PREN value calculator
Pitting Resistance Equivalent Number (PREN)
The PREN value is a measure of the corrosion resistance of a stainless steel.
The detailed test methods are defined in the ASTM G48.
In general, the higher the PREN value, the more corrosion-resistant the steel is.
The PREN value is calculated using the following formulas
PREN = 1 x %Cr + 3,3 x %Mo + 16 x %N
Steels with PREN values above 32 are considered seawater resistant.
| Eingabe | ||||||
|---|---|---|---|---|---|---|
|
Cr %
|
Mo %
|
N %
|
||||
| Calculation of PREN value | ||||
|---|---|---|---|---|
|
PREN value
|
||||
PREN = 1 x %Cr + 3,3 x ( %Mo + 0,5 x %W ) + 16 x %N
Furthermore, in DIN EN ISO 15156 and in the American NACE – for use in an environment containing hydrogen sulfide in oil and gas production – a PREN value ≥ 40 is specified for duplex steels. Exception: With a molybdenum content ≥ 1.5%, a PREN value ≥ 30 is permitted.
In these standards, the calculation of the PREN value, taking into account tungsten [W] in the alloy, is defined as follows:
| Eingabe | ||||||
|---|---|---|---|---|---|---|
|
Cr %
|
Mo %
|
W %
|
N %
|
|||
| Calculation of PREN value | ||||
|---|---|---|---|---|
|
PREN value
|
||||