BS ISO 6306:2019 pdf download – Chemical analysis of steel — Order of listing elements in steel standards
This document specifies an order for listing elements within the chemical composition of steels and most other iron-based alloys, excluding foundry irons.
NOTE This document has been developed and is used by ISO/TC 17/SC 4, but can also be used by other ISO/TC 17 subcommittees.
2 Normative references
There are no normative references in this document.
3 Terms and definitions
No terms and definitions are listed in this document.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at
— IEC Electropedia: available at
4 Order of listing elements in steel standards
The elements are divided into three groups. These groups have no real technical significance but they are considered to provide the easiest means of readily remembering the following order.
Group 1 includes five elements that are regarded as the most important in all types of steel (C, Si, Mn, P and S). Also included in this group are the four elements of the next greatest importance in alloy steels and stainless steels (Cr, Ni, Mo and N).
Group 2 is reserved for any element not assigned in group 1 or group 3. When more than one such element is determined, they should be arranged in alphabetical order of their chemical symbols. Usually these are the following 12 elements: Al, As, B, Co, Cu, Nb, Pb, Sn, Ti, V, W and Zr, which are commonly determined in a wide variety of commercial steels.
Group 3 is reserved for hydrogen H.
The recommended order thus becomes:
— C, Si, Mn, P, S, (Ni), Cr, (Ni), Mo, (Ni), N;
— other elements determined, in alphabetical order of their chemical symbols, such as Al, As, B, Co, Cu,Nb, Pb, Sn, Ti, V, W, Zr;
— H.BS ISO 6306 pdf download.