TugCE wrote:
On some of the Large Ship Engines that I have worked on some of the bolts were torqued to yield. We would place the hydraulic tool on the stud and stretch it using a certain PSI then spin the nut down to hand tight. Once the hydraulic pressure was released it was torqued.
Hi Tug,
Yes the method you describe is common. Those are one use bolts too pulled to yield I'm sure. We use to build mechanical power presses. On the straight side presses, 150 to 500 ton (were where small tonnage builders) we had hollow tie rods to hold the entire press together. We spun the nuts down by hand cold. Then installed 460VAC 3PH calrod heaters down the center. Wait XX minutes, they would expand enough, then rotate the nut YY degrees down. Pull the core heaters and when it shrunk back down the tie rods were pre-loaded. These were from 3 to 6" dia rods with 8 to 9" nuts. No way torque will work practically.
