Is this steel casserole safe for use? [duplicate]

Yesterday I bought this 1 lt (1 qt) steel casserole in a chinese shop, and after boiling one egg, it's decolored and got black spots, as shown:

It's stainless steel, it weights 430g, and I guess it's fake, but i was so cheap that I couldn't resist.

Bäcken is a french brand, but their products look much higher quality than mine.

What it's happing here? How can steel be bad? It's safe to use?

Edit

Cleaned with warm water + soap before first use, then used to cook hard boiled eggs in unsalted water.

food-safety stainless-steel

Best Answer

Certainly it is stainless. It may ferritic stainless , magnetic- 13% chrome, satisfactory for cookware. Most cookware is 304 ( 18-8 type), austenitic, non-magnetic ( mostly). The Backen is clad, it was much more expensive and has a big disc of copper in the bottom for heat distribution and is better to cook with. The weakness of inexpensive stainless is that it is thin with poor heat distribution. As commented, salt/chloride can pit stainless, usually it is not a problem for the relatively short times involved in cooking ( compared to years in a chemical vessel). Mechanical scouring with something like SOS pads would probably clean it the best (not perfect).