Ferrous Materials

Ferrous Materials

Introduction

Engineering materials used to manufacture of articles or products, dictates which manufacturing process or processes are to be used to provide it the desired shape. Sometimes, it is possible to use more than one manufacturing processes, then the best possible process must be utilized in manufacture of product. It is therefore important to know what materials are available in the universe with it usual cost. What are the common characteristics of engineering materials such as physical, chemical, mechanical, thermal, optical, electrical, and mechanical? How they can be processed economically to get the desired product. The basic knowledge of engineering materials and their properties is of great significance for a design and manufacturing engineer. The elements of tools, machines and equipments should be made of such a material which has properties suitable for the conditions of operation. In addition to this, a product designer, tool designer and design engineer should always be familiar with various kinds of engineering materials, their properties and applications to meet the functional requirements of the design product. They must understand all the effects which the manufacturing processes and heat treatment have on the properties of the engineering materials. The general classification

Classification Of Engineering Materials

A large numbers of engineering materials exists in the universe such as metals and non-metals (leather, rubber, asbestos, plastic, ceramics, organic polymers, composites and semiconductor). Some commonly used engineering materials are broadly classified as shown in Fig. 4.1. Leather is generally used for shoes, belt drives, packing, washers etc. It is highly flexible and can easily withstand against considerable wear under suitable conditions. Rubber is commonly employed as packing material, belt drive as an electric insulator. Asbestos is basically utilized for lagging round steam pipes and steam pipe and steam boilers because it is poor conductor of heat, so avoids loss of heat to the surroundings. Engineering materials may also be categorized into metals and alloys, ceramic materials, organic polymers, composites and semiconductors. The metal and alloys have tremendous applications for manufacturing the products required by the customers.

Metals and Alloys

Metals are polycrystalline bodies consisting of a great number of fine crystals. Pure metals possess low strength and do not have the required properties. So, alloys are produced by melting or sintering two or more metals or metals and a non-metal, together. Alloys may consist of two more components. Metals and alloys are further classified into two major kind namely ferrous metals and non-ferrous metals. (a) Ferrous metals are those which have the iron as their main constituent, such as pig iron, cast iron, wrought iron and steels. (b) Non-ferrous metals are those which have a metal other than iron as their main constituent, such as copper, aluminium, brass, bronze, tin, silver zinc, invar etc.

Furnaces For Melting Different Materials

1. Grey Cast Iron

(a) Cupola

(b) Air furnace (or Reverberatory Furnace)

(c) Rotary furnace (d) Electric arc furnace

2. Steel

(a) Electric furnaces

(b) Open hearth furnace

3. Non-ferrous Metals

(a) Reverberatory furnaces (fuel fired) (Al, Cu)

(i) Stationary

(ii) Tilting

(b) Rotary furnaces

(i) Fuel fired

(ii) Electrically heated

(c) Induction furnaces (Cu, Al)

(i) Low frequency

(ii) High frequency.

(d) Electric Arc furnaces (Cu)

(e) Crucible furnaces (AI, Cu) (

i) Pit type

(ii) Tilting type

(iii) Non-tilting or bale-out type

(iv) Electric resistance type (Cu)

(f) Pot furnaces (fuel fired) (Mg and AI)

(i) Stationary

(ii) Tilting