Anyone have any input on repair welding of cast iron. I have a repair in process (not successfull yet).
so far we have tried welding with 55Ni, 99Ni, 309LT, UTP 34N(E CuMnNi-Al), 950 Metal Arc(bronze),Certainium 707(all purpose rod), 880 Weldmold(great for dissimilar metals),7018. We have tried welding with Pre-heat-600deg.+ we've tried welding cold, all passes(short 2") are peened immediately after breaking the arc. The base material is like powder and the weld just simply rolls away with absolutely no fusion. We are attempting to repair a previous repair that was cracked out. Someone evidently welded this about 10-12 years ago as you can see evidence of the weld. There was fusion, as those welds have been ground flush. This is a column pipe for a pump that is used in salt water. I am exhausted trying to find something that will stick. We have been working on this for nearly 24 hours now and still have not found anything to hold. I have my welder attempting to butter pass with SIB now. Anyone with any ideas? I'm at a loss for what to try next.
try torch brazing with some regular ole brazing rod
Hello alumtig, have you tried gas welding this material? Sometimes the old tried and true methods work best. I don't have the specific filler metal designations to give you, but I would venture to say that your welding supplier likely does. This type of rod also requires a special high-temperature flux to be used in conjunction with the rod. I believe it also requires a certain amount of pre-heating and a controlled cooldown rate. You can generally deal with the cooldown by using fire brick enclosures or various types of heat blankets or refractory. Esab also makes a powder-metal injection type torch that I have seen in action for the repair of cast irons, this system also works pretty well. So you may want to check into that too. I have been where you are on numerous occasions, it isn't fun and it's definitely frustrating. Best regards, aevald
Thanks for the input. I didn't get a chance to try any of the oxyfuel processes however the outcome is becoming more promising. I just had a meeting with the customers engineer and suggested a mechanical repair rather than welding. We are now going to drill and tap through the base metal and attached the spider mechanically. The cracking holds no bearing on the structural integrity of the part so the crack will be covered with Devcon and Corglass will be applied over. Hoooray! Its a first for me, I've never come across anything that I could not weld however the repair will still be completed. The most critical area of this repair was to complete it in a specific time frame. We haven't yet accomplished that but I feel at this point we have a greater chance of meeting the deadline than before. Thanks again for the input.
Tracy
By Kix 
Date 10-25-2007 18:44
Edited 10-25-2007 18:47
I use 300+deg of preheat and ER309L stainless wire and tig weld the stuff and when i'm done i heat it up again and allow to cool very slowly. If i have to stick weld it i use Certanium 880 stick rod with 300+deg of preheat and some post heat to allow to cool very slowly. Never had any failures or cracks or problems of any kind.
If the Certanium 880 didn't work it's not cast iron or i mean it's the crap that can't be repaired. There are a few different types of cast iron out there and only a few can be repaired by welding.
"did you try oxy fuel welding with cast iron rod and solar flux, preheat whole piece to 1100 degrees and keep there during the whole weld procedure, then post heat and completely bury in floor dry. leave it there for a day or two and let it cool to ambient in the floor dry, the welding is sort of a stirring motion between the flame, the consumable and parent metal. lotsa flux. neutral flame is important as well
ive welded some pretty ugly cast parts that were impossible to weld any other way.(e.g. 1953 corvette exhaust manifold for which i received no payment and water jacket heat exchanger that was around 150 years old, both were irreplaceable and would lead to very very expensive alternate solutions. a myriad of other one of parts as well)
lucky enough to have had a VERY GREAT teacher and awesome human being bob adams show me how. very old school technique.
they sell different types and grades of the consumable bars.
there has gotta be some of the more seasoned welders out there with a bunch of experience with this technique.
be prepared for an experience if you attempt it , takes team work and perseverance but it should get er done."
this is a post i submitted before, i realize others have suggested the "flame" technique
its totally doable with the right couple of sets of hands
darren
Hi alumtig-I recommend Magna welding alloy (arc welding) to weld any types of cast iron or steel to cast iron without preheating. Welding result -No cracks -good machinable without hard spots - No porosity by using AC or DC machine.
Labib
