W-Shape Edge "Condition" 5

[WinelandV]

Just had an email come in from a fabricator showing what they called an "edge condition" on some W12x35's. I've never seen anything like this, so I'm curious if others have. Any idea what causes it? And, more importantly, any long term adverse effects (increased susceptibility to rusting, hot dipping won't work on affected areas, decreased strength locally, indication of bad steel all around, etc.)?

 

[WinelandV]

Another picture.

 

[WinelandV]

And a third (and last).

 

[EngineeringEric]

Those are some nice photos of a penny, very artistic!

Does the cracking resemble a shearing or splitting of the steel (say from cutting with a press or thermal shrinkage)? I cannot say i have dealt with something like that on my projects to date. but i would not think that it would effect your capacity in the beam unless it is some sort of indicators of bad steel as you mentioned.

 

[JStephen]

Looks to me like when they rolled it, there wasn't enough metal there and that edge didn't project all the way out to the roll at that edge.
Take a good look through the spec (ASTM A6 for A36, not sure what it is for A992) and see if there is anything relating to this.
On A36/A6 plate, you're actually allowed to weld a spot up and then grind smooth as part of the mill work- called plate conditioning, I think. There may be similar provisions for structural.
It looks like you could just grind those spots smooth and be okay, assuming the grinding doesn't reveal other laminations or inclusions.
If there's going to be any dispute about acceptance, backcharging, etc. make sure that gets settled before they start grinding away the evidence.

 

[WinelandV]

EngEric, we were trying to show the plight of the industrial worker and juxtapose the great liberator into it for ironic effect. Errr.... or not.

JStephen, thanks for that info. I'm having the fabricator show us on the part drawing where the "condition" is. Their original email just said "Hey, we're seeing this, but no one thinks it's a big deal." If it's not near a high moment demand area, I think we'll recommend that they just grind it smooth.

 

[hokie66]

I would just try rejecting these beams. They should not have been sent from the rolling mill with those defects. Do you know where they were produced?

 

[WinelandV]

No idea, hokie. I'm trying to get more info, but apparently everyone has already gone home for the night. Hopefully, people will be in tomorrow and not taking the day off.

 

[dhengr]

Winelandv:
Jstephen pretty well hit the nail on the head. That’s an inclusion or a lamination rolled out to the edge of the flg., or they didn’t have quite a big enough bloom/ingot/end of casting to roll the full section. You could/should have a testing lab do a UT scan through the thickness of the flg. tip in that region to see how far/deep (width) into the flg. width the anomaly goes. If shallow, grind it out, arc gouge it out, and weld it up and you are good to go. If it is very deep into the flg. it might be reasonable to reject it, and let the fabricator and his supplier fight it out. The mill will argue that the imperfection is in the same orientation as the primary stresses, so it is no big deal. You might just get by with grinding it out, to clean it up, losing 1% of the flg. tip area to no great avail. This would not be an insignificant defect if the flg. tip was loaded through its thickness.

 

[hokie66]

You are entitled to ask for the mill reports. This steel should not have gotten through quality control of any reputable mill. I would suspect it is some of the Chinese steel which they have been recently dumping on export markets.

 

[dhengr]

I agree with Hokie, but this is a rolling flaw, and doesn’t have much to with mill certs. You can get mill certs. with/for your order, but that requirement better show up in your original spec. or your mill order paper work, or you are not likely to get certs with any confidence. Mills and stl. supply houses have two different stacks of mat’ls. (and they work two different ways), and you pay for the extra effort and tracking, for certs. One can be traced back to a ladle pour, with material props., chemistry, etc., and the other, they are confident will meet a particular ASTM Spec. if tested. But, again, I think these are rolling flaws, and a question of final mill inspection before the product leaves the mill, or their want to slip one by you if they can. These flaws generally show up in the large mass/area/volume of the flg./web region of heavy sections, and are called piping. We never see them and they generally don’t cause any problems because they are in the same orientation as the primary stresses, they really don’t change the net area appreciably. They don’t often show up at flg. tips, that mat’l. is just to far removed, in the rolling process, from the areas which might have slag inclusions in the rolling ingot or casting run.

 

[WinelandV]

Thanks hokie and dhengr. Sorry for not responding sooner, I was on vacation/holiday since last Thursday. While I was out, the decision was made to grind it and see how far the condition goes and, if it's only as deep as what is seen in the pictures, they will do the grind off/weld back in procedure. If it continues in, we're going to have them make us new ones. Unanswered questions that will likely remain unanswered include how these made it out of the mill, why the fabricator accepted it in this condition, and how doing this repair work is quicker/easier/cheaper than just cutting new steel (the beams are only 8' long).

At any rate, thanks again for your help!