A Theory of the Yield Point and the Transition Temperature of Mild Steel

1956 ◽  
Vol 23 (2) ◽  
pp. 219-224
Author(s):  
F. Forscher
Keyword(s):  
Transition Temperature ◽  
Mild Steel ◽  
Strain Rate ◽  
Yield Point ◽  
Structural Model ◽  
Yield Criterion ◽  
State Of Stress ◽  
Yield Point Phenomenon ◽  
Stress And Strain Rate ◽  
Temperature Strain

Abstract Experimental results indicate the dependence of the yield-point phenomenon of mild steel on temperature, strain rate, duration of stress, and stress state. This paper proposes a yield criterion which can account for these variables. The theory is developed on the basis of a “structural” model, by which the behavior of microscopic and submicroscopic elements is idealized. The theory postulates as yield criterion a critical number of relaxation centers (active Frank-Read sources) or, equivalently, a critical size of relaxation centers. The transition-temperature phenomenon is considered to be the result of an inhibition of yielding (upper yield point) by means of geometry, temperature and/or strain rate. A relation is given which expresses its dependence on the state of stress and strain rate.

scholarly journals A constitutive model for Ti6Al4V considering the state of stress and strain rate effects

2019 ◽  
Vol 137 ◽  
pp. 103103 ◽  
Author(s):  
Wenyu Cheng ◽  
Jose Outeiro ◽  
Jean-Philippe Costes ◽  
Rachid M'Saoubi ◽  
Habib Karaouni ◽  
...  
Keyword(s):  
Constitutive Model ◽  
Strain Rate ◽  
The State ◽  
Stress And Strain ◽  
Strain Rate Effects ◽  
State Of Stress ◽  
Rate Effects ◽  
Stress And Strain Rate

scholarly journals An Analysis of the Time and Temperature Dependence of the Upper Yield Point in Iron

1961 ◽  
Vol 83 (4) ◽  
pp. 557-564 ◽  
Author(s):  
P. E. Bennett ◽  
G. M. Sinclair
Keyword(s):  
Experimental Data ◽  
Activation Energy ◽  
Strain Rate ◽  
Temperature Dependence ◽  
Yield Point ◽  
Strain Rates ◽  
Influence Of Temperature ◽  
State Of Stress ◽  
The Relationship ◽  
Tensile Test Data

The influence of temperature and strain rate on the upper yield point of ingot iron was studied. Torsion tests were conducted using strain rates of 12.5/sec, 0.25/sec, and 0.0001/sec over the temperature range 77 to 525 deg K. The upper yield point showed a rapid increase as the temperature was lowered. An increase in the strain rate also caused an increase in the yield point. An apparent activation energy can be associated with the strain rate and temperature dependence of the yield point. This energy is influenced by stress level, and it appears from the present study that the relationship can be described by an equation of the form ΔH=ΔH¯τ¯−ττ¯b. If this relationship is substituted for ΔH in a modification of the Boltzmann relation, the following result is obtained: logγ˙γ˙1=MΔH¯RT1τ¯−τ1τ¯b1−T1Tτ¯−ττ¯−τ1b. This equation describes the experimental data within ± 3000 psi. The results of this investigation compared with tensile test data from other investigators confirm that state of stress is an important factor in determining whether a material will behave in a ductile or brittle fashion.

Yield point phenomenon during strain rate change in nanocrystalline Ni–Fe

2011 ◽  
Vol 65 (3) ◽  
pp. 217-220 ◽  
Author(s):  
S. Van Petegem ◽  
J. Zimmermann ◽  
H. Van Swygenhoven
Keyword(s):  
Strain Rate ◽  
Yield Point ◽  
Rate Change ◽  
Strain Rate Change ◽  
Yield Point Phenomenon

Bond Strength of Pressed Composites

1993 ◽  
Vol 318 ◽  
Author(s):  
Donald A. Wiegand
Keyword(s):  
Compressive Strength ◽  
Transition Temperature ◽  
Low Temperature ◽  
Thin Layer ◽  
Strain Rate ◽  
General Study ◽  
Rate Dependent ◽  
Fracture Patterns ◽  
Graphite Coating ◽  
Temperature Strain

ABSTRACTComposites samples containing 80% and 85% organic filler in a polymer-plastizer binder were produced by mixing, extruding, cutting, drying and pressing. Before pressing the extruded material was in some cases coated with a thin layer of graphite (= one micron) for ease in pressing. As part of a general study of these composites the compressive strength, σm, was determined as a function of temperature, strain rate and the thickness of the graphite coating. Without graphite σm increases with decreasing temperature and increasing strain rate. With graphite σm has the same behavior above approximately −10 C, but is independent of both temperature and strain rate below −10 C for a strain rate of 1.0/Sec. In addition, the low temperature value of Om decreases with increasing graphite thickness. The cracking and fracture patterns are temperature and strain rate dependent and are different with and without graphite. These results indicate that the bond produced by pressing the graphite containing material is stronger than the composite above −10 C and weaker below −10 C so that failure initiates in the composite above −10 C and in the bond below −10 C. With decreasing strain rate this transition temperature decreases. The bonding is discussed.

Elimination of yield point phenomenon in mild steel by warm working

1975 ◽  
Vol 9 (1) ◽  
pp. 35-38 ◽  
Author(s):  
Conrad M. Young ◽  
Bruno Walser ◽  
Ernest P. Abrahamson ◽  
Oleg D. Sherby
Keyword(s):  
Mild Steel ◽  
Yield Point ◽  
Warm Working ◽  
Yield Point Phenomenon

scholarly journals Effect of Anisotropy, Temperature, Strain Rate on deep drawing using Conical Die

2020 ◽  
Vol 3 (1) ◽  
Author(s):  
Ajay Kumar Choubey ◽  
C. Sasikumar
Keyword(s):  
Strain Rate ◽  
Flow Behavior ◽  
Rate Sensitivity ◽  
Blank Holder ◽  
Conical Die ◽  
Ansys Apdl ◽  
Stress And Strain Rate ◽  
Temperature Strain ◽  
Punch Pressure

This paper covers the role of anisotropy, temperature, and strain rate on the flow behavior of the material when a conical die is used instead of conventional blank holder. The effect of anisotropy was investigated using Lankford’s coefficient (r) in three directions (0°, 45°, and 90°). The effect of working temperatures (Room temperature, 100°C - 300°C) on drawing stress and strain rate sensitivity on punch pressure were also investigated in detail. ANSYS APDL was used to investigate the effects of temperature, strain rate and anisotropy. The simulation results have confirmed that the strain variation in the direction of r0 and r45 are more than the variation of r90.

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