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Welding 1" thick stainless

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  • Welding 1" thick stainless

    I welded up a thick stainless steel paddle on a dough mixer for a company that mixes about 200 lbs at a time, it lasted about 2 weeks and they noticed some cracks in it... I'm not sure what the base metal is so I used 316L..., doing some reading I noticed the importance of interpass temperature, I think this may have been my problem, I'm going to vee groove it and watch my interpass temps... before multi passing, any tips would be appreciated.
    I have made sure to use a new stainless brush and keep good gas coverage.

  • #2
    What process are you using?

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    • #3
      If you don't know the material you may be better off using 309L or 312L if you're TIG welding.

      Can you call the manufacturer to find out what the material is?
      Richard

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      • #4
        Originally posted by Portable Welder View Post
        I welded up a thick stainless steel paddle on a dough mixer for a company that mixes about 200 lbs at a time, it lasted about 2 weeks and they noticed some cracks in it... I'm not sure what the base metal is so I used 316L..., doing some reading I noticed the importance of interpass temperature, I think this may have been my problem, I'm going to vee groove it and watch my interpass temps... before multi passing, any tips would be appreciated.
        I have made sure to use a new stainless brush and keep good gas coverage.
        You know, one picture is worth a lot of typing. I'll give you three reasons why.

        1) We can see if it was welded with a bit of skill.
        2) We can judge the extent of cracking.
        3) You have something to show the next guy what you can do.

        I'm not saying you couldn't weld 1" thick stainless with GTAW, but SMAW would have been a better choice. Consider the contraction stresses placed on that tiny weld. Think of hardness in the weld deposit. Think of how long it took.
        If your going to use GTAW, it should be for more of a reason then because you can. That said, shorter welds, ball peen it to relieve the stresses building up. And yes, watch your heat input.

        And because third time is the charm, fix this one and the one after will be perfect.

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        • #5
          I'm tig welding it, I went with 316L because its food grade, I'm using a temp laser to make sure I'm not going over 300 F, I have zero under cut, it is polished smooth afterwards... I've been tig welding for 28 years

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          • #6
            300 series Stainless doesn't typically crack. I would have tig welded it too, a lot cleaner then stick. Food grade stuff is usually 304 so you should have been fine using 308l or 316l. Is it possible its a 400 series stainless? Serms pretty unlikely. If it starts to get too hot it will start going black and weld like ****. Ive never seen that cause cracks though, it will just rust if you dont treat it somehow after. I like to keep it cool, throw some water on it after each pass. You cant heat treat 300 series so it wont affect it but helps to keep it from going black. Maybe you just didnt give it enough weld.

            The only time Ive seen stainless crack is when I was welding a 1" slip on flange once. You could tell it was in the parent metal and not the weld. Manuefactuers defect... Its more likely then you might think
            www.silvercreekwelding.com

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            • #7
              Sounds like you know what your doing... Run a dye pen test on it maybe. Do the cracks go into the parent material and not the weld. If so Id say something messed up with the metal. Not sure what you could do in that case. Grind the cracks out and test with dye pen to make sure they are gone. They will keep coming back / spread if you dont get rid of then completly. If that doesn't work throw it out I guess, kindof hard to explain to a customer though
              www.silvercreekwelding.com

              Miller Trailblazer 325 efi
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              Thermal arc 186 ac/dc
              Lincoln power wave 455m/stt with 10m dual feeder

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              • #8
                There are 2 stems to this paddle, its shaped like a big U with a twist, I'm not sure which side I fixed 2 weeks ago, I'm hoping it wasn't my side that fixed this time.... so I gave it about 15 min between welds to let it cool before I wire brushed with a stainless ( New ) brush.

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                • #9
                  Originally posted by Portable Welder View Post
                  I've been tig welding for 28 years
                  Must be real good then. Post a picture.
                  Someone once said your never to old to learn? Guess 28 years in "tig"is enough of that learning thing?

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                  • #10
                    When you repaired it before, was it completely broken or just repairing some cracks? In the case of cracking, is it possible you didn't chase the cracks out completely and they continued to propagate?

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                    • #11
                      Well, considering the amount of force or torque a dough mixer has available I would assume that it might as well have broken off due to misalignment of the bowl, the clearance to the sides and bottom is not very forgiving and it's advised on most to check that clearance or at least make sure it's not grinding the bottom of the bowl.

                      Our baker broke an aluminum one some weeks ago, I didn't even bother trying as I didn't see a way to weld it and grind it all flush and pretty again, we just bought a new one. But I know he did something wrong, he told me but I don't remember, somehow it started with it jammed or something, so the mixer just torqued it right in half.

                      https://www.webstaurantstore.com/hob...SABEgJXHPD_BwE

                      Bigger than that but same design.
                      if there's a welder, there's a way

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                      • #12
                        Some mix dough and some make dough. I just haven't figured out what I was going to do with mine? There it sits.

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                        • #13
                          Originally posted by Noel View Post
                          Some mix dough and some make dough. I just haven't figured out what I was going to do with mine? There it sits.
                          Maybe a nice center finial on a gate

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                          • #14
                            Originally posted by Noel View Post
                            Some mix dough and some make dough. I just haven't figured out what I was going to do with mine? There it sits.
                            I threw the old one away, it was aluminum.
                            if there's a welder, there's a way

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                            • #15
                              Originally posted by FusionKing View Post

                              Maybe a nice center finial on a gate
                              LOL! That's kind of what I was thinking when I pulled it out of a scrap bin? Or maybe a really big hood ornament for the front of the old Buick?

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