ISO 11971:2020

Steel and iron castings - Visual testing of surface quality

1.1 This document covers the acceptance criteria for the visual testing of the surface of steel and iron castings. 1.2 Acceptance levels utilize Bureau de Normalisation des Industries de la Fonderie (BNIF) and Steel Castings Research and Trade Association (SCRATA) or Casting Technology International (CTI) reference comparators for the visual determination of surface roughness and surface discontinuities described as follows: - surface roughness; - thermal dressing; - mechanical dressing; - non-metallic inclusions; - gas porosity; - fusion discontinuities; - expansion discontinuities; - metal inserts.

Pièces moulées en acier ou en fonte — Contrôle visuel de l'état de surface

General Information

• Status: Published
• Publication Date: 12-Jan-2020
• ICS: 77.040.20 - Non-destructive testing of metals
• ICS: 77.140.80 - Iron and steel castings
• Technical Committee: ISO/TC 17/SC 11 - Steel castings
• Drafting Committee: ISO/TC 17/SC 11 - Steel castings
• Current Stage: 9060 - Close of review
• Completion Date: 02-Sep-2030

Relations

• Revises: ISO 11971:2008 - Steel and iron castings - Visual examination of surface quality
• Effective Date: 23-Apr-2020

Overview

ISO 11971:2020 - "Steel and iron castings - Visual testing of surface quality" specifies acceptance criteria for the visual inspection of steel and iron casting surfaces. The standard defines how to use established visual/tactile comparators (BNIF and SCRATA/CTI) to assess surface roughness and common casting discontinuities, and sets out ordering, test, and reporting requirements for consistent, repeatable surface-quality decisions.

Key topics and requirements

• Scope: Acceptance criteria for visual testing of steel and iron castings, including surface roughness and specific discontinuities.
• Comparator systems: Uses BNIF (BNIF 359) and SCRATA or CTI comparators as reference standards for visual/tactile assessment. Comparators are intended to represent the worst (roughest) condition for an acceptance level.
• Surface conditions covered:
  • Surface roughness
  • Thermal dressing
  • Mechanical dressing
  • Non‑metallic inclusions
  • Gas porosity
  • Fusion discontinuities
  • Expansion discontinuities
  • Metal inserts
• Test method: Surfaces are examined visually without optical aids exceeding 1× magnification. Large-format comparators (recommended ≥ 15 000 mm²) are preferred to reflect the irregular nature of cast surfaces and improve repeatability.
• Acceptance criteria:
  • SCRATA comparator set applicable to steel and iron castings.
  • BNIF comparator categories S1 and S2 usable for all alloys; category S3 for steel castings only.
  • Annex A provides optional roughness and discontinuity acceptance levels and equivalency guidance between BNIF and SCRATA systems.
• Ordering information: Purchaser and supplier should agree on areas to be inspected, number of castings, designated acceptance levels (multiple levels may apply to different surfaces), and any unacceptable discontinuity types.
• Test report contents: Identification of castings, tester name and qualification, comparator reference used, designated category/level for each area, and date of testing.

Applications and users

ISO 11971:2020 is used by:

• Foundries and casting manufacturers performing quality control and delivery inspection
• Quality, inspection, and NDT engineers defining acceptance limits for cast parts
• Purchasing and design engineers specifying surface acceptance criteria on drawings or models
• Third‑party inspectors and certification bodies assessing conformance to agreed surface standards

Practical applications include final inspection of as‑cast or finished cast surfaces, contract acceptance checks, and supplier quality agreements where visual surface quality is critical to function or appearance.

Related standards

• BNIF 359 (BNIF recommendation for reference samples)
• SCRATA / CTI comparator sets (surface quality comparators available from Casting Technology International)
• ISO 11971 references these comparator systems but contains no normative references to other ISO documents.

Keywords: ISO 11971:2020, visual testing, surface quality, steel castings, iron castings, BNIF, SCRATA, CTI, surface roughness, casting discontinuities, casting inspection.

Standards Content (Sample)

INTERNATIONAL ISO
STANDARD 11971
Third edition
2020-01
Steel and iron castings — Visual
testing of surface quality
Pièces moulées en acier ou en fonte — Contrôle visuel de l'état de
surface
Reference number
©
ISO 2020
© ISO 2020
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ii © ISO 2020 – All rights reserved

Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative References . 1
3 Terms and Definitions . 1
4 Ordering information . 1
5 Test method . 2
6 Acceptance criteria . 2
7 Test report . 3
Annex A (informative) . 4
Bibliography . 5
Foreword
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iso/ foreword .html.
This document was prepared by Technical Committee ISO/TC 17, Steel, Subcommittee SC 11, Steel
castings.
This third edition cancels and replaces the second edition (ISO 11971:2008), which has been technically
revised. The main changes compared to the previous edition are as follows:
— “Normative References” added as new Clause 2 and “Terms and Definitions” added as new Clause 3;
subsequent Clauses were renumbered
— Correction in Clause 5 (previously Clause 3) regarding the use of SCRATA comparators for iron
castings
— Table 3 and Table 4 in the previous edition were moved to new Annex A
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www .iso .org/ members .html.
iv © ISO 2020 – All rights reserved

Introduction
The surface roughness of a casting is influenced by the manufacturing process (moulding, grinding,
finishing, etc.), the moulding materials used (sand, coating, etc.), the equipment available and the
alloy cast.
Since cast surfaces do not exhibit the same cyclic regularity as machined surfaces, it is difficult to
evaluate their roughness using conventional mechanical, optical, or pneumatic devices.
The use of visual/tactile comparators is therefore preferred in these circu
...