Performance advantages of ductile iron castings

Ductile iron castings are high-strength materials that can improve the mechanical properties of cast iron after special treatment. During the casting process, the flake free graphite is converted into spheroidal graphite through spheroidization treatment, so that the graphite particles are evenly distributed. This structure enhances the plasticity and toughness of the material, thereby achieving a strength close to that of carbon steel.
Performance advantages of ductile iron castings
High strength and toughness: The comprehensive performance is better than that of gray cast iron, the yield strength can reach more than 400MPa, and the tensile strength and impact toughness are significantly improved.
Wear resistance and corrosion resistance: The spheroidal graphite structure effectively reduces vibration and prolongs the service life; at the same time, it has good anti-oxidation and anti-corrosion capabilities.
Cost-effectiveness: The casting efficiency is high, the cost is lower than that of steel, and it is suitable for large-scale production.
Six major matters to pay attention to when making ductile iron
1. Strictly require chemical composition, the carbon and silicon content of the original iron liquid is higher than that of gray cast iron, and the content of manganese, phosphorus and sulfur in ductile iron is reduced. 2. The temperature of ductile iron liquid out of the furnace is higher than that of gray cast iron to compensate for the loss of molten iron temperature during spheroidization and inoculation. 3. Spheroidization treatment is carried out, that is, spheroidizing agent is added to the molten iron. 4. Inoculation treatment is carried out by adding inoculant. 5. Ductile iron has poor fluidity and large shrinkage, so it requires a higher pouring temperature and a larger pouring system size, reasonable application of risers, chills, and sequential solidification principles. 6. Heat treatment. 1. Annealing: obtain ferrite matrix, improve plasticity and toughness, eliminate stress, and improve cutting performance. 2. Normalizing: obtain pearlite matrix, improve strength and wear resistance. 3. Quenching and tempering: obtain the matrix structure of tempered troostite and good comprehensive mechanical properties, such as spindles, crankshafts, connecting rods, etc. 4. Isothermal quenching: Make parts with complex shapes and high comprehensive performance requirements obtain the matrix structure of lower bainite, as well as comprehensive mechanical properties such as high strength, high hardness, and high toughness, to avoid cracking during heat treatment, such as spindles, crankshafts, gears, etc. Conclusion
Ductile iron is often used to produce parts with complex forces and high requirements for strength, toughness, and wear resistance, such as automobiles, internal combustion engines (engine crankshafts, connecting rods), machinery manufacturing (gears, bearings), construction (steel structures), and ships. It is especially suitable for manufacturing parts that are subject to complex stresses and high loads.