Abstract
Evaluation of Cassava Liquid Effluent as a quenching media of medium Carbon Steel has been investigated. The Medium Carbon Steel Samples were heated at 950oC and soaked for 30 minutes followed by quenching in Cassava Liquid Effluent (CLE) and SAE 40 Engine oil and water the commercial quenchants. The microstructure and the mechanical properties of the quenched samples were studied and the Cooling rate Curves were used to determine the quench severity. The results showed that CLE has the highest tensile strength (1008.14 N|mm2) followed by water (967.413N|mm2) and SAE 40 Engine oil (855.39 N|mm2). The microstructure of the sample quenched in CLE revealed high proportion of martensite with less retain of Austenite. The Cooling Curves showed that CLE has a higher cooling rate compared with SAE 40 Engine oil and water. An AISI steel of grade C1035 was used for comparison of the properties. Result indicated that CLE have excellent values in terms of Tensile Strength and yield strength when compared with standard steel products. Also samples quenched in CLE developed less hardness than samples quenched in water. CLE would be used where cooling severity less than that of water but greater than SAE 40 Engine oil was required for hardening Medium Carbon Steel.
Table of Contents
Declaration i
Certification ii
Dedication iii
Acknowledgement iv
List of Tables v
List of Figures vi
List of Plates vii
List of Abbreviations viii
Abstract xi
Chapter 1 INTRODUCTION
1.1 Background of the Study 1
1.2 Statement of the Problem 2
1.3 Aim and Objectives of the Study 3
1.4 Scope of the Study 4
1.5 Justification 4
Chapter 2 LITERATURE REVIEW
2.1 Review of Current Research on Quenching 5
2.2 Properties of Quenching Media 12
2.3 Quenching Processes 13
2.4 Quenching of Steel 16
2.5 Cassava Varieties 17
2.6 The Effect of Cassava Effluent with Mild Steel 19
Chapter 3 NATERIALS AND METHODS
3.1 Materials 21
3.2 Methods 23
3.3 Characterization of SAE 40 Engine Oil Sample 25
3.4 Heat Treatment Methods 26
3.5 Mechanical Tests 28
3.6 Microstructural Examination 30
3.7 Determination of Cooling Curve 31
Chapter 4 RESULTS AND DISCUSSION
4.1 Results 32
4.1.1 Mechanical properties 32
4.1.2 Comparison of Cassava Liquid Effluent with Standard Steel Product 39
4.2 Microstructures 41
4.2.1 Annealed Sample 41
4.2.2 Tempering Sample 42
4.2.3 Received Sample 43
4.2.4 Water Sample 44
4.2.5 SAE 40 Engine Oil Sample 45
4.2.6 Cassava Liquid Effluent Sample 46
4.3 Cooling Curve 47
Chapter 5 CONCLUSION AND RECOMMENDATIONS
5.1 Conclusion 49
5.2 Recommendations 49
5.3 Contributions to Knowledge 50
REFERENCES 51
APPENDIX 56
List of Tables
2.1: Properties and average cooling rates of quenching media (Addision, 2004) 13
2.2: Characteristics of vegetable oils (Addison, 2004) 16
2.3: Comparative performance of early and resent improved cassava varieties of IITA in south-western Nigeria 18
2.4: Recent improved varieties of cassava obtained from National Root Crop Research Institute Umudike 19
3.1: Chemical composition of the medium carbon steel used 21
3.2: Chemical analysis of cassava waste extract 25
3.3: The allowable physiochemical properties for SAE 40 26
3.4: The viscosity, specific gravity and specific heat capacity of water used 26
4.1: Impact test values of medium carbon steel sample quenched in different medium 32
4.2: Hardness test of medium carbon steel sample quenched in different medium 33
4.3: Tensile test of medium carbon steel sample quenched in water 34
4.4: Tensile strength of medium carbon steel sample received 36
4.5: Tensile test of medium carbon steel sample quenched in Cassava Liquid Effluent 37
4.6: Tensile test of medium carbon steel sample quenched in SAE 40 engine oil 37
4.7: Mechanical Properties of the heat treated medium carbon steel 39
List of Figures
3.1: Billet prepared for drawing 26
3.2: Impact test specimen used 29
3.3: Tensile test specimen used (BS2789 – 2002) 30
4.1: Impact test values with quenching media 33
4.2: Hardness test values with quenching media for medium carbon steel 34
4.3: Tensile test values with quenching media for medium carbon steel 35
4.4: Percentage elongation values with quenching media for medium carbon steel 36
4.5: Engineering fracture strength values with quenching media for medium carbon steel 38
4.6: Yield strength values with quenching media for medium carbon steel 39
4.7: Variation of cooling curves with quenching media 47
4.8: Variation of cooling rate with quenching water 48
LIST OF PLATES
4.1: Optical Micrograph of annealed Sample (×400) 41
4.2: Optical Micrograph of Tempered sample (×400) 42
4.3: Optical Micrograph of Received Sample (×400) 43
4.4: Optical Micrograph of Water Quenched Sample (×400) 44
4.5: Optical Micrograph of SAE 40 Engine Oil Sample (×400) 45
4.6: Optical Micrograph of Cassava Liquid Effluent Sample (×400) 46
LIST OF ABBREVIATIONS
CLE Cassava Liquid Effluent
SEM Scanning Electron Microscopy
OM Optical Microscopy
SAE Society of Automobile Engineers
AISI American Iron and Steel Institute
CHAPTER ONE
INTRODUCTION
1.1 Background of the Study
Quenching is a crucial process within the broader field of heat treatment. It constitutes an important process in manufacturing technology in nearly every industrial sector. These include railway, automotive, aerospace and others (Balogun. (2009): Hassan et al. (2009)).
