Extending life of offshore pipe lines by hot tapping

Journal Article · Sat Nov 01 04:00:00 EST 1986 · Pipe Line Ind.; (United States)

OSTI ID:6390395

Mellon, B

Underbead cracking may occur under these conditions: presence of hydrogen, susceptible microstructure and residual thermal stress. Underbead cracking may be prevented by the elimination of any of these conditions. Hydrogen can be controlled by preheat and careful choice of weld consumables. Careful materials selection and control of weld cooling rate prevents formation of a hardened microstructure. Residual stress can only be removed by post weld heat treatment at temperatures in excess of 500/sup 0/C and this is obviously impractical in the hot-tapping situation. However, since the other two potential sources of cracking can be controlled, the use of careful welding and NDT techniques can provide acceptable weld quality.

• Research Organization: PLT Engineering Ltd., London
• OSTI ID: 6390395
• Journal Information: Pipe Line Ind.; (United States), Journal Name: Pipe Line Ind.; (United States) Vol. 65:5; ISSN PLINA
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
022000* -- Petroleum-- Transport
Handling
& Storage
03 NATURAL GAS
032000 -- Natural Gas-- Transport
Handling
& Storage
42 ENGINEERING
420205 -- Engineering-- Transport & Storage Facilities-- (1980-)
423000 -- Engineering-- Marine Engineering-- (1980-)
COOLING
CRACK PROPAGATION
CRYSTAL STRUCTURE
ELEMENTS
EMBRITTLEMENT
ENERGY SOURCES
FABRICATION
FLUIDS
FOSSIL FUELS
FUEL GAS
FUELS
GAS FUELS
GASES
HEAT TREATMENTS
HIGH TEMPERATURE
HYDROGEN
HYDROGEN EMBRITTLEMENT
JOINING
JOINTS
MATERIALS
MATERIALS TESTING
MICROSTRUCTURE
NATURAL GAS
NONDESTRUCTIVE TESTING
NONMETALS
OFFSHORE OPERATIONS
PETROLEUM
PIPELINES
RESIDUAL STRESSES
SERVICE LIFE
STRESSES
TESTING
THERMAL STRESSES
TRANSPORT
WELDED JOINTS
WELDING