What are the forms of corrosion damage to metal parts?

What are the forms of corrosion damage to Additional Metal Parts? How to prevent and reduce corrosion of parts in mechanical equipment?

There are two types of chemical corrosion and electrochemical corrosion.

1) Correct material selection

According to the environmental medium and service conditions, select appropriate corrosion-resistant materials, such as alloy steel containing nickel, chromium, aluminum, silicon, titanium and other elements; if conditions permit, try to use nylon, plastic, ceramics and other materials.

2) Reasonable design

When designing the structure, try to make all the conditions of the whole part uniform, so that the structure is reasonable, the shape is simplified, and the surface roughness is appropriate.

3) Cover the protective layer

Covering the metal surface with a layer of different materials changes the surface structure and isolates the metal from the medium to prevent corrosion. Commonly used covering materials are metal or alloy, non-metal protective layer and chemical protective layer.

4) Electrochemical protection

Electrochemical protection includes cathodic protection and anodic protection.

The cathodic protection method is mainly to pass a cathodic direct current on the surface of the protected metal to eliminate or reduce the corrosion effect of the metal surface on the protected metal.

The anode protection method is mainly to pass an anode direct current on the surface of the protected metal to form a passivation film on the metal surface, thereby increasing the resistance of the corrosion process. In addition, a metal that is more active than the chemical properties of the part material can be riveted to the part to form a corrosion battery, and the part acts as a cathode without corrosion.

5) Add corrosion inhibitor

According to chemical properties, corrosion inhibitors can be divided into inorganic and organic. Such as potassium dichromate, sodium nitrate, sodium sulfite and other inorganic substances can form protection on the metal surface to separate the metal from the medium; amine salts, agar, animal glue, alkaloids and other organic compounds can be adsorbed on the metal surface to make Both metal dissolution and reduction reactions are inhibited, thereby mitigating metal corrosion.

6) Changing environmental conditions

Remove the corrosive medium in the environment to reduce its corrosive effect. Such as ventilation, dehumidification, removal of sulfur dioxide gas, etc. For commonly used metal materials, controlling the relative humidity below the critical humidity (50%-70%) can significantly slow down atmospheric corrosion. In the pickling workshop and electrolysis workshop, the ground slope and drainage ditch should be reasonably designed, and the ground anti-corrosion isolation layer should be prepared to prevent the acid liquid from penetrating the ground and making it protrude, so as not to damage the storage tank and mechanical foundation.