I'am modifying a 32 steering box for my av8 project. I'am well aware that the f1 box is a better choice but I would like to stay early mid 40's. I cut,squared and chaffered up the box extension tack welding using a tig welder across from each other so there was a 1/2 inch space between each tack weld. I then heated the unit and welded it looked like it was going good when it cooled I noticed it cracked it the center of the weld. I consider myself a good mig welder with 20+ years experience but the tig is still kind of new to me I'am improving though. The welder is a miller diversion 165 I'am using .045 alloy rod. Can anyone tell me what I'am doing wrong? I have inclosed some pictures.
Looks like a casting, tricky to weld with any technique. I'd try pre and post heating (slow cooldown...under a welding blanket or immerse in sand to kitty litter) along with the TIG.
Weld a bit and peen it in while it is cooling. The reason for the crack is shrinkage, kinda like swimming in a cold lake.
what rod were you using ? i have had luck with cast parts using a stainless rod with high nickel or a ni99 rod . like others said pre heat, post heat and peen the weld !
I welded my F1 steering box with a mig and mild steel. No pre-heat, big tack in three places with the shaft in, let it cool and removed the shaft, then I layed into it at about 90 amps. I let it cool naturally and all was good.
A preheat and slow cool down of the part is a must. I,ve used the nickle rod with arc welding on castings. Works fine but the best way to weld castings imho is by using a silicon bronze filler rod with tig. Get it hot,keep it hot, slow cool down.
I agree with 1ton, silicon rod is amazing with cast, I'd try it out on something else first though, it flows kinda funny...
When I welded a '32 flange onto an F-1 box, I preheated all the parts thoroughly with a torch, welded thoroughly with a MIG (same old wire we use for general steel), kept the heat going again with a torch, then let it cool slowly in the 72 degree still air. Luckily no cracks. I'd always heard to use a MIG, not a TIG.
Thank you everyone that gave advice and suggestion's. I went to local welding shop they suggested stainless 309l, preheat and pean weld. I weld successfully with no cracks just have to weld flange and frame.
Chiming in a bit late here, but I've had very good luck welding cast iron with cast iron/nickel mig wire that I got from McMaster-Carr. Here's the link: http://www.mcmaster.com/#ni-55-cast-iron-welding-wire/=mswp6j It ain't cheap, but it works. Used minimal preheat, and room temp cooldown. Ground clean and hit with a needle scaler for texture. Once it's painted, the weld is invisible. I'll back up what the others are saying re: welding cast. I bought the Lincoln Welding School textbook, and they recommend a preheat, peening, and slow cooldown. If anyone should know for sure, it would be those folks. Chris