The Creating A Nail Factory (PDF/DOC)
INTRODUCTION
Over the past years, many new moulding and core-making processes have been introduced in the foundry industries, and in particular ones based on the use of chemical binders. Greensand moulding, however, remains the single most important method for producing casting. Especially when they are required in large numbers involves the use of mechanized moulding plant.
In order to obtain the optimum economic production with green sand plant, it is imperative that foundry managerial and supervisory staffs are familiar with the best method for control and operation.
According to Bcira, (1985), for a quality production of foundry product to be ascertained, all expects of green sand moulding technology from basic raw material, their properties and control, to the many principles involved in the production of green sand moulds must be adequately understood.
The success of any green sand system depends to a large extent on the continual re-use of the mould sand and the essential factor to maintain its properties, and a section on this important aspect is included, together with information on the normal and special tests which may be necessary. The need for sand cooling and the means for carrying it out should be adequately reviewed, as the methods for mould handling on mechanized plants, the requirements for sand storage and for the handling and removal of sand cast mould prior to re-circulation.
Iron casting are so widely used in our highly mechanized society that we tend to take them for granted. In a sense, the iron foundry industry produced an invisible yet vital product, since most casting are further fabricated, assembled and then employed as components of other machinery an equipment. Walton (1984), states that the iron foundry industry employees are about 140, 000 people. It provides as many as 200, 000 differently designed casting every year to more than 50, 000 customer plants. Casting quantities produced to a given design vary from a single casting to millions of pieces. Iron foundries constitute the nations fifth largest manufacturing industry annually as much as 18 million tons of production, with a value of nearly $12billion. The yearly tonnage of iron casting is more than triple that of other ferrous and non ferrous casting combined. It is the second largest metal producing business surpasses in size only by the rolled steel industry.
During the past three decades, ductile iron has emerge from the status of an experimental material and achieved a significant position in the cast metal industry. By combining the processing advantages of grey iron, with some of the engineering property of steel, ductile iron has replaced forging, weldmemts and steel casting in a wide variety of application requiring a high degree of reliability. Because ductile iron is ten percent lighter than steel, it is particularly desirable for application where lighter weight is desirable.
All materials used for the manufacturing of sand mould and cores are termed mould material (Mikhailov, 1989). There materials are divided into the initial materials and moulding mixtures. The main initial materials are silica sand, clay, auxiliary ones, various binders and additives. The property requirement of the material are determined by moulding and casting condition. Hence, proper choice of the composition of a moulding mixture is of prime importance.
Sand is the principal basic moulding materials used by the foundry-man, whether it is for iron, steel, non-ferrous or light-alloy castings. The study of foundry sand constitutes one of the main sections of foundry technology and sand testing has becomes an essential part of the day-to-day control of foundry operation. In the early years of last century, foundry work and preparation of moulding core sands mixtures were still a craftsman’s art. Particular sand was used because of custom or renew for a certain class of work. The experience moulder, often a highly skill craftsman, could produce results with his limited equipment favourably compared to those of the best modern sand plant based on his long experience and rule of thumb methods. His sand mixes were a closely guarded secret and endless varieties of such mixes were in use.
Moulding sand can be defined as raw material used in the making of mould which contain a bounding material usually in the form of clay and occasionally with a small proportion of an organic compound, the whole being suitable moistened with water for moulding purpose.
Though, there are many known deposits of silica sand, clay and the availability of additive in the country, the determination of foundry properties of these materials when used as a foundry sand has not be methodically carried out, also the composition of the sand mixture that gives the optimum water content has not been evaluated. These have become important in order to establish the best properties that can be derived from a particular sand readily available foundry sand mixture in the country but also eliminate most casting defects.
The need for systematic evaluation of working properties of qualities of moulding materials under foundry condition has led to the development of a wide range tests. Some of these tests are concerned with basic chemical and physical characteristics but the majorities are designed to measure bulk properties.
The bulk properties of an aggregate are sensitive to small variation in mixing condition and specimen preparation. So, that rigid standardization in need at all stages. The reproduce ability of tests has been shown to be best in permeability and least in dry strength determination (Morey and Ackerlind, 1947). The properties of the sand will vary according to the type of work being carried out, for example, for light or heavy casting, plain carbon or high-alloyed steel used in a mechanized or jobbing foundry.
1.1 BACKGROUND OF THE STUDY
During the past two decades, the industry has undergone a period of remarkable progress and transition. In this brief span, the number of iron foundries has been cut nearly in half, primarily as a result of the increasing capital requirements necessary to remain competitive while maintaining to meet safety and pollution control regulation and increasing customers requirement for quality.
More so, with the increasing technological development around the world, one would definitely agree that there is need to introduce a new dimension to the quality and standard of the foundry products obtained in the country, given that the economic development in any country is a function of its technological development.
However, many researchers, has done quite a number of works on how to modify or rather, to improve the quality of the moulding sand employed as moulding materials. The dividend of their research work is what we are enjoying nowadays, that is, development in technology.
Besides, it is obvious that more than 75 percent of the materials employed to achieve the so-called technological advancement is constituted by casting. In other words, technological development that as become an object of concern around the world cannot be treated in isolation without considering the quality and standard of casting. A thorough analysis had revealed that most defects embedded in casting is as a result of sub-standard quality of moulding sand employed during production process.
Having considered the fact that the level of technological development obtainable in a country will be drastically affected if the materials employed are characterized by defects. So, the need to characterize the silica sand at Oke-kudu Area, Airport in Ilorin, Kwara State to ascertain or rather to establish the various foundry properties contained in the silica sand and to specify the best one suited for the casting process with their various mechanical properties and defects after casting.
1.2 STATEMENT OF THE PROBLEM
There are many known deposit for silica sand all over the country, which can be employed as a moulding materials for casting, but are lying idle or useless. So, there is need to analyze the silica sand at Oke-kudu Area, Airport in Ilorin so that the deposit, will be adequately and effectively utilized for specific applications.
1.3 SIGNIFICANT OF THE STUDY
The study will reduce the rigour of up grading silica sand and it will make the foundry product cost effective. It will enhance to a great extent the technological and economic development of the nation at large when the casting produced is of good standard and quality. The study will also increase the industries in the country because it will afford the industrialist or rather; the investors the opportunity to have a good knowledge of the available raw materials in the country and for what application they can be employed. This will serve as a guide for the investor to make a right choice what types of foundry operation to embark upon in order to maximize profit.
Lastly, the study will also afford scholar in the field of metallurgical the opportunity to further characterize the silica sand of some other location that are not included in the project.
1.4 AIM AND OBJECTIVES OF THE PROJECT
The aim of this project work is to characterize silica sand at Oke-kudu Area, Airport in Ilorin, to establish the various foundry properties embedded in the sand.
The objectives of the study are as follows:
• Analyze and determine these mechanical foundry properties (green strength, permeability, clay content and moisture content) of the silica sand at Oke-kudu Area, Airport in Ilorin.
• The work will serve as a basis for other scholars to know what is to be done to increase or reduce the amount of specific foundry properties needed for a particular application.
1.5 SCOPE OF THE STUDY
This study will dwell more on the characterization of the foundry properties of silica sand at Oke-kudu Area, Airport in Ilorin. Various foundry properties such as green strength, permeability, refractoriness, moisture content and clay content shall be carried out on these sands. It is highly imperative to note that there is no available equipment to measure refractoriness directly, so the refractoriness of these sand will be estimated based on the clay content present in the silica sands.
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