What are these parts (for an IKEA INGOLF kitchen chair)

I want to replace these plastic widgets in my IKEA INGOLF kitchen chairs with metal ones — but I don’t know what the metal ones are called. This is the chair: https://www.ikea.com/gb/en/p/ingolf-chair-white-70103250/.

Any idea what the bent metal widgets (about 2cm) are called? I’m not sure where I got them from — probably some other furniture.

The 1st image shows 2 of them: one being used to hold the chair together and the other loose. And the 2nd image is a screenshot from the Ingolf assembly manual.