PAW KEYHOLE

I'm using automated equipment and I need setting recomendations for butt welding 0.188 nimonic in a single pass with 0.30 wire. So far my best welds have been at 150-175 amps with a travel speed of 7 ipm, wire feed of 15 ips, arc lenght of 0.080, plasma and shielding gas are both argon. My aim is to get full penetration and a crown of 0.060 apx in a single pass. So far i have attained acceptable penetration but haven't been able to produce a crown, all my coupons have had a concave weld on the surface.

I will appreciate all suggestions, thanks Robotweldor

Are you welding to a certain specification?

Why do you want a .060" crown, that sounds like a lot to me.

Are you putting a bevel on the coupons, or just butting them together? Judging by your amperage, it sounds like your butting them

I welded .125" with PAW, @ 63 amps full penetration with a .030" crown, coupons butted.

Richard

Yes, I'm butting them together, there is no problem with the penetration however I would like to have a crown, so far I would need to put a second pass to get a crown.

A 0.060 crown may be an overkill, maybe a 0.030 is good enough I will let the QA guys decide that. At this point I just want to find a way to produce full penetration and a noticeable crown, then the QA guys will inspect it to MIL-STD-1595.

Today I tried again, looked like I got closer with 175 amps, 15 ipm travel,

I have tried 0.125 stainless steel, just PAW, no KEYHOLE, it was only a trial and it looked good. It is this 0.188 nimonic that I'm having difficulty with.

Suggestions needed!

Thanks to every who has taken the time to read this.

RoboWelder

While I am not familiar with this material, I would say you need the right combination of amperage, travel speed, and wire feed rate.(I know, this goes without saying) Are you able to use less amps? Again I am not familiar with this material, but could you use an Argon/Hydrogen shield in order to be able to reduce the amperage. It sounds as though your too hot thus the filler wants to drop thru. Is your torch standoff no more than needed to get the filler in?

Richard

I did lower my amps today, 125-150. 150 amps at 15 ipm travel produced acceptable penetration and a narrower weld, about 0.065 less than my previous. These settings permitted me to increase wire feed to 30 ipm, but the weld is still under filled. I run into the term "standoff " earlier this morning and I'm glad you have mentioned here also, now since I'm learning the PAW terminology, correct me if I did not get the right definition : STANDOFF is the distance between the material being welded and the torch tip. Isn't? If it is, then my standoff was set at 0.150.

As it pertains to shielding I learned about the argon/hydrogen mix today and is going to be a while before it is available to me. Also I think I have another shielding issue, I was going thru all the consumables that came with the torch and I found only one size end cap it is about 0.600 in diameter. Is this cap big enough to shield the area?

Thanks for your input. RobotWeldor

Hello RobotWelder

Yes, are you using a voltage control to maintain the arc gap (standoff)?

Look at the completed weld, is it contaminated as if there is a lack of shielding?

This material, what cleaning process are you using before welding? Very important, if there are oxides or other contaminates this would give you problems.

Richard