NACE MR0175 / ISO 15156 Sour Service Standard
Engineering definition, metallurgical mechanisms, standard testing specifications, and manufacturing guidelines for closed-die forgings up to 50 kg.
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The international standard defining material requirements for metallic equipment used in oil and gas production environments containing corrosive hydrogen sulfide (H2S).
Technical Explanation & Metallurgical Principles
NACE MR0175 / ISO 15156 establishes strict metallurgical parameters to prevent Sulfide Stress Cracking (SSC), Stress Corrosion Cracking (SCC), and Hydrogen-Induced Cracking (HIC) in sour hydrocarbon service. Key requirements include strict maximum hardness limits (e.g., ≤22 HRC for carbon steels, ≤28 HRC for duplex), heat treatment conditions, and controlled environmental partial pressures.
Key Engineering Specifications & Parameters
| Technical Parameter / Metric | Engineering Benchmark / Value |
|---|---|
| Carbon Steel Limit | Hardness ≤ 22 HRC (≤ 248 HV10 / 197 HBW) |
| Duplex 2205 Limit | Hardness ≤ 28 HRC (solution annealed condition) |
| Nickel Content | Ni restricted to max 1.0% in carbon/low-alloy steels |
Application at Jayesh Forge (Rajkot Plant)
Jayesh Forge manufactures ASTM A350 LF2, SS 316L, and Duplex 2205 flanges strictly compliant with NACE MR0175 with verified hardness certification.
Related Materials, Standards & Products
Applicable Material Grades
Related Metallurgical & Testing Terms
Hydrogen-Induced Cracking (HIC) & SSCC
Stepwise internal cracking that occurs in steel exposed to wet sour gas (H2S) when atomic hydrogen diffuses into the metal and recombines into high-pressure molecular gas at inclusions.
Sour Service (Wet H2S Environment)
Piping and pressure equipment operating in environments containing moisture and hydrogen sulfide (H2S) at partial pressures exceeding NACE threshold limits.
Heat-Affected Zone (HAZ)
The portion of the base forging metal adjacent to a weld seam that has not melted but whose microstructure and properties have been modified by the intense heat of welding.
Questions Regarding NACE MR0175 / ISO 15156 Sour Service Standard
Empirical testing proves that untempered structures with hardness exceeding 22 HRC (248 HV) are acutely susceptible to sudden catastrophic sulfide stress cracking when exposed to wet H2S gas.
Request a Forging Quote with NACE MR0175 / ISO 15156 Sour Service Standard Compliance
Our Rajkot metallurgy desk is ready to review your technical drawings, testing protocols, and delivery schedules for custom closed-die forgings strictly up to 50 kg.