  (Ref. No. MSB-019) |
A number of you have inquired in the past about welding "hairline" cracks on a hydraulic transmission line while there is oil in the line. Our answer has always been - ABSOLUTELY NOT! While some have argued that it is safe to weld on a hydraulic transmission line while there is oil inside, there are simply too many variables that might make it extremely hazardous. Consequently, one should always error on the side of safety - take the oil out! A millwright in Spokane, Washington, inadvertently burned through the steel pipe he was welding - the result; an inferno that blew oil and flames 25 feet into the air. He escaped with minor burn injuries. A mechanic in Hazen, North Dakota, inadvertently burned through the steel pipe that he was repairing. If it were not for the fact that he was working outdoors in the winter, so he was dressed in thick winter coveralls and a face warmer, he would have suffered severe burn injuries. He did however, suffer minor burns to his face. He said that for what seemed an eternity, he was inside the inferno. He likened his experience to being in "hell." Another mechanic was heating a piece of steel tubing on an excavator with an acetylene torch, with the intention of bending it back into position after it had been damaged. The oil was trapped inside the tubing with absolutely nowhere to go. The expansion of the oil from the heat from the torch, caused the steel transmission line to literally burst in his face. He suffered severe facial and chest burns. The IOWA FACE (Fatality Assessment & Control Evaluation) Program reports of a 38-year old welder who died in an explosion and major fire he caused from using a metal 55-gallon barrel as a welding worktable (see related story). REMEMBER THE RULE OF THUMB: For every 1°F you heat trapped hydraulic oil, the pressure rises 50-60 PSI (4 bar). If you have a hairline crack in any steel hydraulic transmission line, DON'T WELD IT WHILE THERE IS OIL INSIDE IT, UNDER ANY CIRCUMSTANCES. If all else fails, get a second opinion. |