Analysis of the advantages of ductile iron in valve materials
As an alternative to steel, nodular cast iron was developed in 1949. The carbon content of cast steel is less than 0.3%, while the carbon content of cast iron and ductile iron is at least 3%. The low carbon content in cast steel prevents the carbon present as free graphite from forming structural flakes. The natural form of carbon in cast iron is in the form of free graphite flakes. In nodular cast iron, this graphite flake is transformed into tiny spheres through a special treatment method. This improved sphere makes the spheroidal graphite cast iron have more excellent physical properties than cast iron and steel. It is the spherical microstructure of this carbon that makes ductile iron have better ductility and impact resistance, while the form of flakes inside the cast iron causes the cast iron to have no ductility. The best ductility can be obtained through the ferrite matrix. Therefore, after the pressure load parts of the ductile iron are processed by the ferritizing annealing cycle, the spherical structure inside the ductile iron can also eliminate the flake graphite in the cast iron. The crack phenomenon. In the microphotograph of ductile iron, the cracks can be seen to terminate after reaching the graphite ball. In the ductile iron industry, these graphite balls are called 'crack terminator' because of their ability to prevent fracture. As a substitute for steel in 1949, the human development of ductile cast iron. Less than 0.3% carbon steel, while the cast iron and ductile iron with carbon content the amount of at least 3%. Low carbon steel makes as free graphite carbon sheet structure will not form. The natural form of carbon in cast iron is the free graphite flake form. In ductile iron, the graphite flakes change through special processing methods into a tiny ball. The improved ball made of cast iron makes has physical properties greater than cast iron and steel. It is this nodular microstructure of carbon, the nodular cast iron has better extension and impact resistance, while the flake form of cast iron results no ductility. To obtain the best ductility, the ferrite matrix therefore, ductile iron pressure containing parts are treated with a ferritizing annealing cycle, ductile iron spheroidal nodules also eliminate the crack phenomenon of flake graphite cast iron internal prone. In microscopic photos of ductile iron, can see the cracks in the procession to the ball after the termination of graphite. In the ductile iron industry, the graphite ball called u0026ldquo; crack terminator u0026rdquo;, because of their ability to prevent breakage. Compared with cast iron, ductile iron It has an absolute advantage in strength. The tensile strength of ductile cast iron is 60k, while the tensile strength of cast iron is only 31k. The yield strength of spheroidal graphite cast iron is 40k, while the cast iron does not show the yield strength and eventually fractures. The strength-to-cost ratio of ductile iron is much better than that of cast iron. Compared with cast iron, ductile iron has the absolute advantage in strength. Tensile strength of cast iron is 60K, while the tensile strength of cast iron is only 31k. The yield strength of ductile iron is 40K, and the iron did not show the yield strength, and ultimate fracture. Ductile iron strength-to-cost ratio is much better than that of cast iron. The strength of ductile iron and the strength of cast steel are comparable. Nodular cast iron has a higher yield strength, with a minimum yield strength of 40k, while the yield strength of cast steel is only 36k. In most municipal applications, such as: water, salt water, steam, etc., the corrosion resistance and oxidation resistance of ductile iron exceed those of cast steel. Due to the nodular graphite microstructure of nodular cast iron, nodular cast iron is better than cast steel in reducing vibration ability, so it is more conducive to reducing stress. An important reason for choosing ductile iron is that ductile iron is less expensive than cast steel. The low cost of ductile iron makes this material more popular, higher casting efficiency, and less machining costs for ductile iron. The strength of ductile iron and steel strength is comparable. Ductile iron has a higher yield strength, yield strength minimum of 40K, while the yield strength of steel is only 36k. In most municipal applications, such as: water, salt water, steam, ductile iron corrosion and oxidation resistance than cast steel. As the spherical graphite cast iron microstructure, the decrease vibration capability, ductile iron better than steel, therefore more conducive to reducing stress. Choose one of the important reasons of ductile cast iron is ductile iron casting low cost ratio. The low cost of nodular cast iron makes the material more popular, casting more efficient, less the cost of machining ductile cast iron.