I need to weld some mild steel half inch plate to a 3.15" hardened steel stock. I wanted to mig weld it, but can stick if that's a better process for it. It's for a hydraulic breaker tool, so I'll have lots of force and impact on the welds, etc. I need help figuring out how to get this welded correct so it'll withstand anything. Thanks!
I think you need to post more info. Welding on the chisel itself ?
Yair . . . HRPServicesTX I reckon digger doug is right, more info and maybe some photos . . . there are folks here who can give you good advise. Generally speaking though such repairs are fairly common. The old strategy with unknown hard stuff was to preheat until spit dances and weld with a properly conditioned low hydrogen stick. Keep welds smooth and blended into the parent metal, no gorilla snot allowed. I have little faith in MIG for such applications but, I am old school. I believe the process these days is quite efficient but as always relies on operator understanding. Cheers.
Preheat well, 7018 low hydrogen rod, baked in a rod oven, and usually DCRP. And once you THINK your weld is where is should be, take your rosebud and get the whole thing cherry red and allow to cool as slowly as possible. That should smooth the grain bounderies at the weld interface. Try to leave the working surface cool or case harden when done. Let me know how it works... Howard
The hydraulic hammer tool is 3.15" blunt point, I need to weld a 6"x1/2" round plate on the bottom with 6, 6"x1/2" flat strap on the sides of the tool running down to the round plate. That will increase the weld surface on the tool and strengthen the plate for the impact force.
I've made several picks for a backhoe, taking chisels for a jackhammer and welding them to a mount made out of mild steel. Good dry stored 7018, and cool it slowly works. I don't know how hard the steel you are using is, but you might not want anything too hard, or it may snap. I have had good luck using T-1 steel for such things, hard enough to resist wear, soft enough to bend rather than snap, but not easy to bend. It is what good cold chisels are made of, also what we made shear blades from, for the first feller-bunchers. 7018 welded carefully works well for T-1. I have also made thumbs for large excavators from it. On edit: you posted the above while I was typing sloooowly. I'm not sure what steel a commercially made hammer point is, but I bet it's not real hard, kinda like T-1, for the reasons above. :beatsme
Mitch504....so don't need to heat it before I weld? Not sure the hardness. It's a Chicago Pneumatic hydraulic breaker for a skid steer..its the tool that comes with that breaker. I'm just trying to make it in a way I get as much weld surface area to hopefully withstand the abuse better. I'll try to find out from the rep tomorrow what grade the hardening is, etc.
Modified Stainless stick rod, Eutectic 680 or equivalent. Welds with a lot less heat than 7018, high nickel content gives it good ductility.
That's a good idea, Lanway. Particularly if it turns out to be very hard, I have seen leaf springs welded with that, no preheat, or anything.
Ok I'll def check that out, thank you. What about running stainless steel wire instead of stick?... Or the stick better for my application?
We used Eutectic Nucleotec 2222 electrodes in case like that, it has almost 50% elongation before failure. Preheat well and beat the crap out of each weld bead with a needle peening gun before welding the next one. Keep the temperature of the workpiece up aound 250 degrees and after welding throw some thermal blankets over it an let it cool as slowly as possible.
Would I use a 1/8 rod for a root pass, then larger rod for 2 passes on top of it, or no need for root pass? Or do you go about welding with this rod completely different than a 6010 or 7018. Those are the 2 rods I use the most.
Like Dis here ? http://www.digrock.com/compachyderm.htm
Yes kinda like that, with a Bell on the bottom to sleeve over the pipe to slam in the ground. I have access to a forge, that will help me heat up the entire weld area very nicely. Also was thinking maybe instead of welding and it failing, I could get a sleeve to go over the breaker tool and drill 2 holes all the way through the tool and sleeve and slip a ¾" grade 8 bolt through them...maybe that would hold better?
Talk about impact loads...and the slightest play in the bolt would make things worse, plus the holes will weaken the tool. Preheat in the forge, weld with 7018 rod, and put it back in the forge, and slowly air cool. If you do it right, the weld itself will have a minimum force on it and merely hold the compaction tool in place for the return stroke. I even have some 7018 AC rod in my oven...and a 300 AMP AC Hobart transformer welder. Howard