Sandvik 254 SMO is a high-alloy austenitic stainless steel developed for use in seawater and other aggressive chloride-bearing media. The steel is characterized by the following properties:
Excellent resistance to pitting and crevice corrosion, PRE = ≥42.5*
High resistance to general corrosion
High resistance to stress corrosion cracking
Higher strength than conventional austenitic stainless steels
Good weldability
*The PRE is defined as, in weight-%, PRE = %Cr + 3.3 x %Mo + 16 x %N
Standards
UNS: S31254
EN Number: 1.4547
EN Name: X1CrNiMoCuN20-18-7
W.Nr.: 1.4529**
SS: 2378*
AFNOR: Z1 CNDU 20.18.06AZ*
* Obsolete. Replaced by EN.
** Nearest equivalent grade.
Product standards
Seamless tube and pipe: ASTM A269, A213, A312, NFA 49-217, EN 10216-5
UNS S31254 (Sandvik 254 SMO) in the form of seamless pipe has been approved by the American Society of Mechanical Engineers (ASME) for use according to ASME Boiler and Pressure Vessel Code section VIII, div. 1. However, there is no approval for UNS S31254 in the form of seamless tube, but according to the ASME paragraph UG-15 it is allowed to use the design values for seamless pipe according to ASME section VIII, div. 1 also for seamless tube.
NACE MR 0175 (sulphide stress cracking resistant material for oil field equipment).
The following figures apply to solution annealed condition seamless tube and pipe.
Wall thickness
Proof strength
Tensile strength
Elong.
Hardness
Rp0.2a)
Rp1.0a)
Rm
Ab)
A2"
HRB
mm
MPa
MPa
MPa
%
%
Metric units, at 20°C
<5
≥310
≥340
675-850
≥35
≥35
≤96
>5
≥310
≥340
655-850
≥35
≥35
≤96
1 MPa = 1 N/mm2
Wall thickness
Proof strength
Tensile strength
Elong.
Hardness
Rp0.2a)
Rp1.0a)
Rm
Ab)
A2"
HRB
inch
ksi
ksi
ksi
%
%
Imperial units, at 68°F
<0.187
≥45
≥49
98-123
≥35
≥35
≤96
>0.187
≥45
≥49
98-123
≥35
≥35
≤96
a) Rp0.2 and Rp1.0 correspond to 0.2% offset and 1.0% offset yield strength, respectively.
b) Based on L0 = 5.65 √S0 where L0 is the original gauge length and S0 the original cross-section area.
Impact strength
Due to its austenitic microstructure, Sandvik 254 SMO has very good impact strength both at room temperature and at cryogenic temperatures.
Tests have demonstrated that the steel fulfils the requirements (60 J (44 ft-lb) at -196 oC (-320 oF)) according to the European standards EN 13445-2 (UFPV-2) and EN 10216-5.
At high temperatures
Intermetallic phases are precipitated within the temperature range of 600–1000°C (1110–1830°F). Therefore, the steel should not be exposed to these temperatures for prolonged periods.
Temperature
Proof strength
°C
Rp0.2
Rp1.0
MPa
MPa
min.
min.
Metric units
100
230
270
200
190
225
300
170
200
400
160
190
500
148
180
Temperature
Proof strength
°F
Rp0.2
Rp1.0
ksi
ksi
min.
min.
Imperial units
200
34
40
400
27
32
600
24
29
700
24
28
900
22
26
Figure 1. Strength values (min. values) for Sandvik 254SMO and allowable stress according to ASME Boiler and Pressure Vessel Code section VIII, div. 1.
