In daily life, almost all the thermos cups we use are labeled with numbers such as 304, 316, 18/8, but most people do not know the meaning of these numbers.
1.304, 316
304 and 316 represent different stainless steel materials. The safety of the insulated cup depends on the material of the inner liner. What materials are usually used for the inner lining of a thermos cup?
At present, there are three main types of stainless steel materials for the inner liner of thermos cups on the market: 201, 304, and 316. 304 stainless steel is internationally recognized as the preferred food grade stainless steel material, which is rust resistant, corrosion-resistant, and environmentally friendly; 316 stainless steel has stronger corrosion resistance, but relatively higher cost. And 201 stainless steel material is mostly used in industry, with much lower safety performance than 304 and 316. Many low-quality insulated cups are made of 201 stainless steel material.
2.18/8
18/8 is another name for 304 stainless steel. Common numbers such as “Cr18” and “Ni8” are found on baby insulated cups. Cr is chromium and Ni is nickel, both of which determine the properties of stainless steel.
In order to maintain the inherent corrosion resistance of stainless steel, it must contain at least 18% chromium and at least 8% nickel. Cr18 and Ni8 are symbols of 18% chromium and 8% nickel content, indicating that this insulated cup is green and environmentally friendly, can prevent rust and corrosion, and is a relatively excellent material.
However, the content of chromium and nickel should not be too high. In typical stainless steel, the chromium content should not exceed 18% and the nickel content should not exceed 12%. So 316 stainless steel, which has better corrosion resistance and high-temperature strength, has 4% more nickel content and 2.5% more molybdenum content than 304.
The outer packaging of insulated cups made of 304 and 316 stainless steel will indicate the material used, representing food grade products. To ensure the quality and safety of thermos cups, it is recommended that consumers choose well-known and reputable brand products.
