Welding Distortion Explained Part 3: Flame Straightening
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- Опубліковано 23 сер 2024
- Part 3 of a four part video series focusing on welding distortion.
Equipment and samples kindly provided by Prof. Dr. Dr.h.c. Ewald Werner, Institute of Materials Science, TUM.
Why does this gem has only 8.8k views?!! Awesome video, thank you!
Thanks ;)
Excellent info! So refreshing to have someone who actually knows what they're talking about! I have a big stainless job coming up with built up triangular sections in stainless steel. I anticipate some distortion issues but knowing there is an option to heat straighten with the oxy torch gives me more confidence! Thanks a lot!
When i started metal fabricating 40 years ago i had old foreman teach me how to flame straighten. We would try to introduce the same amout of heat to the radius on both sides and cool rapidly with water. I used this technique throughout my career I found it to be fast and practical
I have heard about it several times, in rare cases it worked somehow. But this is the first time I really understood how the stress is created by this process and how to get to a good result - thank you!
Glad you find the video helpful. Thanks.
This is an excellent explanation of the needed process to remove weld distortion. Thank you for such excellent content!
Awesome information Alex! thank you so much. Regards from Mexico.
I was taught that heat wedge is used in tandom with external forces , usually the weight of the part itself but also with jacks . you have to impead expansion to create a plastic deformation bulge, this bulge takes up linear space shrinking the part with forces well over 2 tons
Freaking good content. More of this please.
Excellent demos with easy to follow explanations.
This is neat! I don't really do welding and had previously only heard comments from friends that if you weld something it just always flexes uncontrollably. Getting to within 0.1mm at what, 100mm distance, is really impressive. I'm going to have to reconsider welding for some projects...
Hey Alex! Thanks for your seriess of videos regarding this matter. I found my self to have made square tube turned into bananas and through your videos and the comments below I used the TIG as you suggested and it works amazingly. It's hard to tell the color through the welding helmet but overall it's working. I didn't wanted to buy O/A only for this reason.
Fantastic video! Thanks for sharing your knowledge!
Excellent Information. I've learnt a lot from your video series. Thanks for sharing your knowledge.
Hi Fif!
Here, I do have to contradict you a bit:
The wedge shaped heating actually does work perfect **if** the work is constrained. It will leave less residual stress compared to the method you showed at about minute 12.
Now to the method you showed as the right one for non-constrained straightening: First pass was perfect. But the second pass should have heated up *between* the areas of pass one (thus on the flat side, opposed to the T welded on). This would have reduced the stress near the corners. The way you did it increased the the stress even more.
To the flattening of train cars' walls: They do not heat up constrained, but yes, they do heat up a big area with a lot of torches. The cold areas do form a mesh-like structure that is the support/restriction. You could have straightened the sheet metal T you showed with just heating up spots. Not near the corner, but going in at about 1/3 of the width of the land.
As you showed in part 1, heating up the same spot doesn't gain that much.
But still, thanks a lot for all your efforts. I know, just writing the plot and editing takes way more time than the end result.
Hi Nick! Thanks for your encouraging comments!
Very interesting, how you chose your heated spot locations. I must give a try the way you describe straightening the sheet metal T-joint with spots 1/3 the width in from the edges. I'm curious if this works without buckling on so thin a (distorted) sheet.
As they say, I guess there is more than one way to skin a cat.
Filming the scenes for this episode (particularly straightening the unconstrained tubing T-joint) didn't work out well. I had to film this one four times since straightening quantitatively didn't behave the way I wanted to. In my experience, doing it unconstrained with a wedge-shaped heat does not allow to to get the tube all the way straight because of lack of bending-constraint. This is why after two passes in the video I change the strategy to keeping selected areas cold. In comparison to a wedge shaped heat this additionally has the benefit of reducing heat influenced zone size.
All the best and looking forward meeting you again, Fif.
Excellent tutorial
Thanks for the video,it was very usefull
Thanks for sharing, awesome good content!
thanks for sharing, very useful to me !!!
