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  1. #1

    Default Couple questions from a welding class

    I have been welding for 12 years and the last three days I have been in a welding class to certify to weld for the company I am employed by even though I have been welding for them for 2 years. I know a lot of what they teach is for production welding but I wanted to see what you guys thought. They said that a downhill mig weld is stronger than an uphill weld, I disagreed with instructor and he became very defensive.

    Anyways, the main question I would like an answer for is what welder setting would you use for an overhead fillet joint on 3/8" plate? They had us using 26.5 volts and 650 ipm for wire speed, normally I would weld about 24v and 350 and multipass. I can weld pretty good with my settings but with theirs I struggled to produce a decent bead. Is there anything with my settings and making three passes? We also tested with 3/8" plate making 7 vertical down passes with the 26.5v and 650 ipm. By the 7 pass, I don't see how the weld is penetrating at all because you are moving so fast trying to outrun the puddle.

    I just really wanted to see what some of the guys who are certified and weld for a living thought of their procedures. I don't agree with them but if that's what they want then I will do it their way.
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  2. #2

    Default

    Uphill always penetrates better! And with 7 passes, ur metal is getting too hot which is why u r having to move so fast. Let it cool some after each pass, preferably in a water cooling tank.

  3. #3
    Join Date
    Mar 2011
    Location
    st-eustache qc.canada
    Posts
    223

    Default

    rule#1 never argue with the instructor...at least in front of other people.

    And cooling a weld with water is looking for trouble.

    I'll leave the very specialised answers to the guys here that have more science and will provide accurate informations.

  4. #4
    Join Date
    Nov 2011
    Location
    Gilbert, AZ, USA
    Posts
    24

    Default Cooling metal with water makes metal brittle

    Quote Originally Posted by snowbird View Post
    rule#1 never argue with the instructor...at least in front of other people.

    And cooling a weld with water is looking for trouble.

    I'll leave the very specialised answers to the guys here that have more science and will provide accurate informations.

    I was working with a friend and talking about hardening a cheap set of off-brand mini vice-grips. We were pulling out studs from snow tires (I do not ever recommend this after doing it) and the pliers kept bending. Friend recommended we heat treat by heating until red hot, then dipping in water, then repeat a few times. I knew this was a bad idea but I had 3 sets of these cheap-o pliers so I thought I'd humor him.

    The pliers cracked and broke the tip off on the second stud and were rendered useless. There are much better ways to heat treat metal, but water is not a good idea.

  5. #5
    Join Date
    Apr 2012
    Location
    Western Pa.
    Posts
    228

    Default Couple questions from a welding class

    Water is used in Harding and heat treating all the time. If you heated to red hot and dipped in water you were Harding not heat treating.
    Heat treating is returning a certain amount of softness or flexibility to take out brittleness.
    Depending on carbon content, ?
    1st. You would heat red hot quench in water to harden. 2nd you reheat to dull red or better, controlled known temp. Then let cool to desired color or known temp as per tool requirements and quench, this is heat treating to desired toughness & flexibility ie takes out a controlled amount of hardness and brittleness.

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