Extrusion Press

Problem: Customer traditionally used the press force to prestress the columns. To remove the nuts, the press is loaded to 110% of maximum load and the split counternuts are removed. In this case, there was a failure in the hydraulic cylinder and the press could not be used to unload the counternuts. The nuts were burned off which took approximately 2 days to accomplish.

Solution: The old cast steel split counter nuts were replaced with split Supernut® Multi-Jackbolt Tensioners. The preload was achieved by loading the press to 110% of its working load. Some additional preload was achieved by torquing the tensioner's jackbolts to 100 ft-lbs. Without hydraulic help from the main cylinder, the jackbolts would have to be torqued to 460 ft-lbs to achieve equivalent total preload of 3,500,000 lbs. The Torquenut® halves were held together with 1-1/2" high powered Superbolt® Torquebolts®. In the future, the counter Torquenuts® can be unloaded without the hydraulic help of the main cylinder by simply untorquing the jackbolts.