Description
ABSTRACT
This project is titled the designing and construction of gasoline arc welding machine. Gas metal arc welding (GMAW) process can be divided as a metal inert gas (MIG) welding and metal active gas (MAG) welding process. In the process, the electric arc is produced which is used to melt and fuse the given materials. Inert or active shielding gases are passed through the nozzle to protect the weld pool from atmospheric contamination. The development of MIG welding technique has been started in the 19th century when Humphry Davy acquired the electric arc in 1800. From the implementation of inert gas at that time to the use of carbon dioxide gas (CO2), the gas metal arc welding process went through a remarkable development, and that is why it is widely used nowadays in automobile, railway construction, ship buildings, power plant industry, etc. In this paper, the chronological developments of the gas metal arc welding process are discussed.
Cover Page
Title Page
Approval Page
Dedication
Acknowledgment
Abstract
Table of Contents
CHAPTER ONE
1.0 Introduction
1.1 Background of the project
1.2 Statement of the problem
1.3 Aim/objective of the project
1.4 Significance of the project
1.5 Scope of the project
1.6 Limitation of the project
1.7 Definition of terms
CHAPTER TWO
2.0 Literature Review
2.1 Historical background of the study
2.2 Review of types of arc welding electrode methods
2.3 Other welding processes
2.4 Review of welding equipment
2.5 Factors Affect Weld Quality
2.6 Types of arc welding
2.7 Other welding processes
CHAPTER THREE
3.0 construction methodology
3.1 Materials used
3.2 Basic principles of GMAW welding
3.3 Gasoline metal arc welding (gmaw) components
CHAPTER FOUR
4.0 CONSTRUCTION PROCEDURE AND TESTING
4.1 Safety issues of arc welding
4.2 General precautions
4.3 Advantages of GMAW
4.4 Disadvantages of GMAW
CHAPTER FIVE
5.1 Conclusion and Recommendation
5.1 Conclusion
5.2 Recommendation
References
CHAPTER ONE
- INTRODUCTION
1.1 BACKGROUND OF THE STUDY
Gasoline Arc Welding Machine is a type of welding machine that uses a Gasoline as the welding power supply to create an electric arc between an electrode and the base material to melt the metals at the welding point. The arc welding is a fusion welding process in which the welding heat is obtained from an electric arc struck between the work(or base metal) and an electrode. The temperature of the heat produced by the electric arc is of the order of 6000°C to 7000°C.
The use of welding conception has been started since ancient times. The earliest use of welding (Pressure welding) was found in the Bronze Age. During the Iron Age, the Egyptians used the welding process to join iron Pieces [1]. Also, the Iron Pillar of Delhi, India was constructed using Forge Welding process about 310 ADS [2]. From ancient times the development of welding technology has been leading the joining processes. In the year 1800, Humphry Davy discovered an electric arc by using two carbon electrodes ina battery. In the middle of the 19th century, the principles of gas metal arc welding were started after the invention of electric generator [3]. The gas metal arc welding process is widely used nowadays in automobiles, railway construction, ship buildings, and nuclear power plants, etc. The metal can be transferred to the weld pool in three ways, such as globular type, short circuit type, spray type. Pulsed spray metal transfer is introduced after the modification of spray type of metal transfer. Spray metal transfer was used first in this process. Each type of metal transfer has its advantages and is used to satisfy the required arc current and weld penetration [4].
1.2 STATEMENT OF THE PROBLEM
Different welding machines have existed in the past but there problem is that they are manually operated, uses ac source to operate and welding materials are also at higher cost. Gas arc welding machine was invented to overcome these problems. Gas arc welding can be semiautomatic or fully mechanised. In semiautomatic version, the welder concerns himself only with gun-to-work distance, gun manipulation, welding speed. Wire feed rates, electrical settings, and gas flow is pre-set. When the equipment is completely mechanised, all of these variables and welding functions performed automatically without the need for a welder. The power source is a rectifier or motor generator giving DC. DCRP (Direct Current Reverse Polarity i.e. electrode to positive terminal and job to negative terminal) is used, as it gives better melting, deeper penetration and better cleaning action. Most metals can be easily welded including aluminum, carbon steels, low alloy steels, stainless steels, nickel, copper, magnesium, titanium, and zirconium. However, for carbon steels and low alloy steels, MAG or CO2 welding is preferred, because it avoids the use of expensive argon gas
1.3 AIM AND OBJECTIVES OF THE PROJECT
The aim of this work is to design and construct a gasoline arc machine that can be used to weld irons.
The objectives of this work are:
- To build the system prototype.
- To design and construct an electric machine that will create an electric arc between an electrode and the base material to melt the metals at the welding point.
- To build a welding machine that will use a rectified dc power source to operate.
1.4 SIGNIFICANCE OF THE STUDY
A Gasoline Arc Welding Transformers are extensively used today in machine building & general purpose maintenance and fabrication work. Light medium and heavy structural work as a Power Source. These are also used as power source for gas shield and welding with tungsten electrode (TIG) for the welding of Aluminum & Aluminum Alloys.
