When root bending 6061-T6 what's your secret? Do you recommend annealing the straps? I bent a set of straps yesterday and the root bends broke clean in half. There was indications and such in the specimen, but I still think they should of went further then they did. Face bends bent nicely, but the root bends went to about 90 deg and started ripping in the corners till they broke in half.
3'' sched 40 pipe has a wall thickness of about 3/16" . Now when it says in D1.2 that the straps in the un-annealed condition need to be and 1/8" thick, does that mean still with the radiues in the strap or try to get it as flat as you can so it doesn't stress the corners as bad? I also used a plunger type bend tester. Would a wrap around tester be better suited for this type of application? Any tips and tricks for this would be greatly appreciated.
Thanks, Ray C.
Hello Kix;
When working with aluminum, especially the heat treatable alloys, it is important to reduce the thickness to that specified by the specific welding standard, use the proper bend mandrel diameter (due to reduced ductility of HT aluminum) and by all means, use a wrap-around bending machine.
You can send them to me if you don't have a wrap-around.
Best regards - Al
Al,
On the root bends when it says that I can take it down to an 1/8" in D1.2, can I take down the bow till it's almost flat across or do I have to keep it in the same shape? It would make bending them without the corner tears a lot easier if you could take the bow down to allmost flat. Do you see what i'm saying? I agree about the wrap around bender! You can totally tell a difference. The consistency of a perfect horseshoe shape with a wrap around is far beyound that of a plunger style. ;-)
On the root bends, you remove material from the face surface. On the face bends you remove material from the root surface. You will not remove the corners of the root for the root bends, nor do you remove the corners of the face if you are doing face bends.
Best regards - Al
When I was going through this last spring, I found that the easiest procedure was to have the straps milled to .125" from both sides toward the center. After I got them back from the cnc, I used some 220 emery cloth on the edges to take away anything resembling a sharp edge, then used the wrap around bender. 8 root bends, zero breaks.
If only they had been prepared as required by the applicable standard. Only then would they be "legal".
Your procedure removed the areas of interest, i.e., the root or the face. Were there any problems in the root or the face, they would be mystically removed by the machining operation. How convenient.
Al
Al,
Thanks you. Again you have help me.
Doh! Dummy me, after reading your post I had to think for a bit, because it makes no sense...I was thinking about my tensiles, duh! Sorry for the unintended conflict, folks.
Edit: I still had zero breaks in 8 bends, and without annealing. However, my work was all done with 4043 filler; 5356 might give different results altogether.
That's a relief. You had me wondering about the rest of your procedures.
Best regards - Al
I see where Al is coming from now.
If you are going to pass aluminim bends on a regular basis, (especially 6061), whatever you do, make sure you us a wrap-around with a MAXIMUM gap of 1/16" between the roller and the specimen (with a 1/8" specimen, the gap between the two rollers must be a max of 3/16"). Also, even though you can't remove the corners, you are still allowed a 1/8" max radius, and make sure you take full advantage of it.
Topic Welding Industry / Inspection & Qualification / Bend test for 6061-T6 3" sched 40 pipe issues. AWS D1.2
