From TWI job knoweldge 103

[purode333]

Dear sir,

If we see the TWI- Job knoweldge 103, there is table as shown below.
Table 1 Typical compositions of some austenitic stainless steel alloys

ASTM No.
(type) Composition wt% Microstructure
C (max) Si (max) Mn (max) Cr Ni Mo Others Austenite - A
Ferrite - F
304 0.08 0.75 2.0 18/20 8/11 - - A+2/8%F
304L 0.035 0.75 2.0 18/20 8/11 - - A + 2/8%F
304H 0.04 - 0.10 0.75 2.0 18/20 8/11 - - A + 2/8%F
304N 0.08 0.75 2.0 18/20 8/11 - 0.1/0.16N A + 2/8%F
316 0.08 0.75 2.0 16/18 11/14 2/3 - A + 3/10%F
347 0.08 0.75 2.0 17/20 9/13 - Nb : 10xC A + 4/12%F
321 0.08 0.75 2.0 17/19 9/12 - Ti: 5xC A + 4/12%F
310 0.15 0.75 2.0 24/26 19/22 - - 100% A
309 0.08 1.0 2.0 22/24 12/15 - - A + 8/15%F
308L (generally filler metal only) 0.03 1.0 2.0 19/21 10/12 A + 4/12%F

In this table what is meant by 2/8 % F- i know that F is delta ferrtie , only want to know what is 2/8 and why 316L material not shown in table.
Any special reason behind the not showing such common usable material 316L.

Pls giude
Regards
Prasad rode

 

[metengr]

The nomenclature means A (austenite phase) + (and) 2/8 is 2 to 8% ferrite phase range

 

[purode333]

Thanks for the clarify about ferrite phase range.

But why they not shown 316L, however, shown 304, 304L, 304H, 304N.

Why not 316L. Any special reason?

This is most common used material.

 

[metengr]

Possibly was left out because 316L follows 316 regarding ferrite content. The same is true for 309L being left out.

 

[purode333]

Thank you