Cryogenic Tensile, Fatigue, and Fracture Parameters for a Solution-Annealed 18 Percent Nickel Maraging Steel

1978 ◽  
Vol 100 (2) ◽  
pp. 189-194 ◽  
Author(s):  
R. L. Tobler ◽  
R. P. Reed ◽  
R. E. Schramm
Keyword(s):  
Fracture Toughness ◽  
Fatigue Crack ◽  
Maraging Steel ◽  
Room Temperature ◽  
Ambient Air ◽  
Similar Data ◽  
Crack Propagation Resistance ◽  
Percent Nickel ◽  
Tensile Fatigue ◽  
Structural Applications

The mechanical properties of an eighteen percent nickel, solution-annealed 300-grade maraging steel were measured to assist in the evaluation of this material for low-temperature structural applications. Tensile, fatigue-crack growth rate, and fracture toughness tests were perfromed in ambient air (295 K), liquid nitrogen (76 K), and liquid helium (4 K), with the following results: (1) the yield strength of this material increases from 831 MPa at room temperature to 1596 MP a at 4 K; (2) the tensile ductility is moderate with elongation decreasing from 15.5 to 6.7 percent for this temperature region; (3) the estimated values of fracture toughness (KIc) decrease from 165 MPa·m1/2 at room temperature to 83 MPa·m1/2 at 4 K; and (4) the fatigue-crack propagation resistance at intermediate stress intensity ranges is relatively insensitive to temperature. These results are compared with similar data for other cryogenic alloys.

Pressure Cycle Testing of Cr–Mo Steel Pressure Vessels Subjected to Gaseous Hydrogen

2015 ◽  
Vol 138 (1) ◽  
Author(s):  
Junichiro Yamabe ◽  
Hisatake Itoga ◽  
Tohru Awane ◽  
Takashi Matsuo ◽  
Hisao Matsunaga ◽  
...  
Keyword(s):  
Fracture Toughness ◽  
Fatigue Crack ◽  
Room Temperature ◽  
Ambient Air ◽  
Pressure Vessels ◽  
Hydrogen Gas ◽  
Gaseous Hydrogen ◽  
Pressure Cycle ◽  
Leak Before Break ◽  
Gas Pressures

Pressure cycle tests were performed on two types of Cr–Mo steel pressure vessels with notches machined on their inside under hydrogen-gas pressures, between 0.6 and 45 MPa at room temperature. Fatigue crack growth (FCG) and fracture toughness tests of the Cr–Mo steels samples from the vessels were also carried out in gaseous hydrogen. The Cr–Mo steels showed accelerated FCG rates in gaseous hydrogen compared to ambient air. The fracture toughness of the Cr–Mo steels in gaseous hydrogen was significantly smaller than that in ambient air. Four pressure vessels were tested with gaseous hydrogen. All pressure vessels failed by leak-before-break (LBB). The LBB failure of one pressure vessel could not be estimated by using the fracture toughness in gaseous hydrogen KIC,H; accordingly, the LBB assessment based on KIC,H is conservative and there is a possibility that KIC,H does not provide a reasonable assessment of LBB. In contrast, the fatigue lives of all pressure vessels could be estimated by using the accelerated FCG rates in gaseous hydrogen.

Fatigue Crack Growth in a Precipitation-Hardened Martensitic Stainless Steel: Influence of Ageing, Temperature and Loading History

2014 ◽  
Vol 891-892 ◽  
pp. 961-966
Author(s):  
Loic Dimithe Aboumou ◽  
Gilbert Hénaff ◽  
Mandana Arzaghi ◽  
Sylvie Pommier
Keyword(s):  
Fracture Toughness ◽  
Stainless Steel ◽  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Room Temperature ◽  
Martensitic Stainless Steel ◽  
Load Ratio ◽  
Fatigue Crack Growth Resistance ◽  
Variable Amplitude

The 15-5PH (precipitation-hardened) martensitic stainless steel is prone to embrittlement following ageing during service at temperatures between 300°C and 350°C. This results in an increase in strength and a decrease in elongation and fracture toughness. However little information is available on the consequences of long term ageing on fatigue crack growth resistance. In the present study this issue is precisely addressed at room temperature and 300°C, with different load ratio under constant amplitude loading and under variable amplitude loading.At room temperature, the results indicate a marginal effect of the load ratio, regardless of ageing conditions and temperature. While the Paris regime is not affected by ageing, a significant drop in the critical stress intensity value before unstable fracture is observed, reflecting a decrease in fracture toughness of the material with ageing. At 300°C, the FCGRs are higher than at room temperature for all ageing conditions. Variable amplitude loading tests carried out on differently-aged materials showed the same retardation effect.

