scholarly journals The Effect of Heat Treatment on the Oxidation Resistance of Cobalt-Based Superalloys

Metals ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 248 ◽  
Author(s):  
James P. Moffat ◽  
Tamsin E. Whitfield ◽  
Katerina A. Christofidou ◽  
Ed J. Pickering ◽  
Nicholas G. Jones ◽  
...  
Keyword(s):  
Heat Treatment ◽  
High Temperature ◽  
Oxidation Resistance ◽  
Mechanical Integrity ◽  
Carbide Network ◽  
Carbide Phases ◽  
Stellite 21 ◽  
Oxidation Testing

Degradation of the mechanical integrity of cobalt-based superalloys can occur as the carbide network is progressively oxidised during high temperature service. In this study, a heat-treatment aimed at redistributing the carbides was tested on two similar commercial Co-based superalloys, one with high C content (Co-101) and one with low C content (Stellite-21), to determine its influence on oxidation resistance. It was found that the carbide phases in the lower C-containing alloy could be solutioned more readily than the higher C-containing alloy, enabling the continuity of the carbide network to be reduced. This resulted in a reduced attack of the carbides down the interdendritic channels during oxidation testing, but increased thickness of the oxide overscale.

scholarly journals A High Strength Nickel-Base Alloy With Improved Oxidation Resistance up to 2200 deg F

1968 ◽  
Vol 90 (1) ◽  
pp. 1-10
Author(s):  
W. J. Waters ◽  
J. C. Freche
Keyword(s):  
Heat Treatment ◽  
Weight Gain ◽  
High Temperature ◽  
Oxidation Resistance ◽  
Base Alloy ◽  
High Strength ◽  
Nickel Base Alloy ◽  
Cast Material ◽  
Nickel Base ◽  
Cast Condition

A high strength nickel-base alloy has been developed which compares favorably in oxidation resistance with known high strength nickel-base alloys. The alloy, although basically a cast material, also possesses workability potential. After 310 hr exposure to air at 1900 deg F, the alloy had a weight gain of 1.8 mg/cm2. The total affected zone, oxidized material plus depletion zone, was 0.4 mil. This compares with a weight gain of 3.0 mg/cm2 and a total affected zone depth of 3.3 mils for Rene´ 41 after 100 hr exposure at 1900 deg F. In sheet form after 8 hr at 2200 deg F, its oxidation resistance was approximately the same as that of Rene´ 41 at 1900 deg F. Tensile strengths of the alloy after rolling and heat-treatment ranged from an average of 185,000 psi at 1400 deg F to 3000 psi at 2200 deg F. Maximum elongation was 55 percent and occurred at the latter temperature. At 1900 deg F, average tensile strength was 64,500 psi in the as-cast condition, and 54,000 psi after rolling and heat-treatment. Stress rupture data for low and intermediate stress levels were obtained. In the as-cast condition, use temperatures for 500, 100, and 10-hr life at 15,000 psi are 1815, 1895, and 2010 deg F, respectively. At 8000 psi and 2125 deg F, rupture life was 13 hr and compared favorably with some of the strongest known nickel and cobalt-base alloys. The very good high temperature oxidation resistance, good high temperature strength, and at least limited workability of this alloy suggest that it may be applicable for use in advanced gas turbine engine components.

Features of heat treatment of a new steel for the manufacture of hot deformation dies

2021 ◽  
pp. 54-60
Author(s):  
S. E. Krylova ◽  
◽  
E. V. Romashkov ◽  
Keyword(s):  
Heat Treatment ◽  
High Temperature ◽  
Elevated Temperatures ◽  
Heat Exposure ◽  
Microalloyed Steels ◽  
Carbide Phases ◽  
Rational Mode ◽  
Spheroidizing Annealing ◽  
And Behavior ◽  
Combined Cooling

