scholarly journals An Investigation into Creep Cavity Development in 316H Stainless Steel

Metals ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 318 ◽  
Author(s):  
Hedieh Jazaeri ◽  
P. Bouchard ◽  
Michael Hutchings ◽  
Mike Spindler ◽  
Abdullah Mamun ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Creep Strain ◽  
Creep Damage ◽  
Quantitative Metallography ◽  
Robust Techniques ◽  
Creep Cavitation ◽  
Stainless Steel Reactor ◽  
Power Plant Operation ◽  
Cavity Development ◽  
Life Fraction

Creep-induced cavitation is an important failure mechanism in steel components operating at high temperature. Robust techniques are required to observe and quantify creep cavitation. In this paper, the use of two complementary analysis techniques: small-angle neutron scattering (SANS), and quantitative metallography, using scanning electron microscopy (SEM), is reported. The development of creep cavities that is accumulated under uniaxial load has been studied as a function of creep strain and life fraction, by carrying out interrupted tests on two sets of creep test specimens that are prepared from a Type-316H austenitic stainless steel reactor component. In order to examine the effects of pre-strain on creep damage formation, one set of specimens was subjected to a plastic pre-strain of 8%, and the other set had no pre-strain. Each set of specimens was subjected to different loading and temperature conditions, representative of those of current and future power plant operation. Cavities of up to 300 nm in size are quantified by using SANS, and their size distribution, as a function of determined creep strain. Cavitation increases significantly as creep strain increases throughout creep life. These results are confirmed by quantitative metallography analysis.

The Influence of Creep Strain Rate on Creep Damage Formation in Austenitic Stainless Steel

2018 ◽  
Author(s):  
Edward Hares ◽  
Mahmoud Mostafavi ◽  
Richard Bradford ◽  
Chris Truman
Keyword(s):  
Stainless Steel ◽  
Stress Relaxation ◽  
Creep Strain ◽  
Stress Triaxiality ◽  
Creep Damage ◽  
Operating Conditions ◽  
Element Analysis ◽  
Creep Ductility ◽  
User Subroutine ◽  
Lower Test

Motivated by the need to more accurately account for real, in-service, operating conditions, this paper aims to investigate whether creep strain accumulated at different strain rates is equally damaging. Previous research has suggested that creep strain is more damaging when accumulated more slowly in creep of notched bars. The research presented here seeks to address this question by considering the accumulation of creep strain during stress relaxation of notched bars. Repeat stress relaxation tests with varying dwell lengths were conducted so that the relative damaging effects of the early, rapid accumulation and later, slow accumulation of creep strains could be compared. Another aim was to determine how a lower test temperature affects this creep strain accumulation. In repeat relaxation tests the load is reestablished repeatedly after relaxation dwells of equal duration, until rupture of the specimen occurs. The material used was an ex-service powerplant stainless steel Type 316H. Notched bar specimens were used to introduce stress triaxiality at the notch tip to imitate the multiaxial loads plant components are subjected to during in-service operation. The stresses and strains in the specimens were then assessed using finite element analysis; a user subroutine was implemented so the onset and propagation of creep damage could be simulated throughout the specimens’ creep life. The research found that the material in question had a lower creep ductility at 515°C than at 550°C. The research also showed that creep strain accumulated rapidly at the start of a dwell is significantly less damaging than creep strain accumulated more slowly towards the end of the dwell.

Pyrolysis of unsubstituted bicyclic hydrocarbons and gas oil

1982 ◽  
Vol 47 (7) ◽  
pp. 1838-1847 ◽  
Author(s):  
Martin Bajus ◽  
Jozef Baxa
Keyword(s):  
Stainless Steel ◽  
Elemental Sulphur ◽  
Raw Material ◽  
Gas Oil ◽  
Mass Ratio ◽  
Reaction Products ◽  
Pyrolysis Products ◽  
Reactor Material ◽  
Tubular Reactors ◽  
Stainless Steel Reactor

Pyrolysis of tetraline, decaline, 1,1'-bicyclohexane, cyclohexylbenzene and gas oil was studied in stainless steel and quartz flow tubular reactors at 780 and 800 °C, residence time 0.08 to 0.5 s and at the mass ratio of steam to the raw material changing from 0.5 to 1.5. The effect of reaction temperature, the mass ratio of steam to the raw material, reactor material and of the added elemental sulphur on the yields of individual reaction products is reported. Of bicyclic hydrocarbons, condensed hydrocarbons are more stable than those with noncondensed rings, cyclanoaromates being more stable than bicyclanes. Pyrolysis of gas oil in the stainless steel reactor yields greater amounts of ethylene, propylene, butadiene and smaller amounts of methane and ethane, compared to the pyrolysis carried out under identical conditions in the quartz reactor. Elemental sulphur increases the conversion of gas oil into gaseous pyrolysis products.

