Yes, but you need to pay attention to the material and freezing time
304 stainless steel lunch boxes can be put in the refrigerator for freezing, but you need to pay attention to the following points:
Material safety
Qualified 304 stainless steel will not cause heavy metals (such as chromium and nickel) to precipitate due to freezing in a low-temperature environment, and its stability has been certified by food-grade standards. However, it is necessary to avoid storing highly acidic foods (such as lemon juice and vinegar-pickled foods) because acidity may accelerate the migration of metal ions.
Usage suggestions
Short-term freezing is risk-free: Suitable for refrigeration or short-term freezing (such as within a week), long-term freezing may affect the sealing or surface gloss of the lunch box.
Subpackaging is more practical: Cut the food into pieces and use plastic wrap to subpackage it and then put it in the stainless steel box to avoid the whole piece being difficult to use after freezing.
Purchase and alternatives
Give priority to regular products marked with "food grade 304/316", inferior stainless steel may have hidden dangers.
If long-term freezing is required, glass or low-temperature resistant plastic containers are more suitable.
Summary: Freezing is feasible, but it needs to be judged comprehensively based on the characteristics of the food, duration of use and quality of the container.