Results 1 to 16 of 16

Thread: How can we reduce cold cracking in weld

  1. #1
    Join Date
    Feb 2017
    Posts
    14
    Post Thanks / Like

    How can we reduce cold cracking in weld

    Hi,

    Hello everyone. I am serving a fabrication shop as pipe groove welder. I want to enquire that how can we reduce cold cracking from a weld metal. Cold cracking is also known as Hydrogen Cracking. We are using two welding procedures SMAW and GTAW on carbon steel base metal. Thanks for your suggestion.

  2. #2
    Join Date
    Oct 2015
    Posts
    2,810
    Post Thanks / Like

    Re: How can we reduce cold cracking in weld

    We need more info on the joint in question.

  3. #3
    Join Date
    May 2012
    Location
    Ontario, Canada
    Posts
    1,438
    Post Thanks / Like

    Re: How can we reduce cold cracking in weld

    We are using two welding procedures SMAW and GTAW on carbon steel base metal.

    What are they

  4. #4
    Join Date
    Feb 2017
    Posts
    14
    Post Thanks / Like

    Re: How can we reduce cold cracking in weld

    Quote Originally Posted by thegary View Post
    We need more info on the joint in question.
    Base metal Low Alloy steel
    Thickness almost 18.26mm
    Outside Diameter 6in NB (schedule 160)

  5. #5
    Join Date
    Feb 2017
    Posts
    14
    Post Thanks / Like

    Re: How can we reduce cold cracking in weld

    SMAW = stick welding or Shield Metal Arc Welding
    GTAW = TIG welding or Gas Tungsten Arc Welding

  6. #6
    Join Date
    Oct 2015
    Posts
    2,810
    Post Thanks / Like

    Re: How can we reduce cold cracking in weld

    With the limited information I will just give you the basics. use low high rod like 7018 and or preheat the weld area to about 250 degrees. GTAW use a 70 S6 series wire and or preheat to 250-300 degrees. If you are doing an open root preheat the joint to 250 Degrees and use 6010 for the root pass then change to 7018. either use rod that is from a newly opened container or from a rod oven.

  7. #7
    Join Date
    Feb 2017
    Posts
    14
    Post Thanks / Like

    Re: How can we reduce cold cracking in weld

    Quote Originally Posted by thegary View Post
    With the limited information I will just give you the basics. use low high rod like 7018 and or preheat the weld area to about 250 degrees. GTAW use a 70 S6 series wire and or preheat to 250-300 degrees. If you are doing an open root preheat the joint to 250 Degrees and use 6010 for the root pass then change to 7018. either use rod that is from a newly opened container or from a rod oven.
    Thanks Sir ! These instructions sound good to me. But please tell me what sort joint information you want ?
    And yes someone suggest me to use E7018 with 65 degrees min pre-heat which facilitates the solidification of hot weld metal with A=1 weld composition.
    I'll try 6010 for root pass and 7018 for next passes and will let you know about the results. Thankyou !

  8. #8
    Join Date
    Oct 2007
    Location
    Near Dayton, OH
    Posts
    2,499
    Post Thanks / Like

    Re: How can we reduce cold cracking in weld

    Delayed Hydrogen cracking occurs when you have 3 factors all present at the same time. High strength steel, high residual stress, and a source of hydrogen. Examples of the last are moisture in the environment, moisture in the welding consumables, contamination in the weld joint.

    If you can eliminate 1 or more of the factors, the delayed hydrogen cracking with not occur. The first two factors are likely outside of what you as the welder can control. That leaves the third factor, sources of hydrogen.

    Thoroughly clean the weld joint and at least 25mm on either side of the weld joint; inside and outside the pipe. Grease, oil, surface coatings, can all be sources of hydrogen.

    As others have suggested preheat the base metal to at least 100C(212F) to drive off any ambient moisture. Maintain this preheat temperature throughout the entire welding process.

    Complete at least 1/3 of the weld deposit before interrupting welding to avoid the possibility of thermal stresses cracking the weld deposit. If you must interrupt the weld, ensure to re-heat the weld to at least 100C before continuing.

    Use only low hydrogen(rated H8 or less) consumables and processes. I do not recommend using EX010 for the root pass if you are already having trouble with delayed hydrogen cracking. EXX10 SMAW rods are NOT low hydrogen consumables. Stay with GTAW for the root pass and SMAW or FCAW for the fill and cap passes. Ensure that SMAW consumables are properly stored in a rod oven according to the manufacturer's recommendations. Typically for E7018 this means around 300F; but check your specific product. Alternatively, if a rod oven isn't available, only use SMAW consumables from a hermetically sealed container and discard any rod left over after being open for 8 hours. Likewise for FCAW consumables; use them from a new, unopened package. Store in a dry environment or discard after 8 hours of exposure. Re-bake SMAW or FCAW consumables only if recommended by the manufacturer and follow their procedures.

