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  • needing help with my welding

    I've been welding for awhile now, and I'm proud to say I've done pretty **** good for myself...My problem is I don't quite understand the metallurgy behind everything....I just recently started a new job and in the first 2 weeks, I've done stellite(which I've never heard of before), chromoly, cast Iron, aluminum, and Stainless(both I have done plenty of!!!) The thing thats getting to me is how do I figure out which filler to use with which base material?? I'm plenty good enough to weld everything and I know how to adjust my technique, I would just really love some help on how to figure the fillers out?? Itried looking up charts on metals and alloys, and on fill materials as well as the chemical compositions charts on all these subjects, but I'm coming up empty...Any help out there would be greatly appreciated!!! Thanks....Quaz

  • #2
    Quaz,
    What your asking for is a 4 year degree in metallurgy. What I can offer here is a short answer to what I see as a lifetime of conversation into what filler metal to use on what base material under what condition. The variables are often difficult to pull out of the people your doing the project for.

    For aluminum, you cant go wrong 99.9% of the time with http://www.alcotec.com/us/en/support...tion_Chart.pdf

    For stainless, most guys will go with 308L for the gammett of applications. It is very important to understand the application for the part your building. If you are welding 316 stainless with 308L wire then the application had better not be corrosive or the carbon in the 308L is going to disappear very quickly, if it isn't corrosion resistance then why use 316. Do you see where I am going here? It can get to be a big maze sometimes. Often it is best to require the customer in the contract to spell out what they are wanting you to use. Putting the oneness back on them limits your liability as long as it is documented. It also gives you the opportunity if you know the answers to demonstrate that you know what your talking about and not just able to heat metal.

    Other materials such as stellite often will have their own filler wire in a matched material, you see it also with many nickel alloys and the like. The materials can be so specialized that the only option is to use the dedicated filler. Knowing what wire goes with what base is information you can learn from their data sheets as well as the settings they tested at and the mechanical properties they found when testing. Ask the LWS to get you the data sheets for the wire you are using and you'll get an idea of what to ask for.

    Usually with special alloys such as your using the price of the material is such that welding procedures are required for the obvious reasons but also because the material is so costly that replacing or reworking it is to expensive. In these cases the wire is specified, the gas and other essential variable are all outlined for you. This welding procedure also helps to protect you from liability as long as you can demonstrate that you do it the same every time(document everything).

    There is a lot more to discuss such as service conditions, temperature of service, loads either cyclical or dynamic, energy at the transfer in Kj's, mode of transfer and the list goes on.

    You can grab the AWS welding metallurgy book from their bookstore, I keep on at eye level at my desk so I can get to it easily. The welding handbooks are terrific as well, they cover most of what is going on in the industry as long as you stay in the 80/20 rule(80% of the work done is done by 20% of the process, OK it looses a bit in the translation but the principle applies. 80% of the wire sold is 70 series wire and it does most of the work)

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    • #3
      the procedure handbook of arc welding
      available from lincoln's web site has a lot of
      this information.

      frank

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      • #4
        Another thing to be mindful of is the final finishing of the product. If you are welding aluminum and it is going to be anodized, you need to match the filler metal with the base material or else the anodizing dies will stain differently over the weld area. I know that doesn't answer your question, just something to consider.
        Miller Syncrowave 200
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        More stuff than I can keep track of..

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        • #5
          thanks guys!!!! been awhile since i checked this post....i appreciate all the advice and thoughts!!!!!!!

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          • #6
            Base Metals

            Quazi: Another good book from the Lincoln Library is: "Metals and How to Weld Them."

            Dave
            "Bonne journe'e mes amis"

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            • #7
              quaz, hold onto that job, you have an oppertunity to learn, it sound like a very versatile shop, most welders are self taught, learn and listen, when you ask these questions it shows that you care about your work, that is good, take advantage of your challenge, learn and grow, good luck

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