UP-P91 (S1CrMo91)
SAW (submerged arc welding) wires for creep resisting steels

Classification DIN EN ISO

24598-A-S S CrMo91

Material No.


Classification AWS

A5.23 EB91


TÜV 03274, CE

Characteristics and application

Submerged arc welding wire for high temperature, creep resisting, modified 9%Cr-1%Mo martensitic steels (T91/P91). T91/P91 steel is commonly used at service temperatures up to 620°C and the UP-P91 wire has approval for long term service up to 650°C. V, Nb and N additions provide this ‘creep strength enhanced ferritic’ (CSEF) alloy with improved high temperature creep resistance compared to standard CrMo creep resistant alloys. Alloy T91/P91 is widely used in the power generating industry for fossil fuel ultra-super-critical (USC) power plant boilers and turbines; the alloy is also finding applications in the chemical and oil and gas industries.

Base materials

For matching P91, 9%Cr-1%Mo modified, creep resisting martensitic steels.
X10CrMoVNb 9 1
ASTM: A182/A336 grade F91, A213 grade T91, A217 grade C12A, A234 grade WP91, A335 grade P91, A387 grade 91

Typical analysis in %

C: 0,10
Si: 0,32
Mn: 0,50
Cr: 9,20
Ni: 0,45
Mo: 0,95
V: 0,20
Nb: 0,05

Yield strength in Mpa


Tensile strength in Mpa


Elongation in %

4d/5d: ≥17

Typical heat treatment

Preheat temperature: 200°C
Interpass temperature: max. 300°C
PWHT: 760°C

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