Poor Welding and the Colours formed on the surface 1

[JHWC]

Hi All,

I have posted something similar under the section "material and metallurgy engineering", titled: Welding Issue.

As far as concern, the comments were beneficial, stating that the welding was lacking of fusion and penetration (see attached).

However, I have another concern. Does corrosion play a part in the welding failure? In the picture, the corrosion came in different colours (light brown, dark brown). Any indication? In addition, from the surface, could anyone be identified whether the surface was overheated, or it is purely corrosion?

Background:
1. Supporting bracket, that is able to hold the weight of 100 kg.
2. The supporting bracket is made of mild steel, corner joints at 49 degree
3. It was dipped coat with hot galvanising zinc.

Thanks.

 

[mk3223]

Mainly, the rustic areas with color indicated the oxides formed as a result of the welding defect, i.e. inadequate fusion or penetration of the welding. Because of the welding defect, so the steel was rusted. The different colors were resulted from the exposure time the areas open to the air.

 

[gtaw]

I saw the photographs posted on the other board a few weeks back and I hesitated to respond then and I hesitate to respond now. I have a few questions that need to be answered before making any comments:

1) What welds were required by the design drawing?
2) Were the joints prepared in manner specified by the fabrication drawings?
3) Was the welding process specified or left to the welder's discretion?
4) Was the appropriate filler metal specified?
5) Was there an approved WPS for the welder to follow?
6) How long was the bracket in service?
7) Did it carry the load required by the design or did it fail due to an overload?
8) Was the welder qualified and certified by the employer?
9) I'm not sure what is meant by "corner joint at 49 degrees"?
10) Can you provide a sketch of what was specified by the fabrication drawings?

As I said, just a few questions before casting accusations about the welds.

Best regards - Al

 

[qcrobert]

I agree with you Al.

I recently came across a modified trailer stinger that failed with a 390 lb motorcycle scooter attached to it. It's scary that a hitch & tow rv business would weld this (see attached pix).

Robert

 

[qcrobert]

This 90 degree joint exhibited no penetration or fusion. The weld joint was also subjected to constant vibration from up/down motion of motorcycle rack on highway.

 

[gtaw]

Can you say, "Short Circuiting Transfer?"

Can you say, "Incomplete Fusion?"

I miss Mr. Rogers.

Best regards - Al

 

[qcrobert]

and one more highjack for your viewing pleasure.....

 

[gtaw]

Nice.

Probably learn to design connections and weld on a lonely nigh while surfing the internet.

Best regards - Al

 

[Tmoose]

" Gee, I wish I'd known MIG welding was so easy 10 years ago . "

 

[racookpe1978]

Funny. And here I thought you had to melt both sides of the weld, and the filler material, to get a good joint. /s

Guess I learn new hings every day!

 

[kingnero]

@ qcrobert, were both sides of that connection also "welded" ?
I see some evidence of a "weld" on the inside corner, and the third pic shows something on the two sides, but I can't really make out what it is.

http://www.fusionpoint.be

http://be.linkedin.com/in/fusionpoint

 

[qcrobert]

Only one side of the joint was welded. The exterior side was welded all around (four sides).

One side of one joint exhibited complete penetration because it had a root gap. I used a pencil eraser tip to point at the root area.

Robert

 

[kingnero]

OK, thanks... another episode of 'pay peanuts, get monkeys"...

http://www.fusionpoint.be

http://be.linkedin.com/in/fusionpoint

 

[gtaw]

If everyone knew what they were doing, I would be flipping hamburgs for a living. The less they know, the more we make!

We try to step in before Darwin does.



Best regards - Al

 

[Ron]

gate.....Amen!!

 

They could have consulted with me before starting, but that's OK, I also do failure analysis, and it pays much better.

"Everyone is entitled to their own opinions, but they are not entitled to their own facts."