Weld filler for OEM forged steel crank?

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If I were going to weld on a forged steel crank shaft, and then have it machined down to the the appropriate size, What filler rod would be the best to use?This is not a racing crank shaft like a 4340 Cr-Mo. This is just a factory Nissan forged crankshaft. As far as I know it is just regular steel,Lincoln Precisoin Tig 1851980's Miller plasma cutter.Used to own...Hobart Tig Mate.
Reply:A couple things come to mind.  You don't mention where on the crankshaft you want to weld, or why it needs to be welded in the first place.  What you should(or shouldn't) do depends on the answers to these questions.For example:  sometimes factory crankshafts are surface hardened; could be nitrided, carburized, or another related process.  If you're welding on an already machined surface you're probably OK, because previous machining would have removed most or all of any surface hardening treatment.  Surface hardening puts the surface of the crankshaft under compressive stress, which improves the fatigue life of the part.  It's cheaper to do this than it is to use a higher strength grade of steel when you're mass-producing parts.  Welding on hardened parts creates a serious risk for cracking after welding.Crankshafts can also be quenched and tempered for improved strength and durability.  Welding on steel that's heat treated in this fashion weakens the surrounding material in the vicinity of any welding.  Again, this could be critical depending on where you want to weld.Second:  even OEM factory forged crankshafts can be made from higher strength steels.  So you're better off really finding out what your crankshaft is made of before you weld on it.  A local lab can check hardness; which when done correctly can give you a rough idea of whether or not you're dealing with a high(er) strength steel or steel that's heat treated.If this is top dollar equipment you're customizing or trying to repair, some money invested in checking the steel chemistry and/or hardness would be well-spent.  Or, since this is OEM, dig further on the net to find out what the crankshaft is made of.Guessing what filler to use without the right information, is just begging for problems later on....Benson's Mobile Welding - Dayton, OH metro area - AWS Certified Welding Inspector
Reply:Thank you for your reply. I took the crank to Mile High Crankshafts in Denver and Dave told me he would weld what needed to be welded and machine the parts. Basically it is the snout of the crank shaft. The oil pump drive needs to be shortened. Doing this leaves a groove right where the oil seal will sit. This groove has to be filled in and machined down so the oil seal has something smooth to ride on. I decided to leave it in the hands of the professional since it is such a critical part.Lincoln Precisoin Tig 1851980's Miller plasma cutter.Used to own...Hobart Tig Mate.
Reply:Welding crankshafts is fairly common and usually done to build up worn areas or to build up the journals so that they can be offset ground to use different connecting rods. Surface treatments can always be redone after the work and it usually doesnt cause any problems as long as the shop knows what they are doing