scholarly journals Short-Term Creep-Rupture Behaviour of AISI 310S Austenitic Stainless Steel Sheets Manufactured in Salem Steel Plant, a Special Steels Unit of Steel Authority of India Limited, Ministry of Steel, Government of India

YMER Digital ◽  
2021 ◽  
Vol 20 (12) ◽  
pp. 363-373
Author(s):  
A Kanni Raj ◽  
Keyword(s):  
Stainless Steel ◽  
Grain Boundary ◽  
Creep Behavior ◽  
Rupture Life ◽  
Stress Rupture ◽  
Constant Load ◽  
Creep Rupture ◽  
Steel Plant ◽  
Tensile Creep ◽  
Metallographic Examination

The creep behavior of AISI 310S stainless steel taken from SAIL’s Salem stainless steel plant has been investigated by constant load tensile creep test at the temperatures of 973, 1023, and 1073 K and loads of 66.6, 74.8, 86.6, and 94.8 MPa. It exhibits steadystate creep behavior in most test conditions. The double logarithm plot of rupture life and applied stress yielded straight lines at all the three test temperatures indicating that power-law creep due to dislocation climb is the operating mechanism of creep deformation. Linear relationship was obtained for plots of logarithm of rupture life against inverse temperature obeying Arrhenius type of temperature dependence with activation energy of 340 kJ/mol. The stress-rupture data yielded a master curve of Larson-Miller parameter. The plot of Monkman-Grant relationship is typical indicating that rupture is controlled by growth of grain boundary cavities. The metallographic examination of crept samples revealed formation of grain boundary voids and cracks leading to intergranular creep fracture. Deformation twins and carbide precipitates were also observed. Creep-rupture properties are compared with that of AISI 600 ironbased superalloy to analyze quantitatively its behavior

scholarly journals On High-Temperature Materials: A Case on Creep and Oxidation of a Fully Austenitic Heat-Resistant Superalloy Stainless Steel Sheet

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
A. Kanni Raj
Keyword(s):  
Activation Energy ◽  
Stainless Steel ◽  
Grain Boundary ◽  
Creep Behavior ◽  
Rupture Life ◽  
Stress Rupture ◽  
Parabolic Rate Constant ◽  
Tensile Creep ◽  
Inverse Temperature ◽  
Metallographic Examination

The creep behavior of AISI 310S stainless steel taken from SAIL’s Salem stainless steel plant has been investigated by constant load tensile creep test at the temperatures of 973, 1023, and 1073 K and loads of 66.6, 74.8, 86.6, and 94.8 MPa. It exhibits steady-state creep behavior in most test conditions. The double logarithm plot of rupture life and applied stress yielded straight lines at all the three test temperatures indicating that power-law creep due to dislocation climb is the operating mechanism of creep deformation. Linear relationship was obtained for plots of logarithm of rupture life against inverse temperature obeying Arrhenius type of temperature dependence with activation energy of 340 kJ/mol. The stress-rupture data yielded a master curve of Larson-Miller parameter. The plot of Monkman-Grant relationship is typical indicating that rupture is controlled by growth of grain boundary cavities. The metallographic examination of crept samples revealed formation of grain boundary voids and cracks leading to intergranular creep fracture. Deformation twins and carbide precipitates were also observed. Oxidation tests were also carried out isothermally at 973 K, 1023 K, and 1073 K in dry air. The plots of mass gain versus square root time were linear at all the three test temperatures obeying parabolic kinetics of oxidation. It was found that scales are well adherent to the substrate. The plot of parabolic rate constant and inverse temperature was linear giving an activation energy value of 210 kJ/mol. The metallographic examination of an oxidized sample reveals duplex types of scales. Finally, rupture properties are compared with that of AISI 600 iron-based superalloy and oxidation weight gain analysis with surface nanocrystalline AISI 310S stainless steel to analyze quantitatively its behavior.

Creep–rupture model of aluminum alloys: Cohesive zone approach

2014 ◽  
Vol 229 (8) ◽  
pp. 1343-1347 ◽  
Author(s):  
Kyungmok Kim
Keyword(s):  
Aluminum Alloys ◽  
Cohesive Zone ◽  
Rupture Life ◽  
Stress Rupture ◽  
Creep Rupture ◽  
Time Dependent ◽  
Element Analysis ◽  
Rupture Model ◽  
Term Creep

In this article, a creep–rupture model of aluminum alloys is developed using a time-dependent cohesive zone law. For long-term creep rupture, a time jump strategy is used in a cohesive zone law. Stress–rupture scatter of aluminum alloy 4032-T6 is fitted with a power law form. Then, change in the slope of a stress-rupture line is identified on a log–log scale. Implicit finite element analysis is employed with a model containing a cohesive zone. Stress–rupture curves at various given temperatures are calculated and compared with experimental ones. Results show that a proposed method allows predicting creep–rupture life of aluminum alloys.

