Rupture, creep and

General Metallurgical Behaviors in Gas Turbines Creep and Rupture... 

The austenitic grades, used mainly in the solution treated (softened) state, have low strength at ambient temperature but maintain strength at elevated temperatures much better than the martensitics and the ferritics. As can be seen from Figs 7.23 to 7.25, creep and rupture. strengths are far superior... 

Goldfein, S., General Formula for Creep and Rupture Stresses in Plastics, MP, Apr. 1960. 

METALCREEP The National Materials Property Data Network, Inc. creep and rupture stress of aluminum alloys and steels... 

Alloy 602 CA a modification of other 600 alloys is used in heat-treating, annealing furnaces, furnace rolls, high-temperature calcination application, catalytic support systems, and glow plugs in automobiles, vitrification of nuclear waste 800, 45 TM Have high creep and rupture strength and oxidation resistance used... 

Enhancing the creep and rupture properties of fibers is undoubtedly beneficial, but explicit goals cannot be set until component testing is done. 

Continuous-length ceramic fibers used to reinforce CMCs must have optimal mechanical, physical, and chemical properties (described in Chapter 2). This chapter reviews the characteristics of fibers that are commercially available and fibers that are at an advanced stage of development. The performance characteristics of interest include stiffness (i.e.. Young s modulus), strength, thermal and electrical conductivity, creep and rupture resistance, oxidation resistance, all as a function of temperature, and strength and stiffness retention as a fimetion of serviee history. The critical issue of chemical compatibility with prospective interface coatings and the eeramie matrix is addressed in Chapter 4 and Chapter 6. 

Tressler, R.E., and J.A. DiCarlo. 1995. Creep and rupture of advanced ceramic fiber reinforcements. Pp. 141-155 in High Temperature Ceramic Matrix Composites 1, Design, Durability, and Performance. Vol. 57 in Ceramic Transactions, A.G. Evans and R. Naslain (eds.). Westerville, Ohio American Ceramic Society. 

Yun, H.M., J.C. Goldsby, and J.A. DiCarlo. 1995b. Effects of thermal treatment on tensile creep and rupture behavior of Hi-Nicalon SiC fibers. Ceramic Engineering and Science Proceedings 16(5) 987-996. ... 

R. E. Tressler and J. A. DiCarlo, Creep and rupture of advanced ceramic fiber reinforcements, Ceram. Trans., 56,141-155(1995). 

Several investigators have shown that the starting time of tertiary creep and rupture life are related for various alloys according to the relation (e.g., Garofalo et al. [11]) ... 

Alloy 800H is a controlled version of alloy 800. The carbon content is maintained between 0.05 and 0.1% to provide the alloy with better elevated-temperature creep and rupture properties. It is solution-annealed to assure the improved creep and stress-to-rupture properties. 

At temperatures in the creep and rupture strength range, the least of ... 

The design criteria of the ASME Code, Vni-1, and Section III, Division 1, Subsections NC except NC-3200, ND, and NE, are similar to those for Sections I and rv except that the ASME Code, VIII-1, and Section III, Division 1, Subsections NC, ND, and NE require cylindrical shell thickness calculations based on both the circumferential and the longitudinal directions. The minimum required thickness may be set by stresses in either direction. In addition, the ASME Code, VIII-1, permits the combination of primary membrane stress and primary bending stress to go as high as 1.5 5 at temperatures where tensile and yield strength control and 1.25 5 at temperatures where creep and rupture control, where 5 is the allowable tensile stress values. 

The strength level of a material has a significant influence on its selection for a given application. This is especially true at elevated temperatures where the yield and ultimate strength are relatively low and the creep and rupture behavior may control the allowable stress values. In the ASME Code, VIII-1, the criteria for allowable stress at elevated temperatures take into account both the creep and rupture behavior as discussed in Section 2.4. In applying the ASME criteria for allowable stress as given there, the following procedures are used. 

Example 4.1. A user is requesting code approval for a new material that has a minimum specified tensile stress of 120 ksi and a minimum specified yield stress of 60 ksi at room temperature. Tensile and yield values for various heats and temperatures are shown in Fig. 4.5. Creep and rupture data are given in Figs. 4.6 and 4.7, respectively. What are the allowable stress values at 300 and 1200°F based on criteria given in Section 2.4 ... 

At design temperature where creep and rupture strength govern, the lesser of the following ... 

These alloys represent another version of Ni-Cr-Fe alloys and contain 30-44% of nickel. Alloy 800 of this series has been extensively used in heat exchangers in the petrochemical industry, because of its excellent resistance to stress corrosion cracking in chloride environments and cracking in polythionic acid. It offers an excellent resistance to creep and rupture. They are used for high environments where resistance to oxidation and corrosion is required. Incoloy 825 has proved highly successfiil in applications in H2SO4, HCl, phosphoric acid and clean and polluted seawater. 

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