What is the reason for the corrosion phenomenon of automobile metal stamping parts?

In addition to the reasonable mold structure, high manufacturing accuracy, good heat treatment effect, and the correct selection of punches, the service life of the stretch stamping parts we usually use depends on the factors of the correct use and maintenance of the mold. Maintenance is also a link that cannot be ignored! At the same time, we should pay attention to the following points:

• 1. Before installation and use of the stretch stamping parts, it should be strictly checked to remove the dirt, and check whether the guide sleeve and the mold of the stretch stamping parts are well lubricated!
• 2. When the punch and die edges of the drawing parts are worn, they should be stopped and sharpened in time, otherwise the wear degree of the die edges will be rapidly expanded, the die wear will be accelerated, and the stamping quality and die life will be reduced!
• 3. Ensure the service life of the stamping parts, and the springs of the die should be replaced regularly. The automobile sheet metal parts prevent the spring fatigue damage from affecting the use of the stretch stamping parts!

Stamping is a forming and fabrication method of applying external force to sheets, strips, pipes and profiles, etc. by pressure and die to make them plastically deform or separate, so as to obtain workpieces with the required shape and size! Stamping and forging are both plastic fabrication, collectively called stamping blanks. Mainly hot-rolled with steel plate and steel strip!

In order to produce normally, improve the quality of metal stamping parts, reduce costs, and prolong the life of the die, it is necessary to use and maintain the die properly! Strictly implement the die “three inspections” system, and do a good job in die and maintenance work!

We always see corrosion of metal automobile stamping parts, so what causes it to corrode?

The internal factors of metal corrosion, from a thermodynamic point of view, compared with its corrosion products, metals have higher energy, are unstable, and have a tendency to spontaneously transform into low-energy corrosion products, that is, metals are rusted. It is a natural phenomenon. Most metals in the industry are multi-component alloys. The alloy phase structure is different, contains impurities, uneven machining deformation, uneven stress distribution, etc.! These are physical, chemical and electrochemical inhomogeneities. When a water film is formed on the surface, chemical or electrochemical corrosion will inevitably occur!

External factors of metal corrosion:

• 1. The influence of relative temperature, the higher the relative humidity in the air, the thicker the water film on the metal surface, the oxygen in the air penetrates the water film to the metal surface, and the corrosion rate increases significantly when the relative humidity reaches a certain value, this value is called Critical relative humidity! The critical relative humidity of steel is about 70%!
• 2. The influence of temperature, in a dry environment, the metal is not easy to corrode no matter how high the temperature is. When the relative humidity reaches a critical value, the influence of temperature is significantly intensified, and every 10 °C increase in temperature will cause corrosion. The speed is doubled, so in the hot and humid tropics or rainy season, the higher the temperature, the more severe the rust! Therefore, metal will not rust without water and oxygen. 20% of the volume in the air is oxygen. He said that it is pervasive!
• 3. The influence of other materials in the atmosphere: When the atmosphere contains salt spray, sulfur dioxide, hydrogen sulfide and dust, it will accelerate corrosion, so the difference in the size of corrosion under different environments is obvious. The city is higher than the countryside, and the industrial area is higher than the living area. , the coast is higher than the inland, and the high dust is higher than the low dust!