Page 31 - CITS - Fitter Trade Practical - Volume -2

FITTER - CITS

EXERCISE 61 : Checking the different gauges by using
radius, wire, snap, plug, ring etc. with an

accuracy of ± 0.02mm and their heat
treatment practice and hardness testing

by different methods

Objectives

At the end of this exercise you shall be able to
• principles of heat treatment.

Introduction
Modern Engineering applications demand a better fundamental knowledge of metallurgy than ever before. The
engineer must understand the principles underlying metallurgical problems to the metallurgist in manner that can
be interpreted and evaluated. In the absence of metallurgical talent, the engineers, supervisors and Technicians
must be prepared to relay on his own resources for the intelligent solution of many such problems to determine
from the past experience proper training in the field and knowledge of the material processing methods.
Basic factors that must be considered in selecting a material for designing / manuafacturing components.
• Properties required.
• Previous experience/proper training

• Availability
• Cost
• Processing methods
The inherent properties of the material also govern the process to be selected. Hard, brittle cannot be cold-worked
successfully and a material that is brittle at elevated temperature cannot be forged the processing method will
influence of the properties that may obtained in a given past. The various process have commercial limitations
which establish the final that can be obtained in given process without restoring to subsequent finishing operation.
From the foregoing relationship of metallurgy to engineering it should be self-evident why the Engineers and
Technicians should receive training in the fundamental of metallurgy and material behaviour.
The Engineers, Supervisors and metal workers must be able to select and identify a great variety of metal and
alloys. Since there are thousand of alloy steels and non ferrous alloys shop method.
Heat treating is no longer a simple process it actually consisting of very complex procedures and processes that
must careful to avoid difficulties and failures, such as distortion and quench cracking, etc. A good heat treater
should not only know and understand the behaviour of metals but also to learn the basic principles of heat
treatment, and further to heat-treat the specialized type of steels. Many metals became familiar with hardening
and tempering processes that strengthen and harden by heating and rapid cooling. The problems often occur
in metals due to faulty heat treatment and to understand the reasons to avoid such a defects while heat treating
process.
Testing of metals with use of testing machines to find out the properties before and after Heat treatment such
as hardness, tensile and impact strength etc, and non-destructive testing methods used to identify surface, sub
surface and internal defects.
The training courses from Metallurgist to metal workers to understand the work and help the industries.

Definition of Heat treatment
Heat Treatment of steel may be defined as an operation or combination of operations in which steel in its solid
state, is subjected to one or more temperature of cycles in order to achieve or alter certain mechanical properties
to suit service requirements.

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