Prediction of Properties in Type 347 Austenitic Stainless Steel after Long-Term Service at High Temperatures

2007 ◽  
pp. 4920-4925
Author(s):  
Jan Olof Nilsson
Keyword(s):  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
High Temperatures ◽  
Prediction Of Properties

Prediction of Properties in Type 347 Austenitic Stainless Steel after Long-Term Service at High Temperatures

2007 ◽  
Vol 539-543 ◽  
pp. 4920-4925 ◽  
Author(s):  
Jan Olof Nilsson
Keyword(s):  
Stainless Steel ◽  
Elevated Temperature ◽  
Austenitic Stainless Steel ◽  
Nitrogen Uptake ◽  
Σ Phase ◽  
Prediction Of Properties ◽  
Software Packages ◽  
Evolution Of Microstructure ◽  
Good Agreement

The evolution of microstructure during production and elevated temperature service of type 347 austenitic stainless steel in the temperature range 700-800°C was modelled using commercial software packages such as Thermo-Calc and DICTRA and characterized using various microscopical techniques. The growth and coarsening of niobium carbonitrides and σ- phase were modelled as well as nitrogen uptake. Good agreement between predictions and microstructural observations was found.

scholarly journals Oxidation behavior of 316L austenitic stainless steel in high temperature air with long-term exposure

2020 ◽  
Vol 7 (6) ◽  
pp. 066517
Author(s):  
Xi Huang ◽  
Kai Xiao ◽  
Xiaodong Fang ◽  
Zicheng Xiong ◽  
Lihua Wei ◽  
...  
Keyword(s):  
Stainless Steel ◽  
High Temperature ◽  
Austenitic Stainless Steel ◽  
Oxidation Behavior ◽  
316L Austenitic Stainless Steel

Role of Long Term Ageing on the Creep Life of Type 316H Austenitic Stainless Steel Bifurcation Weldments

2016 ◽  
Author(s):  
Ana I. Martinez-Ubeda ◽  
Ian Griffiths ◽  
Oliver D. Payton ◽  
Charles M. Younes ◽  
Tom B. Scott ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Chemical Composition ◽  
Austenitic Stainless Steel ◽  
Grain Boundary ◽  
Creep Damage ◽  
M23c6 Carbide ◽  
Boiler Tube ◽  
Boundary Length

Intergranular creep cracks have been observed in the heat affected zone of the 316H austenitic stainless steel superheater boiler tube bifurcation weldments after long term service at temperature of ∼550°C. The cracking mechanism is believed to be creep dominated. Moreover, chemical composition of defective material compared with similar uncracked components suggests that composition influences susceptibility to creep cracking. A systematic characterization of ratios number of creep cavities/grain boundary length and inter-granular precipitation length/grain boundary length has been undertaken in HAZ of three samples extracted from plants with different specific compositions. Here, the role of precipitation on creep deformation and fracture is explored. Precipitates of both ferrite and M23C6 carbide arising from long term service and associated creep cavitation have been identified using transmission electron microscopy. The creep damage and cracking, and therefore overall service life creep, is discussed by consideration of susceptibility of creep cavity nucleation and subsequently growth arising from specific differences in the chemical composition of the three boiler tube bifurcations.

The Evolution of Residual Stress and Microstructure in Shot Peened S30432 Austenitic Stainless Steel at High Temperatures

2013 ◽  
Vol 768-769 ◽  
pp. 557-563
Author(s):  
Ke Zhan ◽  
Chuan Hai Jiang ◽  
Henry Pan
Keyword(s):  
Residual Stress ◽  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
High Temperatures ◽  
Exposure Time ◽  
Shot Peening ◽  
Thermal Relaxation ◽  
Domain Size ◽  
Line Profile Analysis ◽  
Relaxation Energy

The thermal relaxation behavior of residual stress and microstructure at high temperatures in S30432 austenitic stainless steel after shot peening was investigated by X-ray residual stress analyzer. The effects of exposure time and applied temperature on the residual stress and microstructure relaxation were particularly analyzed and discussed. A significant decrease of the residual stress values were observed in the first period of exposure time, followed by slowing down and then stabilization. It was also observed that a higher applied temperature produced greater relaxation. In terms of microstructure, the domain size and micro-strain were calculated by Voigt method, the results showed that the refined domain size and high micro-strain induced by shot peening were greatly relaxed at the first stage of annealing, then stabilized. With higher annealing temperature, the recrystallization behavior in the shot peened deformed layer was more obvious. Based on the results of line profile analysis, the recrystallization activation energy and micro-strain relaxation energy were calculated, respectively.

The Significance of Thermo-Mechanical Fabrication on Long Term Creep Life of Type 316H Austenitic Stainless Steel Components

2016 ◽  
Vol 853 ◽  
pp. 384-388
Author(s):  
Ana Isabel Martinez-Ubeda ◽  
Alexander D. Warren ◽  
Ian Griffiths ◽  
Peter E.J. Flewitt
Keyword(s):  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Nuclear Power ◽  
Energy Dispersive Spectrometer ◽  
Creep Damage ◽  
Ion Milling ◽  
Creep Life ◽  
Thin Foils ◽  
The Impact

The UK’s Advanced Gas Cooled Reactor (AGR) nuclear power generating plant operates at temperatures up to 550 °C, where creep life is important. We consider Type 316H austenitic stainless steel headers and tubes with thermo-mechanical fabrication histories that result in significantly different initial microstructures. The heat affected zone of weldments, in these thick section headers and thin walled boiler tubes, have been found to be susceptible to creep damage leading to cracking during service. In this work we explore these differences in the long term service aged microstructure and the link to overall creep life of these components. To achieve this, samples containing weldments have been removed from plant after extended periods of service. Specifically parent and HAZ regions have been examined to determine the types of precipitates arising from the long term ageing. In particular, thin foils have been examined in a JEOL ARM transmission electron microscope operating at 200KeV fitted with an Oxford Instruments energy dispersive spectrometer to allow comparison between high resolution images and chemical composition. The thin foils were removed from predetermined locations using gallium ion milling and finally thinned using a low ion current to minimise ion damage. Differences between the distributions and types of precipitates are considered in the context of the initial microstructure arising from the thermo-mechanical history on the loss of creep strength and initiation of creep cavities at grain boundaries. The impact on overall service life is addressed.

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