🔩 Impact tests on welded joints — specimen location and notch orientation (designations VWT, VHT, VWS, VHS) — PN-EN ISO 9016

Materials and NDT PN-EN ISO 9016

Overview

THIS STANDARD IS NOT A MEASUREMENT METHOD — IT IS A DESIGNATION SYSTEM. Scope (clause 1 of ISO 9016:2022 and the PKN card): a method for describing the specimen location and notch orientation in the testing and reporting of impact tests on butt-welded joints. It applies to metals in all product forms, joined by any fusion or pressure welding process. It is applied AS A SUPPLEMENT to the ISO 148 series — it contains the specimen designation and additional requirements for the report. PRINCIPLE (clause 4): the impact test is carried out in accordance with ISO 148-1. The test temperature, the location, type and dimensions of the specimen and the notch orientation are specified by the application standard. Beyond the requirements of ISO 148-1, the notch location can be determined by macro-etching. A scope row with PN-EN ISO 9016 alone therefore says that the laboratory can describe and take a specimen from the joint — it measures the absorbed energy according to PN-EN ISO 148-1, which the scopes put next to it in 18 of 19 entries.

SPECIMEN DESIGNATION — FIVE CHARACTERS (clause 5). The specimen is taken so that its longitudinal axis is perpendicular to the length of the weld. • character 1 — type of notch: U (Charpy U-notch) or V (V-notch); • character 2 — notch location: W — in the weld metal (reference line: the weld centre line at the specimen location), H — in the heat-affected zone (reference line: the fusion line or the bond line; the notch covers the HAZ); • character 3 — orientation: S — notched surface parallel to the surface (corresponds to the "surface notch" of fracture mechanics tests), T — notch through the thickness; • character 4 — a: the distance of the centre of the notch from the reference line in mm (when the centre of the notch lies on the weld metal centre line, a = 0 and this is also recorded); • character 5 — b: the distance from the face side of the joint to the nearer surface of the specimen in mm (when the surface of the specimen is the face side, b = 0 — and this is recorded). For X-, K- and similar welds the face side is the one with the wider weld or the one from which the welding energy was first applied. Examples from the standard: VWT 0/b, VHT a/b, VWS a/b, VHS a/b. When such a designation does not describe the location sufficiently, a sketch referring to the welding procedure specification is attached (5.3).

WHERE AN ERROR HIDES BEHIND A SEEMINGLY CORRECT RESULT: a specimen with the notch not where the application standard requires — e.g. in the weld metal instead of the heat-affected zone. The absorbed energy is then measured correctly, but it concerns another region of the joint. The VWT/VHT designation in the report is the only trace that the notch was where it had to be.

REPORT (clause 8) — beyond what ISO 148-1 requires: a reference to ISO 9016:2022; the specimen designation; the type and dimensions of any imperfections found; a sketch (if required); other information required by the application standard or by agreement between the parties. Annex A gives an example of a typical report.

EDITIONS (state of the PKN cards and the ISO website on 25.09.2026). PN-EN ISO 9016:2022-09 — English-language version, publication 28-09-2022, 20 pages, KT 165 Welding and Allied Processes; it implements EN ISO 9016:2022 and ISO 9016:2022 [IDT]; it replaces PN-EN ISO 9016:2013-05 (English-language and German-language versions), withdrawn on 28-09-2022. The card has no "Withdrawn" header. ISO website: ISO 9016:2022 — edition 3, published 2022-03, stage 60.60. The only change of the 2022 edition according to the foreword: a column was removed from Table A.1 (the report template). The standard to which the test refers — PN-EN ISO 148-1:2017-02 in the Polish-language version (implements ISO 148-1:2016, a separate entry in this database) — is also current according to its card.

HOW ACCREDITATION SCOPES CITE THE STANDARD. Measurement of 25.09.2026 on the database of PL accreditation scopes (1310 laboratories with entries): 19 entries at 15 laboratories — "PN-EN ISO 9016:2022-09" (17) and "PN-EN ISO 9016" without a year (2). Next to it: "PN-EN ISO 148-1:2017-02" (16) and "PN-EN ISO 148-1" (2), as well as ASTM A370 and ASTM E23. Object: welded joints, weld metal, metals and structural products. Methodology: "Praca łamania" [absorbed energy] (10), "Udarność" [impact strength] (2), with the parameters: KV2, KU2, KV8, KU8, initial potential energy of the pendulum 150, 300 and 450 J, temperatures from -196 °C (liquid nitrogen) to +500 °C, in two entries also lateral expansion LE.

THE KEY OF THE "LABORATORIES" TAB: "PN-EN ISO 9016" — 15 laboratories and 19 entries, without any foreign or omitted entries.

HOW FAR THE TEXT EXTENDS: ISO 9016:2022 made available by the publisher covers clauses 1–8 with Tables 1 and 2 and Figure 1 — the whole normative text; we did not have the report template of Annex A.

Method principle

The specimen for the impact test is taken from the butt joint perpendicular to the weld, and the notch location is described by five characters: type of notch (U or V), location (W — weld metal, H — heat-affected zone), orientation (S — parallel to the surface, T — through the thickness) and the distances a (from the reference line) and b (from the face side). The notch location can be determined by macro-etching. The test is carried out according to ISO 148-1, and the temperature and type of specimen are decided by the application standard.

Applications

• Qualification of welding procedures — impact tests of the weld metal and the heat-affected zone
• Acceptance tests of welded joints in steel structures, tanks and pipelines
• Description of the specimen location in reports of Charpy tests of fusion- and pressure-welded joints

Key parameters

Standard

Standard number

PN-EN ISO 9016:2022-09 (wersja angielska; wprowadza EN ISO 9016:2022 [IDT], ISO 9016:2022 [IDT])

Title (PL)

Badania niszczące złączy spawanych metali — Badanie udarności — Usytuowanie próbek, kierunek karbu i badanie

Title (EN)

Destructive tests on welds in metallic materials — Impact tests — Test specimen location, notch orientation and examination

Step-by-step procedure

1. Requirements from the application standard

   Read off the test temperature, the location, type and dimensions of the specimen and the notch orientation — ISO 9016 does not contain them.

2. Taking the specimen

   Perpendicular to the length of the weld; determine the notch location, if necessary by macro-etching.

3. Designation

   Assign a five-character designation, e.g. VWT 0/b or VHT a/b; when this is not sufficient — attach a sketch referring to the welding procedure specification.

4. Impact test

   According to ISO 148-1.

5. Report

   Beyond the data of ISO 148-1: a reference to ISO 9016:2022, the specimen designation, the type and dimensions of imperfections, a sketch, information required by the application standard.

Required equipment and apparatus

Reagents, media and consumables

Health and safety (OHS)

• Pendulum impact tester — guards around the pendulum zone, release interlock
• Cooling of specimens in liquid nitrogen (down to -196 °C) — cryogenic gloves, face protection, ventilation
• Macro-etching — corrosive reagents, fume hood

Frequently asked questions