1.5 SCOPE OF THE PROJECT
The scope of this work covers building Gasoline Arc Welding machine which a semi-automatic or automatic arc welding process in which a continuous and consumable wire electrode and a shielding gas are fed through a welding gun.
1.6 LIMITATION OF THE PROJECT
1) Higher initial setup cost
2) Atmosphere surrounding the welding process has to be stable (hence the shielding gasses), therefore this process is limited to draught free conditions
3) Higher maintenance costs due to extra electronic components
4) The setting of plant variables requires a high skill level
5) Less efficient where high duty cycle requirements are necessary
6) Radiation effects are more severe
1.7 DEFINITIONS OF WELDING TERMS
AC OR ALTERNATIVE CURRENT : In this kind of electricity in which polarity of the current changes its directions from positive to negative and negative to positive 50 times in a second.
DC OR DIRECT CURRENT: Electric current which flows only in one direction. : Output of welding sets can be ac, dc or both ac/ dc.
ARC VOLTAGE: The voltage across the welding arc is known as arc voltage.
ARC LENGTH: The distance from the end of the electrode to the point where the arc makes contact with work surface.
OPEN CIRCUIT VOLTAGE: The voltage between the output terminals of the welding machine when no current is flowing in the circuit. (When the welding set is on but electrode is not in contact with the job.
BASE WELD: The metal to be welded, brazed, soldered or cut. FLUX: A fusible material or gas used to dissolve and / or prevent the formations of oxides, nitrides or other undesirable inclusions formed in the weld metal.
WELD: A localized merger of metal or non metal produced either by heating the material to welding temperature, with or without the application of pressure, and with or without the use of filler material BEVEL: An angular type of edge preparations. (Like hypotenuse of a right angle triangle).
FILLET WELD: A weld of approximately triangular cross section joining two surfaces approximately at right angle to each other.
GROOVE WELD: A weld made between two members to be joined. The standard types of groove weld are as follows. Double – v, double – u, double – j, single v, u, single j etc.
ROOT OF WELD: The points, as shown in cross section at which the bottom of the weld intersects the base metal surfaces.
ROOT OPENING: The separation between the members to be joined, at the root of the joint
FACE OF THE WELD: The exposed surfaces of a weld
WELD TOE: The junction of the weld face and base metal
THROAT OF FILLET WELD: Shortest distance from the root of the fillet weld to the face
WELD REINFORCEMENT: It is added to ensure that the net throat of weld is not less than that of plate welded. In fatigue or under vibrations the weld joint has a higher strength
PENETRATION: The distance, the fusion zone extends below the surfaces of the part or parts being welded. (Weld metal which reaches in the base metal).
HEAT AFFECTED ZONE: The portion of the base metal which has not been melted, but the structure properties of which have been altered by the heat of welding or cutting.
CRATER: A depression at the terminations of the weld. POSITION OF WELDING: Flat, horizontal, vertical and over head.
CHAPTER FIVE
5.1 CONCLUSION
MAG (CO2) welding is a variation of the standard MIG process. In MIG process, generally argon, helium or their mixture are used for shielding the molten weld pool whereas in CO2 welding process, CO2 is used as the shielding gas.
CO2 being an active gas, this process is known as MAG process. CO2 welding is used for welding of carbon and low carbon sheets from 16 gauge (0 to 0.54 inch) to ¼ inch.
It produces deeper penetration than argon.
CO2 is basically a semi automatic process, ion which the arc length and the feeding of electrode wire into the arc automatically controlled.
CO2 may also be used in mechanized and automatic forms where productivity is to be increased and consistent quality in weld object is demanded.
Gasoline arc welding requires a large current, generally of a relatively low voltage after the arc has been struck. The arc is struck between an electrode and the work piece — the base metal. The electrode may have either a largely non-consumable metallic tip or it may be a consumable rod of carbon or a consumable metal rod or wire. In some processes, a separate wire or rod – a welding rod (a rod of filler material that is not an electrode and should not be confused with rod-shaped electrodes used in shielded metal arc welding) may be used to supply filler metal. Welding does not necessarily require the addition of filler metal from a consumable electrode or welding rod. Fusion of two metal surfaces can be produced with only the high temperature of the arc. Some welding process may employ automatic wire feed systems and be totally automated. In other semi-automatic operations, the welder must advance arc along the work piece, but the wire is fed automatically.
5.2 RECOMMENDATION
This project is designed to be used in work shop and industries where welding machine is needed. And should be used and maintain by a qualified personnel because Stick welding, and/or the modification of a Microwave Oven Transformer (M.O.T), can be very dangerous and presents risks of UV radiation, shock hazards, burns, fires, fumes and a multitude of other risks. This project should not be attempted without a thorough understanding of electricity, adult supervision and adequate training. Misuse, or careless use, of tools or projects may result in serious injury and/or death. Use of this content is at your own risk.
