After the bowl cutter,meat grinder,cooking mixer
arrive to you, and you open the plywood box,maybe you can see some rust points on the machine,maybe you will ask why your machine is rusty? Is your machine made from SUS304 or SUS 316?
Firstly, some parts of the machine maybe not SUS304, such as the chain and gear. Because the SUS304 is soft and easy be damaged if SUS304.
But why some parts are made from SUS304, also have some rust points?
Stainless steel refers to steel with stainless and corrosion resistance as the main characteristics, and the chromium content is at least 10.5%, and the maximum carbon content is not more than 1.2%. Among them, 304 stainless steel is a common material in stainless steel, with a density of 7.93 g/cm³, also known as 18/8 stainless steel in the industry. It can withstand high temperature up to 800℃, and has the characteristics of good processability and high toughness.
Why does stainless steel rust?
First of all, let's understand the structure of stainless steel: stainless steel is a crystal solid composed of atomic arrangements. In addition to iron, it also contains other metal components such as chromium, nickel, titanium, etc. Chromium and nickel elements have anti-rust function and can form a passive film to prevent stainless steel from rusting.
The following conditions may cause damage to the protective film on the stainless steel surface, causing corrosion and rust.
1. The surface of stainless steel accumulates dust containing other metal elements or attachments of heterogeneous metal particles. In humid air, the condensed water between the attachments and stainless steel connects the two into a micro-battery, triggering an electrochemical reaction , the protective film is damaged, which is called electrochemical corrosion.
2. Organic juices (such as vegetables, noodle soup, etc.) adhere to the surface of stainless steel. In the presence of water and oxygen, organic acids will be formed, and organic acids will form organic acids to corrode the metal surface for a long time.
3. The surface of stainless steel adheres to substances containing acids, alkalis, and salts (such as alkaline water and lime water sprayed on walls for decoration) to cause local corrosion.
4. In polluted air (atmosphere containing a large amount of sulfide, oxide, and hydrogen oxide), when it encounters condensed water, it will form sulfuric acid, nitric acid, and acetic acid liquid points, causing chemical corrosion.
For example: 304 steel pipes, in the atmosphere of dry cleansing, absolute good resistant to tarnishing ability is arranged, but it is moved on to riviera, in containing the sea fog of a large amount of salts, will soon get rusty;