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Thread: Heating rods - specifically 7018, Ovens, Etc?

  1. #151
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    Re: Heating rods - specifically 7018, Ovens, Etc?

    Quote Originally Posted by Welder Dave View Post
    If it was a weld that had to follow a code and it failed a lawsuit could be successful. If it was a non code weld, I think it would be extremely difficult to prove it was solely because of using non heated 7018. They would have to look at a lot of other factors to determine the cause of the failure. It could be a combination of things. Code work x-rays and other test results are kept for 7 years incase of problems down the road.
    I'd be willing to bet that if an unheated 7018 weld on sub-20mm thickness mild steel broke, then it would be either parent metal (so design problem or over-stress in use) OR, the weld wasn't sound to start with - Other, visible problems like porosity, lack of continuity, slag entrapment, undersized fillet length, etc.
    Last edited by Munkul; 09-18-2020 at 11:39 AM.

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  3. #152
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    Re: Heating rods - specifically 7018, Ovens, Etc?

    The misconceptions about pre-heating:

    https://www.thefabricator.com/thewel...eheating-steel
    Dave J.

    Beware of false knowledge; it is more dangerous than ignorance. ~George Bernard Shaw~

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  5. #153
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    Re: Heating rods - specifically 7018, Ovens, Etc?

    Huh. Seven pages and 152 posts for an OP who can probably count how many rods he's burned on the fingers of two fingers.

    So: "FlyFishn"? Or "ClickbaitTrolln"

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  7. #154
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    Re: Heating rods - specifically 7018, Ovens, Etc?

    He's too busy giving electrical and trailer advice to do any welding. I get the feeling he thought if he knew all the theory it would make learning easier. Doesn't work that way in welding. No substitute for burning rods.
    Last edited by Welder Dave; 09-18-2020 at 02:36 PM.

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  9. #155
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    Re: Heating rods - specifically 7018, Ovens, Etc?

    Quote Originally Posted by MinnesotaDave View Post
    Sure, for specific cases it would be done - as shown in my post #133.

    This does not answer why you wrote:


    I maintain there is no such blanket recommendation and PWHT is just for specific cases as approved by the engineer or entity who wrote the WPS.

    Do you disagree? Source? Or are you going to continue with this ridiculous back-and-forth?


    Piping Inspection Code: In-service
    Inspection, Rating, Repair, and
    Alteration of Piping Systems

    API 570
    FOURTH EDITION, FEBRUARY 2016
    PIPING INSPECTION CODE: IN-SERVICE INSPECTION, RATING, REPAIR, AND ALTERATION OF PIPING SYSTEMS

    8.2.4.3 Controlled-deposition Welding Method (Notch Toughness Testing Required)

    The controlled-deposition welding method may be used in lieu of PWHT in accordance with the following:

    a) Notch toughness testing, such as that established by ASME B31.1, Chapter III Section 323, is necessary when
    impact tests are required by the original code of construction or the construction code applicable to the work
    planned.

    b) The materials shall be limited to P-No. 1, P-No. 3, and P-No. 4 steels.

    c) The welding shall be limited to the shielded-metal-arc welding (SMAW), gas-metal-arc welding (GMAW), fluxcored
    arc welding (FCAW), and gas–tungsten arc welding (GTAW) processes.

    d) A weld procedure specification shall be developed and qualified for each application. The welding procedure shall
    define the preheat temperature and interpass temperature and include the post-heating temperature requirement
    in f(8). The qualification thickness for the test plates and repair grooves shall be in accordance with Table 3.The
    test material for the welding procedure qualification shall be of the same material specification (including
    specification type, grade, class and condition of heat treatment) as the original material specification for the repair.
    If the original material specification is obsolete, the test material used should conform as much as possible to the
    material used for construction, but in no case shall the material be lower in strength or have a carbon content of
    more than 0.35 %.

    e) When impact tests are required by the construction code applicable to the work planned, the PQR shall include
    sufficient tests to determine if the toughness of the weld metal and the heat-affected zone of the base metal in the
    as-welded condition is adequate at the minimum design metal temperature (such as the criteria used in ASME
    B31.3). If special hardness limits are necessary (for example, as set forth in NACE RP 0472 and MR 0103) for
    corrosion resistance, the PQR shall include hardness tests as well.

    f) The WPS shall include the following additional requirements.

    1) The supplementary essential variables of ASME Code, Section IX, Paragraph QW-250 WELDING VARIABLES, shall apply.

    2) The maximum weld heat input for each layer shall not exceed that used in the procedure qualification test.

    3) The minimum preheat temperature for welding shall not be less than that used in the procedure qualification
    test.

    4) The maximum interpass temperature for welding shall not be greater than that used in the procedure
    qualification test.

    5) The preheat temperature shall be checked to assure that 4 in. (100 mm) of the material or four times the
    material thickness (whichever is greater) on each side of the weld joint will be maintained at the minimum
    temperature during welding. When the weld does not penetrate through the full thickness of the material, the
    minimum preheat temperature need only be maintained at a distance of 4 in. (100 mm) or four times the depth
    of the repair weld, whichever is greater on each side of the joint.
    PIPING INSPECTION CODE: IN-SERVICE INSPECTION, RATING, REPAIR, AND ALTERATION OF PIPING SYSTEMS 67

    6) For the allowed welding processes in Item c, use only electrodes and filler metals that are classified by the filler
    metal specification with an optional supplemental diffusible-hydrogen designator of H8 or lower. When shielding
    gases are used with a process, the gas shall exhibit a dew point that is not higher than –60 F (–50 C).
    Surfaces on which welding will be done shall be maintained in a dry condition during welding and free of rust,
    mill scale and hydrogen producing contaminants such as oil, grease and other organic materials.

