Edit: Al has beat me to it, I’m on the Ninth edition. The presence of hydrogen in the weld metal will only lower it’s tensile strength if the hydrogen moves towards the grain boundary’s and Has the propensity to cause a crack. for this you need to have a weld under stress and a susceptible microstructure. Majority of hydrogen is going to permeate out of the weld during the cooling and following 48 hours. This hydrogen, it’s not like nitrogen embrittlement in steel or hydrogen pores in aluminium. It’s absolutely microscopic, occupying the spaces between the crystal lattice. Room temperature just happens to be the temperature when hydrogen gets trapped in the lattice and tends to accumulate in the free space at grain boundaries. it’s been some time since I really researched and read into this subject so I may be incorrect here, so Al please correct me if I’m wrong.