Concerning a Creep Surface Derived From a Multiple Integral Representation for 304 Stainless Steel Under Combined Tension and Torsion

1978 ◽  
Vol 45 (4) ◽  
pp. 773-779 ◽  
Author(s):  
R. Mark ◽  
W. N. Findley

It is shown that a creep surface, defined in terms of a prescribed creep rate, can be determined from the multiple integral formulation representing the creep data. The creep surface for 304 stainless steel was found to be in good agreement with a Mises ellipse. Observed creep rate vectors for this alloy were found to be normal to a Mises ellipse. These results were obtained from creep tests performed on 304 stainless steel under combined tension and torsion at 593°C (1100°F). Creep strains observed for at least 100 hr were adequately represented by a power function of time, the exponent of which was independent of stress. A third-order multiple integral representation together with a limiting stress below which creep does not occur was employed to describe satisfactorily the constant stress creep data.

1970 ◽  
Vol 37 (2) ◽  
pp. 441-448 ◽  
Author(s):  
K. G. Nolte ◽  
W. N. Findley

The assumption that volume changes associated with creep of a nonlinear viscoelastic material are only linearly dependent on the stress history is incorporated into a third-order multiple integral representation. This assumption reduces the number of independent kernel functions in the representation from 12 to 7. The traces of these independent kernels may be determined from two tension, two torsion, and one combined tension and torsion creep tests. Experiments on polyurethane are well represented by this method. The time-dependence of the kernel functions is expressed by time raised to a power with the power differing for different-order kernel functions.


1993 ◽  
Vol 115 (2) ◽  
pp. 200-203 ◽  
Author(s):  
Z. Xia ◽  
F. Ellyin

Constant strain-rate plastic straining followed by creep tests were conducted to investigate the effect of prior plastic straining on the subsequent creep behavior of 304 stainless steel at room temperature. The effects of plastic strain and plastic strain-rate were delineated by a specially designed test procedure, and it is found that both factors have a strong influence on the subsequent creep deformation. A creep model combining the two factors is then developed. The predictions of the model are in good agreement with the test results.


2005 ◽  
Vol 21 (3) ◽  
pp. 145-155 ◽  
Author(s):  
C.-S. Chang

AbstractTo study the cutting forces, the carbide tip's surface temperature, and the mechanism of secondary chip and main chip formation of face milling stainless steel with a chamfered main cutting edge has been investigated. Theoretical values of cutting forces were calculated and compared to the experimental results with SUS 304 stainless steel plate as a workpiece material. Force data from these tests were used to estimate the empirical constants of the mechanical model and to verify its prediction capabilities. A comparison of the predicted and measured forces shows good agreement. A preliminary discussion is also made for the design of special tool holders and their geometrical configurations. Next, the tips mounted in the tool holders are ground to a chamfered width and the tool dimensions are measured by using a toolmaker microscope.


1980 ◽  
Vol 47 (4) ◽  
pp. 755-761 ◽  
Author(s):  
U. W. Cho ◽  
W. N. Findley

Creep and creep-recovery data of 304 stainless steel are reported for experiments under constant combined tension and torsion at 593°C (1100°F). The data were represented by a viscous-viscoelastic model in which the strain was resolved into five components—elastic, plastic (time-independent), viscoelastic (time-dependent recoverable), and viscous (time-dependent nonrecoverable) which has separate positive and negative components. The data are well represented by a power function of time for each time-dependent strain. By applying superposition to the creep-recovery data, the recoverable creep strain was separated from the nonrecoverable. The form of stress-dependence associated with a third-order multiple integral representation was employed for each strain component. The time-dependent recoverable and nonrecoverable strains had different nonlinear stress dependence; but, the time-independent plastic strain and time-dependent nonrecoverable strain had similar stress-dependence. A limiting stress below which creep was very small or negligible was found for both recoverable and nonrecoverable components as well as a yield limit. The limit for recoverable creep was substantially less than the limits for nonrecoverable creep and yielding. The results showed that the model and equations used in the analysis described quite well the creep and creep-recovery under the stress states tested.


