Need: The research in this document is aimed at establishing the feasibility of repairing defects, especially corrosion-caused metal loss, by direct deposition of weld metal in pressurized pipelines without removing them from service.
Benefit: While this might seem inherently dangerous, past experience with “puddle welds” in corrosion pits and with repair and hot tap welding on relatively thin pipe materials suggests that it can be done safely.
Result: From the results of the experiments conducted to establish the limiting parameters to avoid burnthrough, it appears that it is feasible to carry out repair by means of weld metal deposition on remaining wall thicknesses as small as 0.125-in. (3.2-mm) with internal pressure levels as high as 800 psig (54.4 bar).