    7) The welding technique shall be a controlled-deposition, temper-bead or half-bead technique. The specific
    technique shall be used in the procedure qualification test.

    8) For welds made by SMAW, once filling is completed do not allow the weldment to cool below the minimum
    preheat temperature. As well, raise the weldment temperature to 500 F 50 F (260 C 30 C) for a minimum
    period of two hours. This assists out-gassing diffusion of any weld metal hydrogen picked up during welding.
    This hydrogen bake-out may be omitted when H4 filler metal (such as E7018-H4) is specified.


    point 8 answers your questions and also your question about E6010 rods
    Last edited by denlow60; 09-18-2020 at 05:15 PM.

  10. #156
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    Re: Heating rods - specifically 7018, Ovens, Etc?

    Quote Originally Posted by denlow60 View Post
    8) For welds made by SMAW, once filling is completed do not allow the weldment to cool below the minimum
    preheat temperature. As well, raise the weldment temperature to 500 F 50 F (260 C 30 C) for a minimum
    period of two hours. This assists out-gassing diffusion of any weld metal hydrogen picked up during welding.
    This hydrogen bake-out may be omitted when H4 filler metal (such as E7018-H4) is specified.


    point 8 answers your questions and also your question about E6010 rods
    Wow, 500F for two hours. On a big pipe, that must require a big heat source, especially in wind. How is this typically done in the field? What heat source is used?

  11. #157
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    Re: Heating rods - specifically 7018, Ovens, Etc?

    Quote Originally Posted by Kelvin View Post
    Wow, 500F for two hours. On a big pipe, that must require a big heat source, especially in wind. How is this typically done in the field? What heat source is used?
    Resistive heating elements / HF heating elements

  12. #158
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    Re: Heating rods - specifically 7018, Ovens, Etc?

    Quote Originally Posted by snoeproe View Post
    I’ve never seen a pipe fitter welder post heating his/her 6010 root pass. You just dont see that. Nor is it necessary.
    Low carbon steels don’t require post heat. Pre heat is a good idea to drive out hydrogen on thicker steels and while working in cold temps.
    you do not need to preheat less than 0.40 CE.
    but on this list of pipeline almost everything is more than 0.43 CE or more.
    if you don't preheat than you are more likely to get cold cracks

    List below in the pdf


    API SPEC 5L -2012.pdf
    Last edited by denlow60; 09-18-2020 at 08:18 PM.

  13. #159
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    Re: Heating rods - specifically 7018, Ovens, Etc?

    Denlow60, you used a lot of words to admit that your initial blanket statement of PWHT for anything not welded with low hydrogen rods was false.

    Again, you used specific examples instead of backing up your statement.
    Dave J.

    Beware of false knowledge; it is more dangerous than ignorance. ~George Bernard Shaw~

    Airco 300 - Syncro 350
    Invertec v250-s
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    Tried being normal once, didn't take....I think it was a Tuesday.

  14. #160
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    Re: Heating rods - specifically 7018, Ovens, Etc?

    From what I see in post 155, this looks like it is for creating a weld procedure qualification using a controlled deposition welding technique.

  15. #161
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    Re: Heating rods - specifically 7018, Ovens, Etc?

    Quote Originally Posted by MinnesotaDave View Post
    Denlow60, you used a lot of words to admit that your initial blanket statement of PWHT for anything not welded with low hydrogen rods was false.

    Again, you used specific examples instead of backing up your statement.

    well if you have no understanding of welding and what is involved. then I can't help you. either you are blind or you must be right.
    I'm done with the back and forth.

    look for someone else who understands welding and well-realized subjects to communicate on your level.

  16. #162
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    Re: Heating rods - specifically 7018, Ovens, Etc?

    To me most on post just do ag type welding. Ag type of welding does not need to meet any spec's
    There so many industries that have there own spec's for welding (building, oil field , ships, tanks, pressure tanks , pipe lines & more) that you for know for that industry and will want to use a different rod.

    Dave

    Quote Originally Posted by denlow60 View Post
    well if you have no understanding of welding and what is involved. then I can't help you. either you are blind or you must be right.
    I'm done with the back and forth.

    look for someone else who understands welding and well-realized subjects to communicate on your level.

  17. #163
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    Re: Heating rods - specifically 7018, Ovens, Etc?

    Quote Originally Posted by denlow60 View Post
    well if you have no understanding of welding and what is involved. then I can't help you. either you are blind or you must be right.
    I'm done with the back and forth.

    look for someone else who understands welding and well-realized subjects to communicate on your level.
    Lol - funniest response I've seen in a while
    Dave J.

    Beware of false knowledge; it is more dangerous than ignorance. ~George Bernard Shaw~

    Airco 300 - Syncro 350
    Invertec v250-s
    Thermal Arc 161 and 300
    MM210
    Dialarc
    Tried being normal once, didn't take....I think it was a Tuesday.

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  19. #164
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    Re: Heating rods - specifically 7018, Ovens, Etc?

    I think he's right and he communicates with me and pretty much everyone else just fine. LoL

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