The influence of heat treatment parameters on the structure and properties of the promising 70Cr3Mn2WTiB die steel, which is offered for the manufacture of mold parts for aluminum alloy injection molding machines, is revealed. A rational mode of thermal hardening is recommended for the developed steel, including spheroidizing annealing at a temperature of 780 °C with combined cooling; quenching at 1000 °C with oil cooling; high-temperature tempering at 550–600 °C with cooling in calm air. The structure formation and behavior of carbide phases in microalloyed steels at various stages of heat treatment are evaluated. The features of phase transformations and the mechanism of dispersion hardening during high-temperature tempering that provide the required set of mechanical and technological properties are determined. The influence of heat treatment modes on mechanical and operational properties under cyclic loading and heat exposure at normal and elevated temperatures is evaluated. Fractographic studies of zones of cyclic and static crack growth in fractures of samples after testing for crack resistance under cyclic and static loading were performed. The main regularities of changes in the thermal structural stability of chromium steels under cyclic temperature and force influences, depending on the nature of alloying and heat treatment modes, are substantiated, which made it possible to reasonably recommend the developed 70Cr3Mn2WTiB steel for implementation.

scholarly journals Effect of Vacuum Heat Treatment on the High-Temperature Oxidation Resistance of NiCrAlY Coating

Coatings ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1089
Author(s):  
Jiahui Zheng ◽  
Deming Yang ◽  
Yang Gao
Keyword(s):  
Heat Treatment ◽  
High Temperature ◽  
Oxidation Resistance ◽  
High Temperature Oxidation ◽  
Isothermal Oxidation ◽  
Vacuum Heat Treatment ◽  
Temperature Oxidation ◽  
Different Temperatures ◽  
Exposure Testing ◽  
Α Al2o3

NiCrAlY coatings were prepared using high-velocity oxygen fuel spraying (HVOF), and the coatings were removed from the substrate to achieve a uniform shape. Vacuum heat treatment (VHT) of the as-sprayed coatings was conducted at different temperatures (1000, 1100, and 1200 °C), and the specimens were subjected to isothermal oxidation exposure testing in air at 1100 °C for up to 21 h. The results show that the high temperature oxidation resistance of the coating increased gradually with the increase in VHT temperature, and the coating of VHT1200 had higher oxidation resistance. The high temperature oxidation resistance of the coating was related to the microstructure transformation of the coating. In VHT coatings, β-NiAl became a dispersed irregular block morphology. The γ’-Ni3Al in VHT1000 presented a granular morphology. However, in VHT1100 and VHT1200, γ’-Ni3Al became a lamellar morphology. This transformation of microstructure promotes the form of exclusive α-Al2O3 scale. With the increase in VHT temperature, the content of yttrium on coatings’ surface was increased and the pores were gradually eliminated. The concentration of yttrium on coatings’ surface prevented the formation of θ-Al2O3 and low porosity was beneficial in improving the internal oxidation of the coating.

NAS 600

Alloy Digest ◽  
2011 ◽  
Vol 60 (3) ◽  
Keyword(s):  
Heat Treatment ◽  
Corrosion Resistance ◽  
High Temperature ◽  
Physical Properties ◽  
Tensile Properties ◽  
Nickel Alloy ◽  
Oxidation Resistance ◽  
Heat Treating ◽  
Temperature Performance

Abstract NAS 600 is a nickel alloy with 14-17 chromium and has excellent oxidation resistance. The alloy is used extensively in heat treatment furnaces. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties as well as creep. It also includes information on high temperature performance and corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: Ni-688. Producer or source: Nippon Yakin Kogyo Company Ltd.

Influence of ZrO2 on Oxidation Resistant Properties of Glass-Based Coating on Molybdenum Substrate

2010 ◽  
Vol 160-162 ◽  
pp. 1762-1766
Author(s):  
Qing Wei Wang ◽  
Hong Zhi Wang ◽  
Wei Ning
Keyword(s):  
Heat Treatment ◽  
High Temperature ◽  
Viscous Liquid ◽  
Oxidation Resistance ◽  
Heat Treatment Temperature ◽  
Treatment Temperature ◽  
Molybdenum Substrate ◽  
Oxidation Resistant ◽  
Glass Powders

the oxidation resistance of glass-based coating on molybdenum substrate was studied in the paper. The Mo substrates with glass based coating modified by the different concentration of ZrO2 in the coating were prepared and characterized; results showed the oxidation resistance of samples increased firstly and decreased subsequently with increase in ZrO2 concentrations. The influence of different heat treatment temperature was also discussed in the paper. After the sampes were pretreated at the high temperature for 20 minutes, the oxidation resistance properties were improved five times than un-pretreated ones. SEM showed the glass powders in the coating changed into viscous liquid which adhere to the substrate tightly after the samples had been pretreated. Resulting showed the sample exhibited the best oxidation resistance when pretreated at 1300°C.

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