AFNOR steel designation system explanation 3

[ianhoag]

Can anyone explain, or does anyone have a good reference for explaining the AFNOR steel designation system?
I need something similar to the explanations for other designation systems as provided at:

http://www.slideshare.net/worldofsteel/steel-naming-conventions

 

[Goahead]

AFNOR used to have a set of rules determining the designation of steels whereby the first figures expressed 100 times the carbon content, then the letters showed the main alloying elements (C for Cr, N for Ni, D for Mo etc.) and the following figure expressed 4 times the percentage content of the first material in the list.
for example:

16NCD13 indicated a steel with 0.16% C and Ni (~3.25%) + Cr Mo (unspecified content)

Stainless grades were preceded by Z, and then the figure following the letters would indicate the percentage of the element (without division by 4)

However according to:

http://www.keytometals.com/page.aspx?ID=CheckArticle&site=kts&NM=40

they seem to have opted for a serial number classification.

The old designation can still be found in comparison tables like the following:

http://www.grantadesign.com/resources/materials/designations/ferrous.lowalloysteel.htm

http://antongcorp.com/images/file/material-standard-flanges.pdf

(1st page)

http://www.starch.dk/isi/tables/steels.htm

http://www.metalravne.com/selector/html/steel_index.html

http://mdmetric.com/tech/InternationalMaterialGradeComparisonTable.pdf

http://www.meusburger.com/media/files/Materialqualitaeten/Materialqualitaeten_E.pdf

A comprehensive book is:

ASTM DS67C
Handbook of Comparative World Steel Standards (book for sale)

The index from the above can be downloaded from:

http://www.astm.org/DIGITAL_LIBRARY/MNL/SOURCE_PAGES/MNL12064D_index.pdf

http://www.welding-advisers.com/

 

[ianhoag]

Goahead, Thanks! That was the kind of explanation I was looking for. However, I could really use a complete list of the letter codes used by the old AFNOR convention, especially since the standard chemical symbols are not used. We recently replaced a CD4MCu part with CD6MN, using DIN 1.4593 and 1.4468 metals respectively. CD4MCu was originally specified. I thought the CD might indicate something the way X indicates stainless steel. At first, I thought CD might indicate DUPLEX, but both the DIN numbers listed below are listed as fully austenitic, not Austenic & Ferritic as I would expect for DUPLEX. Also, the 4 and 6 do not seem to match any of the rules you stated. Perhaps, the DIN numbers we used are not good matches for the AFNOR designations. Chemical compositions are as follows:
MATERIAL DESIGNATION
1.4593
Country/Standard: Germany / DIN
Subgroup: DIN EN 10283 Corrosion resistant steel castings
Comment: Fully austenitic grade. Numerical designation 1.4557 is replacement of the numerical designation 1.4593 according to EN 10283:2010
Criteria Min. Max.
C None 0.025
Cr 19.5 20.5
Cu 0.5 1
Mn None 1.2
Mo 6 7
N 0.18 0.24
Ni 17.5 19.5
P None 0.03
S None 0.01
Si None 1

MATERIAL DESIGNATION
1.4468
Country/Standard: European Union / EN
Subgroup: EN 10283 Corrosion resistant steel castings
Comment: Fully austenitic grade
Criteria Min. Max.
C None 0.03
Cr 24.5 26.5
Mn None 2
Mo 2.5 3.5
N 0.12 0.25
Ni 5.5 7
P None 0.035
S None 0.025
Si None 1

 

[EdStainless]

The CD alloys are not AFNOR.
These are cast alloy designations.
C is corrosion resistant (low carbon)
D refers to the Cr eq vs Ni eq ratio. They are different fields on the chart, and D is duplex.
The 4 is 0.04% max C and 6 is 0.06% max C
In this case M is moly, Cu is copper and N is nitrogen.

Look at ASTM A995

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