German norm equivalency

[Eckbert]

I'm looking for a American equivalent for the German (SEW) steel 30CrMoNiV5-11, used in steam turbines.
Could someone help me?

 

[TVP]

I believe the correct standard is ASTM A 470, Class 8. I do not have this standard, but perhaps someone else who does have it can confirm.

 

[metengr]

The above is a DIN 1.6946 and refers to an LP steam turbine rotor steel. The chemical composition of this steel is as follows;

DIN 1.6946
C 0.28-0.32
Si 0.30 max
Mn 0.15-0.40
P 0.015 max
S 0.018 max
Cr 1.2-1.8
Mo 0.25-0.45
Ni 2.4-3.1
V 0.05-.15


You absolutely need to review ASTM A470 and evaluate chemical composition and mechanical properties to replace the DIN rotor steel. Ni is too low in Class 8. Classes 5,6 or 7 are a closer chemical match to the DIN steel.

 

[Eckbert]

Thanks, TVP and metengr for the information. I`ll try this standard

 

[TVP]

metengr,

The composition that you listed for 1.6946 does not match what I found for 30CrMoNiV5-11. Stahlschl[ü]ssel 2001 shows the following composition for 30CrMoNiV5-11 (1.6946) from SEW 555:

C = 0.28-0.34
Si = 0.30 max
Mn = 0.30-0.80
P = 0.015 max
S = 0.018 max
Cr = 1.10-1.40
Mo = 1.00-1.20
Ni = 0.50-0.75
V = 0.25-0.35

 

[metengr]

TVP;
Very interesting because my source for the information was from an EPRI Report Volume 1, "Weld Repair of Steam Turbine Discs and Rotors" TR107021 V-1 3963 in my possesion. I suspect they cross referenced the HP rotor disc steel with an LP rotor disc steel in the Table. There is a reference to HP rotor steel as DIN 1.6946 30 NiCrMoV5 11, which is under low pressure disc material. EPRI lists 30 NiCrMoV 4 11 under LP rotor disc material and this would make better sense for the higher nickel content. Can you check on this?

 

[TVP]

The composition that you provided corresponds to the grade 26NiCrMoV11-5 (1.6948) from SEW 555 except that the C content for this grade is 0.22-0.32. Grade 35NiCrMoV11-5 (1.6949) is also close. I could not find 30NiCrMoV4-11.

 

[Eckbert]

I'm actually interested in some material's properties like Young's modulus, Poisson's coefficient and thermal expansion coefficient, measured at high temperatures. Do you know where can I find it?

 

[TVP]

For this type of information you will either need to perform testing on actual samples, or discuss it directly with the steel producer. High temperature properties of this specific alloy are not likely to exist in the public domain.