The Microstructure and Creep Behavior of Cold Rolled Udimet 188 Sheet

2010 ◽  
Vol 17 (3) ◽  
pp. 350-361
Author(s):  
C.J. Boehlert ◽  
S.C. Longanbach
Keyword(s):  
Grain Boundary ◽  
Grain Boundaries ◽  
Creep Behavior ◽  
Volume Fraction ◽  
Solution Treatment ◽  
Tensile Creep ◽  
Dislocation Creep ◽  
Grain Boundary Character Distribution ◽  
Air Cooling ◽  
Cold Rolled

AbstractUdimet 188 was subjected to thermomechanical processing (TMP) in an attempt to understand the effects of cold-rolling deformation on the microstructure and tensile-creep behavior. Commercially available sheet was cold rolled to varying amounts of deformation (between 5–35% reduction in sheet thickness) followed by a solution treatment at 1,464 K (1,191°C) for 1 h and subsequent air cooling. This sequence was repeated four times to induce a high-volume fraction of low-energy grain boundaries. The resultant microstructure was characterized using electron backscattered diffraction. The effect of the TMP treatment on the high-temperature [1,033–1,088 K (760–815°C)] creep behavior was evaluated. The measured creep stress exponents (6.0–6.8) suggested that dislocation creep was dominant at 1,033 K (760°C) for stresses ranging between 100–220 MPa. For stresses ranging between 25–100 MPa at 1,033 K (760°C), the stress exponents (2.3–2.8) suggested grain boundary sliding was dominant. A significant amount of grain boundary cracking was observed both on the surface and subsurface of deformed samples. To assess the mechanisms of crack nucleation, in situ scanning electron microscopy was performed during the elevated-temperature tensile-creep deformation. Cracking occurred preferentially along general high-angle grain boundaries (GHAB) and less than 25% of the cracks were found on low-angle grain boundaries (LAB) and coincident site lattice boundaries (CSLB). Creep rupture experiments were performed at T = 1,088 K (815°C) and σ = 165 MPa and the greatest average time-to-rupture was exhibited by the TMP sheet with the greatest fraction of LAB+CSLB. However, a clear correlation was not exhibited between the grain boundary character distribution and the minimum creep rates. The findings of this work suggest that although grain boundary engineering may be possible for this alloy, simply relating the fraction of grain boundary types to the creep resistance is not sufficient.

Creep rupture of notched bars

1978 ◽  
Vol 360 (1701) ◽  
pp. 243-264 ◽  
Keyword(s):  
Damage Mechanics ◽  
Axial Stress ◽  
Stress Rupture ◽  
Continuum Damage Mechanics ◽  
Constant Load ◽  
Creep Rupture ◽  
Structural Behaviour ◽  
British Standard ◽  
Rupture Criterion ◽  
Circular Notch

The creep rupture of circumferentially notched, circular tension bars which are subjected to constant load for long periods at constant tem ¬ perature is studied by the approximate calculation of stress and damage histories which result from tertiary creep. Stationary-state creep solutions which have been previously obtained by Hayhurst & Henderson (1977) are used in a continuum damage mechanics study of rupture at the minimum sections of circular (Bridgman 1952) and British Standard notched specimens (B.S. no. 3500, 1969). Notch strengthening and weakening are explained in terms of the multi-axial stress rupture criterion satisfied by the material. It is shown how the circular notch may be used as a materials test and that the British Standard notch is a good means of assessing the sensitivity of structural behaviour to the multi-axial stress rupture criterion of the material.

Improvement of Stress-rupture Life for Modified-HR6W Austenitic Stainless Steel

2011 ◽  
Vol 27 (11) ◽  
pp. 1059-1064 ◽  
Author(s):  
Shiyun Cui ◽  
Zixing Zhang ◽  
Yulai Xu ◽  
Jun Li ◽  
Xueshan Xiao ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Rupture Life ◽  
Stress Rupture ◽  
Stress Rupture Life

The Influence of AGR Gas Carburisation on the Creep and Fracture Properties of Type 316H Stainless Steel

2016 ◽  
Author(s):  
Mustafa Nasser ◽  
Catrin M. Davies ◽  
Kamran Nikbin
Keyword(s):  
Stainless Steel ◽  
High Temperature ◽  
Structural Integrity ◽  
Substantial Reduction ◽  
Creep Crack Growth ◽  
Creep Rupture ◽  
Rupture Time ◽  
Metallographic Examination ◽  
Fracture Properties ◽  
Integrity Assessment

