Have you chosen the right stainless steel?

In life, we use stainless steel everywhere, from bridges, trains, and houses to small drinking cups, pens, etc. There are many materials of stainless steel, and you should choose the right stainless steel according to the actual use. This article will discuss in detail how to choose stainless steel in the fields of drinking water and sewage treatment.
Stainless Steel is defined in GB/T20878-2007 as steel with stainless steel and corrosion resistance as its main characteristics, with a chromium content of at least 10.5% and a maximum carbon content of no more than 1.2%.
Stainless steel is the abbreviation of stainless acid-resistant steel. Steel types that are resistant to weak corrosive media such as air, steam, and water or are stainless are called stainless steel; while those that are resistant to chemical corrosive media (chemical corrosion such as acids, alkalis, and salts) are The type of steel is called acid-resistant steel.
The word "stainless steel" does not simply refer to one kind of stainless steel, but refers to more than one hundred industrial stainless steels, each of which is developed to have good performance in its specific application field.
The first thing is to understand the purpose and then determine the correct steel type. Generally used in drinking water or water treatment, choose SS304 or better, SS316. It is not recommended to use 216. The quality of 216 is worse than 304. 304 stainless steel is not necessarily food grade. Although 304 stainless steel is generally a relatively safe material, with corrosion resistance and high temperature resistance, and is not prone to chemical reactions with ingredients in food, only 304 stainless steel marked with special symbols and words such as food grade can meet the food grade requirements. The relevant requirements can be used in the food industry. This is because food-grade stainless steel has stricter standards for the content of harmful metal substances such as lead and cadmium to ensure that no toxic substances are released when in contact with food. 304 stainless steel is just a brand, and food-grade stainless steel refers to stainless steel materials that are certified by the national GB4806.9-2016 standard and can truly come into contact with food without causing physical harm. However, 304 stainless steel does not require that it must pass the national GB4806.9-2016 standard. 2016 standard certification, so 304 steel is not all food grade.