Graphitized petroleum coke is mainly used as a carburizer in the casting of automotive parts to adjust the carbon content of the metal melt, thereby improving the mechanical properties of the material. The following is an analysis of its specific applications and the impact of different specifications:
I. The main application of graphitized petroleum coke in the casting of automotive parts
1. In engine parts, cast iron or cast steel parts such as cylinder blocks, cylinder heads, and crankshafts require high strength and wear resistance. Graphitized petroleum coke improves the hardness and fatigue resistance of the material by optimizing the carbon content. The second is the piston ring: high carbon content can enhance wear resistance and reduce friction loss.
2. The second is the braking system, brake discs, brake drums, and other key automotive parts. Adding graphitized petroleum coke to cast iron can improve thermal conductivity and heat shock resistance and reduce thermal cracking during braking.
3. Then there is the transmission system, such as the gearbox housing, differential housing, and other automotive housings. Carbon can be used to improve the strength and shock absorption performance of the castings and reduce vibration noise.
4. Finally, there are structural parts, suspension parts, brackets, and other structural parts. By optimizing the carbon content to balance the toughness and rigidity of the material, it can adapt to complex stress environments.
II. The impact of graphitized petroleum coke of different specifications on automotive parts
1. In terms of particle size, coarse particles of 15mm and above have a slow dissolution rate and are suitable for long-term smelting processes, such as large castings. The carbon absorption rate is lower but more stable. Fine particles of 0.21mm and below have a fast dissolution rate and a high carbon absorption rate, which are suitable for short-process smelting, such as small and medium-sized accessories, but are prone to oxidation and burning.
2. The carbon content is usually >98%, and high carbon is >99%, which improves the hardness and wear resistance of the material, but excessive amounts may increase brittleness and reduce impact toughness. Low carbon <95% or <98% requires other recarburizers to reduce costs but may introduce more impurities.
3. The sulfur content is generally required to be <0.5%. When the sulfur is <0.3%, the recarburizer is low sulfur, which will reduce the hot brittleness of the casting and improve the high-temperature performance, such as engine parts. When the sulfur is >0.5%, the recarburizer is high sulfur, which may cause microcracks, reduce fatigue life, and require additional desulfurization treatment.
4. When the ash content is less than 0.5%, it is considered low ash content, which means that impurities are reduced, the purity of the molten metal is improved, and the strength of the casting is enhanced. If the volatile content is high, gas will be generated during smelting, which may cause pore defects, and the amount of addition needs to be controlled.
III. Selection suggestions in actual production
For high-load parts such as crankshafts and gears, high-carbon, low-sulfur, and fine-grained petroleum coke is preferred to ensure high strength and durability. For large structural parts such as cylinder blocks, medium-coarse-grained petroleum coke is used to balance carbon absorption efficiency and stability. For cost-sensitive parts, the ash content requirements should be appropriately relaxed, but the smelting process control needs to be strengthened.
In summary, the specifications of graphitized petroleum coke directly affect the mechanical properties, defect rate, and production cost of automotive parts. A reasonable selection of parameters such as particle size, carbon content, and sulfur content can optimize the strength, wear resistance, and thermal fatigue resistance of castings.
