Welding a breaking shaft

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HiI do some reasearch because a need to reweld a broken shaft. This is a snowmobile shaft that keep breaking near the welded sprocket cup (a plate that hold rubber sprockets) like if the shaft had twist and snap. Is there a way to do it properly to avoid re-breaking like preheat/ postheat, special rods (I called sodel and they suggest me the 335) or any other tricks ? Because the weld of the compagny have clearly affected the ductility of the shaft.ThanksFrancisEdit/Delete Message
Reply:It mostly depends on what the shaft is made out of.And you have to know better than "steel" to get the right answer(s).Because "steel" can range from plain low-carbon mild steel (usually weldable), to free-machining steels (usually not weldable or sometimes barely weldable with difficulty), to alloy steels, to stainless steels, etc.  And then you may have to know the possible heat treatment that the shaft may have or had.All those things greatly affect the answer.
Reply:you will have to get some good and sound weld in there without making a huge heat affected zone. what you can do is bevel it about 1/4 to 1/2 the thickness and make sure the very root will be big enough to get your rod into it.  slide a peice of pipe over the shaft that is a nice tight fit before you tack it. weld the shaft flush but with short passes and a good amount of time between passes so your not welding it till its red hot. you can insulate it while its cooling. you want as small of a heat affected zone as possible its important. so now slide that little pipe over the flush weld and then weld it, in 2 or 3 spots on both sides. a little pre heat before you even start wouldnt hurt because it would drive out any moisture. thats how id go about it. it will get you riding again for a bit anyway. few more things to add. that pipe could be cut at 45 and welded that way for more stregnth. and keep the HAZ from being straight and making it shear off right beside the weldNothing Ever Got Done By Quitting, Never Give Up.
Reply:Doug, if the shaft is 1018 CR then what you are describing will work.  However that is an "IF".  As moonrise stated before an answer can be given the Type of shaft needs to be known.  There are some shaft material that will snap if they are welded on period.  It sounds like the shaft is breaking off flush at the edge of the weld.  I'm assuming the shaft runs thru the plate and the plate is welded to the shaft?  If that is the case I would see if it would be possible to mount the plate to the shaft without welding it.  Possibly weld a hub in the plate, and have someone bore it to slide on the shaft with a keyway?  Is this a one time occurrence or is it a repetitive thing?  Even if you could successfully weld the shaft back together the welding is the easy part.  Keeping it true is rarely gonna be possible.  Some pics would help with giving some ideas how to correct the situation.I'm a Lover, Fighter, Wild horse Rider, and a pretty good welding man......
Reply:When i was doing sawmill maintaince we would join 2 short peices of shaft with what they called a double muff style coupler. basically what we would do is cut a keyway on the ends of the shafts so when installed this coupler would join the two. at times if a shaft would break we would take the key cutter out in the field and then install the coupler and get them up running again. it would be funny to see a shaft broken in a way that they could run it one direction because it would catch on the broken edge and not move in the other direction.  thought id share that tooNothing Ever Got Done By Quitting, Never Give Up.
Reply:It sounds like the shaft is breaking off flush at the edge of the weld.  I'm assuming the shaft runs thru the plate and the plate is welded to the shaft?
Reply:Here are some things to remember regarding repairing a shaft\1) The shaft broke in the 1st place. You will never make it stronger than it was originally. In most cases it will become weaker even if the weld is perfect.  Because a shaft can see dynamic loading and vibration, any variations in the material can caus stress concentration in that area.  Welding causes residual stress period. Mechanical Straightening also causes residual stress.  This "built in stress" is an ideal place for a failure. Those concentrations have a bigger effect on something that is subjected to stress that varies up and down. These area can be concentrated at the weld heat affected zone or the weld metal etc.  2) Stubbing a NEW piece on the end of a broken shaft and then machining it to the correct dimensions will avoid the need to "BEND IT BACK" in place. This will also keep the shaft running true and therefore reduce vibrations.3) Stress Releiving a shaft after welding will reduce residual stress, preheat during wellding will also reduce residual stress.4) ANY undercut along the toe of the weld needs to be smoothed out. The shape of the undercut and the fact that it adjacent to an area already subjected to residual stress from welding can cause premature failure.5) If you do not know the material type, grade, and condition of heat treatment it can be very difficult to weld a shaft .6) If you are welding the joint by vee grooving the joint, make sure you use runoff tabs at the ends of the weld to avoid stopping and starting in the area of concern.  7) Know when to say when !I hope the best for you. Maybe something will help.Geraldhttp://weldingdata.com/Have a nice dayhttp://www.weldingdata.com/
Reply:Originally Posted by alteredHiI do some reasearch because a need to reweld a broken shaft. This is a snowmobile shaft that keeps breaking near the welded sprocket cup (a plate that holds rubber sprockets) like if the shaft had twist and snap. Is there a way to do it properly to avoid re-breaking like preheat/ postheat, special rods (I called sodel and they suggest me the 335) or any other tricks ? Because the weld of the compagny have clearly affected the ductility of the shaft.This is a one-off-job.Thanks, Francis
Reply:Thank a lot Guys for all you're help.I have welded the shaft saturday with 335 rods i think it's a high nickel rods. It's made for application when the material is unknown and the weld need to be strong.I will see the result this week.
Reply:Good luck,  What brand is the 335 rods that you used?  just curious as I've never heard of rod with that designation.I'm a Lover, Fighter, Wild horse Rider, and a pretty good welding man......