welding steel to an automotive cast iron spindle????

Date 05-30-2007 20:18

Hello draggbody, it is likely that this spindle is not cast iron, but cast steel instead. Likely not a good idea to cut and weld on this component even if it is cast steel and technically could be welded. You will end up opening yourself up to a host of liability issues that you don't want to be a part of. It's one thing to do this on something that you will be using for yourself and quite another to be selling this as a product to the general public. Just my $.02 Regards, aevald

By draggbody Date 05-31-2007 20:16

so how would you definitively tell the difference??? and IF it were cast steel what would be the procedure for welding it...

By Bob Garner (***)

Date 05-31-2007 21:06

I checked the Fabtech site and they state their spindles are ductile iron.

Among other things, relocating the spindle hub on the upright changes the loads at the ball joints - it's a geometry thing.

I bet Fabtech would not be happy knowing what someone is doing to their product! And then reselling them.

Bob

By draggbody Date 06-01-2007 01:32

so can steel be welded to ductile iron... i know i see stamped on tractors "ductile iron, do not weld"

By billvanderhoof (****)

Date 06-01-2007 04:36

http://en.wikipedia.org/wiki/Ductile_iron
Thats the wiki page for ductile iron. There are two ways to make cast iron ductile, one by alloying additives that nodularize the graphite, the other by an annealing process that does the same thing. Welding would surely disrupt the annealing. I could not predict the result of diluting the alloying agents in the alloyed type material. In both cases diffusion of carbon into the weld metal is going to lead to a hard and probably brittle weld. I would be scared to death if it really is ductile.
Bill

By Tommyjoking (****)

Date 06-01-2007 06:35

not to show my ignorance but.....

I wonder if they are using the old flame welding technique with cast iron filler rod....this is almost a completely lost art I think....I am not very good at it (terrible actually) but it involves high temp flux and an oxididizing flame. This is a softer weld than using a nickel smaw weld. But it is a weld and not a braze....so the need for a large surface to surface bond area is not needed ......a lot of pre and post heat is used and this process basically keeps the ductility alive. I have only known one fellow who could do this with ease and all I can say is I thought it was magic...literally!!

I am not clear on the carbon migration from the steel to the iron that may occur using this method. Using a low carbon steel would eliminate this hazard and prevent graphite from forming from what I understand.

I would be highly interested in some guys with more knowledge in this area posting and getting you a more definitive answer.

By XPERTFAB (**)

Date 06-02-2007 02:28

Not too lost of an art!! if you have ever repaired cast iron Jaguar and Oldsmobile blocks you will aprreciate the use of this method. Have repaired countless cast iron cylinder heads using this method and a good barbeque for the preheat and post heat/cool down. Owing to the machinability fo the deposited weld material, it is truly a better way to go. The high nickel content cast iron repair rods currently offered work well for repairs but when post machining operations requirre a finished surface consisting of both the nickel content filler metal and the base cast material, it gets a little diffciult because of the gummy nature of nickel on tool bits and it tends to demo the wheels on surface grinders. This very method is one of those techniques frequnetly alluded to in this forum as being lost with the old guys. They do not teach it in most welding schools and few people are ever exposed to it. But as with gas welding aluminum, if you put in the effort to school yourself, you will be rewarded throughout your life. Certainly not an immediate gratification sort of skill but rather one more bullet in your bandolier. There is more information in books these days about welding cast then in years before so find yourself one, read up and give it a try. Have fun with your new skill.
XPERTFAB

By Geese_howard (*)

Date 06-06-2007 02:14

Well, i work in a place (and country), where repairing of unadvisable, impossible , unlikely etc, components of every metal you can think of,
is an everyday thing, (because is very far and spare parts are not readily found). I´m a welding engineer in charge of very skilled welders
(some of them have the forementioned "oxyflame cast iron rod Technique", not used very much now because the rods are now not produced because of
the popularity of SMAW ENi-CI and ENiFe-CI electrodes).
Welding cast iron can be quite succesful, if proper techniques are used. Main problems are
- Hardening of HAZ, because of dilution of carbon into the probably already high carbon matrix of the cast iron, leading to martensitic and/or white
iron formation upon cooling in the zone (brittle, low ductility phases). This also can lead to cracking because of dilatation/contaction of the weld.
- Because of the nature of the structure, usually cast iron pieces absorbs lots of oil or water, leading to porosity problems in the weld or HAZ
- Random nature of the composition of the cast iron, some of them have lot of deleterius elements to welding (sulphur, phosporous, Sn, etc.)

Hardening of the HAZ can be minimized by either weld with very high preheat and very slow cooling to prevent "quenching" of the HAZ, plus
post weld heat treatment to eliminate any formed martensite
, or, the complete opposite, weld very cold, no preheat, low diameter electrodes, short straight passes, to make this "brittle HAZ", very thin.
in both cases peening of the weld when is hot is advisable
Other two problems can be minimized by cleaning, or burning impurities and pre "analysis", (chemical and metallographic"), of the iron.

But even we recognize that , when a failure in the weld will almost ceirtanly lead to personal injury or loss, that repair or work should not be done,
as in the case you post. Nobody in the world can assure you a 100% safe repair on cast iron, and if somebody do it, he is lying, i'm very certain
of that

By Tommyjoking (****)

Date 06-07-2007 07:27

I would just like to add that I do not condone what is being done here considering the materials used or the stresses involved...It seems dodgy at best. I was just curious to the method being used if its being sold and apparently holding up..so far...

No matter what process you use on that Iron it is not going to hold the same charecteristics and integrety as it would used in its complete cast original intention.