Heat Treatment of Steel

Heat treatment is given in order to develop the desired properties in steel.
The properties of steel can be controlled and changed by the various heat treatment processes.
Two steel samples with same composition can be given different properties by different heat treatment process.
Heat treatment is given to remove the gases, refine grain size, and relieve internal stresses and strains and to enhance the strength, ductility etc.

Glass

Glass is a transparent or translucent non-crystalline substance made from silica (sand), soda (Na2CO3) and lime (CaO or CaCO3).
When heated, glass does not melt at a specific temperature but becomes plastic instead so that when it is hot, it can be moulded by blowing, casting, rolling or extrusion.
When cooled it does not crystallize or solidify at a fixed temperature. It is a super cooled liquid with a very high viscosity.
Molten glass shall be cooled rapidly to ensure amorphous character but not too rapidly to induce thermal stress.
Pure silica melts at 1700°C thus Na2CO3 and CaCO3 are added to provide oxides which bring down the melting temperature and thus make the process energy intensive.
Fe, Mn, Cu, Cr, Co, Ni oxides are added for colour control of glass.
Poor conductor, low thermal resistance and low coefficient of expansion (3.8 × 10–6 per °C). By coating or treatment, solar gain factor of glass can be modified. Solar gain factor is the ratio of heat admitted to heat incident.
The basic idea is to allow as much as visible light possible while filtering the direct sunlight and heat.

Table of Contents

FRP is composed of fibres and matrix, in which fibers provide strength and stiffness e.g. Carbon, glass, aramid and Matrix protects and transfers load between fibers e.g., Polyester, Epoxy, Vinyl Ester, Urethane etc.

FRP is Anisotropic and has high strength in the direction of the fibers. This anisotropic behavior affects the shear strength, dowel action, and bond performance.
FRP does not exhibit yielding (the material is linear elastic until failure) and thus the design should account for lack of ductility.

These are fibre reinforced bars that can be used at:

Any concrete member susceptible to corrosion by chloride ions or chemicals.
Any concrete member requiring non-ferrous reinforcement due to Electro-magnetic considerations.
As an alternative to epoxy, galvanized, or stainless steel rebars.
At places machinery will “consume” the reinforced member i.e., mining and tunneling.
Applications requiring Thermal non-conductivity.

Ceramic is an inorganic, non-metallic solid prepared by the action of heat and subsequent cooling.
Ceramic materials may have a crystalline or partly crystalline structure, or may be amorphous (e.g., a glass).
Ceramics now includes domestic, industrial and building products and a wide range of ceramic art.

Properties

(i) Structural Ceremics

These type of ceramics demonstrate enhanced mechanical properties under demanding conditions.
Because they serve as structural members, often being subjected to mechanical loading, they are given the name structural ceramics.
This type of ceramics include bricks, pipes, floor and roof tiles.

(ii) Refractories Ceremics

A refractory material is one that can retain its strength at high temperatures
They are used in linings for furnaces, kilns, incinerators and reactors.
The oxides of aluminium, silicon and magnesium are the most important materials used in the manufacturing of refractories.

(iii) White wares Ceremics

This is a class of products that includes porcelain, china, pottery, stoneware and vitreous tile.
They are white to off-white in appearance and often contain a significant glossy or vitreous component.
Imperviousness to fluids, low conductivity to electricity, chemical inertness and an ability to be formed into complex shapes are its properties.

(iv) Technical Ceremics

It is also known as engineering, advanced or special ceramics.
It includes tiles used in space shuttles, missile nose cones, ceramic disk brakes etc.