Test: weld imperfections to ISO 6520-1, ISO 5817 levels and symbols

Questions about what shows on the weld and what stands on the drawing: the imperfection number to ISO 6520-1, its cause, the ISO 5817 quality level and the parts of the symbol. Checked in your browser — the answers go nowhere.

Where the questions come from

The questions are not typed out here: they are built from the same functions that print the imperfection table, the ISO 5817 level table and the breakdown of the symbol. That is why an answer cannot drift away from a table — it is the same number.

How the quiz works

Questions come one at a time. Pick an answer, press “Check” and you see straight away whether you got it; a “Read up” link appears under the question, pointing to the page with the table the answer came from. At the end you get the score and a dated result sheet you can print; “Try again” starts over.

The questions are built from the same tables that appear on the site: defect numbers and names, causes from the defect-fixing table, descriptions of the quality levels and the elements of a weld symbol. The quiz keeps no copy of that data of its own, so it cannot drift away from it.

What the quiz checks and where to read up

• Defect number to ISO 6520-1. The quiz gives a number and asks for the name. The easiest route is through the first digit (the defect group — see the questions below). All defects with numbers and causes are in the weld defects catalogue.
• Defect from its cause. The quiz quotes a cause from the fixing table — for example “current too low, travel too fast, wrong angle” — and asks what it produces. These are the questions closest to real work: at the booth you see the result first and have to work out the cause. A worked example: undercut.
• Quality level to ISO 5817. The quiz describes an application — critical structures, the bulk of structural work, secondary parts — and asks for level B, C or D. The rules and the limits table are on the ISO 5817 page, and the ISO 5817 calculator gives the actual permitted value.
• Weld symbol elements. Arrow, reference line, identification line — the quiz gives the function and asks for the element. The weld symbol basics page takes the whole symbol apart in order.

What to do after the quiz

1. Go back to the questions you missed. The link under each one leads to the table — read the whole row, not just the name.
2. Move from theory to measurement. The visual inspection report shows how the same defects turn into a “permitted” column in millimetres for your thickness and level.
3. Draw a symbol yourself. The weld symbol builder shows how the symbol changes for a weld on the other side, all round or on site.
4. Take the other quiz. The quiz on welding documents and ISO 6947 checks WPS, WPQR, positions and process numbers.

Author: Dmitry Frolov, welder and metal fabricator Updated: 29 September 2026