Grouping system for steels CR ISO 15608:2000

Group 1:
Steels with a specified minimum yield strength ReH ≤ 460 N/mm2 a and with analysis in %: C ≤ 0,25 Si ≤ 0,60 Mn ≤ 1,70 Mo ≤ 0,70b S ≤ 0,045 P ≤ 0,045 Cu ≤ 0,40b Ni ≤ 0,5b Cr ≤ 0,3 (0,4 for castings)b Nb ≤ 0,05 V ≤ 0,12b Ti ≤ 0,05

Sub-group:
1.1: Steels with a specified minimum yield strength ReH ≤ 275 N/mm2
1.2 Steels with a specified minimum yield strength 275 N/mm2 < ReH ≤ 360 N/mm2
1.3 Normalised fine grain steels with a specified minimum yield strength ReH > 360 N/mm2
1.4 Steels with improved atmospheric corrosion resistance whose analysis may exceed the requirements for the single elements as indicated under 1

Group 2:
Thermomechanically treated fine grain steels and cast steels with a specified minimum yield strength ReH > 360 N/mm2

Sub-group:
2.1 Thermomechanically treated fine grain steels and cast steels with a specified minimum yield strength 360 N/mm2 < ReH ≤ 460 N/mm2
2.2 Thermomechanically treated fine grain steels and cast steels with a specified minimum yield strength ReH > 460 N/mm2

Group 3:
Quenched and tempered steels and precipitation hardened steels except stainless steels with a specified minimum yield strength ReH > 360 N/mm2

Sub-group:
3.1 Quenched and tempered steels with a specified minimum yield strength 360 N/mm2 < ReH ≤ 690 N/mm2
3.2 Quenched and tempered steels with a specified minimum yield strength ReH > 690 N/mm2
3.3 Precipitation hardened steels except stainless steels

Group 4:
Low vanadium alloyed Cr-Mo-(Ni) steels with Mo ≤ 0,7 % and V ≤ 0,1 %

Sub-group:
4.1 Steels with Cr ≤ 0,3 % and Ni ≤ 0,7 %
4.2 Steels with Cr ≤ 0,7 % and Ni ≤ 1,5 %

Group 5:
Cr-Mo steels free of vanadium with C ≤ 0,35 %c

Sub-group:
5.1 Steels with 0,75 % ≤ Cr ≤ 1,5 % and Mo ≤ 0,7 %
5.2 Steels with 1,5 % < Cr ≤ 3,5 % and 0,7 < Mo ≤ 1,2 %
5.3 Steels with 3,5 % < Cr ≤ 7,0 % and 0,4 < Mo ≤ 0,7 %
5.4 Steels with 7,0 % < Cr ≤ 10 % and 0,7 < Mo ≤ 1,2 %

Group 6:
High vanadium alloyed Cr-Mo-(Ni) steels

Sub-group:
6.1 Steels with 0,3 % ≤ Cr ≤ 0,75 %, Mo ≤ 0,7 % and V ≤ 0,35 %
6.2 Steels with 0,75 % < Cr ≤ 3,5 %, 0,7 % < Mo ≤ 1,2 % and V ≤ 0,35 %
6.3 Steels with 3,5 % < Cr ≤ 7,0 %, Mo ≤ 0,7 % and 0,45 % ≤ V ≤ 0,55 %
6.4 Steels with 7,0 % < Cr ≤ 12,5 %, 0,7 % < Mo ≤ 1,2 % and V ≤ 0,35 %

Group 7:
Ferritic, martensitic or precipitation hardened stainless steels with C ≤ 0,35 % and 10,5 % ≤ Cr ≤ 30 %

Sub-group:
7.1 Ferritic stainless steels
7.2 Martensitic stainless steels
7.3 Precipitation hardened stainless steels

Group 8:
Austenitic steels

Sub-group:
8.1 Austenitic stainless steels with Cr ≤ 19 %
8.2 Austenitic stainless steels with Cr > 19 %
8.3 Manganese austenitic stainless steels with 4 % < Mn ≤ 12 %

Group 9:
Nickel alloyed steels with Ni ≤ 10 %

Sub-group:
9.1 Nickel alloyed steels with Ni ≤ 3 %
9.2 Nickel alloyed steels with 3 % < Ni ≤ 8 %
9.3 Nickel alloyed steels with 8 % < Ni ≤ 10 %

Group 10:
Austenitic ferritic stainless steels (duplex)

Sub-group:
10.1 Austenitic ferritic stainless steels with Cr ≤ 24 %
10.2 Austenitic ferritic stainless steels with Cr > 24 %

a In accordance with the specification of the steel product standards, ReH may be replaced by Rp0,2 or Rt0.5.
b A higher value is accepted provided that Cr + Mo + Ni + Cu + V ≤ 0,75 %.
c "Free of vanadium" means not deliberately added to the material.