PREN Pitting Resistance Index Calculator
Stainless Alloy Metallurgy: Calculate Pitting Resistance Equivalent ($\text{PREN}$, $\text{PRENW}$), critical pitting temperature (CPT), and seawater suitability.
Alloy Chemical Composition (wt%)
Standard Alloy Presets
Pitting Indices & Critical Temperatures
Standard PREN (Cr+3.3Mo+16N)
--
PRENW (+1.65W): --
Estimated CPT (ASTM G48)
-- °C
In Fahrenheit: -- °F
Seawater Pitting Suitability
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NORSOK M-630 Standard
Duplex PREN₃₀ Index
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Alloy Class: --
Industry Thresholds:
• $\text{PREN} \ge 40$: Mandatory for unchlorinated seawater and subsea equipment (NORSOK M-001 / ISO 21457).
• Grade 316L ($\text{PREN} \approx 24$) is vulnerable to severe pitting and crevice corrosion in marine immersion.
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