Five commonly used casting materials for automotive parts
1. Automotive gray cast iron parts
The representative gray cast iron component in automobiles is the cylinder body, which has a development direction of thin-walled high strength. There are two main methods of implementation: one is the low-carbon equivalent process, which has the main advantage of being easy to achieve and high reliability by changing the burden after the furnace; Low cost with no or minimal use of alloy elements; The requirements for furnace pretreatment and operation are relatively loose. The second is the high carbon equivalent and alloying process, which has the advantage of being relatively mature and having a significant effect on improving strength; The casting performance is good, and the tendency to form shrinkage (porosity) waste is small; The processing performance and thermal conductivity of castings are good.
The representative components of ductile iron in automobiles are crankshaft, camshaft, middle and rear axle housing, various brackets, housings, and other components. At present, the development of as cast high-strength pearlite matrix ductile iron and as cast high toughness ferrite ductile iron is progressing. Mainly obtained by optimizing the smelting process, strictly controlling the S, P content and trace element content in the original molten iron, selecting suitable spheroidizing agents, inoculants, alloy elements and addition methods, and strictly following the flow inoculation process.
3. Vermicular graphite cast iron parts
Vermicular graphite cast iron has been widely used in automotive castings such as exhaust pipes and high horsepower engine cylinder heads. Using vermicular graphite cast iron to manufacture medium and high-power engine cylinder heads can reduce the weight of the cylinder head through design, and also improve the performance of the cylinder head and increase the power of the engine. At present, the application of vermicular graphite cast iron in high-power engine cylinder blocks is increasing, which can reduce thin-walled thickness, eliminate reinforcing ribs, and reduce weight by about 25%.
4. Isothermally quenched ductile iron (ADI)
Isothermal quenched ductile iron has comprehensive mechanical properties with high strength, plasticity, and toughness, which can be roughly divided into two categories: high-strength type with a strength of 1200-1600 N/mm2 and high-strength type with a elongation of about 10% with a strength of 900-1200 N/mm2. Due to its excellent material properties, ADI products have achieved rapid development in developed countries in Europe and America, and have been successfully applied in truck chassis, engines, and car crankshafts.
5. Development of Special Cast Iron
With the improvement of engine performance, the heat resistance requirements of some castings such as exhaust pipes are becoming increasingly high, and high silicon molybdenum ductile iron, medium silicon molybdenum vermicular iron, and high nickel ductile iron continue to appear.