×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

Stainless steel vs alloy steels?

Stainless steel vs alloy steels?

Stainless steel vs alloy steels?

(OP)
Hi guys
I need to reed this forum more often as there is such tremendous amount of useful information for the designer but there I am - still not created a habit as I'm too tired to read it after work.
Anyway.
I was designing a flange today and due to the size of the bolts I went to read Mandatory Appendix 2 of ASME VIII-1 2-2 (e).

(e) Bolts, studs, nuts, and washers shall comply with the
requirements in this Division. It is recommended that
bolts and studs have a nominal diameter of not less than
1/2
in. (13 mm). If bolts or studs smaller than 1/2 in.
(13 mm) are used, ferrous bolting material shall be of alloy
steel.


Having A193-B8 S30400 bolts into the configuration I decided to go and read ASME SA-193 spec and double check what's written in it.
I had the same confusion some time ago but didn't have time to investigate. Also I have studied materials in university but in a country much closer to the Soviet union than USA, well of course in a different language so I can't get the right feeling of what the text implies here:

This specification covers alloy and stainless steel
bolting material for pressure vessels, valves, flanges, and
fittings for high temperature or high pressure service, or
other special purpose applications.


Why the code makes difference between alloy and stainless steels? Aren't stainless steels alloys themselves?
Where does the code tell the difference between one and another?

http://en.wikipedia.org/wiki/Alloy

Reading this:
http://www.tech.plymouth.ac.uk/sme/desnotes/stainl...

3.3 Stainless steels: The addition of more than about 12% Cr renders a steel 'stainless' or corrosion resistant because of a passive layer of chromium oxide Cr2O3 on the surface. Steels containing large amounts of Cr are ferritic, as Cr is a ferrite stabiliser. Stainless steels can be classified into three main types.

Does the ASME BPV code use the same method to differentiate between alloy steel and stainless steel or is there a different criteria?

I could've posted this into the material sub forum but being ASME VIII design I found it more appropriate to post here.

Any info on the subject would be helpful!
Thanks!


RE: Stainless steel vs alloy steels?

The ferrous material refers to ALL type of alloys with main ingredient Fe. The Bronze material is not ferrous material/alloy. Conversely, the Stainless Steel is a ferrous alloy.
Cheers,
gr2vessels

RE: Stainless steel vs alloy steels?

(OP)
Thanks but this wasn't my question glasses

RE: Stainless steel vs alloy steels?

ASME VIII, Div.1 addresses carbon and low alloy steels in Chapter UCS and Stainless Alloys in Chapter UHA.
It defines them differently because of their inherent differing microstructures, mechanical properties, welding requirements, etc.

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources