From www.suppliersonline.com, the following is a compositional range of Alloy 254 (stainless steel).
Carbon 0.02 max
Chromium 19.5 - 20.5
Copper 0.5 - 1
Iron Balance
Manganese 1 max
Molybdenum 6 - 6.5
Nickel 17.5 - 18.5
Nitrogen 0.18 - 0.22
Phosphorus 0.03 max
Silicon...
If you want to find out more about carbon steel in hydrogen service, I suggest you pick up a copy of API 941. It is a reference and guidelines for material selection of low alloy carbon steels in hydrogen service. This document contains the Nelson Curves which relate materials, partial...
It has been my experience in the past, from reviewed Material Certs, that it does. However, if possible, if it cannot be clarified on the cert, then contacting the supplier/manufacturer should help you to ensure that designation.
Also, I did a quick scan of ASME SA-20 which is the standard...
Now that is something I'd like to have .... "unassembled meetings". Maybe more "real" work could be done!! LOL!!
~NiM
From Dave Barry (comedian/author):
"If you had to identify, in one word, the reason why the human race has not achieved, and never will achieve, its full potential, that word...
Tenoa:
Just for your information, the API 941 document (Nelson Curves) is for high temperature hydrogen service. They don't apply to H2S (only) materials considerations or design.
~NiM
I don't know if you've looked into the country of manufacture, but the vendors we have banned from use hail from China and Germany.
And, we are looking at all metals products from Asia and Eastern Europe under a fine-tooth comb. We have gotten rotten castings from Eastern Europe that were...
Has anyone else noted a change in the quality control of these type nuts ('2H', ASMT A194) over the past couple of years?
In this ever-changing world of quality control and quality assurance, we have started digging into this topic. It all started with several field failures when the nuts were...
There is a NACE document Recommended Practice 0590 (Recommended Practice for Prevention, Detection,
and Correction of Deaerator Cracking) that may be of use to you. The deaerators in my plant are all PWHT.
~NiM
Luis:
I must say, you have an intriguing problem there. Nasty service to plan for given the conditions, contents, and material requirements. If you could eliminate one or two items, I think the choices would become much clearer.
With that, let me tell you that I haven't run into this type of...
Tolind:
Do you have a local chapter of NSPE (national society of professional engineers) that you can go to for information?
I, myself, did not work UNDER a PE for the period of time between passing the EIT and taking the PE exam. But, I was able to use PE's that were aware of my work and my...
I'd have to agree with everyone else. Bringing LOTS of reference materials is really a waste of TIME. And remember, you are on a TIMED test.
For me, it was about 10 books for the metallurgical PE. Mainly this was due to the different steels and such I thought I'd encounter. I ended up using...
0707 (Luis):
From the operating 260°C (500°F) and 671-psi Hydrogen partial pressure you state, the most current issue of API 941 Nelson Curves Figure 1 (6th edition, 2004) put you very close but still below the carbon steel curve. The data point is within 20°F (7°C) of the bottom of the curve...
Tom could probably answer a bit better on the commonality across industry, but I'll give my 2-cents.
I work in the Petroleum Refining industry and my comapny has been using MSD (Material Selection Diagrams) on newer projects for about 4-5 years now. Rudimentary material review processes and...
We have asked our piping design companies (contractors) to provide MSD's on recent projects. I would think companies like Fluor-Daniel or Jacobs may be able to provide some insight to what is laid out in a table - as long as you're not a competitor.
What you are trying to do with the...
In reflection on working for my uncle (an engineer) during college...
Don't be afraid nor ashamed to pick up and use a shovel. It is as important as using a computer, your brain, or a book full of information.
AND...
It's not the size of the wall that will stop you. It's the size of the...
I have a book entitled:
"Welding Steels without Hydrogen Cracking" by Bailey et.al. (published by Abington Publishing and distributed through ASM International).
It may give you some more insight.
~NiM
What kind of stream is passing through the valve? (Composition, temperature, pressure...)
The 2¼-Cr steel in some cases will not be a good choice. One of which is alluded to by metengr. Another case would be sulfidation corrosion.
~NiM
There are some things that a civilized being should be entitled to: life, liberty, and the pursuit of happiness. These, as defined by our forefathers are considered to be "certain unalienable rights". (It is in the Declaration of Independance, look it up.)
However, I would tend to agree that...
I agree whole-heartedly with you Greg. We should remove those "so-called" engineers from the workforce that cannot - or in some cases will not - do their profession. I have never once complained about a fellow engineer's passion for doing their work right, even if they are a bit timid. And I...
EdStainless:
Thanks for the info on cost. We've already gotten quotes and the 316 is the least cost alternative. I did reduce the wall thickness to 0.065" on the Duplex 2205 to save some money, but this is a BIG bundle. A mix of Duplex and 316 was $70,000+. However, I didn't go through the...
