Download or read book NEAR THRESHOLD FATIGUE CRACK PROPAGATION IN FERRITIC STAINLESS STEELS AT ELEVATED TEMPERATURES written by KAMEL MAKHLOUF and published by . This book was released on 1991 with total page 169 pages. Available in PDF, EPUB and Kindle. Book excerpt: and without excessive plasticity.
Download or read book Fatigue Crack Growth Behavior of Ferritic and Austenitic Steels at Elevated Temperatures written by M. Nani Babu and published by . This book was released on 2014 with total page 28 pages. Available in PDF, EPUB and Kindle. Book excerpt: For the integrity assessment and damage-tolerant design of components operating at elevated temperatures under cyclic loading conditions, evaluation of fatigue crack growth (FCG) properties in the threshold and Paris regimes is important. The FCG behaviors of a modified 9Cr-1Mo steel (P91) and SS 316L(N) for applications in the prototype fast breeder reactor to be commissioned shortly at Kalpakkam, India have been studied extensively in our laboratory over a wide range of temperatures. Some aspects of high-temperature FCG observed in these investigations will be reviewed in this paper. It has been observed that for many engineering alloys, dynamic strain aging plays an important role in the temperature-dependent variations in deformation and fracture behavior, including the FCG parameters. Another important aspect in deciding the FCG behavior is the crack closure behavior, the mechanisms of which may vary with temperature. Effect of crack closure and DSA on the FCG properties of P91 steel and SS 316L(N) welds will be discussed. The DSA mechanism has been identified from the activation energy for the process determined from the temperature dependence of the crack tip strain rates. During FCG of engineering materials, there can be stress shielding at the crack tip because of various factors, like crack bridging, branching, closure, etc. Effect of stress shielding at the crack tip at different conditions was quantified using a procedure incorporating the inter relations between compliance, crack length, and stress intensity factor. The paper will summarize the results of the above studies.
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1994 with total page 702 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book IUTAM Symposium on Creep in Structures written by S. Murakami and published by Springer Science & Business Media. This book was released on 2013-11-27 with total page 541 pages. Available in PDF, EPUB and Kindle. Book excerpt: These proceedings contain 48 innovative papers consolidating the development of creep research since 1990 and discussing the new horizons in this fundamental field of applied mechanics in the coming century. This volume is useful for researchers and graduate course students in the relevant fields.
Download or read book Fatigue Crack Growth Characteristics of Several Austenitic Stainless Steels at High Temperature written by P. Shahinian and published by . This book was released on 1973 with total page 14 pages. Available in PDF, EPUB and Kindle. Book excerpt: The resistance to fatigue crack growth of annealed stainless steels, Types 304, 316, 321, and 348, was determined at 77, 800, and 1100 F (25, 427, and 593 C). Crack growth rates were related to the stress intensity factor range (?K). With increase in temperature the rate of crack growth for a given (?K) increased. At room temperature the four steels had the same resistance to crack growth. However, at high temperatures crack growth became sensitive to the differences in composition and properties among the steels. At 1100 F (593 C), Type 348 steel had the greatest resistance to crack growth and Type 316 the lowest resistance. As a result, fatigue life was 3.4 times longer for Type 348 steel over Type 316 steel at this temperature. The characteristics of high-temperature fatigue crack growth were examined.
Download or read book Fatigue Crack Propagation in Austenitic Stainless Steels at Cryogenic Temperatures written by Zequn Mei and published by . This book was released on 1990 with total page 230 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Threshold for Fatigue Crack Growth in Ferritic Steels at 300 C written by AA. Beveridge and published by . This book was released on 1973 with total page 13 pages. Available in PDF, EPUB and Kindle. Book excerpt: Edge-cracked test specimens of two ferritic steels were subjected to the loading cycle ?m ± ?a at 300 C. The results showed that whether a crack grows or remains dormant can be predicted from the value of ?K, the range of stress intensity factor during the fatigue cycle. The threshold value ?Kc necessary for crack growth was slightly greater than that of similar steels at room temperature and depended on the ratio ?m/?a. Crack growth data at low rates of crack growth were deduced from an integrated version of the crack growth equation da/dN = B(?K)m, where B and m are material constants. Crack growth rates at 300 C were similar to those at room temperature. The minimum possible rate of fatigue crack growth appeared to be somewhat greater than one lattice spacing/cycle. The methods used have the advantage that no crack growth monitoring instrumentation is required.
Download or read book Fatigue Threshold Regime of a Low Alloy Ferritic Steel Under Closure Free Testing Conditions written by WV. Vaidya and published by . This book was released on 1992 with total page 12 pages. Available in PDF, EPUB and Kindle. Book excerpt: Near-threshold fatigue crack propagation behavior of a high strength steel was investigated in laboratory air under closurefrec testing conditions at R = 0.7 (= Rcff) and at two different K-gradients. Depending on the criterion assumed, the threshold value differed; the criterion of non-propagation gave a lower threshold value than that assumed by the propagation criterion. Nevertheless. the subsequent propagation following a load increase was discontinuous in both cases, and da/dN versus ?K curves obtained on the some specimen during the K-decreasing and the K-increasing test were not necessarily identical in the threshold regime. This behavior, hysteresis, is analyzed mainly from the experimental viewpoint, and it is shown that hysteresis is not an artifact.
