The favorable residual stress field generated by the autofrettage process is increasing the barrel's capacity to withstand pressure during firing—defined as the reloading phase. There are two principal autofrettage processes: swage autofrettage and hydraulic autofrettage. While the theoretical solution for hydraulic autofrettage has been available and accessible for a long time, the available models for swage autofrettage have been quite limited. Both processes include two successive stages of pressure loading and unloading followed by an additional reloading during firing. Reyielding during the firing phase of an autofrettaged barrel is strongly affected by the secondary Bauschinger effect (BE) that involves a reduction of the yield stress in tension due to previous plastic deformation in compression, occurring in the unloading phase of the autofrettage process. The secondary Bauschinger effect can be completely mitigated by introducing a low temperature heat treatment (LTHT) immediately after the autofrettage process, thus increasing the barrel's safe maximum pressure (SMP). The aim of the present work is to quantitatively analyze the effect of low temperature heat treatment on the safe maximum pressure of a gun barrel. Two extreme cases are considered: In the first case, it is assumed that low temperature heat treatment was applied to the barrel, and that it completely mitigated the secondary Bauschinger effect, while in the second case it is assumed that no low temperature heat treatment was applied to the barrel. Both the swage and the hydraulic autofrettage processes are numerically analyzed using a newly developed 3D computer code. The numerical results confirm that a low temperature heat treatment, which fully eliminates the influence of the secondary Bauschinger effect, increases the barrel's safe maximum pressure especially in the case of hydraulic autofrettage.

References

References
1.
Bauschinger
,
J.
,
1881
, “
Ueber die Veranderung der Elasticitatagrenze und dea Elasticitamoduls Verschiadener Metalle
,”
zivilingenieur
,
27
, pp.
289
348
.
2.
Milligan
,
R. V.
,
Koo
,
W. H.
, and
Davidson
,
T. E.
,
1966
, “
The Bauschinger Effect in a High Strength Steel
,”
J. Basic Eng.
,
88
, pp.
480
488
.10.1115/1.3645883
3.
Parker
,
A. P.
,
Underwood
,
J. H.
, and
Kendall
,
D. P.
,
1999
, “
Bauschinger Effect Design Procedures for Autofrettaged Tubes Including Material Removal and Sachs Method
,”
ASME J. Pressure Vessel Technol.
,
121
, pp.
430
437
.10.1115/1.2883726
4.
de Swardt
,
R. R.
,
2006
, “
Material Models for the Finite Element Analysis of Materials Exhibiting a Pronounced Bauschinger Effect
,”
ASME J. Pressure Vessel Technol.
,
128
, pp.
190
195
.10.1115/1.2172967
5.
Perry
,
J.
,
Perl
,
M.
,
Shneck
,
R.
, and
Haroush
,
S.
,
2005
, “
The Influence of the Bauschinger Effect on the Yield Stress, Young's Modulus, and Poisson's Ratio of a Gun Barrel Steel
,”
ASME J. Pressure Vessel Technol.
,
128
, pp.
179
184
.10.1115/1.2172962
6.
Davidson
,
T. E.
,
Kendall
,
D. P.
, and
Reiner
,
A. N.
,
1963
, “
Residual Stresses in Thick-Walled Cylinders Resulting From Mechanically Induced Overstrain
,”
Exp. Mech.
,
3
, pp.
253
262
.10.1007/BF02325841
7.
Kendall
,
D.
,
1970
,
The Effect of Material Removal on the Strength of Autofrettaged Cylinders
,
Benet R&E Laboratories, Watervliet Arsenal
,
New York
.
8.
Troiano
,
E.
,
Underwood
,
J.
, and
Parker
,
A. P.
,
2006
, “
Finite Element Investigation of Bauschinger Effect in High-Strength A723 Pressure Vessel Steel
,”
ASME J. Pressure Vessel Technol.
,
128
, pp.
185
189
.10.1115/1.2172616
9.
Perry
,
J.
, and
Perl
,
M.
,
2008
, “
A 3-D Model for Evaluating the Residual Stress Field Due to Swage Autofrettage
,”
ASME J. Pressure Vessel Technol.
,
130
,
041211
.10.1115/1.2967741
10.
Chakrabarty
,
J.
,
1987
,
Theory of Plasticity
,
McGraw-Hill Book Co.
,
Singapore
.
11.
Gustafson
,
G. B.
, and
Wilcox
,
C. H.
,
1998
,
Analytical and Computational Methods of Advanced Engineering Mathematics
,
Springer
,
New York
.
12.
Davidson
,
T. E.
,
Kendall
,
D. P.
, and
Reiner
,
A. N.
,
1963
, “
Residual Stresses in Thick-Walled Cylinders Resulting From Mechanically Induced Overstrain
,”
Exp. Mech.
,
3
, pp.
253
262
.10.1007/BF02325841
13.
Perry
,
J.
, and
Perl
,
M.
,
2008
, “
The Evaluation of the 3-D Residual Stress Field Due to Hydraulic Autofrettage in a Finite Length Cylinder Incorporating the Bauschinger Effect Factor Based on the “Zero Offset Yield Stress
,”
Proceedings of 2008 ASME PVP Conference
,
Chicago, Illinois
,
Jul. 27–31
, Paper No. PVP2008-61032.
You do not currently have access to this content.