MT on I beam

By jwright650 (*****)

Date 07-27-2009 20:47

I have used MT on S shapes before.

By fbrieden (***)

Date 07-27-2009 21:15

Same here.

By michael kniolek (***)

Date 07-27-2009 21:19

Have you ever seen indications parallel throughout the whole length .
Each indication is about inch to one and three quarter inches long very jagged ( zig zag).
They are spaced four/five inches apart, and do not produce any overall pattern.
When mill scale is present the indication appears to be subsurface (broad fuzzy indication).
When ground down to bright metal the indication Sharpens up and holds some dye from PT.
This is not Code , but I cant help wonder if I have defective beam.
Do you know of any specs I could refer to?
Do you know what this is and what causes it, or know of similar situations?
MDK

By aevald

Date 07-27-2009 23:48

Hello michael, those types of indications could possibly be from laminations that occurred during the manufacturing process. Possibly improper heats prior to rolling and reduction processes or other types of improper process control. Just a hunch on my part and I do believe you have a subpar beam. Best regards, Allan

By CWI555

Date 07-28-2009 09:53

I've seen a lot of various indications in I Beams from several methods. You've stated what the indications look like, but not their location.
Are they in the Web or Flange, and what orientation?

By Mikeqc1 (****)

Date 07-28-2009 15:58

the indications are all on the flange they are parallel with the Beam length.
mdk

By CHGuilford (****)

Date 07-28-2009 16:14

How deep are they?
If you check ASTM A6 section 9, you will find the limits for defects on a beam. If the depth is not beyond the limits -no problem.

By Mikeqc1 (****)

Date 07-28-2009 16:25

Thanks, thats what i will do.
MDK

By jwright650 (*****)

Date 07-28-2009 16:31

If I remember the tolerance is something like <1/16" deep grinding is permitted, >1/16" deep removal by grinding and filler material added back to replace the amount ground out......Don't quote me on that, look it up to be sure, but that seems to be what I remembered.

By 803056

Date 07-31-2009 20:46

I believe you are seeing what are commonly called seams. The problem originates with the ingot or continuous strand casting that has shrink cracks on the surface. They should be removed before rolling, but sometimes they aren't. The rolling process elongates them in a direction parallel to the rolling operation. In general, the loading is parallel to the seams and have little affect on axial loads. However, not all beams are subjected to axial loads exclusively and the seams can be more of a concern.

As mentioned, they should be addressed by ASTM A6.

Best regards - Al

By Mikeqc1 (****)

Date 08-04-2009 13:57

Al, I have gotten a copy of A-6
In 9. Quality
9.1 General
Material shall be free of injurious defects.

What is considered injurious defect?
Perhaps you could guide me a bit to where it is clarified as to what is injurious and what is not.

Any info would help.
MDK

By jrw159

Date 08-04-2009 14:10

Mike,
I am sure Al can elaborate in more detail but in the mean time maybe this will help. It is addressed in the fifth paragraph from the bottom. This is how it was described to me.

http://www.productionmachining.com/articles/workmanship.aspx

"If something can cause harm to a person, or if it can interfere with fit, form or function, it is an injurious defect and its presence is proof
that the material is not of “good workmanship.”

jrw159

By Mikeqc1 (****)

Date 08-04-2009 14:40

THANK YOU,
I WILL INVESTIGATE THE INDICATIONS AND REPAIR ACCORDING TO A-6.
THANKS
MDK

By eekpod

Date 08-04-2009 15:42

I happen to have my A-6 in front of me.
First, are you actually working on W shapes and not I beams? it doenst really matter but just to clarify.
9.3 Structural Size Shapes, Plates ect....its the shapes thats makes this your catagory, because its not a plate.
I'm paprphrasing here but you'll get the point/
see 9.3.1 grinding, chiping of structural shapes shall be subject to the limitations that the area is well ground and faird without abrupt changes in contour and the depression does not extend below the roilled surface by more than;
1/32" for material up to 3/8" thick
1/16" for material 3/8" to 2" thick
1/8" for material over 2" thick

see the others 9.3.2 and such to cover the percentage of area this situation may effect.

How thick is you material??
Chris

By rfieldbuilds (**)

Date 08-06-2009 03:35

So, to summarize, I am hearing that MT is not the best choice for checking flanges. This is a timely post for me. I called for UT on column flanges exibiting open "seams" on the outside edges of the flanges just last week. These columns were all moment frame columns with open or visible defects. Our UTII guy had already shop inspected the columns and continuity plates after welding of the plates.
He felt I was over riding his UT on the continuity plates. I said no, I am simply calling a defect I see. We both UTed the flanges at the locations exibiting the worst examples of "seams" which were visible. To make a long story short, no laminations were discovered existing further than 1/32nd" or 1/16th" from the outside of the flange edge. It seems, the seams are a fairly common occurance as far as I have seen. No problem...