🔩 Liquid penetrant inspection of seamless and welded steel tubes for the detection of imperfections open to the surface — cracks, seams, laps, cold shuts, laminations and porosity — colour contrast or fluorescent penetrants, water-washable, post-emulsifiable or solvent-removable systems, classification of indications (linear, rounded, accumulated, non-relevant), smallest indication considered 1,5–5,0 mm for acceptance levels P1–P4, personnel according to ISO 9712 or ISO 11484, PN-EN ISO 10893-4

Materials and NDT PN-EN ISO 10893-4

Overview

WHAT THE STANDARD COVERS. The PKN catalogue card of PN-EN ISO 10893-4:2011 (English version) gives the scope: “Requirements are specified for the liquid penetrant testing of seamless and welded steel tubes for the detection of surface imperfections. It can be applied to the whole or part of the tube surface. General requirements, the test method, evaluation of indications and the test report are specified” (our translation from the Polish text of the card). We read the text in the sample of ISO 10893-4:2011 (first edition) to 5.3 b) (page 4); we do not have the further procedure conditions (5.3 c onwards), Clauses 6 (evaluation of indications), 7 (acceptance) or 8 (test report).

ACCORDING TO THE TEXT OF ISO 10893-4:2011 (foreword, Clauses 1–5.3 b). The standard was prepared by ISO/TC 17/SC 19 (technical delivery conditions for steel tubes for pressure purposes); the first edition replaces ISO 12095:1994 after technical revision; the foreword lists Parts 1–12 of the ISO 10893 series. Scope (1): requirements for liquid penetrant testing of seamless and welded tubes for the detection of surface imperfections, on the whole surface or part of it according to the product standard; it can also apply to hollow sections. References (2): ISO 3059, ISO 3452-1, ISO 3452-2, ISO 9712, ISO 11484. Definitions (3, in addition to ISO 3452-1 and ISO 11484): tube — hollow long product open at both ends, of any cross-section; seamless tube — made by piercing a solid product, further processed hot or cold; welded tube — made from a flat product formed into a profile and welded along the edges; manufacturer; agreement — contractual arrangement at the time of enquiry and order. General requirements (4): the test is carried out after completion of all primary production operations (rolling, heat treatment, cold and hot working, sizing, primary straightening), unless the product standard or agreement states otherwise; the surface shall be clean, free from oil, grease, sand, scale and other substances that interfere with interpretation; the type of indications and the smallest size of detectable imperfections depend on the tube manufacturing process and the surface finish; the test is carried out by trained operators qualified according to ISO 9712, ISO 11484 or equivalent, supervised by competent personnel nominated by the manufacturer, authorized by the employer according to a written procedure, and NDT operations are authorized by a level 3 individual approved by the employer; third-party inspection — by agreement. Method (5.1): the penetrant is applied to the surface, enters the imperfections, the excess is removed, the surface dried and a developer applied, which acts as a blotter absorbing the penetrant trapped in the imperfections and gives a contrasting background; colour contrast dyes (white light) or fluorescent dyes (UV); three types of systems — water-washable, post-emulsifiable and solvent-removable; for each tube (part) the colour contrast or fluorescent technique with one of these systems is used, and the principles and verification — according to ISO 3059, ISO 3452-1 and ISO 3452-2. Indications (5.2): the method detects imperfections open to the surface — cracks, seams, laps, cold shuts, laminations and porosity; it does not determine the nature, shape or dimensions of the imperfections, and the size of the indication does not directly represent the size of the imperfection; therefore indications are classified as: a) linear — length at least three times the width; b) rounded — circular or elliptical, length less than three times the width; c) accumulated — linear or rounded, aligned or clustered, with a separation not greater than the length of the smallest indication, at least three; d) non-relevant — from localized surface irregularities related to the tube-making process (e.g. machining marks, scratches, sizing and straightening marks); Table 1 gives the smallest diameter D or length L of an indication to be considered in the evaluation: P1 — 1,5 mm, P2 — 2,0 mm, P3 — 3,0 mm, P4 — 5,0 mm. Procedure (5.3): a) the choice of the penetrant system takes into account the tube surface condition and the test category; b) for stainless steel tubes, penetrant materials low in halogens (chlorine, fluorine) and sulphur are used — here the sample ends.

STATUS (PKN catalogue cards as of 02.10.2026). The card of PN-EN ISO 10893-4:2011 (English version, published 28-06-2011, 10 pages, price group E) has no “Withdrawn” heading: Metallurgy Sector, KT 123 Testing of Metal Properties, ICS 25.160.40, 23.040.10 and 77.040.20, “Introduces: EN ISO 10893-4:2011 [IDT], ISO 10893-4:2011 [IDT]”, “Replaces: PN-EN 10246-11:2002 – Polish version”. EVS card ISO 10893-4:2011: “Valid from 24.03.2011”.

