I bought a 60W soldering iron from MR DIY. After about 7 minutes of powering on, the middle part of the iron turned bright red, and a few minutes later, the tip also turned red. Is this normal? I have already exchanged it with the seller, but it's still the same.

I have already exchanged one with the seller, but it is still the same.
When I changed to the second one, it looked fine after 6 minutes on site. I took it home and used it for 10 minutes and it turned like this. They said they can't refund the money, only exchange it, but I have already exchanged it once and it is still the same. They don't have any other brands.

Will there be any problems if I continue to use it? Is it dangerous? or does it have to be thrown away? Why would a large, legal company sell unusable products? Doesn't the government care?

It worked the whole time, it was just that red color that worried me.

Will it really melt? But this product doesn't mention anything about voltage regulator. It says 60W 220~240V, does it really need a voltage regulator?