    If you take these steps you should no longer have any delayed hydrogen cracking problems. IF crack continues, then I suggest you consider root causes other than delayed hydrogen cracking.
    Last edited by A_DAB_will_do; 02-02-2017 at 01:32 PM.
    Benson's Mobile Welding - Dayton, OH metro area - AWS Certified Welding Inspector

  9. #9
    Join Date
    Feb 2017
    Posts
    14
    Post Thanks / Like

    Re: How can we reduce cold cracking in weld

    Quote Originally Posted by A_DAB_will_do View Post
    Use only low hydrogen(rated H8 or less) consumables and processes.
    Is it necessary to rebake the weld deposits if we are using low hydrogen rods (H8 or less)? I mean after completion of welding without allowing it to cool down below the minimum preheat, the temperature should be raised to about 500 F degrees to help outgassing of weld metal.
    Is there any code which recommends this practice of rebaking to avoid any delayed cracking.
    Last edited by Albert Felix; 02-04-2017 at 03:44 AM.

  10. #10
    Join Date
    Oct 2011
    Location
    Hamlin, NY
    Posts
    1,279
    Post Thanks / Like

    Re: How can we reduce cold cracking in weld

    NO.

    Clean properly prepared joint. Dry low hydrogen rod, ie: 7018. Dry warm pipe. No worries mate.
    Ryan

    Miller Multimatic 200 tig/spool gun/wireless remote
    Millermatic 350P, Bernard/XR Python guns
    Miller Dynasty 350, Coolmate 3.5 & wireless remote
    CK WF1 TIG wire feeder
    Miller Spectrum 375 Xtreme
    Optrel e684
    Miller Digital Elite
    Miller Weld-Mask

  11. #11
    Join Date
    Feb 2017
    Posts
    14
    Post Thanks / Like

    Re: How can we reduce cold cracking in weld

    Thanks Ryan for your precious instructions. We applied the same practice but still we were facing delayed cracking when UT examiner came to examine. As other people said, we should consider joint and rod causes.

  12. #12
    Join Date
    May 2011
    Location
    Andover, Ohio
    Posts
    2,568
    Post Thanks / Like

    Re: How can we reduce cold cracking in weld

    Albert, welcome to the forum.
    Lincoln A/C 225
    Everlast P/A 200

  13. #13
    Join Date
    Feb 2017
    Posts
    14
    Post Thanks / Like

    Re: How can we reduce cold cracking in weld

    Thank you @M J Mauer

  14. #14
    Join Date
    Feb 2017
    Posts
    14
    Post Thanks / Like

    Re: How can we reduce cold cracking in weld

    Quote Originally Posted by A_DAB_will_do View Post
    Delayed Hydrogen cracking occurs when you have 3 factors all present at the same time. High strength steel, high residual stress, and a source of hydrogen. Examples of the last are moisture in the environment, moisture in the welding consumables, contamination in the weld joint.

    If you can eliminate 1 or more of the factors, the delayed hydrogen cracking with not occur. The first two factors are likely outside of what you as the welder can control. That leaves the third factor, sources of hydrogen.

    Thoroughly clean the weld joint and at least 25mm on either side of the weld joint; inside and outside the pipe. Grease, oil, surface coatings, can all be sources of hydrogen.

    As others have suggested preheat the base metal to at least 100C(212F) to drive off any ambient moisture. Maintain this preheat temperature throughout the entire welding process.

    Complete at least 1/3 of the weld deposit before interrupting welding to avoid the possibility of thermal stresses cracking the weld deposit. If you must interrupt the weld, ensure to re-heat the weld to at least 100C before continuing.

    Use only low hydrogen(rated H8 or less) consumables and processes. I do not recommend using EX010 for the root pass if you are already having trouble with delayed hydrogen cracking. EXX10 SMAW rods are NOT low hydrogen consumables. Stay with GTAW for the root pass and SMAW or FCAW for the fill and cap passes. Ensure that SMAW consumables are properly stored in a rod oven according to the manufacturer's recommendations. Typically for E7018 this means around 300F; but check your specific product. Alternatively, if a rod oven isn't available, only use SMAW consumables from a hermetically sealed container and discard any rod left over after being open for 8 hours. Likewise for FCAW consumables; use them from a new, unopened package. Store in a dry environment or discard after 8 hours of exposure. Re-bake SMAW or FCAW consumables only if recommended by the manufacturer and follow their procedures.

    If you take these steps you should no longer have any delayed hydrogen cracking problems. IF crack continues, then I suggest you consider root causes other than delayed hydrogen cracking.

    I applied the same practice using low rated electrodes (H8 and H4). The results were exceptional and outstanding. Thank you Sir for your precious instructions. We no longer have delayed cracking problem in welds. Both fillet and groove welds are now free from cracks.

  15. #15
    Join Date
    Oct 2015
    Posts
    47
    Post Thanks / Like

    Re: How can we reduce cold cracking in weld

    Preheat workpice. And run all passes with 7018. 6010 is not a option in this case.

  16. #16
    Join Date
    Sep 2012
    Location
    Wheatland, Wyoming
    Posts
    468
    Post Thanks / Like

    Re: How can we reduce cold cracking in weld

    I expect the improved welds were likely due to changing to a different weld rod that did not have absorbed water. The baking referred to in earlier post meant to bake the weld rod to dry them out.
    Chris
    Auction Addict

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
  •  
Page generated in 1,635,352,098.38623 seconds with 11 queries