HOW MANY LABORATORIES AND IN WHAT FORM (copy of the accreditation scope database, data up to 17.09.2026, read 02.10.2026). The number 10893-4 appears in 10 records at 6 laboratories: AB 001 (five records — the same line in five parts of the scope), AB 313, AB 608, AB 904, AB 1425, AB 1827. In the current scopes on the PCA website (read 02.10.2026, issues from 23.04.2025 to 02.09.2026) the edition with year “PN-EN ISO 10893-4:2011” is given by AB 001, AB 313, AB 1425 and AB 1827 (the last written without a space, “PN-EN ISO10893-4:2011”, so a search for the number with a space in the document text does not find it); the number alone without year — by AB 608 and AB 904. In none of these scopes are the lines with this number marked as suspended. The “Laboratories” tab (“PN-EN ISO 10893-4”) shows 6 laboratories — checked with the tab query on the production server labcoda.pl on 02.10.2026.

WHAT THE LABORATORIES TEST (PCA entries). All six laboratories — steel tubes: surface imperfections (open to the tested surface), penetrant method; in the same line AB 001, AB 904 and AB 1827 also give PN-EN ISO 3452-1, AB 904 — PN-EN ISO 3059, and AB 001 — also PN-EN 571-1:1999. AB 608 and AB 904 have this item with the flexible scope mark “E”.

WHERE A SEEMINGLY CORRECT RESULT IS EASY TO GET. Moment of testing: after all primary production operations, including heat treatment and straightening, unless the product standard states otherwise (4.1). Surface: oil, grease, sand and scale interfere with interpretation; the smallest detectable imperfection depends on the surface finish (4.2). Size: the size of the indication does not directly represent the size of the imperfection — indications are assessed according to the classification and Table 1, and indications smaller than the threshold for the given level P1–P4 are not considered (5.2). Non-relevant indications: machining marks, scratches and straightening marks have to be distinguished from imperfections (5.2 d). Stainless steel: penetrant materials low in halogens and sulphur (5.3 b). Personnel: qualification according to ISO 9712 or ISO 11484 and authorization by a level 3 individual (4.3).

WHAT WE DO NOT STATE. We do not have 5.3 from item c) or Clauses 6–8: penetration and development times, temperatures, viewing conditions, acceptance criteria for indications at levels P1–P4 or report requirements — so we do not state these numbers. The acceptance level is specified by the product standard or agreement — the part we read does not assign levels to products.

Method principle

A penetrant (colour contrast or fluorescent) is applied to the cleaned tube surface and enters imperfections open to the surface; after removing the excess (with water, emulsifier or solvent) and drying, a developer is applied which draws the penetrant out of the imperfections and forms a contrasting background; indications are viewed in white light or UV, classified (linear, rounded, accumulated, non-relevant) and assessed from the smallest dimension appropriate to acceptance level P1–P4.

Applications

• Seamless and welded steel tubes — surface imperfections on the whole surface or part of it; 6 laboratories in PCA scopes
• Hollow sections (tubes of any cross-section) — within the scope of the standard (1)
• Stainless steel tubes — with penetrant materials low in halogens and sulphur (5.3 b)

Key parameters

Standard

Standard number

PN-EN ISO 10893-4:2011 (wersja angielska; EN ISO 10893-4:2011 i ISO 10893-4:2011 IDT)

Title (PL)

Badania nieniszczące rur stalowych — Część 4: Badanie penetracyjne rur stalowych bez szwu i spawanych w celu wykrycia nieciągłości powierzchniowych

Title (EN)

Non-destructive testing of steel tubes — Part 4: Liquid penetrant inspection of seamless and welded steel tubes for the detection of surface imperfections

Step-by-step procedure

1. Moment and preparation

   After primary production operations; surface clean, free from oil, grease, sand and scale (4.1, 4.2). PN-EN ISO 10893-4:2011 current (PKN cards as of 02.10.2026).

2. Choice of system

   Colour contrast or fluorescent technique and one of the three systems, taking into account the surface condition and test category; for stainless steel low-halogen and low-sulphur materials (5.1.2, 5.3 a, b).

3. Testing

   Application of penetrant, removal of excess, drying, developer; times and conditions according to 5.3 c) onwards — outside the part we read.

4. Indications

   Classification: linear, rounded, accumulated, non-relevant; indications from 1,5 mm (P1) to 5,0 mm (P4) are considered depending on the acceptance level (5.2, Table 1).

5. Evaluation and report

   Evaluation and acceptance according to Clauses 6–7 and the product standard, report according to Clause 8 — outside the part we read.

Required equipment and apparatus

Reagents, media and consumables

Health and safety (OHS)

• In the part we read (Clauses 1–5.3 b) the standard gives no safety requirements; for stainless steel it limits the halogen and sulphur content of penetrant materials (5.3 b)

Frequently asked questions