Infrared Almighty Multielement Analyzer Controls the Chemical Composition of Ductile Iron Castings

Infrared Almighty Multi-Element Analyzer Controls the Chemical Composition of Ductile Iron Castings

QL-S3000C computer infrared all-round multi-element analyzer can quickly and accurately control the chemical composition of earth graphite cast iron carbon (C), silicon (Si), cerium (Ce) , manganese (Mn), phosphorus (P), sulfur ( S) Elemental content in the content of molybdenum (Mo), magnesium (Mg) and rare earth. Using the latest computer and microcontroller technology to achieve program control and data processing. It can quickly and accurately measure the mass fraction of various elements in steel and non-ferrous metals, has a high degree of automation, accurate and reliable quantitative dosing, and less reagents, improves the accuracy and precision of analysis, and can directly display the quality score. And print, user-friendly operation.

The choice of carbon (C), silicon (Si), and cerium (Ce)

Because the effect of spheroidal graphite on matrix weakening is small, the amount of graphite in nodular cast iron has no significant effect on mechanical properties. When the carbon content changes in the range of 3.2% to 3.8%, it has no obvious effect on the mechanical properties. . Therefore, when determining the content of carbon silicon in the process, the main consideration is to ensure the casting performance, and the carbon equivalent is selected to be about the eutectic composition. The molten iron with a eutectic composition has the best flowability, has a tendency to form a concentrated shrinkage cavity, and has a high density of casting structures. However, when the carbon equivalent is too high, the graphite tends to float and, to a certain extent, affects the spheroidization. The main reason is that the required amount of residual Mg is high. Increase the number of inclusions in cast iron, reducing the performance of cast iron.

The effect of increasing ferrite in silicon ductile iron is greater than that of gray cast iron, so the level of silicon content directly affects the amount of ferrite in the ductile iron matrix. Silicon in the nodular cast iron has a great influence on the performance, mainly in the solid solution strengthening effect of silicon on the substrate, while silicon can refine the graphite and improve the roundness of the graphite ball. Therefore, the increase of silicon content in ductile iron greatly improves the strength index and reduces the toughness. The spheroidized cast iron has a greater tendency to crystallize undercooling and form a white mouth, and silicon can reduce this tendency. However, the amount of silicon is too high to control the formation of lumpy graphite in the large-diameter ductile iron and reduce the mechanical properties of the casting. The data shows that silicon in nodular cast iron was added in a way that gave a certain degree of improvement in performance.

Manganese (Mn) : Manganese plays a different role in ductile iron than gray cast iron. In grey cast iron, in addition to strengthening ferrite and stabilizing pearlescent, manganese can also reduce the harmful effects of sulfur. In nodular cast iron, the spheroidizing element has a strong desulfurization ability, and manganese no longer has this effect. Because manganese has a serious positive segregation tendency, it is often enriched in the grain boundary of the eutectic group, which promotes the formation of intercrystalline carbides and significantly reduces the toughness of the ductile iron. For thick section ductile iron, the segregation tendency of manganese is more serious. At the same time, the increase of manganese content increases the pearlite content in the matrix, thus increasing the strength index and reducing the toughness. The control of manganese content in highly ductile ductile iron should be more stringent.

Phosphorus (P) : Phosphorus has a severe segregation tendency in nodular cast iron, and it is easy to form phosphorus eutectic at the grain boundary, which severely reduces the toughness of spheroidal graphite cast iron. Phosphorus also increases the tendency of ductile iron to shrink. When ductile iron is required to have high toughness, phosphorus should be controlled to 0.06% or less.

Sulfur (S) : Sulfur in spheroidal graphite cast iron has a strong chemical combination with spheroidizing elements, resulting in sulfides and sulfur oxides. It not only consumes nodulizing agents, causing spheroidizing instability, but also increases the number of inclusions. The rate of decline has accelerated. Sulfur is involved in the recharging agent in the smelting process, and the process control reduces the sulfur content in the raw material as much as possible, and the desulfurization measures before the furnace are taken.

Molybdenum (Mo) : Molybdenum improves the material's high temperature strength and room temperature strength. Due to its use, it easily forms a certain amount of pearlite and carbides and reduces toughness. For Mo ductile iron alloyed with Mo, the material specification requires Mo content 0.3~ 0.7% control.

Magnesium (Mg) and rare earth content : Magnesium is the main spheroidizing element. Rare earths have desulfurization, neutralize anti-balling elements, have a protective effect on Mg, and improve the ability of molten iron to resist decay. However, the rare earth element is a carbide forming element, so the residual amount of the rare earth is controlled as much as possible while ensuring good spheroidization. Re = 0.01 ~ 0.04%, Mg = 0.03 ~ 0.06% to ensure that the ball.

Nanjing Kirin Scientific Instrument Group Co., Ltd.

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