Defects in the UK’s AGR nuclear reactors have been historically found in superheater regions of the boilers. These components are fabricated from type 316H austenitic stainless steel and operate in carbon dioxide gas coolant environments under creep conditions, at temperatures up to 550°C. As a result, some components maybe carburised throughout their life resulting in the formation of a hardened outer surface layer. This layer results from interstitial carbon diffusion and is thought to impact on the creep, creep-fatigue and fracture properties of 316H. Carburisation is currently unaccounted for within high temperature structural integrity assessment procedures. It is essential that carburisation and resulting damage mechanisms are well understood in order to accurately predict the failure of components. This paper aims to investigate the effect of AGR gas carburisation on the creep and fracture properties of type 316H stainless steel. Specimens have been preconditioned within a simulated AGR gas environment. The presence of carburisation has been confirmed through metallographic examination, hardness testing and surface analysis techniques. A series of constant load high-temperature creep tests have been conducted on preconditioned specimens. Compared to as-received material, carburised specimens displayed a significant reduction in creep rupture time with cracking of the outer carburised layer initiating creep crack growth. This phenomenon is seen to occur at very low strains and has been confirmed through interrupted creep testing. The substantial reduction in creep rupture time is postulated to result from embrittlement of the carburised material owing to strong precipitation of carbides along grain boundaries. It is concluded that carburisation can lead to a severe reduction in creep rupture life in test conditions; the possible implications of this with regards to plant conditions are discussed.

Heat Treated Microstructure and Mechanical Properties of K492M Alloy

2014 ◽  
Vol 788 ◽  
pp. 493-497
Author(s):  
Xiang Hui Li ◽  
Lian Li ◽  
Xin Tang ◽  
Qi Dong Gai
Keyword(s):  
Mechanical Properties ◽  
Grain Boundary ◽  
Interdendritic Region ◽  
Rupture Life ◽  
Stress Rupture ◽  
Stress Rupture Life ◽  
Stress Rupture Properties ◽  
Heat Treated ◽  
Columnar Grain ◽  
Rupture Properties

The microstructure, tensile and stress rupture properties of K492Malloy have been investigated in the present study. The results revealed that γ matrix, γ′ phase, carbide and eutectic in the interdendritic region within grain interior and along grain boundary were observed after solidification. After heat treatment, γ' precipitates with two obviously distinct size existed in the dendrite core and interdendritic region, respectively. Meanwhile, the chain-like (W, Mo)6C and Cr23C6carbides precipitated along grain boundary. The investigation of mechanical properties suggested that the tensile strength was initially increased but then decreased with increasing the temperature from 25oC to 760oC. The stress rupture life was 68.2h and 35.8h at 760oC / 655MPa and 870oC / 365MP, respectively. The columnar grain and carbide along grain boundary resulted in intergranular brittle fracture in both test conditions. As a result, the elongation under the conditions of 760oC/655MPa and 870oC/365MP was 1.5% and 1.4%, respectively.

Effect of Heat Treatment on Microstructure and Mechanical Properties for a Ni3Al Base Single Crystal Alloy DDIC6

2007 ◽  
Vol 546-549 ◽  
pp. 1443-1446 ◽  
Author(s):  
Zhi Gang Kong ◽  
Lei Ji ◽  
Shu Suo Li ◽  
Ya Fang Han ◽  
Hui Bin Xu
Keyword(s):  
Heat Treatment ◽  
Single Crystal ◽  
Rupture Life ◽  
Stress Rupture ◽  
Constant Load ◽  
Heat Treatment Condition ◽  
Stress Rupture Life ◽  
Stress Rupture Property ◽  
Single Crystal Alloy ◽  
Proper Size

The effect of heat treatment on microstructures and stress rupture property of a Ni3Al base single crystal alloy DDIC6 was studied in the present investigate. The single crystal specimens were produced by screw selection crystal method. The heat treatment for the alloy was 1300°C/10h+1120°C/4h+870°C/32h and 1300°C/10h+870°C/32h.The microstructures were examined by SEM, TEM and X-ray EDS techniques. The stress rupture tests were carried out in air by constant load creep machines under 1100°C/130MPa with the specimens size of φ5×25 mm. The experimental results showed that the as-cast large size γ′ phases entirely dissolved after 1300°C/10h, and secondary fine γ′ phases precipitated by following aging at 1120°C and 870°C for certain periods of time. The stress rupture life under 1100°C/130MPa increased from 20~30hrs for as-cast condition to 60~100hrs for heat treatment condition. The improvement of the creep resistance of the alloy may attribute to the decrement of the elements segregation at dendrite and interdendritic areas, and the proper size and distribution of γ′ phases.

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