25-6Mo 1.4529 UNS N08926

Introduction:
This is one of four similar specifications for 6%Mo superaustenitics
X NiCrMoCuN 25 20 6 (1.4529), UNS NO8367, UNS NO8925 and UNS NO8926. Each has controlled compositions with nominally 21%Cr 25%Ni 6.5%Mo 0.2%N with some variations (notably Cu and N) between specifications. Compared with common austenitic steels, they are considerably strengthened by the nitrogen addition, and their higher nickel content provides good resistance to chloride stress-corrosion cracking plus less potential to form deleterious phases, eg. sigma. Good resistance to pitting and crevice corrosion in seawater (PRENs average 44-46). Formable and weldable. Design stresses at temperatures up to 400C are given for some types in ASME II.

Composition:
20Cr-25Ni-6Mo-1Cu-0.2N


Similiar Specifications:
ASTM UNS N08367
20-22%Cr, 23.5-25.5%Ni, 6-7%Mo, 0.18-0.25%N, <2%Mn, <0.03%C <0.75%Cu
ASTM UNS N08925
19-21%Cr, 24-26%Ni, 6-7%Mo, 0.10-0.20%N, <1%Mn, <0.02%C, 0.8-1.5%Cu
ASTM UNS N08926
20-21%Cr, 24.5-25.5%Ni, 6.0-6.8%Mo, 0.15-0.25%N, <1%Mn, <0.02%C, 0.8-1.0%Cu
DIN/SEW X1 NiCrMoCuN 25 20 6 1.4529
19-21%Cr, 24-26%Ni, 6-7%Mo, 0.10-0.25%N, <2%Mn, <0.02%C, 0.5-1.5%Cu


Applications:
Uses of the superaustenitic 25%Ni20%Cr6.5%MoCu-N steels include:
Condenser and cooling-water piping for power stations and other installations requiring resistance to
seawater.
Seawater and product piping systems on offshore platforms.
Duct liners and components for flue gas desulphurization plant.
Plate or frame heat-exchangers.
Chloride-contaminated phosphoric and sulphuric acid solutions.
Salt concentration and crystallization.
Pulp and paper plant.
Reverse osmosis high pressure piping.


Product Forms:
Plate,sheet & strip
ASTM UNS N08367 A240
ASTM UNS N08925 A240
ASTM UNS N08926 A240