316L indications

By 123stickweld Date 04-03-2006 14:42

I`m needing any info concerning best way to weld SS overlay in ring groove.I`m using 316L .045 wire with gas mix 75% argon & 25%helium and welding ok but after machining , pt part and have indications some severe others minor. Using closed area to weld,welding gun only used for SS ,part cleaned with MEK ,grinding with stainless steel wheel, brushing with SS wire wheel,changed drive rollers with ones used only when welding SS, new gloves, careful part is free grinding dust,oxide buildup. The material i`m welding on is 4130, preheat is between 350 & 450 degrees,130/140amps,26/30 volts,12/14 ts,process is gmaw-p. My variables are set so to be able to pass chemistry testing .Do you think my problems are that maybe i`m getting too much base material mixed inwith the SS while welding and causing the indication? If so any suggestions would be helpfull.Thanks 123stickweld

By ssbn727 (*****)

Date 04-04-2006 02:07

Hi 123stickweld!

Too much dilution is definitely undesirable!!!
This also depends on quite a few factors...
I have some questions:

Does that MEK have any chlorine in it and is the surface of the 4130 clean and free of any scale???

2. Do you first apply a "buttering" (*309L or P5-309LMo) layer on the 4130 before you overlay with 316L???

3. Are you oscillating your beads as opposed to running stringers in order to achieve less dilution???

4. What is the thickness of the 4130 and why are you preheating to such a high temp and what is your interpass temp???

5. Are you performing Post weld heat treatment???

6. If you're using 25% helium (*increases the arc energy in order to increase fluidity and arc stability which may enable a significantly increased travel speed) in your shielding gas, are you moving fast enough??? Because if you're not moving any faster than you would with a Ar+1-2% O2 or Ar+2-3% CO2 shielding gas mix, then your insufficient travel speed may be the cause of excessive dilution...

7. You say your travel speed is 12-14 inches? per minute???
Is'nt that a bit slow for overlay with 25% helium even if you're oscillating (Weaving) the bead 1" wide???

Anywho, that's enough questions for today but, it seems to me that the procedure needs to be tweaked a bit in order to achieve successfull overlay welding with dissimilar metals such as 316L on to 4130... My Suggestion is to talk to Chuck, otherwise known as "Cmeadows" in this forum because, he's really one of the best resident Stainless steel experts here...
We look foward to your response.

These *facts are referenced from: Avesta Welding's
"The Avesta Welding Manual" - Practice and products for stainless steel welding. ISBN 91-631-5713-6

Respectfully,
SSBN727
Run Silent... Run Deep!!!

By - Date 04-04-2006 13:15

You've covered it all. Very good answers. Regarding the preheat, I think it is right in line with a 4130 if the thickness is 0.6"-2.0". Otherwise, the minimun should no less than 300F. I believe this all boils down to a cleanliness issue. There is nothing more I would add to your response.

Chuck

By 123stickweld Date 04-04-2006 22:24

Hi SSBN727 . The part is machined and free of any scale.2.There is no buttering our procedure was qualifide only using gmaw-p .3.There is no oscillating ,welded running stringers, passed chemistry.4.Thickness of 4130part is 2.5 inches ,my interpass is 425degrees.5.Yes we do post weld heat treatment.6.Have not tried that mix of gas just used what procedure called out .7.Sorry gave wrong travel speed 18/20 ipm. is correct one.No oscillating just stringers.I need to ask about some ? I did`n`t know how to answer them.The ring groove is a seal groove on a flange machined to an API 6A spec. the groove is machined where oscillating is not possible ,reason why stringers are used instead .Thanks for your input 123stickweld.