DESIGN AND CONSTRUCTION OF DUAL-POWERED HEAT TREATMENT FURNACE
ABSTRACT
The Importance of materials in industries cannot be overemphasized in the recent
advancement of material development for automobiles, aerospace, oil and gas industry, etc.
as it has been found to be a veritable tool in improving specific desired properties of metals.
The exorbitant cost of heat treatment furnace which is mainly attributed to its imported nature
has been responsible for its dearth in the material science laboratory of our Universities. The
epileptic nature of power supply in country has also made it imperative to look inward and
develop an alternate power source for furnaces in use in the university. As the country
expends so much of her wealth on importation and equally clamouring for more local
content, it is imperative that Engineers in Training and Engineers come up with solutions to
the national problem. This work was aimed at designing and constructing a dual powered
heat treatment furnace for the Department of Mechanical Engineering Laboratory, University
of Ibadan.
After extensive literature review, Gas was settled for as the alternate power source for
electricity due to its relative availability. Having made conceptual designs using SolidWorks,
the most viable design was selected with decision matrix. Design Calculations were made
with mild steel considered as the charge material as it is the most available ferrous metal/
alloy. The minimum insulation thickness, adiabatic flame temperature of butane, and heat of
combustion were calculated Chrome steel was used as the crucible due to its high melting
point and especially its passivation ability. The Crucible was designed to be a truncated cone
to allow for circulation of hot combustion gases. The final design has a wall thickness of 46
mm; made up of an outer shell thickness of 2 mm steel plate, a Fire Clay -Kaolin based
Insulation thickness of 44mm.A furnace height of 402 mm was generated.
The design and construction of a dual powered heat treatment furnace using the adopted
methodology was achieved. Upon Testing, the constructed heat treatment furnace which has
the capacity of 0.00675 m3 capable of containing 53.06 kg of mild steel, attained a
temperature of 400 C in 11 minutes, thus an average heating rate of 36.3 C/ min while
powered using a blower based gas burner and an average heating rate of 5.3 C/ min while
powered by electricity, the furnace has the ability to switch power source in case of
unavailability of electricity and back to electricity in case of restoration. Furnace lost energy
can be recovered through recuperation. The furnace which can be used to heat treat ferrous
and non ferrous metals alike can be adapted for melting as the crucible is positioned in a
vertical direction.
In this project work, the design and construction of a dual powered heat treatment furnace
using locally available materials for the Department of Mechanical Engineering Laboratory
has been achieved and its performance evaluation carried out.
TABLE OF CONTENTS
ABSTRACT .................................................................................................................................... i
ACKNOWLEDGEMENT ............................................................................................................... iii
DEDICATION .............................................................................................................................. vi
TABLE OF CONTENTS.................................................................................................................. v
LIST OF FIGURES ....................................................................... Error! Bookmark not defined.ix
LIST OF TABLES ......................................................................... Error! Bookmark not defined.xi
INTRODUCTION ........................................................................................................................ 13
1.0 BACKGROUND STUDY ................................................................................................... 13
1.1 TYPES OF HEAT TREATMENT FURNACE ........................................................ 14
1.2 Components of a furnace: ............................................................................................ 15
1.3 STATEMENT OF PROBLEM ............................................................................................ 16
1.4 OBJECTIVES ........................................................................................................... 17
1.5 SCOPE OF STUDY .................................................................................................. 17
1.6 JUSTIFICATION ...................................................................................................... 17
1.7 EXPECTED CONTRIBUTION ............................................................................... 18
1.8 ORGANIZATION OF STUDY ................................................................................ 18
CHAPTER TWO ......................................................................................................................... 19
2.0 LITERATURE REVIEW ................................................................................................ 19
2.1 Types of Heat Treatment Furnace ................................................................... 21
2.1.1 Solar Heat treatment Furnace .................................................................................... 21
2.1.2 Electric Heat treatment Furnaces ........................................................................ 24
2.1.2.1 Induction Furnace .................................................................................................... 24
2.1.3 Infrared Heat treatment Furnace ............................................................................ 25
2.1.3.1 Gas Fired Infrared Heater .......................................................................................... 25
2.1.4 Combustion Furnaces ............................................................................................ 26
2.2 REFRACTORIES ........................................................................................................... 26
2.2.1 Types of Refractories ......................................................................................... 28
2.3 Examples of Refractories ............................................................................................ 28
2.3.1 Fireclay Refractories .............................................................................................. 28
2.3.2 High alumina Refractories ..................................................................................... 29
2.3.3 Chromites Refractories .......................................................................................... 29
2.3.4 Silica Brick ........................................................................................................... 30
2.3.5 Zirconia Refractories ............................................................................................. 31
2.3.6 Oxide Refractories (Alumina) .............................................................................. 31
2.3.7 Monolithic ............................................................................................................ 32
2. 4 Insulation Materials ............................................................................................... 33
2.4.1 Ceramic fibre ......................................................................................................... 34
2.4.2 Natural Fibre insulation: ........................................................................................ 34
2.5 Heat Losses: in a furnace, heat is lost as .................................................................. 35
