Residual stress measurement of butt welded carbon steel pipe by neutron diffraction
- Hitachi, Ltd., Ibaraki (Japan)
In order to estimate crack growth behaviors of fatigue and stress corrosion cracking in pipes, the residual stress distribution near the pipe weld region has to be measured through the wall thickness. Since the penetration depth of neutron is deep enough to pass through the thick pipe wall, the neutron diffraction technique for the residual stress measurement is effective for this purpose. At the first step the residual stress distribution near the weld region in a butt-welded 4-inch carbon steel pipe was measured by the neutron diffraction. Significant stresses extended only to a distance of 30 mm from the center of the weld. The major tensile stresses occurred in the hoop direction in the fusion and heat affected zones of the weldment, and they attained a level greater than 200MPa through the thickness. While the axial residual stress at the inside surface was 40MPa, the stress at the outside surface was {minus}100MPa. This residual stress distribution was compared with the distributions measured by the X-ray diffraction technique and FEM analysis, and they agreed with each other.
- OSTI ID:
- 86169
- Report Number(s):
- CONF-9505104--; ISBN 0-87170-548-6
- Country of Publication:
- United States
- Language:
- English
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