ISO 4992-1:2020

Overview

ISO 4992-1:2020 - Steel castings - Ultrasonic testing - Part 1: Steel castings for general purposes - defines requirements and methods for ultrasonic testing (UT) of ferritic steel castings using the pulse-echo technique. The standard applies to castings that have normally received grain-refining heat treatment and have wall thicknesses up to and including 600 mm. It does not apply to austenitic steels or joint welds. ISO 4992-1:2020 is intended for non-destructive testing (NDT) practitioners, manufacturers and purchasers who need consistent, auditable procedures and acceptance criteria for internal discontinuities in steel castings.

Key Technical Topics and Requirements

• Scope and applicability: UT for ferritic steel castings for general purposes; wall thickness ≤ 600 mm (greater thicknesses require special agreement).
• Testing method: Pulse-echo ultrasonic testing to detect and size internal discontinuities.
• Acceptance levels and classes: Defined acceptance criteria for planar and volumetric discontinuities; specific limits such as a 3 mm FBH reference for class 1 and through‑wall size limits expressed as percentages of wall thickness.
• Wall-section zones: Division into rim zone (one-third of through‑wall thickness, max 30 mm) and core zone; special rim zones with higher requirements for machined or sealing surfaces.
• Sizing and assessment rules: Rules for equivalent reference discontinuity (FBH), point-like vs. extended discontinuities, and how to calculate discontinuity area when through-wall dimension is non-measurable.
• Equipment, probes and coupling: Requirements for ultrasonic instruments, probes and coupling fluids; calibration and checking per referenced calibration blocks.
• Personnel qualification: UT shall be performed by qualified personnel (e.g., per ISO 9712 or equivalent).
• Test reporting and annexes: Requirements for test reports and informative annexes on sound-beam diameters and typical indication types.

Practical Applications and Users

Who uses ISO 4992-1:2020:

• NDT/UT technicians and supervisors performing inspections on steel castings.
• Foundries and casting manufacturers specifying inspection requirements.
• Purchasers and quality inspectors defining acceptance classes for critical components.
• Design and maintenance engineers who require reliable inspection methods for safety‑critical castings.

Typical applications:

• Inspection of pump housings, gearbox casings, valve bodies and other ferritic steel components where internal integrity is required.
• Establishing contract test procedures and acceptance levels for supply or purchase orders.
• Supplementary use with radiographic testing (RT): when RT and UT are combined, acceptance of core-zone defects may be adjusted (see EN 1559-2 and agreement at order stage).

Related Standards

• ISO 16810, ISO 16811, ISO 16827 (UT principles, sensitivity, sizing)
• ISO 2400, ISO 7963 (calibration blocks)
• ISO 22232 series (equipment characterization)
• ISO 9712 (qualification and certification of NDT personnel)
• EN 1559-2 (guidance for combined RT/UT)