(Al+Ti+Zr+Hf+Ta)?0.65, and 0.16?Cr÷(Fe+Ni+Cr+Mn)?0.21, the alloy being essentially free of Cu, Si, and V.

Abstract: Disclosed herein are systems, devices and methods for stress-rupture testing selected materials within a high-temperature liquid salt environment. Exemplary testing systems include a load train for holding a test specimen within a heated inert gas vessel. A thermal break included in the load train can thermally insulate a load cell positioned along the load train within the inert gas vessel. The test specimen can include a cylindrical gage portion having an internal void filled with a molten salt during stress-rupture testing. The gage portion can have an inner surface area to volume ratio of greater than 20 to maximize the corrosive effect of the molten salt on the specimen material during testing. Also disclosed are methods of making a salt ingot for placement within the test specimen.

Abstract: An Fe—Ni—Cr alloy is composed essentially of, in terms of weight percent: 1 to 3.5 Al, up to 2 Co, 15 to 19.5 Cr, up to 2 Cu, 23 to 40 Fe, up to 0.3 Hf, up to 4 Mn, 0.15 to 2 Mo, up to 0.15 Si, up to 1.05 Ta, 2.8 to 4.3 Ti, up to 0.5 W, up to 0.06 Zr, 0.02 to 0.15 C, 0.0001 to 0.007 N, balance Ni, wherein, in terms of atomic percent: 6.5?Al+Ti+Zr+Hf+Ta?10, 0.33?Al÷(Al+Ti+Zr+Hf+Ta)?0.065, 4?(Fe+Cr)÷(Al+Ti+Zr+Hf+Ta)?10, the alloy being essentially free of Nb and V.

Abstract: The method provides heat-resistant chromia- or alumina-forming Fe-, Fe(Ni), Ni(Fe), or Ni-based alloys having improved creep resistance. A precursor is provided containing preselected constituents of a chromia- or alumina-forming Fe-, Fe(Ni), Ni(Fe), or Ni-based alloy, at least one of the constituents for forming a nanoscale precipitate MaXb where M is Cr, Nb, Ti, V, Zr, or Hf, individually and in combination, and X is C, N, O, B, individually and in combination, a=1 to 23 and b=1 to 6. The precursor is annealed at a temperature of 1000-1500° C. for 1-48 h in the presence of a magnetic field of at least 5 Tesla to enhance supersaturation of the MaXb constituents in the annealed precursor. This forms nanoscale MaXb precipitates for improved creep resistance when the alloy is used at service temperatures of 500-1000° C. Alloys having improved creep resistance are also disclosed.

Abstract: A machine for asymmetric rolling of a work-piece includes pair of rollers disposed in an arrangement to apply opposing, asymmetric rolling forces to roll a work-piece therebetween, wherein a surface of the work-piece is rolled faster than an opposite surface of the work-piece; and an exit constraint die rigidly disposed adjacent an exit side of the pair of rollers so that, as the work-piece exits the pair of rollers, the work-piece contacts the exit constraint die to constrain curling of the work-piece.

Abstract: Disclosed herein are systems, devices and methods for stress-rupture testing selected materials within a high-temperature liquid salt environment. Exemplary testing systems include a load train for holding a test specimen within a heated inert gas vessel. A thermal break included in the load train can thermally insulate a load cell positioned along the load train within the inert gas vessel. The test specimen can include a cylindrical gage portion having an internal void filled with a molten salt during stress-rupture testing. The gage portion can have an inner surface area to volume ratio of greater than 20 to maximize the corrosive effect of the molten salt on the specimen material during testing. Also disclosed are methods of making a salt ingot for placement within the test specimen.

