WPS

  1. paul teggart Member

    Messages:
    19
    Location:
    Dungannon, county Tyrone, Northern Ireland
    Hi all,
    I'm (trying) to write a preliminary welding procedure for a butt weld for my employer. Once written I will send a welded sample away for destructive testing at Exova Scotland, I'll also use it to qualify the welders on the shop floor with it. I haven't actually done this before, so if any of you have written a procedure for a butt weld before could you please look at the picture and advise my where I've went wrong, which no doubt I have. I wrote this on a trial version of weld assistant but there's nothing that automated, it just generates a template based on what you've put in there.

    Any advice is greatly appreciated guys, and many thanks in advance.
     
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  2. EAZEE

    EAZEE Member

    Messages:
    215
    Location:
    Kettering, Northants
    Hi Paul,

    Am I right when you are using no root gap? b = 0? Are you using a backing strip? If not then there should be a gap to allow penetration through. It's hard to get a gauge of this as there is no root face also. A normal butt weld would have a root face and root gap. The root would be done at a lower voltage then sprayed over in consecutive runs. This is my opinion only. I know this one is for TIG but it explains what I mean .
    [​IMG]
     
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  3. Brad93

    Brad93 M J B Engineering

    Messages:
    6,062
    Location:
    Essex
    Your wirefeed speed / voltage for the root is well off. Should be an open root. 100-120A.

    The gas flow rate is well off too. needs to be 15-18lpm at least
     
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  4. Mid Wales welder

    Mid Wales welder Welder coding and NDT services

    Messages:
    551
    Location:
    Powys, U.K.
    Hi Paul,
    What job is it you are doing this for? Is it for structural or are you needing to work to any other codes? Do you have any other procedures in place?
    As said above, you should have a root gap and face or at least a gap if your using a backing strap. How thick is the material, it says 10mm in one place and 15mm in another? Either way you wouldn't do that in 3 runs. Your gas is stated as I1 which is pure argon, it should say an M number e.g M14, M24, M26 etc. Your settings aren't bad for the full/cap, maybe travel just slightly faster 350mm/min and have your wire at 14-15mpm. For the root, this all depends on the gap, root face, bevel etc, but I usually go for 60 degree bevel, 1mm root face, 2-3mm gap, 160-170amps, 19-20volts, a nice short ttwd and just adjust my torch angle accordingly to give either more or less penatration.
    I have done a lot of these butt weld procedures, so any other questions you have I'm happy to help!
     
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  5. Brad93

    Brad93 M J B Engineering

    Messages:
    6,062
    Location:
    Essex
    Is that with a backing strap? I usually aim for 120-150A on a open root?
     
  6. Richard.

    Richard. Member

    Messages:
    18,134
    Location:
    Cambridgeshire
    I can't see the picture but a wps needs to have a criteria to meet. You haven't specified what the weld actually has to do or be. You also haven't specified the form of testing required to get it to pass or fail.
    You set the criteria as your the guy writing it. Ideally to do this you should be qualified. For example if it needs to be full fusion only then it's tested to either DT macro/nick break or NDT UT
    If it's a test of joint strength then it's DT face/root and side bends
    Toughness DT charpys.
    You need to produce these joints under your own wps and test them repeatedly till you get consistent results before shelling out big money to have it qualified.
    What I'm saying is your wps must be written to accommodate the actual test requirements and the test requirements must be set to accommodate the weld requirements
    Quick example. You (welding engineer) calculate a particular welded joint is going to be put under 3 tonnes of pressure. You decide the test best to describe the loading is a side bend test. You also decide it's paramount for 100% weld fusion with a 2mm max cap and root and there for you also require a macro test. Send your samples and criteria to be tested. If it meets the criteria then there is only you to blame if it falls apart as you set the goal posts. Dodgy business if you don't know what your doing or calc things up wrong.
     
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  7. Mid Wales welder

    Mid Wales welder Welder coding and NDT services

    Messages:
    551
    Location:
    Powys, U.K.
    Said perfectly :thumbup:
     
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  8. Mid Wales welder

    Mid Wales welder Welder coding and NDT services

    Messages:
    551
    Location:
    Powys, U.K.
    No that's open root, with a backing strap I would just use the same setting all the way out. Butt welds are so finicky, the slightest change in prep means different settings. I would do 120-150A if the root face was smaller or the gap bigger. I usually find it's easier to get a uniform root with a 1mm land and 2-3mm gap, then go up to 170 or so amps. The torch angle makes a difference too, it's really down to the prep that's in front of you.
     