2.6 Waste Heat Recovery: . ................................................................................................ 35
2.6.1 Charge Pre-heating ...................................................................................................... 35
2.6.2 Preheating of Combustion Air ............................................................................... 36
2.6.3 Other Uses: .......................................................................................................... 36
2.7 Furnace Design Considerations ................................................................................. 36
2.8 Ferrous and Non Ferrous Metals/Alloys ....................................................................... 37
2.8.1 Ferrous metals........................................................................................................ 37
2.8.2 Non Ferrous Metals:. ............................................................................................. 38
2.9 Locally Available Insulating Material .......................................................................... 38
2.9.1 Kaolin;. ................................................................................................................. 38
2.9.2 Ash:. ....................................................................................................................... 39
2.9.3 Saw Dust: . ............................................................................................................. 39
2.9.4 Charcoal dust:. ....................................................................................................... 39
2.10 OTHER MATERIALS ..................................................................................................... 40
2.11 Thermal Properties of an Insulating Material ............................................................. 40
2.11.1 Thermal Conductivity ........................................................................................... 41
2.11.2 Specific Heat Capacity ......................................................................................... 41
2.12.3 Thermal Diffusivity: ............................................................................................. 41
CHAPTER 3 DESIGN, METHODS AND IMPLEMENTATION ..................................................... 42
3.1 Design Criteria………………………………………………………………42
3.2 Constraint .................................................................................................................. 42
3.3 Design Calculation ........................................................................................................ 43
3.3.1 Charge Material Consideration .............................................................................. 43
3.3.2 Crucible Volume: .................................................................................................. 43
3.3.3 Furnace Chamber Volume/Dimension: ................................................................. 44
3.3.4 Adiabatic flame Temperature of Butane Gas: ..................................................... 44
3.3.5 Enthalpy of Combustion; ....................................................................................... 47
3.3.6 Rate of Energy Released from Gas .......................................................................... 49
3.3.7 Stochiometric Air Requirement ............................................................................... 50
3.3.8 Furnace Energy Requirement: ................................................................................ 51
3.4 Design Concepts ........................................................................................................ 52
3.4.1 Material Part Selection .......................................................................................... 52
3.4.2 Design Concepts and Selection ................................................................................ 54
3.4.2.1 Design Concept ONE .......................................................................................... 55
3.4.2.2 Design Concept TWO ........................................................................................ 56
3.4.2.3 Design Concept THREE ..................................................................................... 57
3.5 DECISION MATRIX ................................................................................................. 58
3.6 Minimum Insulation Thickness ................................................................................... 58
3.7 Critical Radius Calculation ........................................................................................... 59
3. 8 Fabrication / Construction ........................................................................................ 61
CHAPTER FOUR. TESTING, PERFORMANCE EVALUATION AND RESULTS ................................. 67
4 .1 Furnace Operation Principle...................................................................................... 69
4.2 Furnace Operation: .................................................................................................... 69
4.3 BILL OF ENGINEERING MEASUREMENT & EVALUATION .............................................. 69
4.4 Testing ....................................................................................................................... 71
4.4.1 GAS: ...................................................................................................................... 71
4.4.2 ELECTRICITY: .................................................................................................... 72
4.5 Safety Precaution....................................................................................................... 74
CHAPTER ONE
INTRODUCTION
1.0 BACKGROUND STUDY
In the world of materials, Heat treatment is an aspect that cannot be over emphasized as it
imparts desirable properties to materials, thus increasing their ability to perform the intended
function more effectively. Invariably as all industries use various materials therefore
activities of these industries depend directly or indirectly on heat treatment.
Heat treatment may be defined as the controlled heating and cooling of material in order to
deliberately improve their properties (e.g. mechanical, thermal, corrosion, microstructure,
hardness, ultimate tensile stress, fatigue strength, Impact strength).
Heat treatment has been found to be a resourceful technique for improving thermal properties
(heat capacity, coefficient of expansion, thermal conductivity), corrosion properties and
micro structural properties of engineering materials. Heat treatment is often associated with
increasing the strength of material, but it can also be used to refine the grain size, relieve
internal stress, to improve machinability and formability as well as for restoring the ductility
after a cold working. The tool for heat treating materials is known as heat treatment furnace
According to Rajan et. al. (1988), a heat treatment furnace is a heating chamber that is a
refractory or lagged enclosure which contains the charge and retains heat that should be
measurable as well as controllable. However, it is observed that in a heat treatment furnace,
the heat is not measured but the temperature.
Hence, a heat treatment furnace is a heating chamber that is a refractory or lagged enclosure
which contains the charge and retains heat at a temperature that should be measurable as well
as controllable. Heat treatment furnaces with effective temperature sensing, heat retaining
capacity and controlled environment are necessary for heat-treatment operations to be
successfully performed. (Alaneme and Olanrewaju, 2010) Furnace ideally should heat as
much of material as possible to a uniform temperature with the least possible fuel and labour.
