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Up Topic Welding Industry / Inspection & Qualification / Why did this fail Charpy V-notch impact
- - By Mikeqc1 (****) Date 07-30-2008 15:45
Why did this fail Charpy V-notch impact

Could anyone tell me why this has been rejected for Impact testing?
Material SA-516 Grade 70
10mm x 10 mm x 55mm bar
-50 f
Orientation longitudinal
Sample 1 impact strength = 47    Mils lateral expansion=  43    % shear fracture area = 50
Sample 2 impact strength = 13    Mils lateral expansion=  18    % shear fracture area = 20
Sample 3 impact strength = 24    Mils lateral expansion=  23    % shear fracture area = 20
AVRG.= 28
ASME S-5 per SA-20
And did the lab even need to report the Mils lateral expansion and % shear fracture area because in S5.4 the recorded results Shall include test soecimine orientation , size , tempature, absorbed energy value , and, if specified in the po for other than class VI plates lateral expansion and opposite the notch. The percent shear fracture shall also be recorded if specified by the po.
My PO states normalized with supplement S-5 SA-20, of course I will request that the parts be retested as the test bars were not normalized, but Im not sure why they consider these results as failures.
MDK
Parent - - By GRoberts (***) Date 07-30-2008 16:40
What was your acceptance criteria?  What code does the work fall under?
Parent - - By Mikeqc1 (****) Date 07-30-2008 16:50
ASME
S-5 per SA-20
the steel is 3/4 thk sa516 gr 70
Parent - By HgTX (***) Date 07-30-2008 17:09
What are the specific Charpy requirements stated in the ASME code you cite?  There should be a minimum average and also a minimum for any individual value.

Because different standards require different parameters to be reported, many labs are in the habit of reporting everything so that they don't accidentally leave something out.

Hg
Parent - - By CWI555 (*****) Date 07-30-2008 16:50
More information is needed for an accurate answer. However; just looking at the numbers, sample 2 looks a bit low. Can't tell you anything more than that without specifics.
Parent - - By Mikeqc1 (****) Date 07-30-2008 17:06
what  more is needed?
do you have ASME?
Parent - - By CWI555 (*****) Date 07-30-2008 17:58
I have access to most codes.
Are there specific contractural requirements,
I.E. acceptance criteria, specifications etc.

Is this straight up straight down ASME with no other modifiers?
Parent - - By Mikeqc1 (****) Date 07-30-2008 18:15
The PO that we made out for the purching of this material stated SA 516 GR 70 3/4 in thk plate normalized with special supplement S5 per SA20. that is all no more no less.
I take that as this steel needs to meet MIN requirments of SA20 S5, and im not sure why they rejected this piece.
I do not want to sway anyones answers so i do not want to write out the criteria for impacts. if there is somthing that was over looked by me, i would not include this in the post.
MDK
Parent - - By new tito (***) Date 07-30-2008 18:38
I don't deal with Charpy test, but looking at SA-20 S5, it appears that the test should have passed.  The minimum value measured was above the minimum allowed.

Have you contacted the lab and asked why it failed?
Parent - By Mikeqc1 (****) Date 07-30-2008 18:47
That is the conclusion i have come to , I dont think this should have failed as you said the lowest result was above the min set for 1 impact and the average was within. I will look into why they have this as a reject.
MDK
Parent - - By CWI555 (*****) Date 07-30-2008 19:37
It's a legitimate failure. The minimum singular impact value is 16 for 1 specimen. (SA-20 table A2.15) Your test data shows a value of 13 in sample 2.

Regards,
Gerald
Parent - - By new tito (***) Date 07-30-2008 22:00
I guess it would help to have the unit of measurement that the lab reported in?

Table A1.15 shows a minimum of 12ft-lbs
Table A2.15 shows a minimum of 16 J

A(2) is for SI units.
Parent - By michael kniolek (***) Date 07-31-2008 01:29 Edited 07-31-2008 01:45
it was ft/lbs 12 ft-lbs table A1.15
but, i wonder about lateral expansion and shear frac % any 1 know if this could be the rejection cause?
sorry about not showing the unit of measure.
this order has really been messed up, 2 line items on the po
the first was a burned shape that was not normalized at the mill, cut then when they looked at the po ....oooops so they sent them out for treatment, then when i got them.....no impacts
the second was normalized at the mill but not impact tested
so...during my review of the MTR no impact results and no report for independent testing.
i received an E-mail saying "sorry we missed that part of the PO requirments will have the test done"
ok no big deal
i get the report with .an email saying the impacts failed, i think we should have the test bars normalized......
ya think, well anyway i guess thats why they were the cheapest bid, gotta train the new suppliers.
thanks to all for the input, ill need to call them to find out what the problem is.
i wonder if the report has fallen victim to cut and paste syndrome.
MDK 
Parent - - By CWI555 (*****) Date 07-31-2008 10:11
Thats true, I assumed apples to apples
Parent - - By js55 (*****) Date 07-31-2008 19:23 Edited 07-31-2008 19:25
I know of no spec, code, etc. that requires numbers pass a requirement in both impact strength and lateral expansion. Some codes switch based upon materials or tensile strength, etc, but not both at the same time.
And they are not translatable.
And I gotta say, those numbers overall look low for 516-70, even at -50.
Parent - - By CWI555 (*****) Date 07-31-2008 19:39
API 620 2008 Paragraph Q 2.2.3
c) The longitudinal charpy v notch impact values shall conform to table Q-2. (minimum 25ft-lb, 1 set can go to 20 without retest.
d) Each test shall consist of three specimens, and each specimen shall have a lateral expansion opposite the notch of not less than 0.015 in. (15 ml) as required by ASTM A353, A553, and A645.

Regards,
Gerald
Parent - - By js55 (*****) Date 07-31-2008 20:25
Well, there ya go. As soon as you start makin absolute statements (even with proviso's) it'll surely bite ya in da azz.
thanks Gerald.
Parent - - By CWI555 (*****) Date 07-31-2008 20:54
They are not the usual, but when you get into cryogenic service temperatures they start poping up.
Parent - - By js55 (*****) Date 07-31-2008 21:15
And then when you get into really cryo's with fully austenitics they can completely go away.
As in using notched tensiles for nickels/coppers etc in B31.3, instead of impacts.
Parent - - By michael kniolek (***) Date 08-02-2008 01:59
well, i have recieved the new reports for the imapct tests and the NORMALIZED test bars  for the 2.5" did pass, and the .75" test report was victim to a mistake and has been changed, thanks for the input on this subject. I thought i was taking crazy pills for a minute.
MDK
Parent - By CWI555 (*****) Date 08-04-2008 10:17
If you have some pass them around
Up Topic Welding Industry / Inspection & Qualification / Why did this fail Charpy V-notch impact

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