Steam Cracking and Steam Reforming of Waste Cooking Oil in a Tubular Stainless Steel Reactor with Wall Effects

2009 ◽  
Vol 23 (11) ◽  
pp. 5663-5676 ◽  
Author(s):  
Julien Gornay ◽  
Lucie Coniglio ◽  
Francis Billaud ◽  
Gabriel Wild
Keyword(s):  
Stainless Steel ◽  
Steam Reforming ◽  
Waste Cooking Oil ◽  
Wall Effects ◽  
Cooking Oil ◽  
Stainless Steel Reactor ◽  
Steam Cracking

Preliminary Review of the Influence of Cavitation Behavior in Creep Damage Constitutive Equations

2014 ◽  
Vol 940 ◽  
pp. 46-51 ◽  
Author(s):  
Xin Yang ◽  
Qiang Xu ◽  
Zhong Yu Lu ◽  
Simon Barrans
Keyword(s):  
Reference Value ◽  
Creep Damage ◽  
Preliminary Review ◽  
Current Application ◽  
Cavitation Damage ◽  
X Ray ◽  
Creep Cavitation ◽  
Cr Steels ◽  
Cavitation Behavior ◽  
Damage Equation

This review paper mainly consists of from two aspects: (a) the evolution of the cavitation damage equation from Dyson to current application in high Cr steels by traditional techniques; (b) quantitation analyses of cavitation behavior in brass, copper, dual phase steel from X-ray microtomtograph. Though there is a lack of experimental data for high Cr steels by X-ray microtomography currently, but (b) has provided reference value for studying creep cavitation behavior in high Cr steels. This paper will be the fundamental of development new creep damage constitutive equation through quantitation analyses of X-ray tomography.

scholarly journals Partial Oxidation of Ethanol Using VOx/SBA-15 and VOx/Fumed Silica Catalysts in a Bench-scale Stainless Steel Reactor

2017 ◽  
Vol 62 (3) ◽  
pp. 345-350 ◽  
Author(s):  
José Miguel Hidalgo-Herrador ◽  
Zdeněk Tišler
Keyword(s):  
Stainless Steel ◽  
Partial Oxidation ◽  
Fumed Silica ◽  
Continuous Flow ◽  
Flow Reactor ◽  
Vanadium Content ◽  
Total Conversion ◽  
Continuous Flow Reactor ◽  
Stainless Steel Reactor ◽  
Oxidation Of Ethanol

Two VOx/SBA-15 catalysts and three VOx/SiO2-fumed silica, with 5, 10 and 1, 5, 10 %wt. vanadium content respectively, were tested in a stainless steel continuous flow reactor for the partial oxidation of ethanol. The catalysts were tested at 150 – 300 °C. Products were analyzed by GC-FID, GC-OFID and GC-MS. The aim was exploring the problematics which could be found when more industrial close conditions are used. The total conversion of ethanol and selectivity to acetaldehyde were different than the expected ones. For VOx/SiO2-fumed silica, the total conversion was higher with a lower selectivity to acetaldehyde compared to VOx/SBA-15 catalysts.

scholarly journals Creep-Rupture Behavior and Creep Strain Distribution of Welded Joints of 304 Stainless Steel Thick Plates.

1996 ◽  
Vol 45 (12) ◽  
pp. 1328-1333 ◽  
Author(s):  
Hiromichi HONGO ◽  
Masayoshi YAMAZAKI ◽  
Takashi WATANABE ◽  
Junichi KINUGAWA ◽  
Yoshio MONMA
Keyword(s):  
Stainless Steel ◽  
Creep Strain ◽  
Welded Joints ◽  
Strain Distribution ◽  
Creep Rupture ◽  
304 Stainless Steel ◽  
Thick Plates ◽  
Rupture Behavior
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