How to read Impact test report

Date 02-28-2011 22:19

There is no formula. And for good reason. Its not a test of what is considered real material properties that can lend itslef to mathematical evaluation. Its a QC test method.
As for passing it will be determined either by code or contract requirements. Your impact energy (absorbed energy)seems decent and would generally be acceptable per most codes I am aware of.
Your lateral expansion sucks and I can think of no code that would allow sucha result.
Your percent shear is also not so good but no codes that I know of require this evaluation.
As a general understanding impact energy emphasizes the strength of the material in its resistance to a rapid rate of fracture. Lateral expansion is more ductility oriented. Though they are both quite interelated with this test. I'm gonna take a wild guess and say that if you dropped your test temp just little you'd find your energy dropping like a rock.
What is the material?
I'd be a lot more comfortable with MLE (mils lateral expansion) of ~35 or so and my percent shear sittin around 50% anyway.

By welder5354 (**)

Date 03-01-2011 02:17

Js55.
The impact reports for the FUSIOIN LINE is documented below.

Absorbed Energy=======Lateral Expansion=======Percent Shear factor
======64=================29================== 90
======69=================30================== 90
======90=================36================== 100

The material is Duplex 22%. The pipe was welded with GTAW (pass 1) FCAW (remainder).
The code was Norsok standard M-601 (2008 edition)
Would you be able to give me a brief explainion on how all those
numbers above are factor for a pass of fail.

By fschweighardt (***)

Date 03-01-2011 12:14 Edited 03-01-2011 12:32

If you are getting that kind of difference between the weld (maybe the centerline of the weld?) and the fusion zone with duplex, all may not be well with your procedure. Duplex should have way better impact in the weld metal. What is your ferrite number? If you use a rutile based FCAW electrode, and a fairly high FN, O2 levels in the weld can have significant effects on toughness. If you didn't overmatch Ni in the filler(s) you will probably also see high FN, which again, lowers impacts

Jeff is right on with the acceptance criteria of the impacts, that has to come from contract package, code, engineering calcs, or somewhere like that.

It looks like Norosk 601 is calling for 27J @ -46C (or min design temp) OR .38mm lateral expansion. Technically, you seem to have passed based on the 27J. However, I personally would not use your current procedure untill I got some better numbers in the WM

By js55

Date 03-01-2011 13:46

You need to read the contract and standard and find out what it is they are looking for.
Be aware of the test temp as fred mentioned.
Also, given the low weld metal results I would also agree with fred in that you might take a look at your FN. Its probably high. Duplex will demonstrate lesser impact toughness (though generally greater strength) with greater volume percent of ferrite. Especially through lateral expansion.
Your fusion line numbers will probably represent mostly unaffected base metal. Unless you tilt your charpy notch it will not follow the fusion line or HAZ. Its an old cheaters trick (though not really-its more like fudgin a bit). You can't tilt your specimen on thinner walls which are typical of duplex.
You're gonna have trouble with FCAW at low temp. The duplex structure tells you it has a ductile to brittle transition so there is little room for error or broad parameters. If spec allows I would not even mess with duplex fillers. I would go nickel. Nickel does not have a ductile to brittle transition and will pass your impact testing easily. In fact, you will probably end up paying a recalibration fee to the lab because the nickel filler will stop the hammer and the machines don't like that. You will still need to control parameters however because of the HAZ.

By fschweighardt (***)

Date 03-01-2011 15:15

Another item is pipe wall thickness. If you have heavy wall pipe, you may get a very rapid solidification of a bead, which "freezes" the microstructure at a high ferrite level. This is most common with the root and maybe hot pass. Heat input is one of the most important variables with duplex

By welder5354 (**)

Date 03-01-2011 22:43

Hi there, well the pipe was 4 in sch 120. So that was fairly heavy, i guess you would say
I was looking at the CVN on the wire and it was rated at -50. The gas was 80% argon + 20 % CO2.
The biggest problem i found with the pipe was that the machine shop put about a 40 deg bevel on
the pipe. I found that too wide and really should have sent it back for re-machining. So having said
that i was putting a lot of weld metal in the groove.
So do you think that could have been PART of the problem?

By fschweighardt (***)

Date 03-02-2011 00:03

lots of weld metal usually means lots of heat input, which usually means low ferrite, which gives lots of ductility, but not so much strength. There are a ton of variables that can mess with duplex properties

Heat input profile
O2 levels in WM
FN
on and on

post all the info you can and lets see what we come up with

By welder5354 (**)

Date 03-11-2011 03:36

Hi and i wonder if somebody could give me a an explanation of 323.3.5 Acceptance Criteria
from ASME B31.3-2008
(2) For lateral Expansion Criteria;
If the value of lateral expansion for one specimen in a group of three
is below 0.38 mm (0.015 in) but not below 0.25 mm (0.01 in), and if the average
value for three specimens equals or exceeds 0.038 mm (0.015 in), a retest of three
additional specimens may be made, each of which must equal or exceed the
\specific minimum value of 0.38 mm (0.015 in).

So in my previous message my lateral expansion were 4,8,& 5.
So how do i calculate to know wether those numbers are good or bad.
I just can't seem to figure this one out.
tks for any explanation.
:confused:

By fschweighardt (***)

Date 03-11-2011 12:00 Edited 03-11-2011 12:07

You will have to see what units. I thought that the lab had missed some decimals for mm measurements when I first looked at your post, but then they got more usual numbers for the fusion zone test. you might see mils (or thousandths), and mm as the usual units for this test

By welder5354 (**)

Date 03-13-2011 15:51

Tks guys, but i guess, like myself, nobody is able to answer my question.
It seems like we all have the same problem trying to interpret codes.
Sometimes we read them, but really we don't understand them.

By fschweighardt (***)

Date 03-15-2011 03:03

What are the units on the report?? miles, inches, mils, mm?????????

Have you reviewed Norsok 601, which was the first code you referenced? it states that 27J OR the lat expansion is a pass, as I mentioned several posts ago

3 posts later, you want to try understand the B31.3 averaging/retest rules, and you still DON'T KNOW WHAT UNITS YOUR TEST REPORT IS IN.

somebode e-mail this guy a clue

By welder5354 (**)

Date 03-16-2011 03:05 Edited 03-16-2011 03:19

Excuse me sir, but if everybody knew everything, then we would not need this site.

The lateral expansion is in mils.
There are a lot of folks on here (maybe inspectors as well), who does not know
how lateral expansion of 4 mils is derived from a weld charpy V-Notch
impact test report.
All i was asking was a little explanation on lateral expansion (mils) and how those values
were calculated the get that end result.
A lot of folks looking at Lateral Expansion (mils) 4; 8 or 5 will not know if that is a pass or fail.

By fschweighardt (***)

Date 03-17-2011 01:26

Now that we know the dimensions, we look at the code. As above, at first you identified NORSOK 601 as the code to meet. Fine. If you are only using NORSOK, 27J or .38mm lat expansion passes. You have ~28J average, and none of your values fall below 70% of the minimum You can approve the test if you want. However, as Jeff and I have pointed out, your lat expansion sucks, and you may well be using a borderline procedure.

By Victor Taylor Taylor Date 03-25-2011 20:54

Hi:

If your lateral expansion is in mils, then the absorbed energy will almost certainly be reported in ft/lbs and not Joules.

It looks to me like the results you obtained for the weld would not be acceptable by any code. It's hard to say what the problem may be since I don't have much information about the process you are using but it's safe to say the results are unacceptable.