Ductile iron covers generally there is little rusty situation, but once there is such a phenomenon, we need to rust it, then how should the rust it, this article for everyone to explain the simple.
At present, there are two kinds of derusting methods for ductile iron covers, one is throwing and rusting, and the other is spray and rust. There is a gap between the two. The so-called projectile rust is mainly used for high-speed rotation of shot blasting machine Of the impeller, the abrasive dispersed to the surface of the nodular cast iron cover, the use of the collision of its surface rust and stains removed.
And the injection of rust is oil and water separation through the treatment of compressed air from the nozzle high-speed jet from the nozzle, the use of pressure and ductile iron cover the surface of the collision. For the ductile iron cover the correct way to rust for everyone to explain this simple, when we encounter this situation, the above two methods can choose one.
1, compared with cast iron, ductile iron in terms of strength has an absolute advantage. Ductile iron tensile strength is 60k, while the tensile strength of cast iron is only 31k.
2, the yield strength of ductile iron is 40k, while the cast iron does not show the yield strength, and eventually the fracture.
Ductile iron strength - cost ratio is far better than cast iron.
3, the strength of ductile iron and cast steel strength is comparable. Ductile iron has a higher yield strength, the yield strength of the lowest 40k, while the yield strength of cast steel is only 36k.
In most municipal applications, such as: water, salt water, steam, etc., ductile iron corrosion resistance and oxidation resistance are more than cast steel.
4, due to ductile iron spherical graphite microstructure, in reducing the vibration capacity, ductile iron is better than cast steel, so more conducive to reduce stress.
One of the important reasons for choosing ductile iron is that ductile iron is less expensive than cast steel. The low cost of the maintenance of cast iron covers makes this material more popular, with higher casting efficiency and less machining costs for ductile iron
5, the low carbon content in the cast steel makes the carbon present as free graphite do not form structural flakes, and the natural form of carbon in the cast iron is in the form of free graphite flakes.
6, the ductile iron load parts are subjected to ferrite annealing cycle of the process, the ductile iron inside the spherical structure can also eliminate the cast iron within the thin graphite easily crack phenomenon.
7, in the micro-photo of the nodular cast iron, you can see the crack procession to the graphite ball after the termination. In the ductile iron industry, these graphite balls are called "crack terminator."