Interessant! Der stirnseitige Abbrandkrater ist überraschend, das hätt ich nicht erwartet. Das Schliffbild der neuen Elektrode ist echt komisch, auch hier, hätte nicht gedacht das Wolfram zum schmieren neigt, normal ist das Zeug so hart/spröde, da hätt ich eher feine Ausbrüche erwartet.
Grüss Dich, Stefan! Danke für deinen netten Kommentar, verfolge deine Videos immer mit großem Interesse! Hoffe wir sehen uns irgendwann mal wider. PS: Das mikroskopische Schmieren hat vmtl. mit der lokalen Erhitzung zu tun.
Every solid at room temperature is just a frozen liquid, so when you add enough heat and/or pressure, it will flow like a liquid. So even Tungsten flows like a viscous liquid, at the cut edge of the chip. If the chips are small enough then the pressure is high enough and the surface looks like someone has dragged a scoop through the ice cream. Also, the sharp geometry of the tip hugely magnifies the current density and electric field, you can likely change this end crater size by flatter geometry at the tip but also by changing amps and ramps.
Alex, just found your channel through your milling machine rebuild. Absolutely super content and especially the heat distortion series. I enjoyed it very much and finally managed to understand reasons behind it. The quality of your videos will surely make you much more popular here on TH-cam... if only more people would watch it from educational rather than entertainment purposes. Viele Grüsse aus Finnland! Jonas
Thank you very much for your kind comment, Jonas. I'm glad if you find the content useful. I fully agree with you, people seem to use the internet (and also youtube) mostly for entertainment. Kind greetings, Alex
electron microscopy for the win on machining youtube! So as material science! So as Dr. Wang! Glory Glory for everyone! *Sorry about going a little bit crazy here, but it is a long time since I have seen such deeply satisfactory content - science and practice hand in hand, science in our everyday life - on display. I wonder if it would be interesting to see robrenz flat stone under the microscope, hm
EDX can probe a couple of microns into the surface, which might help answer your question at 5:38. You'd need synchrotron XPS, sputtering, or a FIB cross-section to really be able to do depth profiling. We have a FIB/SEM + EDX at work, if you send an electrode I might be able to provide a FIB cut with EDX.
Great content on your channel Alex! I heard you mentioned in one of Stefan's videos. Excellent series on the weld distortion stuff BTW. For this video it was also very informative. One thing to note with Tungsten is any little flake of W that contaminates the weld is generally bad. This is especially true on RT welds (radiographed) because the W with really stick out in a radiograph since W is so dense, most welds that are RT'd will fail the inspector. One really good practice is to run the electrode in at or slightly above normal weld current for maybe 10 or 15 seconds on a scrap piece. That way any little W flake will likely fall of in the scrap weld bead and not contaminate the good weld. P.S. I like to polish my electrodes and slightly ball the tip smooth.
Really nice work! My only wish is that you examined some cross sections to evaluate the depth of penetration. By the way, La2O3 has a lower boiling point than W (4200C vs. 5500C). So it stands to reason that part of the cause of the La depleted regions is not just differing diffusion rates but the La2O3 boiling off!
Very interesting topic and great presentation of the material... I guess it doesn't hurt to have access to an SEM just laying around the shop. Keep up the great work, it's really appreciated. Also, think it would be nice if you ever get the chance to do an in-depth review of the SEM and its processes.
I would love to know what's below the surface. I re-grind my electrodes by skinning the tip, as if sanding the contamination off and then a little into the W. Always works, so i've always assumed that contamination is only skin deep.
Isn't the crater more likely due to sputtering, similar to DCEP cleaning cycle when welding aluminium? Argon and other gas gets ionized and hits the negative electrode, where it causes sputtering or oxidation.
Great video,that cavity looks scary, Also watch you video on restoration of the Micron incredibly. I don't know where you learned all that so young,but I just know thet I'll follow you from now on. Keep going....
i wonder what the abrsive properties will be of the fat part were the aluminium with the tungsten crystals.....whould that behave like a lap? always intresting, the microscopic world.....there in the crater of minerals looks almost organic, like a coral reef with al sorts of creatures......
Nice video. From the scales I saw in the pictures, is there any reason why this could not be viewed with an ordinary metallurgical microscope? Beyond the xray specturm analysis of course.
Actually, a standard metallurgical microscope should be fine for this, too. However the electron beam microscope has much more depth of field and contrast, which may be a benefit.
I was always told you're not supposed to radial grind tungsten but instead grind it so the striations are vertical or axially aligned with the electrode, supposedly makes a more stable arc.
A good question. I assume the cavity will be larger, the higher the current. If I find the time I'll take some pictures of electrodes that had different amperages.
Excellent!
ATB, Robin
A lifetime of welding and this is the first time I have seen such a thing.
Next time I dip my tungsten I will not be able to get this out of my head! Fascinating stuff Alex. Thanks for sharing with us.
Interessant!
Der stirnseitige Abbrandkrater ist überraschend, das hätt ich nicht erwartet.
Das Schliffbild der neuen Elektrode ist echt komisch, auch hier, hätte nicht gedacht das Wolfram zum schmieren neigt, normal ist das Zeug so hart/spröde, da hätt ich eher feine Ausbrüche erwartet.
Grüss Dich, Stefan! Danke für deinen netten Kommentar, verfolge deine Videos immer mit großem Interesse! Hoffe wir sehen uns irgendwann mal wider. PS: Das mikroskopische Schmieren hat vmtl. mit der lokalen Erhitzung zu tun.
Every solid at room temperature is just a frozen liquid, so when you add enough heat and/or pressure, it will flow like a liquid. So even Tungsten flows like a viscous liquid, at the cut edge of the chip. If the chips are small enough then the pressure is high enough and the surface looks like someone has dragged a scoop through the ice cream. Also, the sharp geometry of the tip hugely magnifies the current density and electric field, you can likely change this end crater size by flatter geometry at the tip but also by changing amps and ramps.
Alex, just found your channel through your milling machine rebuild. Absolutely super content and especially the heat distortion series. I enjoyed it very much and finally managed to understand reasons behind it. The quality of your videos will surely make you much more popular here on TH-cam... if only more people would watch it from educational rather than entertainment purposes.
Viele Grüsse aus Finnland!
Jonas
Thank you very much for your kind comment, Jonas. I'm glad if you find the content useful. I fully agree with you, people seem to use the internet (and also youtube) mostly for entertainment.
Kind greetings, Alex
electron microscopy for the win on machining youtube!
So as material science!
So as Dr. Wang!
Glory Glory for everyone!
*Sorry about going a little bit crazy here, but it is a long time since I have seen such deeply satisfactory content - science and practice hand in hand, science in our everyday life - on display.
I wonder if it would be interesting to see robrenz flat stone under the microscope, hm
Fascinating. Great stuff Alex!
EDX can probe a couple of microns into the surface, which might help answer your question at 5:38. You'd need synchrotron XPS, sputtering, or a FIB cross-section to really be able to do depth profiling. We have a FIB/SEM + EDX at work, if you send an electrode I might be able to provide a FIB cut with EDX.
Thanks for your interesting suggestion. Maybe this could be done with a simple ground electrode cross section as well. If I find the time, I'll try.
Great content on your channel Alex! I heard you mentioned in one of Stefan's videos. Excellent series on the weld distortion stuff BTW. For this video it was also very informative. One thing to note with Tungsten is any little flake of W that contaminates the weld is generally bad. This is especially true on RT welds (radiographed) because the W with really stick out in a radiograph since W is so dense, most welds that are RT'd will fail the inspector. One really good practice is to run the electrode in at or slightly above normal weld current for maybe 10 or 15 seconds on a scrap piece. That way any little W flake will likely fall of in the scrap weld bead and not contaminate the good weld. P.S. I like to polish my electrodes and slightly ball the tip smooth.
Very good information, thank you!
Really nice work! My only wish is that you examined some cross sections to evaluate the depth of penetration. By the way, La2O3 has a lower boiling point than W (4200C vs. 5500C). So it stands to reason that part of the cause of the La depleted regions is not just differing diffusion rates but the La2O3 boiling off!
this was fantastic, sharing with my friends who are welding instructors...Cheers
Awesome, thank you!
Very interesting topic and great presentation of the material... I guess it doesn't hurt to have access to an SEM just laying around the shop. Keep up the great work, it's really appreciated. Also, think it would be nice if you ever get the chance to do an in-depth review of the SEM and its processes.
Thanks, and I'll try to find the time to show the SEMs at work one time.
I would love to know what's below the surface. I re-grind my electrodes by skinning the tip, as if sanding the contamination off and then a little into the W. Always works, so i've always assumed that contamination is only skin deep.
Amazing! Thank you for sharing this amazing images and information. Do you have one of this analisis of a weld with SHIELD METAL ARC WELD. Regards.
Klasse Video und interessante Ergebnisse!
Fascinating; thank you for sharing this!
I will never look at a tungsten electrode the same way after seeing this!
Wonderful set of observations. Thanks.
Many thanks!
Fantastic! Excellent presentation! Always was curious how or if the electrodes age with use .
Thx,
Bernhard
Isn't the crater more likely due to sputtering, similar to DCEP cleaning cycle when welding aluminium?
Argon and other gas gets ionized and hits the negative electrode, where it causes sputtering or oxidation.
Very Interesting.
Thanks for posting this video.
Thanks. I often stare at my misshapen electrode and wonder what I am looking at.
I can only hit the like button once, although everyone involved in making this deserves individual credit!
Thank you I’ve been really curious about the benefits of the different grades of tungsten explain some of it.
Great video,that cavity looks scary,
Also watch you video on restoration of the Micron incredibly.
I don't know where you learned all that so young,but I just know thet I'll follow you from now on.
Keep going....
Many thanks, glad you find the content interesting.
Very informative video, thank you for sharing.
Cheers from Sweden
Bengt
but is a crater a problem?
stunning
i wonder what the abrsive properties will be of the fat part were the aluminium with the tungsten crystals.....whould that behave like a lap?
always intresting, the microscopic world.....there in the crater of minerals looks almost organic, like a coral reef with al sorts of creatures......
Good question, however, without more close analysis I can only assume.
Nice video. From the scales I saw in the pictures, is there any reason why this could not be viewed with an ordinary metallurgical microscope? Beyond the xray specturm analysis of course.
Actually, a standard metallurgical microscope should be fine for this, too. However the electron beam microscope has much more depth of field and contrast, which may be a benefit.
You are right about the depth of field. I had not considered that.
I was always told you're not supposed to radial grind tungsten but instead grind it so the striations are vertical or axially aligned with the electrode, supposedly makes a more stable arc.
Wow, that cavity is surprisingly deep! Is the depth a function of current?
A good question. I assume the cavity will be larger, the higher the current. If I find the time I'll take some pictures of electrodes that had different amperages.
wow, that was awsome, thank you!
So I understand W to stand for Wolfram? (Tungsten)
Yes, to my best knowledge the abbreviation "W" is also used in the English language (hope that's right). Probably from latin.
"Hey guys, I'm just going to use the EM real quick."
Fantastic!!
I never dip in the puddle 🤥
Very cool.
Thanks, Tristan. I hope you're fine.