Modeling of Ratchetting in Biaxial Experiments

1992 ◽  
Vol 114 (1) ◽  
pp. 56-62 ◽  
Author(s):  
C. Guionnet
Keyword(s):  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Constitutive Equation ◽  
Tensile Stress ◽  
Dynamic Recovery ◽  
Inelastic Strain ◽  
Kinematic Variable ◽  
Torsional Loading ◽  
Tubular Specimens ◽  
Biaxial Experiments

A new unified viscoplastic constitutive equation has been developed for interpreting ratchetting experiments. The model is based essentially on a generalized Armstrong-Frederick equation for the kinematic variable; the coefficient of the dynamic recovery term in this equation is a function of both instantaneous and accumulated inelastic strain which is allowed to vary in an appropriate manner in order to reproduce the experimental ratchetting rate. The validity of the model is verified by comparing predictions with experimental results for austenitic stainless steel (17-12 SPH) tubular specimens subjected to cyclic torsional loading under constant tensile stress at 600°C.

Bursting of Tubular Specimens by Gaseous Detonation

1961 ◽  
Vol 83 (4) ◽  
pp. 519-527 ◽  
Author(s):  
P. N. Randall ◽  
I. Ginsburgh
Keyword(s):  
Stainless Steel ◽  
Carbon Steel ◽  
Austenitic Stainless Steel ◽  
Steel Specimen ◽  
Pressure Vessels ◽  
Gaseous Detonation ◽  
Brittle Transition ◽  
Steel Tubing ◽  
Hot Rolled ◽  
Tubular Specimens

The paper describes some experimental work designed to investigate the bursting of pipe and pressure vessels by gaseous detonation. The test specimens were 3.25-in-OD tubes, 12 in. long, and of 0.040 to 0.070-in. wall thickness. The specimens, cut from hot-rolled carbon-steel pipe, and also from drawn carbon-steel tubing, were tested at several temperatures, which were chosen to produce failures both above and below the brittle transition temperatures for the two materials. In addition, an austenitic stainless-steel specimen was tested under very severe conditions in several unsuccessful attempts to fragment it.

Initiation of Stress Corrosion Cracking; Migration of Chloride in Oxide Films on Austenitic Stainless Steel

CORROSION ◽  
1964 ◽  
Vol 20 (9) ◽  
pp. 269t-274t ◽  
Author(s):  
C. R. BERGEN
Keyword(s):  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Crack Initiation ◽  
Tensile Stress ◽  
Stress Corrosion ◽  
Stress Corrosion Cracking ◽  
Base Alloy ◽  
Corrosion Cracking ◽  
Stress Cracking ◽  
High Nickel

Abstract The mechanism of stress corrosion crack initiation can perhaps be understood by noticing the similarities among the several corrodent-crack susceptible alloy systems. In a number of such systems the specific ion responsible for cracking is relatively large. The corrosion product formed in a corroding medium containing such ions would imbibe them. Under appropriate conditions, due to their size, the larger ions would tend to diffuse to the region of the oxide film under highest tensile stress where local high tensile stress in the base alloy would be reflected. It is postulated that the appropriate conditions for diffusion are present in stress cracking systems and that the migration of the ion to which cracking is ascribed leads to high local concentrations in turn causing a local increase in corrosivity. Where the physical properties of the alloy are such that crack propagation can occur, stress corrosion cracking results. Tests of the above hypothesis have been conducted with the chloride-austenitic stainless steel system. It was shown that chloride will migrate reversibly under the influence of tensile stress. It was also shown that the presence of nickel will inhibit the migration of chloride up a tensile gradient and the immunity to cracking of high nickel austenitic stainless alloys is attributed to this effect.

Morphology of Stress-Corrosion Cracks In Notched Specimens of Austenitic Stainless Steels

CORROSION ◽  
1964 ◽  
Vol 20 (5) ◽  
pp. 174t-178t ◽  
Author(s):  
J. C. SCULLY ◽  
T. P. HOAR
Keyword(s):  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Tensile Stress ◽  
Stress Corrosion ◽  
Stress Corrosion Cracking ◽  
Stainless Steels ◽  
Austenitic Stainless Steels ◽  
Shear Stresses ◽  
Maximum Shear Strain ◽  
Notched Specimens

Abstract The pattern of stress-corrosion cracking of notched specimens of an 18 Cr-8 Ni austenitic stainless steel stressed in 42 percent aqueous magnesium chloride solutions is described. It illustrates the action of both tensile and shear stresses in promoting fracture: cracks are nucleated along directions of maximum shear strain and their propagation paths are determined by these and the acting tensile stress.

Observations of multipoles in creep deformed 20 Cr 30 Ni steel

1978 ◽  
Vol 36 (1) ◽  
pp. 332-333
Author(s):  
J.-O. Nilsson ◽  
G. L. Dunlop
Keyword(s):  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Tensile Stress ◽  
Single Crystals ◽  
Work Hardening ◽  
Opposite Sign ◽  
Strain Fields

Introduction: Previously, reports have been made on the existence of multipoles in f.c.c. single crystals deformed in easy glide at room temperatures and theories have been developed for their effect on work hardening. It has been suggested that multipoles consist of a series of dipoles held closely together hy interaction of their strain fields (Fig.1) so that often individual dislocations cannot he resolved hy conventional techniques. The present investigation has analysed multipoles which have heen observed in a 20 Cr 30 Ni austenitic stainless steel deformed in creep at 800°C and a tensile stress of 30 MPa.Results and Discussion: An example of multipoles seen in crept material is shown in Fig. 2. Adjacent dislocations in multipoles were identified as having burgers vectors of opposite sign by observing the change in dislocation image spacing obtained with equal and opposite diffracting vectors (+g and -g). An example of this is shown in Fig. 3.

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