Here is a list of commonly used cast iron: 1. Grey Cast Iron 2. White Cast Iron 3. Mottled Cast Iron 4. Nodular Cast Iron 5. Malleable Cast Iron 6. Alloy Cast Iron. 1. Grey Cast Iron: Composition: It is basically an alloy of carbon and silicon with iron. It contains C = 2.5- 3.8%; Si = 1.1-2.8%; Mn = [...]
Wever categorises iron binary equilibrium diagrams into four main classes: 1. Phase Diagram with Open γ-Field: Alloying elements like Ni and Mn raise Ae4 and lower Ae3 as well as Ae1 temperatures, narrowing the range of α-phase and extending the range of γ-phase, and when present in sufficiently high concentrations, point 0 in Fig 1.42 (1) and more, make γ-phase [...]
In Fe-Fe3C diagram, three important invariant (at a constant temperature) reactions take place as described below: 1. Peritectic Reaction: A peritectic reaction, in general, can be represented by an equation: where, L represents a liquid of fixed composition, S1 and S2 are two different solids of fixed composition each. Fig. 1.23 illustrates the peritectic region of Fe-Fe3C diagram. The invariant [...]
In this article we will discuss about:- 1. Introduction to Allotropy of Iron 2. Thermodynamics of Allotropy in Iron 3. Effect of Pressure 4. Geometry of BCC and FCC Crystal Structures of Pure Iron 5. Solubility of Carbon in Alpha and Gamma Irons. Contents: Introduction to the Allotropy of Iron Thermodynamics of Allotropy in Iron Effect of Pressure on Allotropy [...]
In this article we will discuss about:- 1. Introduction to the Iron-Carbon Equilibrium Diagram 2. Phases in Fe-Fe3C Diagram 3. Critical Temperatures 4.Transformations and Microstructures of Slowly Cooled Steels 5. Methods Used to Distinguish between Free-Ferrite and Free-Cementite 6. Limitations. Contents: Introduction to the Fe-Fe3C Equilibrium Diagram Phases in Fe-Fe3C Diagram Critical Temperatures in Fe-Fe3 C Equilibrium Diagram Transformations and [...]
There are six basic types of cast iron with several varieties of each as given below: Type # 1. White Cast Iron: White cast iron has all its carbon in the combined cementite form (i.e., free of graphite). Cementite is hard, brittle and white compound. As the fractured surface of white iron looks silvery-white and dull as the fracture occurs [...]
In this article we will discuss about:- 1. Introduction to Cast Irons 2. Composition and Cooling Rate of Cast Irons 3. Comparison of Properties 4. Science of Development of Microstructures. Introduction to Cast Irons: Cast irons are iron-carbon (and silicon) alloys having carbon or carbon equivalent value, more than 2% (actually it is 2.1 1%), i.e., more than the maximum [...]
Malleable irons, both pearlitic and ferritic are obtained after malleablizing-annealing of white cast iron of controlled compositions. As this annealing heat treatment takes long time, moreover there are difficulties in cooling thick sections rapidly enough to get the original white cast iron, S.G. iron has replaced the malleable iron in many applications. However, thin-section components that require maximum machinability and [...]
Grey irons have graphite flakes dispersed in the steel-matrix, usually, of pearlite or ferrite (the amount of Mn could be as high as 1.2% for pearlitic, or as low as 0.1% for ferritic matrix). The heat -treatment has little or no effect on the size and shape of the graphite as obtained after casting. However, the carbon-diffusion-paths being shorter in [...]
The graphite could be in flake (grey) form, or as nodules (ductile iron). These cast irons are divided in following classes: I. Nickel-alloyed, austenitic graphitic irons (Ni-Resist)- Both grey and nodular forms are used for high corrosion resistance, and for high-temperature service. II. High silicon (14.5% Si) grey irons are used in applications requiring corrosion-resistance. III. High silicon (4-6%) grey [...]