ISO 5948:2018

Overview

ISO 5948:2018 - Railway rolling stock material - Ultrasonic acceptance testing - specifies test conditions and acceptance levels for ultrasonic (NDT) acceptance tests on railway components such as tyres, axles and wheels. It applies when product standards require mandatory ultrasonic tests or when optional tests are made mandatory (see ISO 1005‑1, ISO 1005‑3, ISO 1005‑6). The 2018 (third) edition adds hollow‑axle testing, a technique for determining ultrasonic permeability of axles, and tighter acceptance criteria for high‑speed or high‑axle‑load service.

Key topics and requirements

• Scope & timing: Testing is performed after final heat treatment and before corrosion protection; axle permeability tests have specific sequencing (e.g., after end facing/centre drilling but before marking).
• Personnel & location: Tests are normally at the manufacturer’s works and personnel must be qualified to ISO 9712 (or equivalent).
• Equipment & probes:
  • Pulse‑echo ultrasonic instruments capable of 1 MHz to 10 MHz.
  • Probe selection per Table 1; devices should limit the “dead zone” (typical limits: 30 mm generally, 10 mm for wheel/tyre treads, 15 mm for hollow‑axle bore scans).
  • Automated ultrasonic testing is preferred.
• Reference blocks & sensitivity:
  • Sensitivity settings are made using reference reflectors/blocks so specified discontinuity sizes can be reliably detected across the scanned volume (Distance‑Gain‑Size (DGS) / Distance‑Amplitude Curve (DAC) methods referenced).
  • The same couplant must be used for instrument setup and testing.
• Scanning & evaluation:
  • Defined scanning areas, probe orientations (axial/radial/longitudinal), and methods for estimating discontinuity size, evaluating loss of back‑wall echo, and determining ultrasonic permeability.
• Acceptance levels: Clause 13 provides acceptance criteria for discontinuity detection and axle permeability; these can be varied by agreement between purchaser and manufacturer.

Applications and users

• Intended for manufacturers, NDT engineers, quality managers, and procurers involved in railway rolling stock manufacturing and acceptance.
• Used to set consistent inspection protocols for wheels, tyres, solid and hollow axles - critical for safety, reliability, and compliance with product contracts.
• Useful for labs implementing automated ultrasonic acceptance testing, establishing reference blocks, and setting acceptance criteria for high‑speed/high‑load applications.

Related standards

• ISO 5577 - Ultrasonic testing vocabulary
• ISO 9712 - Qualification and certification of NDT personnel
• ISO/TS 18173 - NDT general terms
• Product standards: ISO 1005‑1, ISO 1005‑3, ISO 1005‑6

Keywords: ISO 5948:2018, ultrasonic acceptance testing, railway rolling stock, tyres, axles, wheels, NDT, ultrasonic permeability, DGS, DAC, ISO 9712, reference blocks.