Steady-State Creep Analysis of the Weight Loadings of Furnace Tubes on Multiple Supports

1959 ◽  
Vol 81 (2) ◽  
pp. 115-125
Author(s):  
J. L. Jacobowitz ◽  
C. K. Mader
Keyword(s):  
Steady State ◽  
Internal Pressure ◽  
High Temperatures ◽  
Tube Wall ◽  
Steady State Creep ◽  
Design Consideration ◽  
Secondary Effects ◽  
Creep Stress ◽  
Creep Analysis ◽  
Very High

Analysis of creep stress-strain relationships is made for horizontally supported furnace tubes including the effect of tube weight and internal pressure. Steady-state creep effects through the tube wall due to axially symmetrical heal input are also analyzed for these conditions. The original Bailey approach to the pressure problem only is extended to the larger scope undertaken. Maximum permissible tube spans are derived based on accepted criteria for creep stress and deflections. The results of this work indicate that maximum allowable tube spans may often be theoretically increased beyond present usual design limits except for a few specific materials and instances where short spans are required at very high temperatures. In actual tube design, consideration should be given to experience in operation of any particular type of furnace so that secondary effects may be minimized. Increased economies in costs and flexibility in furnace layout as well as rational span determination are expected from use of these results.

On Creep Rupture Characteristics in STS304 Stainless Steels

2006 ◽  
Vol 326-328 ◽  
pp. 1309-1312
Author(s):  
Seon Jin Kim ◽  
Yu Sik Kong ◽  
Young Join Noh ◽  
Won Taek Jung ◽  
Sang Woo Kwon
Keyword(s):  
Steady State ◽  
Creep Rate ◽  
Stress Exponent ◽  
Stainless Steels ◽  
Elevated Temperatures ◽  
Creep Rupture ◽  
Steady State Creep ◽  
Rupture Time ◽  
Steady State Creep Rate ◽  
Creep Stress

In this study, the creep rupture tests of STS304 stainless steels were investigated at three different elevated temperatures of 600, 650 and 700 under the constant creep stresses. Creep rupture characteristics such as creep stress, creep rupture time, steady state creep rate and so on were evaluated. The behaviors of creep rate curve and initial strain are compared at three different elevated temperatures. The stress exponent (n) at 600, 650 and 700 based on steady state creep rate showed 22.5, 20.6 and 11.4 respectively. By increasing the temperature, the stress exponent is decreased. At the temperature of 700, the lowest stress exponents are shown and this behavior is also observed in the case of stress exponent based on rupture time. The creep life prediction by LMP method is presented and the equation of this result is as follows: T(logtr+20)=-0.005152-14.56+24126.

scholarly journals Steady-State Creep of Fe-4.1 at%Mo Alloy at High Temperatures

1980 ◽  
Vol 21 (5) ◽  
pp. 309-318 ◽  
Author(s):  
Hiroshi Oikawa ◽  
Makoto Saeki ◽  
Seiichi Karashima
Keyword(s):  
Steady State ◽  
High Temperatures ◽  
Steady State Creep

EFFECT OF RESIDUAL STRESS AND REINFORCEMENT GEOMETRY IN AN ANISOTROPIC COMPOSITE ROTATING DISC HAVING VARYING THICKNESS

2012 ◽  
Vol 01 (04) ◽  
pp. 1250035
Author(s):  
VANDANA GUPTA ◽  
S. B. SINGH
Keyword(s):  
Residual Stress ◽  
Steady State ◽  
Creep Behavior ◽  
Yield Criterion ◽  
Steady State Creep ◽  
Thermal Residual Stress ◽  
Rotating Disc ◽  
Varying Thickness ◽  
Creep Analysis ◽  
Sic Particle

The influence of the thermal residual stress and reinforcement geometry on the creep behavior of a composite disc has been analyzed in this paper. The creep analysis in a rotating disc made of Al-SiC (particle/whisker) composite having hyperbolically varying thickness has been carried out using anisotropic Hoffman yield criterion and results obtained are compared with those using Hill's criterion ignoring difference in yield stresses. The steady state creep behavior has been described by Sherby's creep law. The creep parameters characterizing difference in yield stresses have been used from the available experimental results in literature. It is observed that the stresses are not much affected by the presence of thermal residual stress, while thermal residual stress introduces significant change in the strain rates in an anisotropic rotating disc. Secondly, it is noticed that the steady state creep rates in whisker reinforced disc with/without residual stress are observed to be significantly lower than those observed in particle reinforced disc with/without residual stress. It is concluded that the presence of residual stress in an anisotropic disc with varying thickness needs attention for designing a disc.

scholarly journals Effect of Material Parameters on Steady State Creep in a Thick Composite Cylinder Subjected to Internal Pressure

2009 ◽  
Vol 6 (2) ◽  
pp. 20 ◽  
Author(s):  
Tejeet Singh ◽  
V.K. Gupta
Keyword(s):  
Steady State ◽  
Internal Pressure ◽  
Significant Variation ◽  
Operating Temperature ◽  
Radial Strain ◽  
Steady State Creep ◽  
Strain Rates ◽  
Composite Cylinder ◽  
Significant Extent ◽  
Material Parameters

 The steady state creep in Al- SiCP composite cylinder subjected to internal pressure was investigated. The creep behavior of the material were described by threshold stress based creep law by assuming a stress exponent of 5. The effect of size and content of the reinforcement (SiCP ), and operating temperature on the stresses and strain rates in the composite cylinder were investigated. The stresses in the cylinder did not have significant variation with varying size and content of the reinforcement, and operating temperature. However, the tangential as well as radial strain rates in the cylinder could be reduced to a significant extent by decreasing size of SiCP, increasing the content of SiCP and decreasing operating temperature. 

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