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  9. Mid Wales welder

    Mid Wales welder Welder coding and NDT services

    Messages:
    551
    Location:
    Powys, U.K.
    I should say that with 1mm wire as that would make a difference also.
     
  10. Brad93

    Brad93 M J B Engineering

    Messages:
    6,062
    Location:
    Essex
    Do the easy thing and get someone like Mid Wales Welder to do your procedure, testing & welder qualification. Will work out cheaper in the long run.
     
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  11. Mid Wales welder

    Mid Wales welder Welder coding and NDT services

    Messages:
    551
    Location:
    Powys, U.K.
    Haha cheers Brad! ;)
     
  12. Brad93

    Brad93 M J B Engineering

    Messages:
    6,062
    Location:
    Essex
    Well I don't think we have any other testing companies are on here!
     
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  13. Mid Wales welder

    Mid Wales welder Welder coding and NDT services

    Messages:
    551
    Location:
    Powys, U.K.
    Not sure if that's a good or bad thing lol. There are plenty of people that do it, but we are very helpful and reasonably priced! So it wouldn't hurt to give us a call ;)
     
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  14. paul teggart Member

    Messages:
    19
    Location:
    Dungannon, county Tyrone, Northern Ireland
    Guys, been on holidays just reading this now. Thank you all for your info. I will take it on board.
     
  15. paul teggart Member

    Messages:
    19
    Location:
    Dungannon, county Tyrone, Northern Ireland
    H
    Hi guys, the saga continues. It turns out the company had a PQR for butt weld that has a broad range to cover our requirements.
    So the boss says onto the next, (I don't think he likes me). I told him that writing welding procedures is something usually reserved for welding Engineers.
    He then proceeded to say "I thought that's what you were". i replied that I wish I was so I could make decent money, but no, I've done CSWIP 3.1, actually embarrassed by how little I know about writing WPS.

    Anyhow, the next one just happens to be for 41CrMo4 shaft (100mm) welded to S355 plate (25mm). The drawing on my "(p)WPS" says 10mm plate, I have to change that.
    Was wondering if any of you guys could run your expert eyes over it just to see if anything's grossly wrong.

    Guys I really appreciate any help with this as I'm going out of my mind with this stuff lol.

    Many thanks, Paul.
     
  16. Brad93

    Brad93 M J B Engineering

    Messages:
    6,062
    Location:
    Essex
    Your filler metal classification is incorrect. Actually to be truthful I'm not entirely sure that G3Si is suitable for that shaft.
     
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  17. paul teggart Member

    Messages:
    19
    Location:
    Dungannon, county Tyrone, Northern Ireland
    Thanks Brad93.
    To be honest, as these are chromoly shafts going into conveyor pulleys/drums, I've been trying to sidestep the whole welding completely and advise customers to use a locking element like KLAB/Ringfeder or taper lock, but they sometimes insist on welding, especially in larger shafts as these locking elements can become expensive for larger diameter shafts.

    I'm going to look at the filler and then get test pieces tested with Exova and hopefully they pass. If they don't then maybe this will spur my boss into shelling out for a professional to write it.

    Thanks again Brad93.
     
  18. Liquid Metal

    Liquid Metal Member

    Messages:
    434
    Location:
    Essex, UK
    Dealing with Chromoly, is GS3i or ER70S6 going to the best way of going about it? Spray transfer mig considering the travel speeds, isnt the easiest thing to do around a 100mm shaft. Considering heat build up, too much scope for stop/start problems (if done in quarters for example) as well as lack of penetration/fusion due too torch angle if its incorrect.
    Welding it in two halves (0>180 degrees) will be much easier if it is Tig or stick welded. That will also give you a better chance of getting a better metallurgical match for the two materials, ie 309LSi or 312 stainless filler for example without it costing a small fortune in consumables.
    Just a thought?
     
  19. Brad93

    Brad93 M J B Engineering

    Messages:
    6,062
    Location:
    Essex
    You need to be very very careful that the material you choose is suitable for the intended application. Give me a PM and I’ll pass you on some details of someone who can advise if you ever come across such a shaft.
     
  20. Brad93

    Brad93 M J B Engineering

    Messages:
    6,062
    Location:
    Essex
    In the end for this particular application and the shaft in question, Paul went with ESAB OK Autrod 13.22. Luckily his company had some reels already from a few years previous. They had consulted a welding engineer before who advised that filler metal.
     
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