Abstract: An alloy is composed essentially of, in terms of weight percent: 6 to 8.5 Cr, 5.5 to 13.5 Mo, 0.4 to 7.5 W, 1 to 2 Ti, 0.7 to 0.85 Mn, 0.05 to 0.3 Al, 0.08 to 0.5 C, 0 to 1 Nb, with the balance Ni, the alloy being characterized by, at 850° C., a yield strength of at least 25 Ksi, a tensile strength of at least 30 Ksi, a creep rupture life at 12 Ksi of at least 45 hours, and a corrosion rate, expressed in weight loss [g/(cm2 sec)]10?11 during a 1000 hour immersion in liquid FLiNaK at 850 ° C., in the range of 6 to 39.

Abstract: An alloy consists essentially of, in terms of weight percent: 6 to 8.5 Cr, 5.5 to 13.5 Mo, 0.4 to 7.5 W, 1 to 2 Ti, 0.7 to 0.85 Mn, 0.05 to 0.3 Al, up to to 0.1 Co, 0.08 to 0.5 C, 1 to 5 Ta, 1 to 4 Nb, 1 to 3 Hf, balance Ni. The alloy is characterized by, at 850° C., a yield strength of at least 36 Ksi, a tensile strength of at least 40 Ksi, a creep rupture life at 12 Ksi of at least 72.1 hours, and a corrosion rate, expressed in weight loss [g/(cm2sec)]×10?11 during a 1000 hour immersion in liquid FLiNaK at 850° C., in the range of 8 to 25.

Abstract: An apparatus for materials processing utilizing a rotating magnetic field comprises a platform for supporting a specimen, and a plurality of magnets underlying the platform. The plurality of magnets are configured for rotation about an axis of rotation intersecting the platform. A heat source is disposed above the platform for heating the specimen during the rotation of the plurality of magnets. A method for materials processing utilizing a rotating magnetic field comprises providing a specimen on a platform overlying a plurality of magnets; rotating the plurality of magnets about an axis of rotation intersecting the platform, thereby applying a rotating magnetic field to the specimen; and, while rotating the plurality of magnets, heating the specimen to a desired temperature.

Abstract: An essentially Fe- and Co-free alloy is composed essentially of, in terms of weight percent: 6.0 to 7.5 Cr, 0 to 0.15 Al, 0.5 to 0.85 Mn, 11 to 19.5 Mo, 0.03 to 4.5 Ta, 0.01 to 9 W, 0.03 to 0.08 C, 0 to 1 Re, 0 to 1 Ru, 0 to 0.001 B, 0.0005 to 0.005 N, balance Ni, the alloy being characterized by, at 850° C., a yield strength of at least 25 Ksi, a tensile strength of at least 38 Ksi, a creep rupture life at 12 Ksi of at least 25 hours, and a corrosion rate, expressed in weight loss [g/(cm2 sec)]10?11 during a 1000 hour immersion in liquid FLiNaK at 850° C., in the range of 3 to 10.

Abstract: An essentially Fe-free alloy consists essentially of, in terms of weight percent: 4 to 11 Co, 6.5 to 7.5 Cr, 0 to 0.15 Al, 0.5 to 0.85 Mn, 11 to 20 Mo, 1 to 3.5 Ta, 0.05 to 9 W, 0.03 to 0.08 C, 0 to 0.001 B, 0.0005 to 0.005 N, balance Ni, the alloy being characterized by, at 850° C., a yield strength of at least 25 Ksi, a tensile strength of at least 45 Ksi, a creep rupture life at 12 Ksi of at least 10 hours, and a corrosion rate, expressed in weight loss [g(cm2sec)]10?11 during a 1000 hour immersion in liquid FLiNaK at 850° C., in the range of 5 to 20.

