Issuing body
API
Latest edition
3rd Edition (2016, R2022)
Region
USA, Global
Equipment items
8
Scope
Supplementary welding requirements (PWHT, hardness, impact, NDE) beyond ASME IX.
Key requirements (7)
- Supplementary welding requirements for chemical/oil/gas industries — beyond ASME IX.
- Mandatory PWHT thresholds tighter than ASME VIII.
- Hardness limits: 200 HB (CS), 235 HB (1.25Cr-0.5Mo / 2.25Cr-1Mo) for sour service typical.
- Charpy impact requirements at MDMT for all weldments where production weld is impact-tested.
- PMI (positive material identification) required on alloy components.
- Hydrogen-induced cracking (HIC) prevention: low-hydrogen consumables, preheat, controlled diffusible H ≤ 8 mL/100g.
- Heat input control for impact-toughness-controlled materials.
Related standards (2)
Applied to 8 equipment items
Pressure Vessels & Reactors
Piping & Fittings
Materials, Welding & Coatings