Welding Problem #1

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dgoddard
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Welding Problem #1

Post by dgoddard »

I have at least a couple of problems but I am going to post them separately
Background Info.
Equipment............... Hobart Handler 187
Operating modes.......Flux core or MIG modes
Gas on hand ............ Argon 75% CO2 25%
Substrate.................. Hot Rolled Steel
Weld ........................ Hard Facing
Weld Alloy ................ Armor Wear (particular claim impact and wear resistance primary use digging teeth)
Application mode ...... Wire feed "Flux" core wire 0.035 dia
Experience level ....... To say that I am a duffer borders on praise.

I wanted to do some hard facing and ended up having to buy a 10 lb coil as it was the smallest available and was a special order to boot. I got it from my local AIRGAS dealer. They claimed to have little information on its use but advised me to call up a particular supplier and specifically ask for help from a woman that they said was really knowledgeable about welding issues. I did, and her advice was that it should go on pretty normally but that at least a little bit of preheat was pretty much necessary and at least desirable. Also she was adamant that since it was flux core it was necessary to use a negative electrode polarity (DCEN) and no shielding gas would be necessary.

My first jobs with it were experimental and not too important but that stuff was awful to use. I finally got around to a project of some importance. I was making a subsoil Plow (AKA single tine ripper) and was hardfacing the "foot" on the end of the shank prior to welding to the shank. It is 1 inch wide Hot rolled steel. After changing the tip, covering the gas ports, reversing the polarity to DCEN I was ready to go. I tried laying down a bead or two, and they were so full of blow holes they could only be described as steel foam. I ground them off and tried again, same results, ground them off and held the tip closer, better but still too crapy to use.

I decided that something had to be wrong. I am no great shakes as a welder but those beads were the worst I had ever laid down. Even on a bad day when I have to grind out half of my weld beads, I don't make beads that bad. So despairing any hope of success I decided to try something.... Anything.... and see if I could improve the results. I put the polarity back to DCEP and turned the gas back on. I then proceeded to lay down about 4 lineal feet of flawless beads. On a good day, I am not that consistent! Note please I said "flawless" Not "uniform" or "straight" (I am a self professed duffer after all). ! The beads were pretty much 1/4 inch beads but might vary in thickness with an occasional missed spot that I had to go back and do over. BUT! they were utterly without blow holes and showed good penetration and adherence to the parent metal. I did check the wire by cutting it off and touching the end to a grinder and the presence of a small core is confirmed, though it looks smaller than I expected based on what I know of ordinary flux core. There was a thin coating of slag on the beads but it came off very easily with a wire wheel on my angle grinder

Now:
-- The welding "expert" was strongly recommended by my local dealer at solving problems and seemed very knowledgable and allegedly is an accomplished welder heerself. She was quite clear and emphatic that that the flux core "ARMOR WEAR" hard facing wire was going to require DCEN and no shielding gas. There is no chance that I misunderstood what she was telling me. I speak enough welding lingo to understand and I asked the question various ways just to make sure that I had it right. It was to be the opposite polarity of what I used for mig welding and the same polarity listed on the machine for flux core, and no gas was needed.

So what gives:
-- Was the expert just not so expert.
-- Do I need to check to see if my welder is wired internally so the polarity is backward. Ordinary solid or flux core wire seems to work reasonably.
-- Does anyone here have any experience with hardfacing wire welding
-- Does anyone here have any experience with the specific alloy called "ARMOR WEAR"

Any relevent comment or suggestion will be appreciated.
I never met anybody that I couldn't learn something from.
redneckalbertan
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Re: Welding Problem #1

Post by redneckalbertan »

http://www.hobartbrothers.com/product-d ... 26trade%3B

Reading the manufacturers site I would say that your expert was quoting what is written by the manufacturer.

I have no experience with this particular wire, but have limited experience with hard facing wires and more with tubular wires in general. Except for playing with hard facing wire a couple time when I had the opportunity, all of the hard facing has been done with rods.

