ChlorideSCCAssessment

Package: neqsim.process.corrosion

Standards: NORSOK M-001 Rev 6, ISO 15156-3, EFC 17, MTI Publication 15

Evaluates whether an alloy is susceptible to chloride-induced stress corrosion cracking (Cl-SCC) based on temperature, chloride concentration, and material type. Each alloy family has a defined temperature–chloride envelope beyond which SCC risk is unacceptable.

Supported Material Types

Material Max Temperature Basis Key Limitation
304L Lowest tolerance Avoid above 50°C with chlorides
316L Moderate tolerance O2 presence reduces limit by 25°C
22Cr duplex Good resistance Max ~120–200°C depending on Cl
25Cr super duplex Very good resistance Max ~150–250°C depending on Cl
Nickel alloy (625/C-276) Excellent resistance Max 300–350°C

Risk Classification

Risk is based on the temperature margin (operating temperature minus maximum allowable temperature):

Margin Risk Level
< −30°C Low
−30°C to −10°C Medium
−10°C to 0°C High
≥ 0°C Very High

Quick Start

Java

import neqsim.process.corrosion.ChlorideSCCAssessment;

ChlorideSCCAssessment scc = new ChlorideSCCAssessment();
scc.setMaterialType("316L");
scc.setTemperatureC(80.0);
scc.setChlorideConcentrationMgL(50000);
scc.setOxygenPresent(true);
scc.setStressRatio(0.8);
scc.evaluate();

System.out.println("SCC Acceptable: " + scc.isSCCAcceptable());
System.out.println("Risk Level: " + scc.getRiskLevel());
System.out.println("Max Allowable T: " + scc.getMaxAllowableTemperatureC() + " °C");
System.out.println("Temperature Margin: " + scc.getTemperatureMarginC() + " °C");
System.out.println("Recommended Upgrade: " + scc.getRecommendedUpgrade());

Python

from neqsim import jneqsim

ChlorideSCC = jneqsim.process.corrosion.ChlorideSCCAssessment

scc = ChlorideSCC()
scc.setMaterialType("316L")
scc.setTemperatureC(80.0)
scc.setChlorideConcentrationMgL(50000)
scc.setOxygenPresent(True)
scc.evaluate()

print(f"Acceptable: {scc.isSCCAcceptable()}")
print(f"Risk: {scc.getRiskLevel()}")
print(f"Upgrade to: {scc.getRecommendedUpgrade()}")

Input Parameters

Method Type Default Description
setTemperatureC(double) double 60.0 Operating temperature (°C)
setChlorideConcentrationMgL(double) double 0.0 Chloride concentration (mg/L)
setMaterialType(String) String “316L” Alloy type: “304L”, “316L”, “22Cr”, “25Cr”, “Nickel alloy”
setStressRatio(double) double 0.8 Applied stress as fraction of yield (0–1)
setOxygenPresent(boolean) boolean false Dissolved O2 present (> 10 ppb) — reduces limit by 25°C for austenitic
setAqueousPH(double) double 7.0 pH of aqueous phase

Output Methods

Method Return Type Description
isSCCAcceptable() boolean Whether SCC risk is acceptable
getRiskLevel() String “Low”, “Medium”, “High”, “Very High”
getMaxAllowableTemperatureC() double Maximum allowable temperature for this material + chloride level
getMaxAllowableChlorideMgL() double Maximum allowable chloride for this material + temperature
getTemperatureMarginC() double Operating T minus max allowable T (negative = margin available)
getRecommendedUpgrade() String Suggested material upgrade if risk is unacceptable
getNotes() List<String> Assessment notes and warnings
toMap() Map All results as a LinkedHashMap
toJson() String Complete JSON report

Typical Temperature–Chloride Limits

These are approximate limits for austenitic stainless steels (316L):

Chloride (mg/L) Max T (°C) without O2 Max T (°C) with O2
< 50 200 175
50–500 120 95
500–5,000 80 55
5,000–50,000 60 35
> 50,000 40 15

Duplex and super duplex grades tolerate significantly higher temperatures and chloride levels.