Stainless to mild?

  1. slim_boy_fat

    slim_boy_fat Forum Supporter

    Thinking [well] ahead to my weather vane project, before I commit to cutting out the N S E W letters and possibly wasting some of the little stainless I have, can I weld the stainless to mild steel round bar [6mm iirc] successfully using ordinary MIG?

    Or should I just do them in mild sheet and hope to get 'shiny' paint? :(
     
  2. Hood

    Hood Forum Supporter

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    Stainless to mild should really be done (well it shouldn't as I hate seeing it but.....) with a stainless wire as it will be a brittle weld otherwise. Whether that will matter, in your application, or not will depend on whether it will be subject to vibration/flex etc.
     
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  3. Paul.

    Paul. Moderator Staff Member

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    For sticking letters to a weather vane it will be fine, done it many times on ornamental stuff without problems.
     
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  4. Kent

    Kent Member

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    Just get it done its not structural. You can use stsinless as a feature with mild steel, even running stainless welds onto mild etc
     
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  5. slim_boy_fat

    slim_boy_fat Forum Supporter

    Thanks Paul, I guess that's what I was hoping to read. :thumbup:
     
  6. Richard.

    Richard. Member

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    Winds up your way would probably put that into structural joint category lol. :clapping:
    312 filler as a minimum and expect to be putting it back on twice a year :clapping:
     
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  7. Ian James Member

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    I have re shafted many hand forks with stainless dairy tube over the years using normal MIG wire and have never had one brake at the weld come to think about it I have a garden for at the mo done in the same way
     
  8. Paul.

    Paul. Moderator Staff Member

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    About 40 years ago I made a heavy rake from a short length of steel box section and 6mm dia stainless tines, stick welded together with fincord m steel electrodes I still have it its done loads of work with myself and quite a few having borrowed it and its still as good as when I made it.
     
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  9. Hood

    Hood Forum Supporter

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    Well from my experience of mild to stainless welds with 6013's it makes for a brittle weld. The last time I mentioned it I was told it wasn't the case although one member (sadly no longer with us) agreed it was the case, suppose everyone has their own thoughts and opinions.
     
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  10. MichaelV

    MichaelV Forum Supporter

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    Although as noted above, it’s perhaps not critical in the application at hand, when more critical joints are made between carbon and stainless steels, 309MoL consumables are recommended.

    Thanks
    Michael
     
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  11. Richard.

    Richard. Member

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    It will have lower strength that’s for sure. Brittle.. I dunno. Possibly. I haven’t tried and tested it.
    In theory it shouldn’t be because steel is more ductile than stainless and diluted stainless with steel I’d guess would be a more ductile joint. That’s just my thinking out loud mind as I’ve not tried it. I think you could control this brittleness though. Putting your run in a little hotter/slower would soon see it to be lot less brittle but lower strength toughness again.
    Are you sure it broke through brittleness or lack of strength.
     
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  12. Hood

    Hood Forum Supporter

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  13. Richard.

    Richard. Member

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  14. TechnicAl

    TechnicAl Member

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    Look up the Schaeffler Diagram and you can work it out.........calculate mild steel, calculate the grade of stainless......draw a line between the two.....then calc the filler you intend to use.......draw a line from that point to half way along the first line.........then graduate the filler line into 10 segements which equate to 10% dilution levels.......MIG will be 20-30%

    Have fun

    PS joining stainless to ms should result in a brittle joint but good enough for a wind vein......depending on where you live I suppose
     
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  15. Hood

    Hood Forum Supporter

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    I have seen a simple thing like a guard over a housed bearing that was welded to a steel gunwale with steel rod (I presume 6013) crack after the first week at sea, re-welded with 316 (so not even the correct rod) and so far after 3 years or more it has not cracked . I have seen many similar things over the years so not even what you would call structural.
     
  16. TechnicAl

    TechnicAl Member

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    It really all depends on the amount of dilution. The lower the dilution the better the joint should be. High dilution will result in a weld metal thats similar to CrMo steels....so stronger than MS...but less tough...the toughness governs fatigue.....As for corrosion the presence of the more noble stainless should result in the MS corroding faster with the weld being in between......
     
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  17. zeppelin builder

    zeppelin builder Member

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    You get intergranular corrosion too
    However i dont think the cockerel will mind the roost
     
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  18. dannyp Member

    i've welded stainless to mild quite a few times when needs must, just spudded on with the mig quite often on exhausts and it's allways been fine. tho it only really been things that have to hold themselves there.

    one thing id be intrested to experiment with, would be the diffrence between diffrent prosseses i get the inpression TIG dosent tolerate things you really shouldnt do as well as say mig. but if there is anything in that or not and i'll just not count MMA as some of the the things we try to stick back together with rods and hope......
     
  19. TechnicAl

    TechnicAl Member

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    TIG should give higher dilution....which is probably what you mean
     
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  20. gt6s Member

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    Just weld it. MIG with steel wire will work just fine.

    Laurence
     
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