Hi Ron
Are you using the ER80S-D2 for better impact resistance, or is there another good reason for overalloying your filler?
Basically, to weld spray transfer you are looking at a shielding gas with less than 20% CO2 present. Typically around 8 - 18% CO2 in Argon should do the job you are looking at.
This requirement is not to get a high tensile strength, but rather to ensure that you are getting spray transfer. Your filler will in any case be much stronger than your base metal. You will just have to perform a PWHT to get good properties.
Regards
Niekie Jooste
Fabristruct Solutions
Hi Nieki;
The reason I am using ER80S-D2 filler metal is that the weld procedure quals have been failing in the base metal. There is a PWHT after welding and I have been using ER70S-3 filler metal. After Talking to National Standard, ( that is the brand of filler wire we use) they suggested I use this dual grade wire. They suggested I continue to use the 98/2 Argon Oxy.mix we currently use with our steel wire but I also want to experiment with a argon CO2 mix. Thanks for the guide lines on CO2 I will probably go with a mix that is in the 8-10% range.
Ron B
There won't be much change in alloy content/strength in switching from 2% oxy to 5-10% CO2. As far as oxidation, I have heard oxygen is as potent an oxidizer as 3-5% CO2 depending on the source. So it is probably about a wash. ER80S-D2 is probably a good choice to keep the strength of the weld metal up after PWHT, but another one to consider would be ER70S-6. It has about the same range for C and Mn as D2, but no moly. It could be more available and economical though. You said though, that your procedure quals have been failing in the base metal. Did you mean weld metal since that is what you are looking at changing?
Sorry about that I did mean the weld metal not base metal.
hi Ron,
At my job we weld alot of 516-70 plate (for asme tanks).
The best gas mixture I have found is 98/2 argon /ox. mix .
I have tried argon/co2 mixes(90/10 & 95/5) as well as trigon mix(ar/ox/co2). and these did not perform no where near as well as the ar/ox mix on our full penetration welds. If you clean off the mill-scale and set your machine properly you will have very min. splatter or sil .deposits especially with the 70s-6 wire.
good luck,
mikew
Hi mikew;
Thanks for the feed back, our choice of gas here is 98/2 for all steel wire. I am going to use ER80S-D2 filler metal because of the PWHT after welding but for a comparison on tensile strengths I am doing a test plate with argon Co2. We have never used any CO2 mixes here and I have tried one tri mix and that didn't impress me either. From the feed back I am getting it sounds pretty like six of one and half a dozen of another.
Where are the welds cracking? Center line? Toes?
kam
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