Need Help Identifying Steel

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The drive shaft on my little outboard motor snapped in half.  I was gonna just buy a new one, but they cost about $250!!!  It's about   5/8" dia.  So I'm having a machinist friend of mine bevel the edges, and then chuck it up in a lathe and center drill both halves for a slight press fit for a pin.  I'll tack (tig) and then indicate the shaft for straightness.  So after all that - here's my question:  The shaft is about 35 years old and there's not a speck of rust on it anywhere.  It's even laid around out in my garage for about a year in some pretty damp conditions.  HOWEVER - before you say stainless - it's magnetic.  Soooooo, what is it?  And will stainless filler be okay?
Reply:Have a look at this link....however the short answer is that some stainless is magnetic.Last edited by tanglediver; 12-03-2007 at 12:55 AM.City of L.A. Structural; Manual & Semi-Automatic;"Surely there is a mine for silver, and a place where gold is refined. Iron is taken from the earth, and copper is smelted from ore."Job 28:1,2Lincoln, Miller, Victor & ISV BibleDanny
Reply:Some axle material, in this case drive shaft, has a small amount of vandadium. It helps in the acid, rust and pitting department. I doubt what you've got is much different than that or any hydraulic ram.So the shear pin was what?  ...
Reply:I can tell you that 17-4 SS is spring grade, weldable, and yes, magnetic. If the grade of steel is in question, you usually can't go wrong with 309 as a filler. It will work on SS to mild, SS to chromo, SS to SS, and it works on some of the other alloy steels well also, like 4130.And then, after so much work...... you have it in your hand, and you look over to your side...... and the runner has run off. Leaving you holding the prize, wondering when the runner will return.
Reply:martensetic stainless steel? the same stuff as in knifes and cookery, I have been informed that it can be welded however the weld will not be as strong as the origonal metal.
Reply:Try to find some Eutectic 680 or super missleweld they are fancy names for 312 SS it is a step above 309 and is used to weld metals of question and dissimilar metals I have used these for years with no problem available in stick & tigor mig if you can find it
Reply:This is the problem i see with using 309 if the base material is alot harder then the only way to make the welded area stronger will be by work hardening the SS after welding. So maybe also look into a D2 tool steel. That might be good for this repair also. --Gol'
Reply:Originally Posted by jkmolaThe drive shaft on my little outboard motor snapped in half.  I was gonna just buy a new one, but they cost about $250!!!  It's about   5/8" dia.  So I'm having a machinist friend of mine bevel the edges, and then chuck it up in a lathe and center drill both halves for a slight press fit for a pin.  I'll tack (tig) and then indicate the shaft for straightness.  So after all that - here's my question:  The shaft is about 35 years old and there's not a speck of rust on it anywhere.  It's even laid around out in my garage for about a year in some pretty damp conditions.  HOWEVER - before you say stainless - it's magnetic.  Soooooo, what is it?  And will stainless filler be okay?
Reply:Originally Posted by Go1lumThis is the problem i see with using 309 if the base material is alot harder then the only way to make the welded area stronger will be by work hardening the SS after welding. So maybe also look into a D2 tool steel. That might be good for this repair also.
Reply:Here are some pics of the shaft.  Hopefully, they are in enough detail to give you an idea of what I'm talking about.  The hole that is bisected by the break is for a press pin that drives the impeller for the water pump.
Reply:I think your screwed because of where the break is..Only way out of this is to cut it a couple of inches after the splines and pin a new piece in and re-drill the pump pin hole in the same place..You can have it spun in a lathe so everything stays true..Drill it..Bore it..Pin it..Weld it..This may be your only answer short of the cost for a new one..If you can't find anyone to fix it I'll fix it..JMHO......zap!Last edited by zapster; 12-04-2007 at 10:30 PM.I am not completely insane..Some parts are missing Professional Driver on a closed course....Do not attempt.Just because I'm a  dumbass don't mean that you can be too.So DON'T try any of this **** l do at home.
Reply:A couple of thing to note:You have splines at each end of the shaft, this is a good indication that the shaft is, at least in part, hardened.Second; the shaft is apparently one diameter its entire length.   If so it might make more sense to have your machinist friend buy you some ground stock and have him cut the splines on the end.   It is a bit more work so you will likely have to spend a buck or two for his work but you would end up with a solid shaft.   If the diameter of the shaft is the same as commonly available SS shafting then this might be very doable.Third; someone above mentioned the issue of a bent shaft tearing up your drive unit.   this is a very real possibility and you need to realize that the shaft will need to be very straight over its length.    How much for this specific application can't be said at he moment.In any event I would make a judgment as to the motor even being worth while to repair.   That based on a new shaft from the manufacture or a custom made shaft.   I wouldn't bother with welding it up at all.I'd avoid the welding due to experience in industrial maintenance with attempts at welding shafts in rotating applications.   You need the right combination of factors to get a repair that is anything more than temporary.    It is unfortunate with respect to the breaks location as I might have suggested having a collar made to join the two broken sections.In any event lots of luck with whatever avenue you take.Dave