🔩 Penetrant testing of steel forgings — detection of discontinuities open to the surface, written procedure, surface condition for quality classes, viewing conditions and classification of indications, PN-EN 10228-2

Materials and NDT PN-EN 10228-2

Overview

WHAT THE STANDARD COVERS. Scope from the PKN card, in full (our translation): "This European Standard describes techniques and acceptance criteria to be used for the penetrant testing of steel forgings. The method described is used for the detection of surface discontinuities" (on the card without a full stop at the end). We have a sample extract of SIST EN 10228-2:2016 (EN 10228-2:2016 of June 2016, approved by CEN on 3 October 2015) from the cover to clause 13 a) (page 7) and an extract of the white draft prEN 10228-2 of August 2014 up to Figure 1 (page 8). Foreword: the standard was prepared by ECISS/TC 111 "Steel castings and forgings" (secretariat AFNOR); it superseded EN 10228-2:1998, and Annex A lists the significant technical changes; the EN 10228 series has four parts — 1: magnetic particle inspection, 2: penetrant testing, 3: ultrasonic testing of ferritic or martensitic steel forgings, 4: ultrasonic testing of austenitic and austenitic-ferritic stainless steel forgings. Normative references: EN ISO 3059 (viewing conditions), EN ISO 3452-1, -2 and -4 (general principles, testing of penetrant materials, equipment), EN ISO 9712 (personnel) and EN ISO 12706:2009 (vocabulary).

COURSE ACCORDING TO THE STANDARD (Clauses 4–13 of the 2016 edition). At the enquiry and order the following are agreed: the manufacturing stage at which the forging is tested, the areas to be examined, the type of penetrant (colour contrast or fluorescent), the required quality class or classes for individual surfaces, the recording and acceptance criteria if different from those in Table 2, the presence of the purchaser and the approval of the written procedure. Testing is performed according to a written procedure — a product specification, a procedure written for the application or this standard supplemented with details — which contains at least 16 items: from the description of the forgings, personnel qualification and manufacturing stage, through the type of products, surface condition and viewing conditions, pre-cleaning and drying, penetrant application with temperature and penetration time, excess penetrant removal, developer application with development time, to the method of marking indications, acceptance criteria, post-cleaning and the test report. Personnel according to EN ISO 9712. Products (penetrant, emulsifier, remover, developer) conforming to EN ISO 3452-1, compatible with the material and enabling the required recording level to be achieved (Table 2); equipment conforming to EN ISO 3452-4, e.g. spray gun, aerosol, immersion tank. Function test: sensitivity of the penetrant according to EN ISO 3452-2; the temperature of the forging should be within the limits specified by the manufacturer of the products. Final acceptance testing, where practicable, on the forging in the delivery condition. The surface clean, free from scale, oil, grease, machining marks, paint and other contaminants; roughness according to Table 1 — with Ra ≤ 12.5 µm only quality class 1 can be achieved, with Ra ≤ 6.3 µm classes 1, 2, 3 and 4. Testing covers, where practicable, 100 % of the surface to be tested; the process according to EN ISO 3452-1. Viewing starts immediately after the developer is applied and continues periodically until the end of the development time, when the final assessment of indications is made. Viewing conditions according to EN ISO 3059: colour contrast penetrants — white light of at least 500 lx on the surface, without glare and reflections (lower illuminance may be agreed); fluorescent penetrants — at least 5 min for the operator's eyes to adapt to the reduced background lighting and at least 5 min warm-up of the UV-A lamp. Classification (13 a): a linear indication is "isolated" when it is not aligned with another linear indication or when it is separated from it by more than five times the length of the longer of the two. The 2014 draft continues: interacting indications (aligned, separated by no more than five times the length of the longer one) are assessed as one continuous length measured between the outer ends; the cumulative length is the sum of the lengths of linear indications within the reference surface of 148 mm × 105 mm (A6 format); a linear indication has a length greater than three times its width, a rounded one — not greater; false indications due to geometry (change of section, slot) and surface finish (scar, machining mark) are not taken into account. The wording of 13 a) and the earlier clauses in the draft is close to the 2016 edition but not identical (in the draft the recording criteria are in Table 1, in the 2016 edition — in Table 2).

STATUS (state of the cards on 30 September 2026). The card of PN-EN 10228-2:2016-07 (Polish version) has no "Withdrawn" header — the standard is CURRENT: published 28-09-2018, 14 pages, price group G, Metallurgy Sector, KT 123 for Testing of Metal Properties, ICS 77.140.85 and 77.040.20, "Introduces: EN 10228-2:2016 [IDT]", "Replaces: PN-EN 10228-2:2000 - Polish version". The PKN search for "PN-EN 10228-2" (30 September 2026): the 2016-07 edition in the Polish and English versions without a label and PN-EN 10228-2:2000 (Polish version) with the label "Withdrawn and replaced by PN-EN 10228-2:2016-07 - English version".

HOW MANY LABORATORIES AND IN WHAT FORM (copy of the accreditation-scope database, data loaded up to 17 September 2026, read on 30 September 2026). All notations of number 10228-2: 14 records at 10 laboratories — the same number of cells in the current PCA documents. AB 001 (the Office of Technical Inspection, UDT) has this entry in five laboratory testing departments — in Poznań, Warsaw, Płock, Kraków and Gliwice — marked with an asterisk (tests on the basis of which the laboratory formulates opinions and interpretations). The notation "PN-EN 10228-2:2016-07" is used by 8 laboratories, without a year — AB 608 and AB 904. The "Laboratories" tab looks for notations that BEGIN with "PN-EN 10228-2" and will show all 10 laboratories — checked with the tab's query on the production server labcoda.pl on 30 September 2026: 10. Current scopes on the PCA website (read on 30 September 2026, issues from 23.04.2025 to 02.09.2026): all entries are in the issues in force and none is suspended.

