small pitting problem while using spray arc
RSS | Subscribe | Contact Us | Advertise | About Us
Results 1 to 11 of 11
  1. #1
    Join Date
    Oct 2018
    Location
    Montana
    Posts
    8

    small pitting problem while using spray arc

    Hello ive been welding some 150 ton hydraulic rams/cylinders that run 10,000psi for our company for around 3 years now. I only do around 10 a year. I use a millermatic 350p, LA100 wire .045, and was using a 75/25 mix. I decided to switch to 90/10 so i could use spray arc mainly for this application. On the first 2 ive done, ive had a decent amount of small pitting and have been having to grind and re-weld. The tubing is made out of 4140 Q&T i believe. I basically weld a large threaded cap onto the end of the tube that has a big v-groove, and i do anywhere from 3-5 passes. Any reason the 90/10 would cause this? The 75/25 did this every once in a while, but I'm just making sure that the 90/10 isnt the problem. Name:  WP_20160512_003.jpg
Views: 340
Size:  120.4 KB
    Name:  WP_20160512_001.jpg
Views: 337
Size:  57.4 KB

  2. #2
    Join Date
    Jun 2012
    Location
    Ct
    Posts
    2,003

    Re: small pitting problem while using spray arc

    Any pics of the pitting? I just dabble in spray arc myself, not enough experience with it to really be of any help

  3. #3
    Join Date
    Oct 2018
    Location
    Montana
    Posts
    8

    Re: small pitting problem while using spray arc

    next time i will try to take a few pics of the pitting, its real small, but at times can be throughout a few inches or so. I'm starting to think it has something to do the the type of steel. Being 4140 i believe its pretty high carbon, so maybe that has something to do with it, since i weld a few similar applications as well, but using a more mild steel like 1018 and i never have pitting. I also pre-heat these with a torch before hand, not sure if that makes a difference.
    Last edited by john@duff; 12-05-2018 at 03:05 PM.

  4. #4
    Join Date
    Dec 2010
    Location
    SoCal-LA
    Posts
    8,793

    Re: small pitting problem while using spray arc

    I just got done with a good sized job using 90/10 gas and ER70-S6. Went right into spray, and if my standoff was too long it would bubble. I figured it was the intense heat in the spray arc. I kept the standoff short and cured the problem.

    Perhaps bigger nozzle and more gas would help?
    Weld like a "WELDOR", not a wel-"DERR"
    MillerDynasty700DX,Dynasty350DX3ea,Dynasty200DX,Th ermalArc400GTSW,LincolnSW2002ea., MillerMatic350P,MillerMatic200withspoolgun,MKCobra Mig260,Lincoln SP-170T,PlasmaCam/Hypertherm1250,HFProTig3ea.

  5. #5
    Join Date
    Oct 2007
    Location
    Vandalia, Ohio near Dayton
    Posts
    2,486

    Re: small pitting problem while using spray arc

    Quote Originally Posted by shovelon View Post
    I just got done with a good sized job using 90/10 gas and ER70-S6. Went right into spray, and if my standoff was too long it would bubble. I figured it was the intense heat in the spray arc. I kept the standoff short and cured the problem.

    Perhaps bigger nozzle and more gas would help?
    X2. intermittent traces of what you call pitting could be a sign you're right on the verge of inadequate shielding gas coverage. A picture of what you describe would be really helpful in confirming the cause of the problem.

    But I think shovelon's advice is a good place to start.

    Just switching from 75/25 to 90/10 shouldn't cause any problems.
    Benson's Mobile Welding at your worksite or place of business. Serving Dayton, Ohio and the surrounding metro areas.
    AWS Certified Welding Inspector (#XXX10731) and Certified Welding Educator (#XXX1008E)

  6. #6
    Join Date
    Oct 2018
    Location
    Montana
    Posts
    8

    Re: small pitting problem while using spray arc

    Im running 25-30 cfh for my gas on my millermatic 350p, you would think that would be enough right? But it is possible I had the tip a little far off at times seeing how I am just getting into spray, and using one hand to turn my chuck while running the gun with the other. I only welded two cylinders yesterday, but if it happens again on the next set i weld i will definitely take some pictures. Basically looks like a handful of small pinholes.

  7. #7
    Join Date
    Feb 2015
    Posts
    421

    Re: small pitting problem while using spray arc

    On the 350p in pulse spray it seems to run hot and wants good gas coverage. Try going down a guage on the thickness settings if you are moving slower. I have a 350amp Tweco velocity gun and run the tip flush with the bigger nozzle, gas about 35 and run a tighter arc on the machine settings. I think I have a 3 second pre flow. I push only with a very slight angle, to much and it will pit on the backside. Hope some of this will help you.
    ESAB Rebels 215/235, Hypertherm 85, 45xp, Miller 350p, Synchrowave 350 LX, Thermal Arc 185, Everlast 255EXT, TD 60i

  8. #8
    Join Date
    Jun 2016
    Location
    Not there
    Posts
    2,772

    Re: small pitting problem while using spray arc

    Lose the LA100 and get a roll of S3. No S6 either. The 90/10 shouldn't be a problem..........unless the idiot it the mixer is named Kutk-Roy
    Last edited by Bonzoo; 12-06-2018 at 07:09 AM.

  9. #9
    Join Date
    Oct 2018
    Location
    Montana
    Posts
    8

    Re: small pitting problem while using spray arc

    i will definitely try upping the gas a little, and work on my tip angle, i do catch myself angling it at times on long welds while turning my chuck with my off hand. I think those two things should help out. I will also look into this other type of wire as well. When i first started welding these a few years ago I had terrible pitting, and i believe it was er70, so i was lucky enough to get ahold of the guy that welded a few of these for us before i stated and he said to use the LA100 and that he had the best luck with it. But that doesnt mean he didnt try everything. Thanks for all the input guys!
    Last edited by john@duff; 12-06-2018 at 10:10 AM.

  10. #10
    Join Date
    Mar 2013
    Posts
    976

    Re: small pitting problem while using spray arc

    Since you're welding on alloy steel I would be a little careful with the selection of wire and how you use it.

    http://weldinganswers.com/how-to-weld-4140-steel/

  11. #11
    Join Date
    Oct 2018
    Location
    Montana
    Posts
    8

    Re: small pitting problem while using spray arc

    Thanks for putting that website on the thread. I ended up posting to that thread and they told me to continue to use the la100 for my application. Learning a little bit everytime I use this forum. Thanks again!

Tags for this Thread

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
RSS | Home | Penton Media | Contact Us | Subscribe | For Advertisers | Terms of Use | Privacy Statement