High Temperature Stress-Strain Properties of a Low-Carbon Steel from Hot Machining Tests

1973 ◽  
Vol 187 (1) ◽  
pp. 263-272 ◽  
Author(s):  
M. G. Stevenson ◽  
P. L. B. Oxley
Keyword(s):  
Cutting Speed ◽  
Machining Process ◽  
Dynamic Strain ◽  
Low Carbon ◽  
Dynamic Strain Ageing ◽  
Stress Strain ◽  
Strain Ageing ◽  
Wide Range ◽  
Hot Machining ◽  
Conventional Machining

Machining tests are described in which the cutting speed is kept constant and the primary shear zone temperature varied through a wide range by preheating the workpiece. Variations of the constants σ1 and n of the assumed stress-strain equation σ = σ1 εn with temperature, for an estimated strain rate of 900/s, are obtained. These show a range of temperature in which dynamic strain ageing takes place. This is consistent with results of conventional machining tests on the same material in which dynamic strain ageing takes place in the secondary zone in a certain speed range. Implications of the results for the machining process are discussed and explanations suggested for variation of force with speed in conventional machining and force with temperature in hot machining.

High Temperature Stress-Strain Properties of a Low-Carbon Steel from Hot Machining Tests

1973 ◽  
Vol 187 (1) ◽  
pp. 263-272 ◽  
Author(s):  
M. G. Stevenson ◽  
P. L. B. Oxley
Keyword(s):  
Cutting Speed ◽  
Machining Process ◽  
Dynamic Strain ◽  
Low Carbon ◽  
Dynamic Strain Ageing ◽  
Stress Strain ◽  
Strain Ageing ◽  
Wide Range ◽  
Hot Machining ◽  
Conventional Machining

Machining tests are described in which the cutting speed is kept constant and the primary shear zone temperature varied through a wide range by preheating the workpiece. Variations of the constants σ1 and n of the assumed stress-strain equation σ = σ1 εn with temperature, for an estimated strain rate of 900/s, are obtained. These show a range of temperature in which dynamic strain ageing takes place. This is consistent with results of conventional machining tests on the same material in which dynamic strain ageing takes place in the secondary zone in a certain speed range. Implications of the results for the machining process are discussed and explanations suggested for variation of force with speed in conventional machining and force with temperature in hot machining.

Investigation of Dynamic Strain Ageing Effects of Low Alloy Steels 15Kh2MFA and 15Kh2NMFA

2005 ◽  
Vol 482 ◽  
pp. 367-370
Author(s):  
Miroslava Ernestová
Keyword(s):  
Strain Rate ◽  
Tensile Tests ◽  
Dynamic Strain ◽  
Low Alloy Steels ◽  
Strain Rates ◽  
Dynamic Strain Ageing ◽  
Strain Ageing ◽  
Lower Strain ◽  
Wide Range ◽  
Alloy Steels

The paper summarizes results of tensile tests in low alloy steel (LAS) specimens (steels 15Kh2MFA and 15Kh2NMFA). Slow Strain Rate Tensile tests (SSRT) were performed in air at temperatures from 22 to 325°C over a wide range of strain rates from 2.5×10-6 to 1.67×10-3 s-1. The possible effect of strain rate and temperature to mechanical properties of tested LAS is searched for. The dynamic strain ageing (DSA) was observed within certain temperature ranges at lower strain rates tested and its hardening effect in terms of the maximum strengthening stress decreased linearly with the increase of log strain rate. It has been found that the occurrence of susceptibility to environmentally assisted cracking (EAC) of tested steels in high temperature water (HTW) is corelated to the DSA behavior. The result suggest that DSA reduces ductility of reactor pressure vessel (RPV) steel and its role in enhancing the EAC of RPV steels should not be neglected, in view of the coincidence with susceptibility zones for DSA and EAC in terms of strain rate and temperature. A reasonable coincidence was observed between the susceptibility to DSA exhibited by SSRT in air and with the EAC behavior observed in laboratory experiments.

Static and Dynamic Strain Ageing in Two-Phase Gamma Titanium Aluminides

2000 ◽  
Vol 646 ◽  
Author(s):  
U. Christoph ◽  
F. Appel
Keyword(s):  
Titanium Aluminide ◽  
Titanium Aluminides ◽  
Deformation Behaviour ◽  
Dynamic Strain ◽  
Dynamic Strain Ageing ◽  
Two Phase ◽  
Fast Kinetics ◽  
Strain Ageing ◽  
Wide Range ◽  
Dislocation Pinning

ABSTRACTThe deformation behaviour of two-phase titanium aluminides was investigated in the intermediate temperature interval 450–750 K where the Portevin-LeChatelier effect occurs. The effect has been studied by static strain ageing experiments. A wide range of alloy compositions was investigated to identify the relevant defect species. Accordingly, dislocation pinning occurs with fast kinetics and is characterized by a relatively small activation energy of 0.7 eV, which is not consistent with a conventional diffusion process. Furthermore, the strain ageing phenomena are most pronounced in Ti-rich alloys. This gives rise to the speculation that antisite defects are involved in the pinning process. The implications of the ageing processes on the deformation behaviour of two-phase titanium aluminide alloys will be discussed.

Dynamic strain ageing and crack propagation in the 2091 AlLi alloy

1993 ◽  
Vol 29 (11) ◽  
pp. 1379-1384 ◽  
Author(s):  
D. Delafosse ◽  
G. Lapasset ◽  
L.P. Kubin
Keyword(s):  
Crack Propagation ◽  
Dynamic Strain ◽  
Dynamic Strain Ageing ◽  
Strain Ageing

Fracture toughness in the dynamic strain ageing regime

1991 ◽  
Vol 25 (11) ◽  
pp. 2585-2588 ◽  
Author(s):  
M. Srinivas ◽  
G. Malakondaiah ◽  
K.Linga Murty ◽  
P.Rama Rao
Keyword(s):  
Fracture Toughness ◽  
Dynamic Strain ◽  
Dynamic Strain Ageing ◽  
Strain Ageing

Dynamic Strain Aging during Tensile Deformation of Extruded AZ81 Magnesium Alloy

2013 ◽  
Vol 652-654 ◽  
pp. 1937-1941 ◽  
Author(s):  
Si Qian Zhang ◽  
Liang Mao ◽  
Li Jia Chen
Keyword(s):  
Dynamic Strain Aging ◽  
Strain Aging ◽  
Tensile Deformation ◽  
Rate Sensitivity ◽  
Dynamic Strain ◽  
Dynamic Strain Ageing ◽  
Strain Ageing ◽  
Serrated Flow ◽  
Chatelier Effect ◽  
Solute Atoms

Serrated flow has been observed in AZ81 alloy during tensile deformation. The observed static strain ageing effect and negative strain rate sensitivity suggest that the serrated flow is due to interaction between dislocations and solute atoms, know as dynamic strain ageing (DSA). The Portevin-Le Chatelier effect is observed at temperatures between 150oC~200oC and 125oC~200oC. In the microstructure of deformed samples dislocations and twins is observed. It is suggested that the occurrence of the dynamic strain aging is associated with interactions between solute atoms and dislocations.

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