Additive Manufacturing of Pressure Equipment - Progress? 1

[marty007]

Hello,

Does anyone know if there has been any progress within the ASME committees on additive manufacturing of pressure equipment?

Today I was shown an ultra-compact heat exchanger, that was additively manufactured in Inconel 625.

Fortunately, it is still small, and meets the exclusion criteria of most States (<6" dia), but the client wants to scale this up larger in the near future.

Any news?

Cheers,
Marty

 

[TGS4]

There is a large and active group working on a framework for additive manufacturing. There are a multitude of issues, as each I've must be addressed specifically.

Progress is being made. If you're interested, they met in the Wednesday morning of Code Week. The next one is Aug 1 in DC.

 

[XL83NL]

Marty, do you have a link for that HEX in 625 you mentioned?
There was a similar thread on AM about 3 years ago;

https://www.eng-tips.com/viewthread.cfm?qid=391985

 

[EdStainless]

You have to remember that today there are none of the additive process that can result in having mechanical properties that are the same in different orientations within a part. And the resulting microstructures, toughness, and fatigue properties are anyone's guess until you make a part and destructively test it.
And then we are not even talking about internal defects.
For small non-load critical parts it is great. And if you need intricate internal flow passages it is wonderful. But structural parts, not yet.

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P.E. Metallurgy, Plymouth Tube

 

[XL83NL]

Well summed up Ed. Thanks

 

[marty007]

Thanks everyone for your responses.

XL83NL - no there is nothing available online.

EdStainless - Regarding the destructive testing, I was thinking along these lines as well. I wonder if it would be prudent to have these parts proof tested until it is proven that material quality is reproducible.

Cheers,
Marty

 

[TGS4]

As far as I know, the initial framework will involve burst testing of sample parts. I also understand that the only material currently under consideration is 316SS powder bed fusion, with a maximum design temperature 50°F colder than the start of time-dependent properties governing the allowable stress. Both mechanical strength and fatigue resistance are being examined. Hot Isostatic Pressing (HIP) is likely to be included in the procedure to permit closer-to-forged densities.

However, it should be noted that additive manufacturing is rather advanced, and it is quite likely that you have already flown on an airplane that has additive-manufactured parts in the jet turbine. That includes ETOPS 180 minute aircraft.

 

[DriveMeNuts]

I attended a presentation by Imeche in the UK recently about Additive manufacturing.

I learnt that the material properties of Stainless steel AM after being heat treated and cleared of flaws using a CT scan, is somewhere between conventional rolled and forged Stainless.

The first ISO standard for additive manufacturing is for Stainless steel and is due to be released this year if it hasn't already been released.

Additive manufacturing technology appears to be very advanced in the laboratory. It now seems to be at the stage of gaining experience and confidence in applying it to the real world.

Applications do still seem to be limited by the size of the AM machine and NDT scanner.

 

[EdStainless]

The CT scan of a part costs more than building it.
HIP is required to assure full density.
Yes, AM parts are flying.
These are cases where the original machined part had a 50x SF and the AM part is half the weight and still has a 20x SF.
And none of them, are in fatigue limited applications.
The work with Ti 6-4 is the mast advanced, working with SS is more difficult.
The next step will be to develop alloys that are optimized for AM, and then run the process closed loop in order to control microstructure and grain size.

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P.E. Metallurgy, Plymouth Tube