ISO 3845:2024

Overview

ISO 3845:2024 - Full ring ovalization test method for the evaluation of the cracking resistance of steel line pipe in sour service specifies a full-scale laboratory test to assess the susceptibility of steel line pipe (and other tubular components) to hydrogen-related cracking in sour environments containing wet hydrogen sulfide (H2S). Published 2024 by ISO/TC 67, the standard defines the test principle, apparatus, reagents, sampling, monitoring and reporting requirements for exposing a sealed short-length pipe (“full ring”) to a sour test solution while applying controlled hoop stress by mechanical ovalization.

Key Topics and Requirements

• Test principle: Mechanical ovalization of a full-ring specimen produces circumferential (hoop) stress at two diametrically opposite inner-surface locations; the specimen is then exposed single-sided to a sour test environment.
• Specimen scope: Applicable to seamless, longitudinally welded (with/without filler), helical welded pipe, girth welds, and other tubular components (flange necks, bends). Also applicable to corrosion resistant alloys (CRAs).
• Monitoring and measurement:
  • Regular in-situ non‑destructive testing (NDT), notably ultrasonic testing (UT), to detect crack initiation and propagation.
  • Hydrogen permeation measurement options to quantify hydrogen transport.
  • Post‑test NDT (magnetic particle testing, penetrant testing, visual) and metallographic examination.
• Apparatus and procedure: Detailed provisions for containment, seals, internal/external loading components, specimen preparation, test cell preparation, solution parameters, and test duration.
• Documentation: Required test and loading reports and annexed guidance (UT calibration, strain gauge installation, solution analysis by iodometric titration, example reports, acceptance guidance).
• Safety: Explicit warning on hazards of H2S and requirement to follow national health and safety regulations.

Practical Applications

• Assessing pipeline integrity and material selection for oil & gas and lower carbon energy systems exposed to sour service.
• Qualification of pipe grades, weld procedures, fittings and corrosion-resistant alloys against HIC (hydrogen-induced cracking), SSC (sulfide stress cracking) and SOHIC.
• Comparing performance of manufacturing routes (seamless vs welded), welds, and heat treatments under representative residual-stress conditions.
• Supporting procurement specifications, failure investigations and fitness-for-service evaluations where sour corrosion cracking is a concern.

Who should use ISO 3845:2024

• Corrosion and materials engineers, pipeline operators, integrity teams and QA/QC laboratories.
• NDT providers and test labs performing full-ring evaluations and hydrogen permeation measurements.
• Manufacturers of line pipe, fittings and CRAs, and standards committees developing acceptance criteria.

Related Standards (selected normative references)

ISO 2400, ISO 3059, ISO 3452, ISO 6892-1, ISO 7963, ISO 9934, ISO 11666, ISO 16810, ISO 17635, ISO 17638, ISO 8501-1, ISO 8044, ISO 4787.

Keywords: ISO 3845:2024, full ring ovalization test, sour service, H2S, steel line pipe, hydrogen-induced cracking, sulfide stress cracking, ultrasonic testing, hydrogen permeation, pipeline integrity.