The composition of chemical elements of ductile iron and what applications and precautions

- Sep 20, 2018-

Ductile iron, which is a high-strength cast iron material from a professional point of view, and the comprehensive performance of the material is close to that of steel. Therefore, in order to use this material correctly and reasonably, it is necessary to learn and understand it. The expertise so that you can achieve your goals, and at the same time, you can achieve the intended use.


1. Definition and application of ductile iron

Ductile iron, which is a kind of spheroidal graphite obtained by spheroidization and inoculation treatment, can effectively improve the mechanical properties of cast iron, as well as the plasticity and toughness of cast iron, so it is higher in strength than carbon steel. Based on these advantages, this kind of material can be used to make some parts with high stress, high strength and toughness. The so-called "steel with iron" mainly refers to ductile iron. In addition, at present, the development of ductile iron is very rapid and widely used, second only to gray cast iron.


2. The chemical element composition of ductile iron and the characteristics of pearlitic ductile iron

Ductile iron, which is the main element in the composition of chemical elements, but in addition to iron, there are other chemical elements, and they occupy different proportions, specifically: carbon 3% - 4%, silicon 1.8% - 3.2%, the total amount of three elements of manganese, phosphorus, sulfur is not more than 3%, and there are appropriate amounts of spheroidized elements such as rare earth and magnesium. In addition, in the market, there are spectral standard samples of ductile iron for component analysis and reference.


The characteristics of pearlitic ductile iron are medium strength, toughness and plasticity, high comprehensive performance, good wear resistance and shock absorption performance, and good casting process performance. The performance of this kind of ductile iron can be changed by heat treatment process. . Therefore, this type of ductile iron can be used to manufacture various power mechanical crankshafts, camshafts, connecting shafts, connecting rods, gears, clutch plates and hydraulic cylinders.


3. Precautions for ductile iron

Ductile iron, which has some precautions, is:


(1) The chemical composition should be strictly controlled, and the original iron liquid is also required. The carbon content should be higher than that of gray cast iron, and the content of manganese, phosphorus and sulfur in the ductile iron should be appropriately reduced.

(2) The temperature of the molten iron should be strictly controlled to compensate for the loss of molten iron during spheroidization and incubation.

(3) When the material is spheroidized and inoculated, an appropriate amount of spheroidizing agent and inoculant may be added, but not excessive, so as to avoid various problems that affect the performance and use effect of the ductile iron, and the quality of the product.