API (rotating equipment) touches on the subject very slightly. But safe to say no, there really is no a code for shaft repair. It is large portion of our work though.

In order to answer your question one needs to know more about what you are working on and what kind of results you expect.

One applicable filler would be ER120 S-1 with a PWHT: If you just want to restore an area to its original configuration. However I suggest you do a hardness survey before welding. You will need to know your mechanical requirments of the base material to determine PWHT temperature.

I have no idea what or where your stress concerns maybe on this shaft. If it is a high speed or sees high stress's I suggest you consult an Engineer.

It depends on what the area on the shaft does. If it is a bearing fit, then thermal spray is the process to use. It produces a mechanical bond, with no metallurgical affect to the shaft. If it is an area that sees bending or dynamic loads, thermal spray may not be suitable. Plasma spray may work in that case. I believe there is an AWS standard on welding rotating equipment and another on thermal spray. Search the publications links at www.aws.org. Also, search the web for Praxair. They do this type of work and I believe one of their folks posts here sometimes.

Also, here's a link to Metallizing info: http://www.adtdl.army.mil/cgi-bin/atdl.dll/tc/9-237/Ch12.htm

After you go there, scroll down to Section III.

Electroplating is another approach. Probably with hard chrome.
Bill

Now you all don't laugh at my suggestion: consider using putty, i.e. Devcon's titanium putty. Devcon has many case histories of its successful use in the repair of scored shafts, damaged pump housings, damaged castings, and other large pieces of equipment.

http://www.devcon.com/devconfamilyproduct.cfm?familyid=124

I had doubts about the efficacy of this putty but decided to try it about 8 years ago. At that time I had just purchased an old 20" metal cutting bandsaw that needed repairs. One of the problems with it was that its main drive shaft was scored in two places from worn out bearings. The shaft is a complex one with several different diameters and tapers and replacement shafts are no longer available for this old Walker-Turner bandsaw. Remembering Devcon's claims about their titanium putty, I decided to try rebuilding the shaft with it. After a friend of mine turned the scored areas down a little, I applied the putty and let it harden. An hour later my friend started to turn the putty repaired areas down to the correct diameter. The putty ruined the edge of the high-speed cutting tool and he had to switch to a carbide one to complete the job. A second problem was that the bandsaw's aluminum, split sheave variable-speed pulley was worn. Because one half was badly worn, the other half wobbled as the pulley turned. This caused the saw's speed to cycle through a fast-slow range - not desirable when cutting metal. I repaired the worn hub of this sheave with titanium putty also and we turned it down to the correct diameter. Since being put together with new bearings and other parts, the bandsaw has been running well for the past 8 years.