Two Methods for Determination of Fatigue Crack Propagation Limit Curves and their Application for Different Materials

2007 ◽  
Vol 345-346 ◽  
pp. 395-398 ◽  
Author(s):  
János Lukács
Keyword(s):  
Fracture Toughness ◽  
Fatigue Crack ◽  
Crack Propagation ◽  
Fatigue Crack Propagation ◽  
Research Work ◽  
Stress Intensity Factor Range ◽  
Crack Propagation Resistance ◽  
Threshold Stress Intensity Factor ◽  
Propagation Limit

There are different documents containing fatigue crack propagation limit or design curves and rules for the prediction of crack growth. The research work aimed to characterise the fatigue crack propagation resistance of different materials using limit curves and determination of limit curves under different loading conditions, based on statistical analysis of test results and the Paris-Erdogan law. With the help of the characteristic values of threshold stress intensity factor range (Kth), two constants of Paris-Erdogan law (C and n), fatigue fracture toughness (Kfc) or fracture toughness (KIc) two reliable method can be proposed. The limit curves calculated by both methods represent a compromise of rational risk (not the most disadvantageous case is considered) and striving for safety (uncertainty is known).

Enhancement of Fatigue Crack Growth and Fracture Resistance in Ti-6Al-4V and Ti-6Al-6V-2Sn Through Microstructural Modification

1977 ◽  
Vol 99 (4) ◽  
pp. 313-318 ◽  
Author(s):  
G. R. Yoder ◽  
L. A. Cooley ◽  
T. W. Crooker
Keyword(s):  
Fracture Toughness ◽  
Fatigue Crack ◽  
Yield Strength ◽  
Crack Propagation ◽  
Plane Strain ◽  
Plane Strain Fracture Toughness ◽  
Propagation Resistance ◽  
Crack Propagation Resistance ◽  
Strain Fracture ◽  
Mill Anneal

Significant enhancement in fatigue crack propagation resistance and plane strain fracture toughness was obtained in commercial purity Ti-6Al-4V and Ti-6Al-6V-2Sn through microstructural modification. Alloys studied were in the form of 25.4 mm-thick plate with interstitial oxygen contents of 0.20 and 0.17 weight percent, respectively. Heat treatments were chosen to provide widely varied microstructures; these included a mill anneal, recrystallization anneal and a beta anneal. The most beneficial heat treatment for improving these crack tolerance properties was found to be the beta anneal. However, the beta anneal resulted in yield strength reductions of 9 to 14 percent, from levels associated with the original mill anneal. The recrystallization anneal provided significant enhancement of plane strain fracture toughness and marginal improvement in fatigue crack propagation resistance with negligible loss of yield strength.

Pipeline Steel Fracture Toughness and the Need for a Toughness Database of API 5L Line Pipe

2020 ◽  
Author(s):  
Lyndon Lamborn ◽  
Shenwei Zhang ◽  
Sergio Limón ◽  
Roger Lai
Keyword(s):  
Fracture Toughness ◽  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Fracture Mechanics ◽  
Crack Growth ◽  
Pipeline Steel ◽  
Data Sets ◽  
Similar Data ◽  
Line Pipe ◽  
Toughness Test

Abstract In order for the pipeline industry to usher in the next-level fracture mechanics engineering analysis, reasonable and prudent fracture toughness characterizations are needed to improve burst pressure predictions and fatigue crack growth analysis of pipelines with planar cracks. Converting Charpy V-Notch (CVN) value to fracture toughness via different empirical correlation models derived throughout the years, while laudable, have inherent shortcomings. The main issues being that the Charpy toughness test is not a fracture mechanics-based measurement and the transferability of sub-scale fracture toughness testing is often not completely understood nor is correctly applied. This paper expands on these shortcomings and presents solutions which are supported by fracture toughness data obtained from the pipe boy and seam weld of API 5L line pipe steels. In this manner, best available toughness derivations for mean toughness in base metal and long seam welds are presented. Suggestions for standard fracture mechanics sub-scale coupon testing, such as ASTM E1820, on pipeline steel samples are delineated with rationale for each test type. The transferability of fracture toughness from sub-scale coupon testing results to that exhibits in full-scale pipe failure are demonstrated in the paper. This fracture toughness test database and other similar data sets can be combined and serve as the basis for establishing an industry wide Pipeline Material Database which would mirror established material databases in the aerospace industry such as NASGRO and AFMAT. It is envisioned that a centralized and validated Pipeline Material Database will be expanded to include fatigue crack growth rate data and other pipeline material characterization data sets. These data will support minimizing material assumptions and increase the accuracy of structural integrity predictions to improve the overall pipeline performance. This combined database would be accessible to engineers, analysts, and researchers and updated at regular intervals as more data becomes available.

Fracture toughness and fatigue crack propagation in high strength steel from room temperature to −180°c

1975 ◽  
Vol 7 (3) ◽  
pp. 465-472 ◽  
Author(s):  
Tadashi Kawasaki ◽  
Seiji Nakanishi ◽  
Yozo Sawaki ◽  
Kenichi Hatanaka ◽  
Takeo Yokobori
Keyword(s):  
Fracture Toughness ◽  
Fatigue Crack ◽  
Crack Propagation ◽  
Fatigue Crack Propagation ◽  
High Strength Steel ◽  
Room Temperature ◽  
High Strength
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