ISO 2400-2025 PDF

Full title and description

St ISO 2400-2025 — Non‑destructive testing — Ultrasonic testing — Specification for standard block No. 1. This International Standard specifies the dimensions, material, manufacture, inspection and marking requirements for a steel standard block used to set, check and verify manual ultrasonic test equipment.

Abstract

The 2025 (3rd) edition of ISO 2400 defines the requirements for a steel standard (reference) block No. 1 for ultrasonic non‑destructive testing (UT). It replaces the 2012 calibration‑block edition, updates terminology (from “calibration block” to “standard block”), tightens velocity‑measurement requirements (three perpendicular directions), clarifies manufacture and heat‑treatment details, and adds a CAD reference for block geometry. The standard is intended to ensure reliable, repeatable setup and verification of manual UT equipment.

General information

• Status: Published.
• Publication date: 21 March 2025 (Edition 3, 2025).
• Publisher: International Organization for Standardization (ISO).
• ICS / categories: 19.100 — Non‑destructive testing.
• Edition / version: 3 (2025).
• Number of pages: 8 pages.

Scope

This document specifies the material, manufacture, geometry, tolerances, marking and verification procedures for a steel block (standard block No. 1) used to set, check and verify ultrasonic test equipment in manual ultrasonic testing. The standard covers the block’s nominal dimensions and features, required steel grade (typical: S355J0 or equivalent), sound‑velocity determination in specified directions, permissible modifications, and requirements for traceability and marking. It replaces and updates the previous ISO 2400:2012 edition.

Key topics and requirements

• Designation and purpose of standard block No. 1 for manual ultrasonic testing (UT).
• Material: typically steel grade S355J0 or equivalent; requirements for homogeneity and heat treatment.
• Dimensions and tolerances for the block geometry, including reference features used for probe positioning and time‑of‑flight checks.
• Sound‑velocity measurement procedures — explicit requirement for measurements in three perpendicular directions to capture anisotropy.
• Manufacture, heat treatment and surface condition requirements to ensure repeatable acoustic properties.
• Marking, identification and traceability requirements; provisions for CAD file reference for dimensional verification.
• Verification and checking procedures for use in setting and checking UT equipment; guidance on permissible modifications to blocks.

Typical use and users

Primary users are NDT/UT technicians, welding inspectors, calibration and testing laboratories, quality managers in fabrication and power/pressure‑equipment industries, and organizations that perform manual ultrasonic inspection of welds and components. The block is used for setup, routine checks, verification after instrument repair or change of transducer, and to establish consistent time‑of‑flight and sensitivity settings.

Related standards

ISO 2400:2025 is linked to earlier editions ISO 2400:2012 and ISO 2400:1972 (both withdrawn) and is typically used alongside personnel‑ and procedure‑oriented NDT standards such as ISO 9712 (qualification and certification of NDT personnel) and other UT practice documents. Users often reference national transpositions and complementary NDT standards when implementing calibration and verification programs.

Keywords

ISO 2400, ultrasonic testing, UT, standard block, calibration block, reference block, non‑destructive testing, S355J0, time‑of‑flight, sound velocity, block geometry, NDT equipment verification.

FAQ

Q: What is this standard?

A: ISO 2400:2025 is an International Standard specifying a steel standard block (No. 1) for setting, checking and verification of manual ultrasonic test equipment used in non‑destructive testing.

Q: What does it cover?

A: It covers the block’s material, dimensions and tolerances, manufacture and heat treatment, sound‑velocity determination (including measurements in three perpendicular directions), marking, traceability and verification procedures for use in UT setup and checks.

Q: Who typically uses it?

A: NDT/UT technicians, welding inspectors, calibration laboratories, QA/QC personnel in manufacturing, energy, oil & gas, and any organization performing manual ultrasonic inspections.

Q: Is it current or superseded?

A: Current — ISO 2400:2025 (Edition 3, published 21 March 2025) is the active edition; it supersedes ISO 2400:2012 and earlier versions.

Q: Is it part of a series?

A: It is part of the body of ISO standards for non‑destructive testing (ICS 19.100) and is commonly used in conjunction with other UT and NDT standards (for example ISO 9712 on personnel qualification). It is a standalone specification for the reference block but functionally related to broader UT practice standards.

Q: What are the key keywords?

A: Ultrasonic testing, standard block No. 1, calibration/reference block, S355J0, sound velocity, time‑of‑flight, NDT, verification, block geometry.