Abstract: A method for joining together a pair of flanged metal pipe sections at their respective flanges. The sections have heat sensitive material juxtaposed to, in contact with or bonded to the interior thereof. The method includes the step of providing coolant passages, each of the passages being located adjacent to respect of one of the flanges in proximity to the heat sensitive material for heat exchange therewith. The flanges are brought into a welding position and coolant is passed through the passages. The flanges are then welded together and coolant is continuously passed through the passages until the resultant welded flanges have cooled. An apparatus for effecting this method is also provided comprising a coolant passage adjacent to the flange and in heat exchange relationship with the flange. The coolant passage has an inlet for introducing coolant and an outlet for exhausting coolant therefrom.