Strange Impact values
Strange Impact values
(OP)
Hi there guys,
I'm not altogether familiar with mechanical testing so hoping you guys can help, it is really only a general question.
We sent some welded (Sub-arc and flux-cored GMAW) samples off for mechanical testing. There is nothing too special in the materials 350MPa C-Mn Steel with slightly overmatched fillers, no heat treatment.
When we got the mechanicals back, the impacts were all ok, but I noticed that the values in the HAZ were higher than the weld centre.
The Hardness were also higher in the HAZ than the weld ( as would be expected )With the higher hardness, I would have expected the HAZ to be slightly more brittle, and as such have lower impact strength.
Am I reading this right, and that with all things being equal, the HAZ should have lower impact energy?
Declan
I'm not altogether familiar with mechanical testing so hoping you guys can help, it is really only a general question.
We sent some welded (Sub-arc and flux-cored GMAW) samples off for mechanical testing. There is nothing too special in the materials 350MPa C-Mn Steel with slightly overmatched fillers, no heat treatment.
When we got the mechanicals back, the impacts were all ok, but I noticed that the values in the HAZ were higher than the weld centre.
The Hardness were also higher in the HAZ than the weld ( as would be expected )With the higher hardness, I would have expected the HAZ to be slightly more brittle, and as such have lower impact strength.
Am I reading this right, and that with all things being equal, the HAZ should have lower impact energy?
Declan





RE: Strange Impact values
So in your case the HAZ was stronger, giving it higher impact values, but not so strong that it became brittle.
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Plymouth Tube
RE: Strange Impact values
RE: Strange Impact values
RE: Strange Impact values
RE: Strange Impact values
this clears things up a bit. I always understood that hardness and impact strength were related in way of;
high hardness - low impact strength
low hardness - high impact strength
obviously not.....
thanks again
Declan
RE: Strange Impact values
The low value can be the result of improper machining of the coupon or the location at the tip of the notch relative to the specific grain structure of the weld metal or the HAZ.
Declan,
Absorbed energy values are related to both strength and ductility - not ductility alone.
RE: Strange Impact values
RE: Strange Impact values
Toughness can also be characterized by the area under the stress strain curve which represents the endrgy to fracture.
So although there is a general realtionship between hardness or stength and toughness, there are many factors that contribute to the brittle/tough equation.
Hope this helps
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