Alloy choice to comply with A105? 2

[ccaissie]

We are fabricating an ANSI A105 flange, 6"-900# class RFWN with engineered modifications.

I have been told that A105 requires a carbon manganese alloy similar to AISI 1330, but with less manganese.

What stock alloy is appropriate?

Regards,

Colin, UET Mixers Inc.

 

[metengr]

Review ASTM A105 Standard Specification

http://www.astm.org/cgi-bin/SoftCart.exe/index.shtml?L+mystore+gyhm8818

 

[kenvlach]

Perhaps helpful: Grade 1 & 2 compositions of ASTM A266, 'Standard Specification for Carbon Steel Forgings for Pressure Vessel Components' satisfy A105 wrt. C, Mn, P & S (A266 is actually stricter re P & S). Additional analyses would be necessary to ensure not exceeding A105 limits on Cu, Ni, Cr, Mo, V & Nb (Cb). However, invoking the Supplemental Requirements S12 & S15 of A266 for Grades 1 & 2 limits these same elements. These elements can also be limited by invoking S1 of A788 referenced by A266.
A266 Grade 2 has similar mechanical properties to A105.

Also, Grade III of ASTM A765, 'Standard Specification for Carbon Steel and Low-Alloy Steel Pressure-Vessel-Component Forgings with Mandatory Toughness Requirements' has chemistry & mechanical properties similar to A105.

Caveat: A105 doesn't mention vacuum induction melting (allowed for the 2 other specs. per Melting Practices in A788). A105 explicitly required fully killed steel which seems to be met by referenced Melting Practices in A788.

 

[metengr]

I believe ccaissie should also read ASME B16.5, which is fabrication of Pipe Flanges and Flanged Fittings. In this case, the appropriate list of materials that can be used is in Table 1A of ASME B16.5. If other materials are going to be used in lieu of A105, they have to meet ASME Section II material specification requirements, not ASTM (unless identical to ASME).