Good vid, but also see Keith Fenner on straightening shafts.
Thank you--tomorrow I shall try some of these techniques in my shop.
thanks, you set me straight. BTW when will they make a built-in piezo torch starter to eliminate the scratch starter.
Nicely done.
Thank you sir.
Good demo, thanks...
Would it be possible for the hobbyist who doesn’t have oxy-acetylene equipment to flame straighten using one of the high temperature gases (eg Vortex MAP X) that are readily available for DIY use? Very, very impressive content. Thank you.
Can a quick cooling with compressed air work to shrink the material more in a area?
Masterclass sir
Glad if you find the content helpful. ATB
Is it possible (perhaps benificial) to use the TIG torch for straightening? I guess you can be even more specific with TIG for where you apply the heat?
To be honest I haven't tried the TIG-torch for straightening yet. But I guess nothing speaks against it. Not melting the surface will surely be more difficult with the TIG-torch than with the O/A-torch. I'd try holding a longer arc as in TIG-welding.
I guess I'll just have to test then with some square tubing. I currently do not own a oxyacetylene torch or tubes so I need to get by with what I got. I'm currently trying to build a CNC with steel (80x80x5) and really got surprised with how much it can bend by welding. Strong forces... I need to learn to control them to my advantage. Your videos have really helped me understand what is actually going on, so thanks!
@@liposly I've found it hard to gauge the temperature of the heat spot, because you have to look through such a dark shade due to the luminous intensity of a TIG arc. It's important not to allow a puddle to develop. How did you get on?
So the rapid heat expands a thin area, then the heat dissipates to the whole part.
Good Demonstration. May I know the exact name of that table which is used for assembly purpose.
The table is a product from the German company "Siegmund". Thanks.
Does this work on round steel pipe as well?
Are you using a cutting tip, or a heating tip? 🙂
Hello Alex, could you please tell me what I can do to weld sheet metal that is one mm thickness. I only have a SMAW type that is transformer powered. Goes down to 20 amps with five amp increments. How would I weld stainless steel without using TIG ??? Thanks you Alex and peace to you too I really like your channel.
Hmm, with the coarse increments on your transformer SMAWing 1mm thick stainless steel may be tricky, however with the right choice of electrodes it may very well work out. I'm not able to assist you in the electrode selection, I'm afraid. All the best!
@@anengineersfindings Thank you for giving it a stab at it. Well made and really interesting too. Peace
Hello, Thank You. I have very similar problem now , but I have a solid metal of 15 mm pieces . How much I need to heat . because I went quickly through it, but no effect. Maybe I need to heat it much more due to a thickness?
With 15mm thick material, I'd say you have to apply at least 5mm diameter red hot spots to provoke a "strong" flame straightening effect. However, keep in mind that the effect is very strongly dependent upon the part geometry and constraining.
@@anengineersfindings Thank You , I tried all , I even cut a along shape ditch across of part and welded it with MMA .. but it didnt help.. I guess because one side of it is welded to a frame.. If I could send you a picture or short video to your privat email, would you be so kind to look into it?
Sure I'll try to help, you find my email address via my channel site.
friend , the reason you have no success with the wedge is because they often use external forces in tandom so maybe you forgot they use the weight of the work piece to push the plastic deformation into position for the shrink ? Fantastic video by the way dont change a thing ...
Thank you Sir for your kind comment. I wanted the straightening mechanism shown on it's own in the beginning of the video. Using external forces (by increasing workpiece rigidity) is shown after roughly minute 14 via using clamps. I've separated this because interestingly there is not just one textbook recommending the heat wedge without mentioning that it makes mostly sense with heavy parts, additional weights or clamping. The video should show the difference.
Ah I see, its hot and cold speed, then cool down slowly. Heat up to expand say to 2mm, but it cools down to move about 1mm leaving 1mm moved when at room temp.
I think your wedge might have been upside down
3/4 of a tenth of a millimeter... LOL... Some of you might understand... Most wont........
You sound like Nikki lauda during his racing year i swear
:D thanks, I guess.