I have some details to weld up at work. The surfaces need to be built up .250". The surface is .75 wide x 4" long. Are there any tricks for doing this with a tig welder? It's all I have access to so stick welding is out. It just seems to take forever and a day to do this and I feel like I'm putting too much heat into the overall piece. The material is A2, I'm pre-heating also. Thanks for the help. I can try to post a pic later.
Tig welding question
- Thread starter moto367
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laser3kw
Well-known member
as an option, could you weld another piece of material on to it and forgo the build process?
APEowner
Well-known member
That's what I'd do. if it need to be solid for a machining operation afterwards I'd still do that but I'd bevel the edges so that the mating pieces met at the points and then fill the resulting v-grooves.
Robert Hall
Well-known member
If you are trying to build up an area, that is a huge amount to do, and yes, your HAZ without decent heat control will anneal the metal.
Using a lot of heat to build up is not the way to do it either. Use enough heat for proper fusion but no more. More heat makes the weld lay flat. If you want to build, you need to use less heat.
Pics would certainly help.
Using a lot of heat to build up is not the way to do it either. Use enough heat for proper fusion but no more. More heat makes the weld lay flat. If you want to build, you need to use less heat.
Pics would certainly help.
dr_clyde
Well-known member
Depending on the machine, attaching an arc stinger would be pretty easy. TIG and stick are fundmentally the same machine.
Attaching a plate would be the cleanest way.
Either way. If you must build up with a TIG , use a large diameter filler, run lay wire technique and just push the rod in steadily, overlapping beads by about 1/2 a bead.
Attaching a plate would be the cleanest way.
Either way. If you must build up with a TIG , use a large diameter filler, run lay wire technique and just push the rod in steadily, overlapping beads by about 1/2 a bead.
Is this a die or similar wear surface being A2 tool steel? It's going to take some time, but certainly not impossible. Keep the heat down, especially between passes. Don't go crazy with a large diameter filler as it will take more heat to get properly fused into the base. Overlap to avoid gaps in the build up. Pretty simple to do actually. Make sure to over build if they need to machine sharp corners on it. What filler are you using?
Thanks for all the replies. Here is a pic (sorry about the quality). What this is is a cutting edge where the white paint line is. The surface is acting as a slide for the mating piece to run on. Think of this as scissors. I like the idea of welding a piece on but I don't know if it would hold up to the scissor action. I guess I could try it and see. What really ***** is I have about 20 of these things to do. Rather than bring them to me when they wear one out they threw them in a box until they were out! 
Attachments
HellaFab
Well-known member
set it up in a vise on a bench, do a pass on it and then onto the next one while that cools.
Charge by the hour.
Charge by the hour.
JESTERxHEAD
Member
Not sure of your application, so if you have 20 or so of these blocks that wear out easily in that little area and you have to build up to repair that surface it sounds like you would be better off getting a hold of the tool designer and re-designing it so there is a recessed insert that's bolted in and easily replaced out of more durable material than A2. But if you absolutely need to fix these I would just build up the weld.
Techie1961
Well-known member
I might go with something a bit different for tool steel. I would preheat so it is nice and hot and maintain it while you are welding. Keep hammering on it (peining the welds) while you add more passes and then have the whole thing deep stress relieved and then harden it back to where you want it to be.
APEowner
Well-known member
Now that I know the application I think a bolt on edge would be a better fix. It's clearly a wear point that's going to need to be serviced again. I'd weld up one to get them going again and then fix the others with a bolt on edge.
laser3kw
Well-known member
^^^^ most better option
bolt on wear items
Chuck122
Well-known member
Plus unless you have a2 tig rods, they will wear quickly. How about hardfacing. Not that I have any experience with the process but it could be helpful. As others have pointed out you can stick with your tig. The screw-in wearable inserts are a good idea assuming the client is willing to. Perhaps there can't be screw heads on the surface in this application ?
If I were you I'd just weld the **** out of it if that's what the customer asked and not take it upon myself to reengineer their ****. Perhaps it is more cost effective for them(perhaps for you too) to hire a welder(you) every once in a while to build it up.
If I were you I'd just weld the **** out of it if that's what the customer asked and not take it upon myself to reengineer their ****. Perhaps it is more cost effective for them(perhaps for you too
) to hire a welder(you) every once in a while to build it up.welder4956
Well-known member
You can clamp it to a block of aluminum to absorb the heat and keep it cooler. A2 is an air-hardening alloy and you can expect the base metal underneath the weld to harden to around Rockwell C60 or more. This is much higher than Stellite, but you might go with a tungsten carbide wearfacing wire to make them last longer. TIG is actually a good way to do this job, so don't feel bad that it is all you have available.
JESTERxHEAD
Member
A2 is most stable at 56-58 HRc A block of that size with a torn up edge on it like that is most likely at 55-57 range. A2 when it gets anywhere at or above 60 HRc it will break off. And I wouldn't use any heat sink when welding this. the key is to bring it to an exact temp and cool it slowly. Aluminum will make the weld inconsistent. IMHO.
OP- if you plan on welding this in the hardened state I'd suggest you preheat the block 25 degrees F below the original tempering temperature (you dont want to draw the material back any further) maintain at least 300 deg. F. when welding then cool to 150 deg F. after welding. When done toss it back in the oven at 25 degrees below original tempering temp. (that is to reduce the stress without making the material softer) If the part is 57-58 HRc I would probably guess it was tempered between 900-700 deg. F. Knowing the exact hardness will define your temperatures.
If you have to heat the part up past the original tempering temp then you will make the wear point softer. Also, you should only use air hardening steel filler rod.
No sweat brother, A2 is actually a very easy tool steel to weld compared to some.