Hydrogen Absorption Capability of High Strength Weld Wire and Weld Metal for Line Pipe

摘要

The hydrogen absorption capability of high-strength weld wire andweld metal with 1000 MPa for line pipes was investigated in order toprevent the cold-cracking of high-strength weld metal for line pipes byapplying hydrogen traps to high-strength weld metal. Hydrogenconcentration immediately after cathodic-charging and that afterholding for 72 hours at 45℃ indicated the maximum value at thetempering temperature of weld wire at 600℃. Especially, the hydrogenconcentration after holding for 72 hours at 45℃ indicated 2 ppm at thetempering temperature of the weld wire at 600℃. A hydrogen trap sitewas identified with molybdenum and chromium carbide fromTransmission Electron Microscope (TEM) observation and ElectronDispersive Spectroscopy (EDS) analysis because the maximumhardness indicated the maximum value at the tempering temperature ofthe weld wire at 600℃. The hydrogen concentration due to hydrogentraps was confirmed in the high-strength weld metal for line pipes.