What is heat treatment process ?

know the Heat Treatment...!

Heat treatment is defined as the operations involving the heating and cooling of a metal or an alloy within a solid-state to obtain desire properties (physical or chemical) without change composition. The heat treatment process is carried out to change the grain size, modified the crystal structure of the material, and relieve the stress set up in the material after hot or cold working. Heat treatment also uses in many manufacturing processes, eg. glass working. The heat treatment process is performed in the furnace or oven with a controlling the environment of step-by-step heating and cooling within a specific period of time, apart from this the gases are used to control the furnace environment in some processes.

Fig.1 - Heat treatment process of gears

Heat treatment consists of heating of metal near of above re-crystallization temperature of the material, hold for a particular time, and then finally cooling the metal in some medium which may be air, water, brine, oil, etc. Heat treatment associate with increasing material strength and also changes manufacturing aspects like improves machining, formability, and also restores ductility while operation gets over the material.

Fig.2 - Cooling effect on the grain structure of steel

The objective of heat treatment processes are :

Refine grain size.
Helps to archive the desire mechanical, physical, or chemical properties of the material.
Reduce/ Eliminate internal residual stress.
Increase the machinability of material.
Change surface composition by diffusion.
Resoftening the hardened steel.

Classification of heat treatment processes :

the heat treatment process can be classified into the following types

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Quenching process

Quenching also called Hardening, is a heat treatment process in which steel is heated up to austenite temperature (above it's critical temperature), hold for some time and then cooled in water, oil or molten salt (rapid cooling). Due to rapid cooling, it results very hard structure - martensite (hardest form of Steel). fig.- steel component quench in oil. Due to hardening process hardness of steel increases and bitterness also increases. (brittleness increases hence hardened Steel nay not directly use). Quenching is always follow by tempering process. Due to rapid cooling in hardening process metal shape shrink, internal residual stresses are setup. That's the reason why hardening is follow by tempering.

Additive Manufacturing processes

What is Additive Manufacturing? As the name suggests, Additive Manufacturing (also known as 3D printing) is a group of manufacturing techniques , which manufacture parts by adding successive layers of material with the help of computer control systems. Various materials that can be used in additive manufacturing (AM) are plastic, metal, concrete, also human tissue. In the additive manufacturing process, Computer-Aided Design (CAD) is created and utilized to manufacture 3-Dimension (3D) objects. Various CAD-CAM software is required to Design, Analyze, and Manufacture parts. Once CAD data is produced, Slicing software slices the design in different layers (as required by different AM processes), and then data utilized to manufacture required material parts. Different terms like “3D printing” and “rapid prototyping” are also casually used to describe Additive manufacturing, but each one is a subset of additive manufacturing. Hence in the simple sense, Additive manufacturing technology

Mathematic modeling of polymer extrusion process

Q-3. Briefly explain the mathematical modelling of any one of the manufacturing processes. Ans: Mathematical model of polymer extrusion process : Polymer material consists of long chain molecules. In extrusion of thermoplastic polymers, important parameters are Material flow and type of flow Heat transfer in flow Residence time Mixing of particles in flow in multiple polymers, etc. To analyse these parameters, mathematical models are useful. Using governing equations and boundary conditions (B.C), a model is created and a solution is obtained for particular B.C. Governing equations: To model any flow and thermal transport in the manufacturing process, conservation of mass, conservation of energy and the force momentum balance equation is used. The equations are as follow, Where, ρ is density, t is time, T is temperature, V is the velocity vector, μ is dynamic viscosity, F is body force, p is pressure, Cp is specific heat at constant pressure, β is coefficient of volumetric ther

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