2002 ◽  
Vol 11 (3) ◽  
pp. 247-262 ◽  
Author(s):  
Masao Sakane ◽  
Hiroto Tokura

This paper studies the biaxial creep damage of type 304 stainless steel at 923 K. Biaxial tension creep tests were carried out using cruciform specimens and the effect of stress biaxiality on rupture lifetime and creep voiding was discussed. Mises equivalent stress and the equivalent stress based on crack opening displacement were a suitable parameter to assess the biaxial creep damage. The equivalent stress proposed by Huddleston overestimated the biaxial creep damage by more than a factor of two. Stress biaxiality had almost no influence on the orientation of voided grain boundaries and the critical value ofparameter A. Tests of alternative loading direction significantly dispersed the biaxial creep damage resulting in larger creep lifetime.


1986 ◽  
Vol 108 (2) ◽  
pp. 119-126 ◽  
Author(s):  
S. Murakami ◽  
N. Ohno ◽  
H. Tagami

In order to evaluate the validity and limitations of the creep-hardening surface model proposed by the present authors, a series of creep tests for type 304 stainless steel were performed at 600°C under various non-steady multiaxial loadings. The test time and the interval of stress change were 960 hr and 48 or 96 hr, respectively, and five kinds of stress histories consisting of randomly varying stress magnitude, stress direction and interval of stress change were employed. It was found that the creep-hardening surface model describes sufficiently well the creep behavior observed in this work.


1984 ◽  
Vol 21 (3) ◽  
pp. 518-529 ◽  
Author(s):  
J. F. Nixon ◽  
G. Lem

Little creep data is available for frozen, fine-grained saline soils. Salinity accelerates the creep rate of a frozen soil under load and reduces its shear strength owing to the higher unfrozen water contents in the pore phase. Creep data for saline fine-grained soils are required by engineers and scientists working in areas of coastal or offshore permafrost. The data are also used in projects involving artificial freezing of saline soils.This paper describes the results of 34 creep tests and 11 time-dependent strength tests carried out on saline soils. The tests were carried out for two different research programs; consequently, two different fine-grained soil types were used. Most of the tests were carried out in a constant stress and constant temperature creep test environment. Some were completed in a triaxial (constant strain rate) test format, in order to extend the data base to an area of higher strain rates. The range of temperatures was −2.3 to −25 °C, the range of stresses in the creep tests was 30–400 kPa, and the salinity was varied from 0–35 parts per thousand (ppt). Particular attention was paid to the lower stresses (30–200 kPa) and intermediate to high salinities (18–35 ppt). A high percentage of the creep tests was completed in the temperature range −5 to −10 °C, as this appears to be a typical ground temperature in coastal permafrost areas in Arctic Canada.Results indicate that the presence of pore fluid with a salinity approaching that of seawater causes a 10- to 100-fold increase in uniaxial creep rate, which can result in significant decreases in shear strength and foundation bearing capacity in saline permafrost areas.Soil resistivity tests were also carried out on frozen samples of different salinities. A strong correlation between resistivity and pore water salinity emerged. This has application in the interpretation of results from electrical resistivity surveys in permafrost. Key words: permafrost, saline, creep, strength, resistivity, fine-grained, offshore permafrost.


1974 ◽  
Vol 41 (1) ◽  
pp. 243-248 ◽  
Author(s):  
W. N. Findley ◽  
K. Onaran

It is shown that defining an incompressible material as one whose response to stressing or straining is insensitive to volumetric-type changes in strain or stress allows the derivation of incompressible forms for multiple integral representations, through the third order, which have only three kernel functions both in the creep formulation and the relaxation formulation for small strains. Earlier work had yielded four kernel functions in the relaxation and three in the creep formulation. Linearly compressible formulations are also discussed and compared with available creep data.


1969 ◽  
Vol 91 (4) ◽  
pp. 575-580 ◽  
Author(s):  
I. Le May ◽  
K. J. Truss ◽  
P. S. Sethi

This paper describes comparative creep tests made on an austemtic stainless steel in atmospheres of air, nitrogen, argon, and vacuum. The results indicate that the steel was weakened under the oxidizing conditions occurring in air as compared with its behavior in argon and vacuum, the results for nitrogen being inconclusive. Significant differences in ductility and creep rate characteristics in the different environments were noted, and much greater surface cracking was observed in the tests in nonoxidizing atmospheres. It is suggested that the air-weakening observed can be explained in terms of an interaction between the oxidation and deformation mechanisms involved.


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