The furnace also requires a control system to regulate the temperature in the furnace
accurately. In heat treatment furnace, as in melting furnace, heat is transferred via two modes;
convection and radiation.
A good heat treatment furnace should possess some qualities
· It must be safe to the user
· Must minimize heat loss
The primary objective in the heating stage is to maintain uniform temperatures as uneven
heating can lead to a part of the charge material expanding faster than the other, causing
distortion or cracking.
1.1 TYPES OF HEAT TREATMENT FURNACE
There are various types of heat treating furnace:
· Fuel Fired Heat Treatment Furnace powered by the combustion of fuel to release
energy in the presence of air
· Electrically Powered Heat Treatment Furnace powered through the passage of
electric current through a heat element (highly resistance material) e.g. Kanthal wire,
Silicon Carbide, etc.
· Solar Powered Heat Treatment Furnace: in this furnace, the heat source is from
the sun as it radiates solar energy which can be focused to the crucible by parabolic
mirrors or Fresnel lens thus increasing the temperature.
· Infra Red Heat Treatment Furnace; a form of either electric or fuel fired heat
treatment in which electromagnetic radiation range 780nm to 1400nm is dissipated
from an emitter/ emitter tube which may be made of carbon, nichrome, quartz
tungsten, etc.
· Induction Heat Treatment Furnace; a form of electric heat treatment in which a
copper tubing of high conductivity is wound into helical coil contained within steel
shell support and connected to electrical source
1.2 Components of a furnace
1.2.1 Energy source: this is the source of energy for the heating of the furnace, it forms the
basic classification of heat treatment furnace and is broadly classified into two;
· Fuel powered by the combustion of fuel to release energy in the presence of air
· Electrically powered through the passage of electric current through a heat element
(highly resistance material).
1.2.2 Refractory Chamber: this is an enclosure that is constructed of insulating material so
as to retain heat in the furnace. The insulating material facing the hot face should be
chemically inert while the material facing the surrounding should have low thermal
conductivity in the case of composite walls. The main aim is to minimize heat loss to the
furnace surrounding.
1.2.3 Instrumentation and Control System: heat treatment furnace operation retains heat
at certain temperature, thus the need to maintain such temperatures by means of control and
temperature measurement devices
1.2.4 Crucible: this contains the charge material and in some cases may be the same as the
refractory chamber and in other cases may be a separate entity contained within the refractory
chamber but possesses high thermal conductivity, high melting point and chemically inert.
1.2.5 Heat Exchanger/Exhaust: found basically on fuel fired furnaces, exhaust conveys
the combustion product to the surrounding while heat exchanger uses the exhaust gases in
preheating charge or combustion air thereby improving the overall furnace efficiency
1.2.6 Charging / Discharging door: this is an access to the crucible in other to load the
charge material or unload it.
1.3 STATEMENT OF PROBLEM
The exorbitant cost of heat treatment furnace has been responsible for its dearth in the
material science laboratory of our Universities.
The epileptic nature of power supply in country has made it imperative to look inward and
develop an alternate power source for furnaces in use in the university.
It is therefore of outmost importance to design and fabricate an eco friendly low cost heat
treatment furnace with dual power sources, to be used interchangeably to be put to functional
use. Thus, the need to exploit locally available materials.
This would invariably reduce the total heavy dependence of foreign equipment and increase
the stock of locally made ones.
1.4 OBJECTIVES
The general aim of this project is to design and fabricate a dual-powered heat treatment
furnace for the Material Science Laboratory of the Department of Mechanical Engineering,
The University of Ibadan.
The specific objectives are
To carry out a detailed design of a dual-powered heat treatment furnace and produce its
working drawing in AutoCAD/Solid works
To fabricate a Dual-Powered Heat Treatment Furnace
To carry out Performance Analysis of the Fabricated Dual-Powered Heat Treatment Furnace.
1.5 SCOPE OF STUDY
It is expected that the dual-powered heat treatment furnace will be fabricated with readily
available materials and put to good use in the Material Science Laboratory of the Department
of Mechanical Engineering
It would also provide an option in terms of the alternate power source in event of the
unavailability of one power source.
1.6 JUSTIFICATION
The desire to see heat treatment effectively carried out in a furnace that shall not be restricted
to a single power source but rather two, such that, in case of the unavailability of one, heat
treating activities shall not be stalled.
Such furnace that is safe, energy efficient, cost effective and ultimately eco-friendly in the
Material Science Laboratory of the Department of Mechanical Engineering.
1.7 EXPECTED CONTRIBUTION
It is expected that at the end of completion of this work, a Dual-Powered Heat Treatment
Furnace would have been fabricated and shall be of indispensable value to the Material
Science Laboratory.
1.8 ORGANIZATION OF STUDY
Extensive Literature review
Market Survey to determine availability of materials.
Detailed design and CAD modelling using SolidWorks®
Consultation with Engineering Students, Technicians, Technologist
Material Acquisition
Furnace Fabrication/Construction
Furnace Testing/ Performance Analysis
.