Valve Standard Reference
NACE MR0103
NACEMaterials Resistant to Sulfide Stress Cracking in Corrosive Petroleum Refinery Environments
NACE MR0103 specifies the metallurgical requirements for materials used in petroleum refinery environments where wet hydrogen sulfide (H₂S) can cause sulfide stress cracking (SSC).
Overview — NACE MR0103
NACE MR0103 specifies the metallurgical requirements for materials used in petroleum refinery environments where wet hydrogen sulfide (H₂S) can cause sulfide stress cracking (SSC). While the related standard NACE MR0175 (ISO 15156) applies to upstream oil and gas production environments, MR0103 covers the specific conditions found in refinery process streams — typically higher temperature, lower pH, and different H₂S partial pressures. Both standards may be co-specified on the same valve for refinery projects.
Scope
Applies to all metallic components in refinery pressure vessels, piping, heat exchangers, and valves in wet H₂S service including hydroprocessing units, amine units, sour water strippers, and crude distillation where H₂S-containing aqueous phases are present. Covers carbon steel, alloy steel, stainless steel, and nickel alloys.
Applicable Valve Types
All valve types in wet H₂S refinery service
Gate, Globe, Ball, Butterfly, Check valves
Applicable Pressure Classes
Key Requirements — NACE MR0103
Carbon steel hardness limit: ≤22 HRC (Rockwell C) for base metal and welds
Heat treatment: PWHT (Post Weld Heat Treatment) required for carbon and low-alloy steel valves
Maximum yield strength for carbon steel: 90 ksi (620 MPa) in most conditions
Austenitic stainless steels: cold worked material hardness ≤22 HRC
Nickel alloys: Alloy 625, Alloy C-276 permitted in specific tempers
Hardness testing: Brinell (HBW) or Rockwell (HRC) at critical locations
Excludes high-strength steels like AISI 4140 in quenched and tempered condition
Testing Requirements — NACE MR0103
Brinell or Rockwell hardness testing of body, bonnet, and trim
PWHT verification by hardness test
Traceability to heat treatment records
Documentation Required for NACE MR0103 Compliance
NACE MR0103 compliance certificate
Hardness test report (all pressure-containing parts)
PWHT records for carbon and alloy steel valves
Material Test Reports (MTR) per EN 10204 3.1
Related Standards
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