scholarly journals Study on Cracks in a Flange Corner and Thermowell Protection Pipe Connecting Portion in a Reaction Column under a High-Temperature and High-Pressure Hydrogen Environment

2017 ◽  
Vol 66 (9) ◽  
pp. 655-660
Author(s):  
Shigeo SUZUKI
Keyword(s):  
High Pressure ◽  
High Temperature ◽  
Hydrogen Environment ◽  
Reaction Column ◽  
Pressure Hydrogen

High-Temperature Fatigue Properties of Single Crystal Superalloys in Air and Hydrogen

2001 ◽  
Author(s):  
Nagaraj K. Arakere
Keyword(s):  
High Pressure ◽  
Shear Stress ◽  
High Temperature ◽  
Fatigue Life ◽  
Single Crystal ◽  
Room Temperature ◽  
Turbine Blades ◽  
The Core ◽  
Blade Tip ◽  
Pressure Hydrogen

Hot section components in high performance aircraft and rocket engines are increasingly being made of single crystal nickel superalloys such as PWA1480, PWA1484, CMSX-4 and Rene N-4 as these materials provide superior creep, stress rupture, melt resistance and thermomechanical fatigue capabilities over their polycrystalline counterparts. Fatigue failures in PWA1480 single crystal nickel-base superalloy turbine blades used in the Space Shuttle Main Engine (SSME) fuel turbopump are discussed. During testing many turbine blades experienced Stage II non-crystallographic fatigue cracks with multiple origins at the core leading edge radius and extending down the airfoil span along the core surface. The longer cracks transitioned from stage II fatigue to crystallographic stage I fatigue propagation, on octahedral planes. An investigation of crack depths on the population of blades as a function of secondary crystallographic orientation (β) revealed that for β = 45+/- 15 degrees tip cracks arrested after some growth or did not initiate at all. Finite element analysis of stress response at the blade tip, as a function of primary and secondary crystal orientation, revealed that there are preferential β orientations for which crack growth is minimized at the blade tip. To assess blade fatigue life and durability extensive testing of uniaxial single crystal specimens with different orientations has been tested over a wide temperature range in air and hydrogen. A detailed analysis of the experimentally determined Low Cycle Fatigue (LCF) properties for PWA1480 and SC 7-14-6 single crystal materials as a function of specimen crystallographic orientation is presented at high temperature (75 F – 1800 F) in high-pressure hydrogen and air. Fatigue failure parameters are investigated for LCF data of single crystal material based on the shear stress amplitudes on the 24 octahedral and 6 cube slip systems for FCC single crystals. The max shear stress amplitude [Δτmax] on the slip planes reduces the scatter in the LCF data and is found to be a good fatigue damage parameter, especially at elevated temperatures. The parameter Δτmax did not characterize the room temperature LCF data in high-pressure hydrogen well because of the noncrystallographic eutectic failure mechanism activated by hydrogen at room temperature. Fatigue life equations are developed for various temperature ranges and environmental conditions based on power-law curve fits of the failure parameter with LCF test data. These curve fits can be used for assessing blade fatigue life.

Creep and Rupture Behavior of Low Alloy Steels in High Pressure Hydrogen Environment

1965 ◽  
Vol 87 (2) ◽  
pp. 313-318 ◽  
Author(s):  
J. W. Coombs ◽  
R. E. Allen ◽  
F. H. Vitovec
Keyword(s):  
High Pressure ◽  
Creep Rate ◽  
Low Alloy Steels ◽  
Hydrogen Attack ◽  
Hydrogen Environment ◽  
Alloy Steels ◽  
Test Materials ◽  
Rupture Properties ◽  
Pressure Hydrogen ◽  
Rupture Behavior

The creep and rupture properties of steels were investigated at 1000 deg F in an environment of argon at 50 psig pressure and hydrogen at 900 psig pressure. An SAE 1020 steel, a 0.5 percent Mo-steel, and a 1 percent Cr-0.5 percent Mo steel were used as test materials. The strength of the steels was lower and the creep rate higher in hydrogen than in argon. The data are discussed in respect to the effect of stress on the rate of hydrogen attack.

Hydrogen environment assisted cracking in X70 welding heat-affected zone under a high-pressure hydrogen gas

2020 ◽  
Vol 109 ◽  
pp. 102746
Author(s):  
Thanh Tuan Nguyen ◽  
Un Bong Beak ◽  
Jaeyeong Park ◽  
Seung Hoon Nahm ◽  
Naehyung Tak
Keyword(s):  
High Pressure ◽  
Heat Affected Zone ◽  
Hydrogen Gas ◽  
Hydrogen Environment ◽  
Pressure Hydrogen
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