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1554 views
02:16 Apr-06-2005
Bob Ducanis
outsourcing NDT testing of machined parts

Hello,

I am new to the group and would like to ask a few questions if I may to obtain some recommendations of NDT testing techniques and possible firms that may be able to do the testing.

We are a high volume machine shop and have been machining parts that are subject to pressure. The parts are machined from 7/8" SQUARE 316 Stainless bar stock. We have made the parts for 15 years. Recently our end-use customer ran across a few parts that began leaking under pressure after assembly. We can detect no visible cracks or defects on the surface of the parts.

Can anyone advise if 'EDDY CURRENT' is a sutiable non-destructive test method for the condition stated and the material involved?

Are there firms that we could send parts to to have the NDT performed?

Thanks in advance for your replies.

Bob Ducanis


 
07:03 Apr-07-2005
Dave Wilk
Re: outsourcing NDT testing of machined parts Hi Bob- I think I would suggest penetrant inspection instead of eddy current. This would depend on the actual part configuration but it may be better suited for detecting potential leaks in the parts. I work for an independant lab that could provide just that type of services. (We're a NADCAP approved aerospace facility with all major certifications). You can send me an RFQ at (602) 275-3467 and maybe we can help you out!



 
04:17 Apr-07-2005

Dent McIntyre

Consultant, NDE Manager NDELevel III/3
NDT Consultant,
Canada,
Joined Nov 1998
243
Re: outsourcing NDT testing of machined parts ----------- Start Original Message -----------
: Hi Bob- I think I would suggest penetrant inspection instead of eddy current. This would depend on the actual part configuration but it may be better suited for detecting potential leaks in the parts. I work for an independant lab that could provide just that type of services. (We're a NADCAP approved aerospace facility with all major certifications). You can send me an RFQ at (602) 275-3467 and maybe we can help you out!
------------ End Original Message ------------

This sounds to me like a situation I ran into many years ago. The bar stock we were using had piping down the centre that had been drawn to a tiny stringer. We were using this material for plugs. And found leaks through these tiny stringers during pressure tests. PT tests did not find them.

I also work for a testing lab and we can test these parts for you. ET will not likely find what I have described here.

Send me an e mail for more information.




 
06:55 Apr-07-2005

S.V.Swamy

Engineering, - Material Testing Inspection & Quality Control
Retired from Nuclear Fuel Complex ,
India,
Joined Feb 2001
780
Re: outsourcing NDT testing of machined parts ----------- Start Original Message -----------
: Hello,
: I am new to the group and would like to ask a few questions if I may to obtain some recommendations of NDT testing techniques and possible firms that may be able to do the testing.
: We are a high volume machine shop and have been machining parts that are subject to pressure. The parts are machined from 7/8" SQUARE 316 Stainless bar stock. We have made the parts for 15 years. Recently our end-use customer ran across a few parts that began leaking under pressure after assembly. We can detect no visible cracks or defects on the surface of the parts.
: Can anyone advise if 'EDDY CURRENT' is a sutiable non-destructive test method for the condition stated and the material involved?
: Are there firms that we could send parts to to have the NDT performed?
: Thanks in advance for your replies.
: Bob Ducanis
------------ End Original Message ------------

Dear Bob,

Leaking under pressure is not really unusual since a small seam on the bar or a find piping can cause such problem. It should be possible to pinpoint the point of leak by careful pickling and grinding. If the leak path is close to the surface, eddy current is a good option. If on the other hand, it is deep within close to the centre of the bar, focussed immersion ultrasonic testing using high frequencies may be the better choice.

We would have loved to help you by exploring the leak but we are in India.

Swamy




 
04:36 Apr-08-2005

Randy Plis

Sales,
Metals Testing Company,
USA,
Joined Jun 2002
9
Re: outsourcing NDT testing of machined parts Hello Bob,

Yes, there are a number of production oriented test labs that can assist you in this application. Metals Testing Company www.mtc62.com is one such company located in South Windsor, CT (USA). We are also Nadcap approved and primarily support the aerospace industry. Please call 1-860-289-8225 to discuss your application in greater detail. Thanks.

----------- Start Original Message -----------
: ...a high volume machine shop and have been machining parts that are subject to pressure. The parts are machined from 7/8" SQUARE 316 Stainless bar stock. We have made the parts for 15 years. Recently our end-use customer ran across a few parts that began leaking under pressure after assembly. We can detect no visible cracks or defects on the surface of the parts.
: Can anyone advise if 'EDDY CURRENT' is a sutiable non-destructive test method for the condition stated and the material involved?
: Are there firms that we could send parts to to have the NDT performed?
: Thanks in advance foryour replies.
: Bob Ducanis
------------ End Original Message ------------




 
05:14 Apr-11-2005
Marty Wenzig
Re: outsourcing NDT testing of machined parts ----------- Start Original Message -----------
:Your e-mail regarding the testing of parts, was forwarded to me. I'm sure that you're finding out that all NDT Professionals have their own techniques in problem solving. Please consider my approach.

I think the prudent, economical approach would be to gas (helium) Leak Test the units. This test would be more sensitive (3 to 4 decades more sensitive) than your current approach. It will also verify if the fittings to the test unit are failing. Helium Leak Testing is sensitive, economical, and can be a “go no/go” type of test. There are variations on how to do this type of testing. My initial thought is to blank off one end of the part, and evacuate the inside with a vacuum pump to a low pressure; and subject the outside to a helium gas. If your part leaks, it will leak quite quickly. Helium leak testing can find leakage rates in the 1.0 X 10-8 range (if needed).

My company is ISO 17025 accredited in Nondestructive testing. Our quality program addresses (besides the ISO standards) 10CFR50 Appendix B; MIL-I-45208 and the ASME B&PVC Section III.

We are ASNT / ACCP Professional Level III's in all five (5) methods offered in this program; ASNT NDT Level III (certified by examination) in (6) six methods; ISO 9712 Level 3 (including the Pressure Equipment Directive EN 473); and NAVSEA Examiners(we support a number of industry segments in PT, UT, RT, VT, MT and LT.

I would welcome the opportunity to support your testing needs. You can call me at 412.963.1900. Also, you may want to check out our website at www.itls-labs.com .

A.M. (Marty) Wenzig

------------ End Original Message ------------




 


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