Case Studies

Critical "V" Outage Tooling Design and Manufacture

V64.3A2 Front Hollow Shaft Repair

 

During a major outage, a V64.3A2 client of Eta Tech attempted to unthread the connection between the front hollow shaft (FHS) and the central tie bolt after unstacking the rotor on site. Unfortunately, significant galling was encountered such that the tie bolt could only be partially unthreaded before the connection locked up. Since new replacement components required very long lead times to procure, this client sent the FHS and tie bolt to Eta Tech for separation attempts and potential repair. After numerous attempts at separation using standard heating/cooling methods proved unsuccessful, Eta Tech engineered a FHS sleeve repair to salvage the components. The sleeve design was substantiated by Finite Element Method (FEM) Analysis and shown to represent no debit in threaded connection strength or life. Metallurgy of the sleeve was carefully selected to provide compatibility with the existing components, and special machining tools and inserts were specified and procured to minimize the removal of sound parent material. FHS repair through this sleeve insert methodology was completed in a timely manner and the components thus salvaged and returned to site. The repaired components are currently back in service and operating successfully!

 

Critical "V" Outage Tooling Design and Manufacture Critical "V" Outage Tooling Design and Manufacture Critical "V" Outage Tooling Design and Manufacture Critical "V" Outage Tooling Design and Manufacture