The main reason why powder metallurgy products are prone to rusting is due to exposure to air. When they are exposed to air, they are affected by oxygen and water vapor, leading to chemical reactions on the surface, forming compounds such as iron oxide and causing rusting on the surface. In coastal areas with high humidity, corrosion of powder metallurgy products is more severe. In addition, in some cases, not only will the surface of the product be corroded, but the surface of the internal connecting holes may also be corroded, which can seriously affect their performance and even lead to scrap.

To prevent rusting of powder metallurgy products, the following methods can generally be adopted:

1. Rust prevention treatment of iron powder:

Since the purchased iron powder is a kind of powdered solid, there are many pores between the iron powder particles. If it comes into contact with moist air, it will rust and clump quickly, making it unusable. Therefore, the purchased iron powder should be packed in sealed thick plastic bags with dry agents inside, and then put into thick woven bags for easy lifting.

2. Storage of iron powder:

When storing iron powder in a warehouse, the principle of first-in-first-out should be followed. Additionally, during storage, it is best to seal it to avoid environmental influences that could cause shrinkage or other problems.

3. The use of iron powder pressing process: 

During the production process of pressing the synchronizer hub, the iron powder should be mixed with the collar as needed. Do not bring out all the iron powder at once due to multiple tasks, to ensure the use and quantity of iron powder per shift, and strictly control the stock of mixed iron powder between processes.

Powder metallurgy products

4. Storage of synchronizer hub blank: The synchronizer hub blank has low strength and is prone to damage. It must be handled carefully and placed in the plastic tray of the turnover truck. If the billet is sintered and pressed within 48 hours, there is no need for additional packaging protection. If the time exceeds, the overturned car will be wrapped and sealed with plastic film to prevent moist air from entering.

5. Rust prevention test method: Do not use rust prevention after sintering, and use 30 # engine oil for precision machining of powder metallurgy wheel hubs; Immediately after sintering, dip in a film of anti rust oil, and use 30 # engine oil for precision machining of powder metallurgy gear wheels. Combustion combination, that is, vertically dipping WD40 anti rust oil and using 30 # engine oil for precision machining of powder metallurgy gear wheels.