Forming Gas Monitoring

Shielding gas is introduced into the pipe during root welding to protect the weld from oxygen on the inside. If too much oxygen gets in, you get porosity in the weld and it won't seal properly. So you have to keep an eye on the residual oxygen in the pipe and set the gas cleanly and with enough flow. If the gas amount doesn't fit or it sucks in air, the root just won't be clean – then better redo it than leave a crappy weld.