Download or read book Study of Near threshold Fatigue Crack Propagation in Pipeline Steels in High Pressure Environments written by and published by . This book was released on 1981 with total page 142 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Fatigue at High Temperature written by R. P. Skelton and published by . This book was released on 1983 with total page 434 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Small crack Test Methods written by James M. Larsen and published by ASTM International. This book was released on 1992 with total page 228 pages. Available in PDF, EPUB and Kindle. Book excerpt: Reviews the most recent methods for testing small cracks in a variety of materials, providing detailed quantitative information on necessary procedures for data acquisition. Emphasizes the characterization of small, three-dimensional fatigue cracks, initiated either naturally or artificially. The ei
Download or read book Fatigue Crack Propagation in Types 304 and 308 Stainless Steel at Elevated Temperatures written by and published by . This book was released on 1976 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The fatigue crack-growth resistance of Type 304 stainless steel base metal and Type 308 stainless steel weld metal at 593°C (1100°F) was investigated. Specimens of both materials in the as-received (or as-welded) and thermally aged conditions were tested. The crack-growth rates were found to be exponentially related to the stress-intensity factor range, .delta. K. This relation, determined by regression analysis, was statistically appropriate and generally provided a good fit to the data. Confidence levels for new crack-growth rate observations were estimated, and comparisons of mean crack-growth rates were made. The results of the present investigation suggest the following conclusions: The fatigue crack-growth rates at 593°C (1100°F) in the Type 308 stainless steel metal are statistically lower than in the Type 304 stainless steel base metal in both the aged and as-welded (or as-received) conditions. Thermal aging at 593°C for 1000 h results in lower fatigue crack-growth rates in the base and weld metal tested at 593°C. Moreover, this difference in crack-growth rate was found to be greater than previously reported for lower-temperature tests. Load changes and hold periods at each crack-growth increment increase the scatter in results by a factor of approximately three.
Download or read book Elevated Temperature Near threshold Fatigue Crack Propagation in Aluminum Alloys written by Mark Leo Renauld and published by . This book was released on 1993 with total page 296 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Metal Plasticity and Fatigue at High Temperature written by Denis Benasciutti and published by MDPI. This book was released on 2020-05-20 with total page 220 pages. Available in PDF, EPUB and Kindle. Book excerpt: In several industrial fields (such as automotive, steelmaking, aerospace, and fire protection systems) metals need to withstand a combination of cyclic loadings and high temperatures. In this condition, they usually exhibit an amount—more or less pronounced—of plastic deformation, often accompanied by creep or stress-relaxation phenomena. Plastic deformation under the action of cyclic loadings may cause fatigue cracks to appear, eventually leading to failures after a few cycles. In estimating the material strength under such loading conditions, the high-temperature material behavior needs to be considered against cyclic loading and creep, the experimental strength to isothermal/non-isothermal cyclic loadings and, not least of all, the choice and experimental calibration of numerical material models and the selection of the most comprehensive design approach. This book is a series of recent scientific contributions addressing several topics in the field of experimental characterization and physical-based modeling of material behavior and design methods against high-temperature loadings, with emphasis on the correlation between microstructure and strength. Several material types are considered, from stainless steel, aluminum alloys, Ni-based superalloys, spheroidal graphite iron, and copper alloys. The quality of scientific contributions in this book can assist scholars and scientists with their research in the field of metal plasticity, creep, and low-cycle fatigue.
Download or read book An experimental assessment of hysteresis in near threshold fatigue crack propagation regime of a low alloy ferritic steel under closure free testing conditions written by Waman V. Vaidya and published by . This book was released on 1991 with total page 36 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Comparison of Environmentally influenced Near threshold Fatigue crack growth Behavior in High and Lower strength Steels at Conventional Frequencies written by and published by . This book was released on 1982 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Recent studies in a wide variety of steels, of yield strengths ranging from 290 to 1740 MPa, have indicated that environmental influences on corrosion fatigue crack propagation at near-threshold levels (growth rates below approx. 10/sup -6/ mm/cycle), may be markedly different from those at higher growth rates. In this paper, the effect of such environments, specifically dry gaseous hydrogen and moist room air, on near-threshold cyclic crack growth is reviewed and comparisons made between behavior in high and lower strength steels. It is shown that, in lower strength steels (yield strength less than or equal to 700 MPa), near-threshold growth rates in dry hydrogen exceed those in moist air by up to two orders of magnitude at low load ratios only, whereas for steels of strength levels above approx. 700 MPa, the presence of hydrogen results in lower near-threshold growth rates compared to moist air regardless of load ratio. Such behavior is rationalized in terms of the competing effects of hydrogen embrittlement and oxide-induced crack closure mechanisms.
Download or read book Effects of Strength and Grain Size on Near threshold Fatigue Crack Growth in Ultra high Strength Steel written by and published by . This book was released on 1976 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Fatigue tests were performed on ultra-high strength steels to assess (i) the influence of strength at constant grain size, and (ii) the influence of grain size at constant strength, on threshold stress intensity and near-threshold crack propagation rates. The results constitute part of a larger program of research to characterize the microstructural influences on fatigue crack propagation at growth rates less than 10−5 mm/cycle in an attempt to provide a basis for the design of alloys resistant to low growth rate fatigue failure.