I have never had good results with gassless wires. Especially with a small tubular wire, like this .035, it can be hard for manufacturers to get good even distribution of the flux inside the wire. Giving less than superb results.

I would be very surprised if your welders polarity was marked wrong by the manufacturer.

Reading the data sheet on this wire, it says the wire weld best with EN but works with EP satisfactorily. I would (with gas) switch the machine back to straight polarity and see how it does.
hammermill
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Re: Welding Problem #1

Post by hammermill »

It says it spray welds which I see as code for run it hot. Also extra shielding by running gas should help.

That said all the hardface I have done is stick
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warmstrong1955
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Re: Welding Problem #1

Post by warmstrong1955 »

I haven't used that particular wire either, and none that small diameter. Most of what I laid on was either Stoody or Lincoln. Some self shielding, some not. Some straight, and some reverse.

Trick to hard-facing, is to get enough penetration to where it will stick, but not so much where you dilute it with the parent metal, and don't get as hard of a bead. That's why they recommend straight polarity on some wires & electrodes. You can run reverse, it will just have more dilution. Depending on the parent metal, you may have to to make it work.

What Hammer said....more heat helps.

As far as using gas, we received some Eutectic wire we got for a test, that was supposed to be self shielding. Talk about ugly. We turned the gas back on, and it was fine. I don't know if that effects the hardness of the bead at all, but without the gas, it was cross-checking and a smack with a hammer could break of pieces of bead.

I too have never done well with self shielding wires, with the exception of hard facing wires.

Bill
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steamin10
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Re: Welding Problem #1

Post by steamin10 »

I have limited experience with hard facing materials. Some applications are plow points for wear in the soil, patterns for bucket protection for stone and pavement materials, and some applications for wear resistance in metal to metal contact areas where sheet or meal scraps bear on edges or chutes.


For the most part, I prefer stick with a medium preheat, around 3-400*, that lessons cracking, and promotes penetration. With the advent of wire machines, and extensive wire types, the wires I have used were not my choice but provided by management. Most complex alloy cored wires I used benefited from common gas cover, and heating of the substrate. In longevity, we went back to stick because it failed less to cracking over time, and allowed more heat at installation. Teh wire applications did not fair so well, I suspect the beads were cooler and smaller, allowing hidden stresses in the beads, that cracked more. Experiments with post heat to red, did not seem to matter.

I dont remember the brands over time, as there were many trials. But my experiences seem to follow others in this vein of work.
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redneckalbertan
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Re: Welding Problem #1

Post by redneckalbertan »

What did you end up doing for the project and how did it work?
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dgoddard
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Re: Welding Problem #1

Post by dgoddard »

redneckalbertan wrote:What did you end up doing for the project and how did it work?
Well as I said in my opening post, I laid down 4 lineal feet of the weld with very nice beads by using DCEP and Argon 75% CO2 25%. That was the hard facing part of the project! Based on warmstrong1955's comment, I saw no cross checking and I tried smacking it with a hammer and with a 4lb cross peen hammer was able to but a tiny dent in the hard facing but nothing shattered off or seemed degraded. I have put the tool into use,
SEE AT:http://www.chaski.org/homemachinist/vie ... 12&t=99704 And so far no problems.

I suppose I might try DCEN with Argon 75% CO2 25%, but I do not know what I would look for unless something obvious happened. My entire interest in ever using ordinary flux core wire is when the metal has rust that is difficult to remove because of how the part is shaped or if I have to weld outdoors where there is a breeze. But most of my welding is done indoors where wind is not an issue. Of course the fact that the substrate in this case is just hot rolled steel may be accounting for how well the stuff sticks, And maybe if there were a different substrate I would have to use DCEN.
I never met anybody that I couldn't learn something from.
redneckalbertan
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Location: South Central Alberta

Re: Welding Problem #1

Post by redneckalbertan »

I thought you had more hard facing to do, that's why I asked. The straight polarity will have less penetration than reverse polarity so there will be less dilution of the hard facing material with base material. Probably little to no visual difference in the finished product, it may sound and look different while welding because of the opposite direction of electron flow.
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