Weld issue - high carbon content discovered , supposedly 1018
Weld issue - high carbon content discovered , supposedly 1018
(OP)
New to the forum here, looks like an incredible source of knowledge in these groups and glad to meet you all.
We have a small bracket that is failing, and in a cross section I noticed what I would describe as a brittle looking crack in the weld. Upon sectioning more parts, and doing an SEM analysis, we are seeing a very high carbon content in the base metals, which are "supposed" to be 1018. We are seeing carbon in the 3 - 4% range! Presently awaiting material certs from the supplier, if they even have them (we haven't required certs). Any thoughts on why we could see THIS high of a carbon content? Maybe they are using a high carbon steel for some reason? It is a flat 1/8 plate, with a ~1/4 pin welded on the back side of a through hole in the plate.
Thanks for any advice
Scott
We have a small bracket that is failing, and in a cross section I noticed what I would describe as a brittle looking crack in the weld. Upon sectioning more parts, and doing an SEM analysis, we are seeing a very high carbon content in the base metals, which are "supposed" to be 1018. We are seeing carbon in the 3 - 4% range! Presently awaiting material certs from the supplier, if they even have them (we haven't required certs). Any thoughts on why we could see THIS high of a carbon content? Maybe they are using a high carbon steel for some reason? It is a flat 1/8 plate, with a ~1/4 pin welded on the back side of a through hole in the plate.
Thanks for any advice
Scott





RE: Weld issue - high carbon content discovered , supposedly 1018
I wouldn't trust EDX to do quantitative analysis unless you have someone who is very well versed.
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P.E. Metallurgy, Plymouth Tube
RE: Weld issue - high carbon content discovered , supposedly 1018
Aidan McAllister
Metallurgical Engineer
RE: Weld issue - high carbon content discovered , supposedly 1018
http://www.lincolnelectric.com/en-us/support/proce...
http://www.arcweld.co.nz/Data/Default/Documents/Li...
Got pictures ?
Got drawings ?
2 down, 18 to go.
RE: Weld issue - high carbon content discovered , supposedly 1018
I will add a couple pictures as well, these are longitudinal, as you will see in a minute......
RE: Weld issue - high carbon content discovered , supposedly 1018
RE: Weld issue - high carbon content discovered , supposedly 1018
Send it to a materials lab for full analysis, as this won't really help you, asking a bunch of internet bozos to do a failure analysis on a vague description ("brittle looking crack") and those pictures.
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RE: Weld issue - high carbon content discovered , supposedly 1018
RE: Weld issue - high carbon content discovered , supposedly 1018
Do check the chemistry to verify material.
RE: Weld issue - high carbon content discovered , supposedly 1018
It could be something as simple as hydrogen embrittlement.
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P.E. Metallurgy, Plymouth Tube
RE: Weld issue - high carbon content discovered , supposedly 1018
Can you provide more information on the bracket loading and orientation of the weld, also what is the welding procedure for this component? Is the bracket stress relieved post weld? How long do the brackets last in service? What NDT is performed on the weld.
“Do not worry about your problems with mathematics, I assure you mine are far greater.” Albert Einstein
RE: Weld issue - high carbon content discovered , supposedly 1018
Is the weld made in one continuous pass?
I'm guessing TIG
The etch makes it look like something between a fillet and plug weld.
What is the pin made of?
14/6