The inside and outside materials of thermos bottle are different.

The reason why the internal and external materials of thermos bottle mouth are different is mainly due to the different functions and costs of various materials.

1. The inside of the vacuum flask is 3 16 stainless steel, and the outside is 304 stainless steel. This configuration makes the material cost of the thermos cup the highest. 3 16 stainless steel has stronger corrosion resistance than 304 stainless steel, and 3 16 stainless steel has better chloride corrosion resistance, so it is often used to manufacture medical devices and other products.

2. 304 stainless steel inside and outside, this configuration makes the material cost of the thermos cup second. 304 stainless steel is a widely used stainless steel material with good corrosion resistance, toughness and rust resistance, and its price is cheaper than 3 16 stainless steel.

3. The inner layer is 304 stainless steel, and the outer layer is 20 1 stainless steel, so that the material cost of the thermos cup is the lowest. The nickel content of 20 1 stainless steel is lower than that of 304 stainless steel and 3 16 stainless steel, so it is often used to manufacture low-priced products.

In a word, the difference between the internal and external materials of thermos bottle mouth is mainly based on the consideration of function and cost.