Welding on fluid filled or pressurized pipelines: Transient 3D analysis of temperature, microstructure, stress and strain

Technical Report · Mon Nov 04 04:00:00 EST 1991

OSTI ID:6814492

Goldak, J A ^[1]

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1. Carleton Univ., Ottawa, ON (Canada)

It is frequently necessary to add new branch connections to existing pipelines; two general types of welds are used: circumferential fillet welds around ends of reinforcing sleeves, and groove welds completely around the joint. Successful hot-tap welds (welds made on pressurized pipelines) must avoid two problems: too high a peak temperature on inner surface, resulting in local rupture or burnthrough, and too high cooling rates caused by the flowing gas/liquid inside the pipeline, resulting in hydrogen-assisted cracking in heat-affected zone (HAZ). This report presents results of a feasibility study of the 3D finite element thermal and stress analysis of welding on fluid-filled, pressurized pipelines. Peak inner-surface temperatures, HAZ cooling rates at 540 C, HAZ hardness and microstructures are presented. Ten different welds were considered; conditions examined comprised branch or sleeve welds on various pipe diameters and thicknesses, on methane and propane filled pipelines. Better data on reinforcement profiles and weld pool sizes are needed. HAZ cooling rates at 540 C computed for methane filled pipelines are somewhat higher than Kiefner model predictions; those for propane filled pipelines are in agreement with experiment.

• Research Organization: American Gas Association, Inc., Arlington, VA (United States). Pipeline Research Committee; Carleton Univ., Ottawa, ON (Canada)
• Sponsoring Organization: AGA; American Gas Association, Inc., Arlington, VA (United States)
• OSTI ID: 6814492
• Report Number(s): AGA-93007091; CNN: Project PR-206-013
• Country of Publication: United States
• Language: English

Related Subjects

03 NATURAL GAS
032000* -- Natural Gas-- Transport
Handling
& Storage
42 ENGINEERING
420205 -- Engineering-- Transport & Storage Facilities-- (1980-)
ALKANES
CALCULATION METHODS
DOCUMENT TYPES
FABRICATION
FINITE ELEMENT METHOD
HEAT AFFECTED ZONE
HYDROCARBONS
JOINING
JOINTS
METHANE
NATURAL GAS DISTRIBUTION SYSTEMS
NUMERICAL SOLUTION
ORGANIC COMPOUNDS
PIPELINES
PRESSURIZATION
PROGRESS REPORT
PROPANE
SLEEVES
STRESS ANALYSIS
THREE-DIMENSIONAL CALCULATIONS
WELDED JOINTS
WELDING
ZONES