your opinion please

By mountainman (***)

Date 12-06-2007 22:18 Edited 12-06-2007 22:29

what is the question? was your expectation of that weldment to stop the forklift?

By EVWELDER (**)

Date 12-06-2007 22:53

No not to stop the forklift were the weld broke should it have broken in a diffrent place.

By mountainman (***)

Date 12-06-2007 23:03

the picture to me looks like the weld fractured in the cross section, i would think that would be more desirable than at the toes of the weldment, hence proper fusion. after all it was a forklift, somethings gotta give, right?

By aevald

Date 12-06-2007 23:03

Hello EVWELDER, I'm having to read into your question a bit here so bear with me. From the picture that you included in your post, the part faired pretty well considering the impact of a forklift. 6061 is a heat-treatable aluminum, in this case the T-6 indicates it has been heat-treated and will give it additional strength. Upon welding with the 4043 it will lose a bit of strength in both the weld metal(4043 doesn't posess equal strength compared to the 6061T-6) and the adjacent parent metal(HAZ). Having said all of this, the part really looks pretty much as it should be expected to look for the punishment it took. Hope I interpreted your question correctly. Best regards, aevald

By EVWELDER (**)

Date 12-07-2007 03:02

Thanks aevald I have seen alot of your comments you always have a good answer I am fighting a sales guy over this broken weld he thinks he knows about welding never welded a day in his life this will help with my argument.

By DaveBoyer (*****)

Date 12-07-2007 04:50

To elaborate some more on aevald's post, the 6061T6 is quite a bit stronger than the 4043 weld metal, and the nature of the T6 heat treated tube is that it won't bend and crush untill nearly at the failure point. These 2 factors make the apearance of these parts much different than if a similar assembly was made from mild steel and hit with the same forklift. In steel the weld might have held, but there would be a lot of deformation to BOTH tubes due to the more ductile nature of the material and the closely matched strength of the weld material.

By EVWELDER (**)

Date 12-10-2007 23:57

Well let me ask you guys this what is the strength diffence between the 4043 fill metal and the 6061-t6 base metal.

By DaveBoyer (*****)

Date 12-11-2007 05:34

Without looking it up My guess is that the 6061-T6 is probably twice as strong as the weld metal.

By Stephan (***)

Date 12-07-2007 06:33

evwelder,

just as a humble addition to the already posted excellent statements coming from the other fellows, a question from my side.

I have embedded your picture but tagged with two details which have awoken my interest.

Could you explain where the details "a" and "b" are coming from?

- Is "a" the "cleaning-zone"?

You know, it is interesting for me since it appears to have an approximately similar width as the weld-seam itself.

And furthermore:

- What is the darkened area to be recognized in "b"? --> Can we see here a piece of the inner side of the broken and then torn smaller diameter tube?

As I said only for my personal interest...

Thanks in advance and best regards,
Stephan

By jarsanb (***)

Date 12-07-2007 14:58

Good eye Stephan. With how this picture appears, with the very fine edge at the upper toe and the discoloration of the smaller tube at the weld end, it kind of looks like this could have been severve lack of fusion along that bottom leg. Hard to tell from the picture. The smaller tube has discoloration around the end but no apparent tears or chuncks of the weld left on it. I would think with proper fusion this "break" would be much more irregular.

By jarsanb (***)

Date 12-07-2007 15:01

notice the upside down V shape along the torn toe of the fillet. The small tube should have a matching tear profile.

By Stephan (***)

Date 12-08-2007 12:01

jarsanb,

thank you!

You got me.

It's truly hard to interpret this a bit more detailed from the picture and of course it might be as well that the weld by itself could have weaken the smaller tube's wall for an amount, of that even the reduced cross section was torn in that area of dilution. This again would eventually explain the "regularity" of the path of cracking.

But yes, I would agree with you, and as well as described in your second post this detail has caused me additionally to ask the question. There is sure a "trace" of a "positive - negative" reflection in the path of crack which looks like a kind of "serration", please see also the embedded picture.

But nonetheless it looks a bit strange for me.

It might be interesting to know what the thickness of the smaller tube was. When having a look upon the gouge in the smaller tube, it could have a higher wall thickness since it doesn't appear to have been broken through its wall thickness cross section.

This again could cause us to consider a higher heat dissipation into the smaller tube and this again leads me to cite you (I hope you don't mind) "...looks like this could have been severe lack of fusion along that bottom leg...".

But to repeat myself, just as a humble personal interpretation of the low resolution picture.

Perhaps evwelder will finally point us in the right direction.

Thanks and best regards,
Stephan

By EVWELDER (**)

Date 12-08-2007 13:10

All I can tell you the thickness of bothe tubes is 1/8" material I will ask to see if I can be sent pitures of the other side looking into the smaller tube.

By CWI555

Date 12-08-2007 20:48 Edited 12-08-2007 20:50

Evwelder,

Some observations. The camera that took this picture is a canon powershot A460 5mp. It used a 5.8F/aperture.
Judging from the out edge aberrations, as supported by the fact that it was taken with a 22mm focal length at 200iso, which implies the macro was on as that camera in normal view is 38 to 152mm focal. Coupled with the DPI of 180 it appears to have been re-sized. It was also taken Jun 20th 2007 if the camera date was set properly.

You may be asking why I am sounding like a smart-ass, here is why.

The idea that pictures never lie is not true. Trying to arm chair analyze a single low res photo for failure analysis or even an educated guess is a mistake in my opinion. Especially one that appears to have been touched up by shrinking it, and one taken by a point in shoot with such a tiny lens. (note the barrel affect at the outside edges of the photo)

This is an attempt to assist as any information anyone could give you would be based on their knowledge of the welding processes and materials you've quoted, rather than by specifics of the limited information provided in the photo.

I would advise a series of pictures with proper lighting at macro settings on iso 100 or less setting taken with a camera with at least a 35mm lens/SLR with a +2 or so diopter filter. (an actual lens, not the pseudo dials given on some SLR's) or as a minimum, one of the 8mp large Len's models from cannon or sony.
Pocket point and shoots are nice for the family vacation, but they leave something to be desired for evidentiary photographs.

Again, I really am not trying to be a smart ass, but if you want valid information, a better image(es) would be required.

My opinion for what it's worth,
Gerald

By EVWELDER (**)

Date 12-10-2007 14:04

I guess I was asking for it when I asked everybody's opinion I was just wanting to know if were the weld broke was a concern if it should have or shouln't have broke somewhwere else I seem to be more confused more than ever.

By DaveBoyer (*****)

Date 12-11-2007 05:38

I think the break occured where it should have. The smaller tube is close to failure where it is kinked and starting to tear. See My post above as to how this part will look different compaired to a mild steel part after being hit with a forklift.