WALWORTH® Ball valve - Sunbelt Supply Co.
WALWORTH® Ball valve - Sunbelt Supply Co.
WALWORTH® Ball valve - Sunbelt Supply Co.
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NACE SERVICE VALVES<br />
The National Association of <strong>Co</strong>rrosion Engineers (NACE) establishes<br />
standards for materials resistant to sulfide stress cracking (SSC) to<br />
be used in hydrogen sulfide (H 2 S) bearing hydrocarbon service.<br />
NACE standard MR0175-2002 defines a sulfide stress cracking<br />
region based on the relationship of H 2 S present to the total<br />
operating pressure.<br />
IMPORTANT CONSIDERATIONS WHEN SPECIFYING NACE SERVICE:<br />
1. Hydrogen Ion <strong>Co</strong>ncentration (PH)<br />
2. <strong>Co</strong>ncentration and Total Pressure of Hydrogen Sulfide (H 2S)<br />
3. Water, Carbon Dioxide (CO 2) and Chloride <strong>Co</strong>ncentration<br />
4. Service Temperature<br />
The customer may select <strong>valve</strong>s made out of alloy or carbon steel<br />
material with controlled hardness and/or stainless steel material<br />
depending on the severity of the fluid. For <strong>valve</strong>s that have bodies<br />
26 www.walworthmx.com<br />
This must be considered when specifying <strong>valve</strong>s for service where H 2 S is<br />
present as a proper selection of materials is a customer responsibility.<br />
Sulfide stress cracking in materials not suitable for H 2 S service can result<br />
in a sudden failure with damage to equipment and harm to personnel.<br />
with a controlled hardness of RC 22, B7M studs and 2H nuts may be<br />
combined with a customer selection trim and manufactured to meet<br />
NACE MR0175-2002 requirements.
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