ITEMS AND CHARACTERISTIC. Steel forgings — 8 laboratories, forgings without further specification — AB 001 and AB 1754. Characteristic: surface discontinuities (mostly "external, open to the tested surface"), penetrant method (AB 1505 with the designation PT). The entries have no numerical ranges.

ALONGSIDE THIS STANDARD. In the same entries there are: PN-EN ISO 3452-1:2021-12 — general principles of penetrant testing (AB 001, AB 1827, AB 1978; AB 904 without a year, together with PN-EN ISO 3059), and — in cells where metallic products and materials also stand next to forgings — also at AB 313, AB 1336, AB 1425, AB 1505, AB 1754 and AB 608 (without a year). At AB 001 the same entries also contain PN-EN 571-1:1999, and at AB 608 PN-EN 571-1 without a year — according to the PKN card withdrawn on 06-08-2013 and replaced by PN-EN ISO 3452-1:2013-08, which, withdrawn on 03-12-2021, was in turn replaced by PN-EN ISO 3452-1:2021-12, where the chain ends (state of the cards on 30 September 2026). Forgings are tested by the penetrant method without this standard at three laboratories — according to PN-EN ISO 3452-1 alone: AB 1141 (forgings of metallic materials, one of two entries also with PN-EN 571-1:1999 — see above), AB 1348 (metallic products, including forgings) and AB 1889 (welded joints and steel forgings, notation "PN-EN ISO 3452-1:2021-02"). Separate Knowledge Base entries exist for magnetic particle testing (PN-EN 10228-1) and ultrasonic testing of ferritic and martensitic steel forgings (PN-EN 10228-3), penetrant testing according to PN-EN ISO 3452-1 and personnel qualification according to PN-EN ISO 9712.

WHERE A SEEMINGLY CORRECT RESULT IS EASY TO GET. First — quality class and surface: classes 2, 3 and 4 require a roughness of Ra ≤ 6.3 µm; on a surface with Ra up to 12.5 µm only class 1 can be achieved — a result "no indications" on a rough surface for a higher class is no proof. Second — agreements: without an agreed quality class, areas of examination and type of penetrant, the report does not say what was assessed. Third — products and temperature: the set of products must have a verified sensitivity (EN ISO 3452-2), and the temperature of the forging must be within the limits of the products' manufacturer — a forging that is too cold or too hot changes the penetration. Fourth — viewing: colour contrast penetrants at no less than 500 lx, fluorescent ones only after 5 min of eye adaptation and warm-up of the UV-A lamp; viewing lasts until the end of the development time. Fifth — classification: indications aligned closer than five times the length of the longer one count as one — assessed separately they give an underestimated length. Sixth — reach of the method: penetrant testing detects only discontinuities open to the surface; subsurface and internal ones require other parts of the series (magnetic particle, ultrasonic).

WHAT WE DO NOT GIVE. The extract of the 2016 edition ends at clause 13 a), and that of the draft — at Figure 1: we do not give Table 2 (recording levels and acceptance criteria for quality classes 1–4), the clauses on recording and acceptance (14), removal of defects (15), cleaning (16) and the test report (17), or Annex A with the changes from EN 10228-2:1998.

Method principle

A penetrant (colour contrast or fluorescent) is applied to the cleaned surface of the forging and enters the discontinuities open to the surface; after the penetration time the excess is removed, a developer is applied and the indications are viewed under white light of at least 500 lx or under UV-A radiation. The indications are classified (isolated, interacting, linear, rounded) and assessed according to the agreed quality class — the criteria are in Table 2 of the standard (NOT GIVEN).

Applications

• Steel forgings — surface discontinuities open to the tested surface — in the scopes of 10 laboratories, including five departments of UDT (AB 001)
• Acceptance testing of forgings in the delivery condition according to the quality class agreed at the order

Key parameters

Standard

Standard number

PN-EN 10228-2:2016-07 (wersja polska i wersja angielska; EN 10228-2:2016 IDT)

Title (PL)

Badania nieniszczące odkuwek stalowych — Część 2: Badanie penetracyjne

Title (EN)

Non-destructive testing of steel forgings — Part 2: Penetrant testing

Step-by-step procedure

1. Agreements and procedure

   Manufacturing stage, areas, type of penetrant, quality class, criteria; written procedure with at least 16 items; personnel according to EN ISO 9712. PN-EN 10228-2:2016-07 current (state of the card on 30 September 2026).

2. Surface

   Cleaned, free from scale, oil, grease, paint; roughness according to Table 1 for the quality class; temperature of the forging within the limits given by the manufacturer of the products.

3. Penetration and development

   Process according to EN ISO 3452-1: pre-cleaning and drying, penetrant (temperature, penetration time), removal of the excess, drying, developer (development time); coverage of 100 % of the surface to be tested where practicable.

4. Viewing

   From the application of the developer periodically until the end of the development time; ≥ 500 lx (colour contrast) or UV-A after 5 min of adaptation and 5 min of lamp warm-up (fluorescent).

5. Classification and assessment

   Isolated and interacting indications (separation 5 × the length of the longer one), linear and rounded; assessment according to Table 2 for the quality class — criteria NOT GIVEN; test report.

Required equipment and apparatus

Health and safety (OHS)

• Aerosol penetrant products are usually flammable and the solvents volatile — ventilation, no ignition sources; protection of eyes and skin against UV-A radiation with fluorescent penetrants
• SUBSTANTIVE NOTE: higher quality classes (2–4) require a surface with Ra ≤ 6.3 µm; the method detects only discontinuities open to the surface

Frequently asked questions