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 [...]
The equipment used to transform iron into steel by removing the impurities is called a converter. The first converter was developed by Bessemer and since then many other processes have also been developed. 1. The Bessemer Process: An Englishman, Henry Bessemer, first invented the Bessemer converter in 1856. The converter is a steel container, shaped like a concrete mixer, lined [...]
In this article we will discuss about:- 1. Preparation of Wrought Iron 2. Properties of Wrought Iron 3. Uses. Preparation of Wrought Iron: It is prepared from pig iron by burning out C, Si, Mn, P and sulphur in a puddling furnace. So wrought iron is a purer form of pig iron. Pig iron contains 6% or more of these [...]
Iron has got the following three allotropic forms of crystal at different temperatures. When iron is heated from normal temperature to high temperature (molten state), it undergoes all the allotropic forms. 1. Alpha Iron: It occurs from normal temperature of 910°C and has got body-centred cubic lattice crystals. (a) Ferromagnetic alpha iron which occurs from normal temperature to 770°C. (b) [...]
In this article we will discuss about:- 1. Meaning of Pig Iron 2. Impurities in Pig Iron and their Effects 3. Distinction of Pig Iron from Cast Iron. Meaning of Pig Iron: All iron produced in blast furnace whether in molten state or cast into pigs is called pig iron. Iron ore, coke and limestone are charged into a blast [...]