Views: 199 Author: Site Editor Publish Time: 2021-08-21 Origin: Site
The recent news that "the inner wall of stainless steel drinking cups for tea is easily corroded and releases heavy metal chromium harms human health" has attracted the attention of many citizens. As ordinary consumers, how should we buy stainless steel cups? How to use stainless steel cups correctly? This paper has a comprehensive introduction to stainless steel cups.
What is stainless steel？
Stainless steel is the abbreviation or collective term for stainless steel and acid-resistant steel. Among them, the steel that does not rust in weak corrosive media such as the atmosphere and fresh water is stainless steel; the steel that resists corrosion in harsh corrosive media such as acid, alkali, salt and seawater is acid-resistant steel. From the perspective of chemical composition, stainless steel refers to steel with a chromium content of at least 10.5% and a carbon content of at most 1.2%.
In order to obtain the required structure and various physical and chemical properties, elements with a certain content range are added to the stainless steel. These elements are usually called alloying elements. The alloying elements added to stainless steel are mainly metal elements, such as chromium, nickel, molybdenum, silicon, copper, manganese, tungsten, etc., and there are also non-metal elements such as carbon and nitrogen. The structure and properties of stainless steel are mainly determined by the alloying elements in the steel under many conditions.
How to choose stainless cups?
Observe the stainless steel cups first. In appearance, the food-contacting surface of metal drinking cups should be smooth, free of dirt and rust, and the welding part should be smooth, free of pores and cracks. The stainless steel coffee cup should be silvery white, slightly dark, moderate hardness, good toughness, and not easy to break and deform. You should also carefully check whether the outer packaging of reusable tea cup indicates the manufacturer’s name, address, telephone number, and container’s implementation standards. Choose a reliable brand. The steel used in some stainless steels may come from recycled steel scrap. Therefore, consumers must carefully select branded products when purchasing, and avoid unlicensed and unlicensed products. At the same time, pay attention to the type of stainless steel marked on the product. The quality of stainless steel product types are ranked as follows: austenitic stainless steel cup>ferritic stainless steel cup>martensitic stainless steel cup.
Secondly, touch the stainless steel tea cups. Good quality stainless steel reusable coffee cup have smooth and delicate hand feeling, no burrs, no deflation, no holes and other defects. Good quality stainless steel cups are obviously heavier than unqualified metal tea cup.
Finally, test it. Method 1: Prepare a lemon and pour the lemon juice on the surface of the metal drinking cups with handles. After 10 minutes, dry the lemon juice. If there are obvious marks on the surface of the stainless coffee cup, it means that the stainless steel products are of poor quality and are easily corroded. Method 2: Pour a cup of white vinegar into a stainless steel coffee cups with lids, leave it overnight, pour out the white vinegar and observe the surface of the stainless steel product. If there are obvious traces or rust, the product is of poor quality.