With modern metal welding techniques it is possible to refurbish many types of damage to rotors by welding on attachments or weld rebuild. Rotors have been manufactured by welding together individual forgings for many years, but it was not until the 1950s that welding, as a means of repair, developed into a modern refurbishment technology. The development of modern weld materials and weld fusion processes now allows the restoration of many damaged rotors to a fully operational condition, and normally within a relatively short time period. The welding techniques are proven, and procedures exist allowing the deposit of compatible materials. The quality of the finished components is entirely satisfactory. The condition of the repaired rotors are sufficient to allow them to be returned to service without any limitation being placed on their operating steam conditions, or load. The following sections will describe the more commonly applied of these techniques, and outline the steps through which the rotors are taken to restore their condition.

In considering weld repair applications that are presently available, there are four areas to be considered:

• Local weld repair of deteriorated surfaces This form of repair is required when the rotor surface has deteriorated locally due to some mechanism, and it is necessary to restore its condition before return to service

• Total weld rebuild of a damaged wheel If a wheel has suffered rubbing damage, as shown in Figures 9.6.19 and 9.6.20, it may be necessary to machine away the complete (or a portion...