Influence of crack length and grain boundaries on the propagation rate of short cracks in austenitic stainless steel

2012 ◽  
Vol 67 (7-8) ◽  
pp. 677-680 ◽  
Author(s):  
M. Scharnweber ◽  
W. Tirschler ◽  
V. Mikulich ◽  
S. Jacob ◽  
C.-G. Oertel ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Crack Length ◽  
Grain Boundaries ◽  
Propagation Rate ◽  
Short Cracks

Crack Growth Rates and Corrosion Fatigue of Austenitic Stainless Steels in High Chloride Solutions

2011 ◽  
Vol 488-489 ◽  
pp. 97-100 ◽  
Author(s):  
Clemens Vichytil ◽  
G. Mori ◽  
Reinhard Pippan ◽  
M. Panzenböck ◽  
Rainer Fluch
Keyword(s):  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Crack Propagation ◽  
Crack Growth ◽  
Fatigue Limit ◽  
Corrosion Fatigue ◽  
Stainless Steels ◽  
Austenitic Stainless Steels ◽  
Propagation Rate ◽  
Corrosive Environment

Purpose: Applications for highly corrosive environments and cyclic loading are often made out of austenitic stainless steels. Corrosion fatigue and crack propagation behaviour has been studied to determine failure processes and damage mechanisms. Approach: CrNiMo stabilized austenitic stainless steel and CrMnN austenitic stainless steel in solution annealed and cold worked condition are compared. S/N curves and crack propagation rate curves are recorded in 43 wt% CaCl2solution at 120 °C, which resembles most severe potential service conditions. For comparison these experiments are also performed in inert glycerine. Additionally, the electrochemical behaviour of these materials has been studied. Findings: The CrMnN steels have excellent mechanical properties but are very susceptible to stress corrosion cracking in the test solution. The fatigue limit as well as the threshold for long crack growth are significantly reduced in corrosive environment. Moreover these steels exhibit a remarkable increase in the propagation rate, which is extremely pronounced in the near threshold region. This effect is enhanced by cold working. CrNiMo steels also show a reduction in the fatigue limit, but it is less pronounced compared to CrMnN steels. The threshold is significantly reduced in corrosive environment, but propagation rate is lower in corrosive environment compared to inert glycerine. Possible explanations of this surprising behaviour are discussed.

Structural Changes in a 304-Type Austenitic Stainless Steel Processed by Multiple Hot Rolling

2011 ◽  
Vol 409 ◽  
pp. 730-735 ◽  
Author(s):  
Zhanna Yanushkevich ◽  
Andrey Belyakov ◽  
Rustam Kaibyshev
Keyword(s):  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Dynamic Recrystallization ◽  
Grain Boundaries ◽  
Hot Rolling ◽  
Structural Changes ◽  
The Other ◽  
Dynamic Processes ◽  
Mean Size ◽  
The Mean

The microstructure evolution and the dynamic processes of grain refinement in a 304-type austenitic stainless steel during multiple calibre hot rolling at temperatures of 700-1000°C were studied. The structural changes are characterized by the elongation of original grains towards the rolling axis and the development of new fine grains, the mean size of which decreases with decreasing the deformation temperature. During multiple rolling at 1000°C, the new grains resulted from the development of discontinuous dynamic recrystallization involving a bulging of frequently corrugated grain boundaries. On the other hand, the new grain boundaries leading to remarkable refinement of original microstructure were developed at temperatures below 800°C as a result of continuous strain-induced reactions.

scholarly journals Effects of Electromagnetic Stirring on the Cast Austenitic Stainless Steel Weldments by Gas Tungsten Arc Welding

Metals ◽  
2018 ◽  
Vol 8 (8) ◽  
pp. 630 ◽  
Author(s):  
Sheng-Long Jeng ◽  
Dai-Ping Su ◽  
Jing-Ting Lee ◽  
Jiunn-Yuan Huang
Keyword(s):  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Grain Boundaries ◽  
Arc Welding ◽  
Gas Tungsten Arc Welding ◽  
Electromagnetic Stirring ◽  
Gas Tungsten Arc ◽  
Welding Defects ◽  
Gas Tungsten ◽  
Notched Tensile Strength

Cast austenitic stainless steel (CASS) often contains high contents of silicon, phosphorus, and sulfur to prompt low melting phases to form in the welds. As a result, welding defects can be induced to degrade the welds. This study’s purpose was to investigate the effects of electromagnetic stirring (EMS) on the CASS weldments. The results showed that the ferrites in the heat affected zone (HAZ) had tortuous grain boundaries, while those that were close to the fusion lines had transformed austenites. EMS could reduce the influence of the welding heat to make the grain boundaries less tortuous and the transformed austenites smaller. Although their temperature profiles were almost the same, the gas-tungsten-arc-welding (GTAW) weld had smaller grains with massive ferrite colonies and more precipitates, while the GTAW+EMS weld had denser ferrite colonies with multi-orientations, but fewer precipitates. The hardness of the base metals and HAZs were typically higher than that of the welds. For both of the welds, the root was the region with the highest hardness. The hardness decreased from the root to the cap regions along the thickness direction. The GTAW weld had a higher hardness than the GTAW+EMS weld. At room temperature, the GTAW+EMS weld had a higher notched tensile strength and elongation than the GTAW weld. This could be attributed to the observation that the GTAW+EMS weld had dense and intersecting dendrites and that more austenites were deformed during tensile testing.

Precipitation Behavior of High-Nitrogen Low-Nickel Austenitic Stainless Steel at Intermediate Temperature

2012 ◽  
Vol 724 ◽  
pp. 359-362
Author(s):  
De Ning Zou ◽  
Rong Liu ◽  
Jiao Li ◽  
Kun Wu ◽  
Xiao Hua Liu
Keyword(s):  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Grain Boundaries ◽  
Volume Fraction ◽  
Intermediate Temperature ◽  
Air Cooling ◽  
Precipitation Behavior ◽  
Lower Aging Temperature ◽  
Electron Microscopy Analysis ◽  
Microscopy Analysis

The precipitation behavior of nitrides and carbides occurred in aging process for 10Cr21Mn16NiN austenitic stainless steel at intermediate temperature was investigated by use of thermodynamic calculation, metallography and electron microscopy analysis. The precipitates evolved from chain-like initiatively along grain boundaries at lower aging temperature, to that along grain boundaries and inside the grain of austenite with more content as the temperature rising gradually. When aging at 800 °C, precipitates became layered tablet shaped and the composition was ascertained the mixture of Cr2N and M23C6. At a certain temperature, the volume fraction of precipitates for the aged testing steel by air cooling was slightly higher than that by water quenching.

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