Abstract: An essentially cobalt-free alloy consists essentially of, in terms of weight percent: 6.3 to 7.2 Cr, 0.5 to 2 Al, 0 to 5 Fe, 0.7 to 0.8 Mn, 9 to 12.5 Mo, 0 to 6 Ta, 0.75 to 3.5 Ti, 0.01 to 0.25 Nb, 0.2 to 0.6 W, 0.02 to 0.04 C, 0 to 0.001 B, 0.0001 to 0.002 N, balance Ni. The alloy is characterized by a ?? microstructural component in the range of 3 to 17.6 weight percent of the total composition. The alloy is further characterized by, at 850° C., a yield strength of at least 60 Ksi, a tensile strength of at least 70 Ksi, a creep rupture life at 12 Ksi of at least 700 hours, and a corrosion rate, expressed in weight loss [g/(cm2sec)]10?11 during a 1000 hour immersion in liquid FLiNaK at 850° C., in the range of 5.5 to 17.

Abstract: A method of in-situ reconditioning a heat exchanger includes the steps of: providing an in-service heat exchanger comprising a precipitate-strengthened alloy wherein at least one mechanical property of the heat exchanger is degraded by coarsening of the precipitate, the in-service heat exchanger containing a molten salt working heat exchange fluid; deactivating the heat exchanger from service in-situ; in a solution-annealing step, in-situ heating the heat exchanger and molten salt working heat exchange fluid contained therein to a temperature and for a time period sufficient to dissolve the coarsened precipitate; in a quenching step, flowing the molten salt working heat-exchange fluid through the heat exchanger in-situ to cool the alloy and retain a supersaturated solid solution while preventing formation of large precipitates; and in an aging step, further varying the temperature of the flowing molten salt working heat-exchange fluid to re-precipitate the dissolved precipitate.

Abstract: An austenitic stainless steel alloy, consists essentially of, in weight percent 2.5 to 4 Al; 25 to 35 Ni; 12 to 19 Cr; at least 1, up to 4 total of at least one element selected from the group consisting of Nb and Ta; 0.5 to 3 Ti; less than 0.5 V; 0.1 to 1 of at least on element selected from the group consisting of Zr and Hf; 0.03 to 0.2 C; 0.005 to 0.1 B; and base Fe. The weight percent Fe is greater than the weight percent Ni. The alloy forms an external continuous scale including alumina, and contains coherent precipitates of ??-Ni3Al, and a stable essentially single phase FCC austenitic matrix microstructure. The austenitic matrix is essentially delta-ferrite-free and essentially BCC-phase-free.

Abstract: The method provides heat-resistant chromia- or alumina-forming Fe-, Fe(Ni), Ni(Fe), or Ni-based alloys having improved creep resistance. A precursor is provided containing preselected constituents of a chromia- or alumina-forming Fe-, Fe(Ni), Ni(Fe), or Ni-based alloy, at least one of the constituents for forming a nanoscale precipitate MaXb where M is Cr, Nb, Ti, V, Zr, or Hf, individually and in combination, and X is C, N, O, B, individually and in combination, a=1 to 23 and b=1 to 6. The precursor is annealed at a temperature of 1000-1500° C. for 1-48 h in the presence of a magnetic field of at least 5 Tesla to enhance supersaturation of the MaXb constituents in the annealed precursor. This forms nanoscale MaXb precipitates for improved creep resistance when the alloy is used at service temperatures of 500-1000° C. Alloys having improved creep resistance are also disclosed.

Abstract: An austenitic stainless steel alloy consisting essentially of, in terms of weight percent ranges 0.15-0.5C; 8-37Ni; 10-25Cr; 2.5-5Al; greater than 0.6, up to 2.5 total of at least one element selected from the group consisting of Nb and Ta; up to 3Mo; up to 3Co; up to 1W; up to 3Cu; up to 15Mn; up to 2Si; up to 0.15B; up to 0.05P; up to 1 total of at least one element selected from the group consisting of Y, La, Ce, Hf, and Zr; <0.3Ti+V; <0.03N; and, balance Fe, where the weight percent Fe is greater than the weight percent Ni, and wherein the alloy forms an external continuous scale comprising alumina, and a stable essentially single phase FCC austenitic matrix microstructure, the austenitic matrix being essentially delta-ferrite free and essentially BCC-phase-free. A method of making austenitic stainless steel alloys is also disclosed.