No announcement yet.

Welding notions: Metallurgy of welding, Epitex growth, dilution ratio

  • Filter
  • Time
  • Show
Clear All
new posts

  • Welding notions: Metallurgy of welding, Epitex growth, dilution ratio

    Welding notions: Metallurgy of welding, Epitex growth, dilution ratio

    sorry for the question, unfortunately I don't have welding texts and manuals with notions of metallurgy, could you kindly provide me with clarifications on . Epithesial growth, and dilution ratio thanks

    POLITECNICO DI MILANO Metallurgia della saldatura Progetto del corso Irene Menéndez Valle 1/10/2014 Metallurgia della saldatura Irene Menéndez Valle Indice La saldatura…

  • #2
    Epithesial growth, and dilution ratio. Chicken soup for the welder.

    Now I'm not sure to what depth you wish to swim in this pool of knowledge, but it's a deep pool, I'm keeping it simple because I'm stupid and tired of swimming.

    The weld is all those ingredient blended together and poured in a pot, pan, or a tray.
    How well they are blended, will decide what sinks, what floats, how thick, how thin, and what remains dispersed in the mixture.

    I'm not saying there won't come a time when things aren't harder to swallow, but I sure hope they don't think a bowl of puree will be the answer to a good meal when the time comes.​

    The temperature of the pot, it's quench, will pull heat from the mixture. A broccoli harder to make smooth then an apple, hotter the melt, more the stir, the greater the dilution.

    Not unlike the material thickness and type being welded, it's properties for conduction. Carbon, Stainless steel, Aluminum or Cast Iron? Lots happens in Nano seconds.

    ​ While soaking the eggs in cold water after boiling stops further cooking from the out side inward, the shell like a slag covering slows the welds cooling and solidification. That's how you change the texture of the yolk, a combination of time, temperature and if it was a weld, force or pressure from EM voltage force. Bigger or smaller droplets. Grains /texture of a weld the same way.

    Allowed to dry, it will dry from the out side inward, like a drying pond. That pulling/shrinkage stretches the grains.


    It could be a weld contraction crater. The weak surface bonds that have formed were not strong enough to hold the surface together.
    The contraction pull is what causes the cracking.
    So while the welder may be told, amps, volts, current type and still exists that he will screw it up with a long arc, to fast a travel or to slow, to hot, to wet.

    So, a major element turns from a liquid to a solid as it forms a grain, attaches to another in it's transformation, and sucks them up or attaches as it movers along to a solid. Like dumping sand in a bucket. Slow the pour, add some shake and you can fit more in the bucket because it settles and packs tighter.

    Anyhow...So depending on the current, it's akin to how fine you chopped and long you are blending the ingredients. The voltage stirs and thins the mixture so it's going to dry quickly or slowly will eventually.

    In the case of the watering hole, the sun, ground and dirt of the area will decide.
    A weld will dry/solidify, from the bottom, outsides then the middle. And the appearance of a ripple trail as it's pulled along will indicate a speed to the melting taking place and the travel to get away from it. Insides gets pulled as things cool.

    Click image for larger version

Name:	Picture2.png
Views:	156
Size:	490.8 KB
ID:	622514

    I hope this helps to understand these occurrences a bit better.
    In a small picture, no matter how you cut the potatoes, or what size you cut them, they will still make soup. What changes however is in the bigger picture, the difference is a thick chunky soup, or a thicker broth soup. Course grain not as strong in tensile but very ductile. A finer grain equates to higher tensile less ductility.


    • #3


      • #4
        I'm sorry if I reopen the discussion, you could use more technical terms, I translated it into Italian it looks like a recipe for a grandmother's soup of a vegetable minestrone, maybe with some drawings thanks sorry for the inconvenience thanks..


        • #5
          Originally posted by pietromarruggio View Post
          I'm sorry if I reopen the discussion, you could use more technical terms, I translated it into Italian it looks like a recipe for a grandmother's soup of a vegetable minestrone, maybe with some drawings thanks sorry for the inconvenience thanks..
          It was a soup recipe. And a simple explanation. The documents which you provided offered a good explanation as well.
          - 9 -
          Welding metallurgy
          Irene Menéndez Valle
          The growth of crystal grains in the weld bead is strongly influencedfrom the heat flux and
          by the orientation and size of the grains of the base metal. Of
          Usually, on a microscopic scale crystal grains tend to solidify so as toextend the structure of the base metal into the molten area. This type of growth is
          called "
          epitaxial chin".
          Figure 13.- Epitaxial accretion.The presence of pre-fenzial directions of growth according to thermal flow lines and
          according to particular crystallographic direction allows the growth of the grains that
          are more favourably oriented to the detriment of neighbouring grains which are less oriented
          Favorably, this growth is called "competitive".
          Figure 14.- Competitive epitaxial growth.If the bath has an elliptical shape, the grains develop with epitaxial growth
          through the edge of the blending line perpendicular to the interface
          solid-liquid. Then, as solidification proceeds, the direction of growth proceedsof grains curves
          to follow the trend of the maximum temperature gradient, which
          It remains perpendicular to the solid-liquid separation surface (see fig. 12a).On the other hand, if the bathroom has the shape of a drop elongated as thesolidification proceeds the direction of the gradent maximum temperature is maintained

          The truth is for most it doesn't matter. Really, who cares about grain growth.
          Like a magic trick it' is supposed to have us wondering how it works. Yet it appears that it does with a wide range of welding operators, in a wide range of conditions. 70,000 psi is what matters isn't it.

          Sorry my analogy wasn't up to answering your question by help you understand, it's one of those things that doesn't matter much to many people. It occurs and many things effect how and why.
          Just like soup. If you have teeth to chew and no trouble swallowing, fine food or big chunks doesn't matter. But if you concerned with impact properties at sub zero temps, a fine grain and narrow HAZ could be a facture away with a sudden impact instead of a bend and stretch.


          • #6
            I read this, real good.


            • #7
              You can see this in fussy pics of 7018 where the operator was really dilligent about setting, arc length travel and even weave speed.


              • #8
                The beginning of time probably looked like soup, claim scientists (

                Butch Cassidy: [to Sundance] Boy, I got vision, and the rest of the world wears bifocals.

                Ain't life a Butch. I try and use soup and no one gets it but big brains do and it's all fine an dandy. ​


                • #9
                  what you say is absolutely right, I was just doing some studies and wanted to learn more about the subject, thanks for your availability, sorry for the inconvenience.