Many parts are given heat treatment operation to enhance certain properties such as hardness, strength, toughness, ductility and corrosion resistance and to increase uniformity of the properties. Heat treatment is a procedure or operation involving heating a metal part to a high temperature followed by controlled cooling. The process of heating a part above the high critical temperature to Austenitizing temperature and holding at this temperature for a certain time followed by cooling in suitable quench medium. The two primary functions of a good liquid quenchant is to minimize the formation of gradient which may lead to increase in distortion and cracking and also facilitate the hardening of the steel by controlling heat transfer during quenching. (ASM 1995: Budimski 1999) Many researcher have reported from their studies that traditionally, water and oil (especially SAE engine oil) are the common quenching media used when appreciable hardness is desired (Avner, 1984)
The mechanical properties of a quenched component are dependent on many factors such as the composition of steel, type of quenching medium, geometry of the component, tempering temperature, measurement, tolerances and variation in process equipment and operation (ASM, 2007)
Water is the conventional quenching medium (Isah etal, 2008). This can be attributed to its low costs, availability, ease of handling, relatively no pollution problem, since it can be disposed easily. In practice water is used for quenching plain carbon steels and few grade of low alloy steels. (Mohammed, 2007). Water quenching breaks down the layer of scale formed on the surface of work piece, thereby eliminating any other further surface clearing.
Though water generous, and affordable and its high cooling rate has the problem of inducing crack or dimensional changes on the quenched components, Other quenchant such as oil don’t induce enough hardness. Polymer, although expensive has the problem of varying concentration during the quenching process but can provide severity between those of water and oil. Brine has a problem of corrosive attack on the equipment and component used for the development of a quenching medium with good paying (Economies) like water, but, brine also produces more quenching severity than water. Even though Brine has less severity of quench and yet produces appreciable hardening.
During the traditional cassava processing starch storage root for garri production in Africa, the liquid effluent which is squeezed out from the mesh is normally discarded as waste. These starchy water which are neglected and of environmental nuisance are indeed “green gold” where their economic value can be harnessed. The question expected to be answered by this work is whether Cassava Liquid Effluent can be used as a quenchant to induce hardness in steel, produce severity lower than water but better them oil. With the use of Cassava Liquid Effluent as a quenching medium, a waste to wealth initiative would have been provided and an alternative quenching medium to water, oil and the expensive polymer quenchants would be developed.
1.2 Statement of the Problem
Water and brine could be used to quench some grades of steel but do not produce good result, with low carbon steels, the reason being that the rate of cooling is high in the temperature range of martensite formation. This increase exposes steels to simultaneous influences of transformational and thermal stresses. The combined effects of these stresses increase the risk of crack formation (Olison, 2001).
Over the years, engine oil has been found to be a suitable quenchant for carbon steel. When quenched in engine oil, carbon steel could be hardened without cracking. However, two major problems associated with quenching in engine oil are; at times engine oil is combustible and could only be used under controlled atmosphere (either reducing or neutral) as the oxidation of the oil results in the formation of carbon cyclic acid and sludge which affects the induced hardness and colour of the work piece. On the safety side, engine oil is hazardous to operate. Hence, there is the need to develop a quenchant that is of low cost like water, environmental friendly, non-corrosive and effective in inducing the required hardness without the problem of distortion and residual stresses.
Based on the above mentioned reasons, this research focuses on use of cassava liquid effluent waste as quenchant for hardening medium carbon steel.
1.3 AIM AND Objectives of the Study
This work is aimed at evaluating the suitability of using Cassava Liquid Effluent as a quenching medium for hardening medium carbon steel. The specific objectives targeted in this work are:
- To harden medium carbon steel using Cassava Liquid Effluent as a quenchant.
- To examine the microstructures of the quenched samples using optical microscope.
- To determine the tensile test, impact test and engineering fracture strength of the quenched samples.
- To develop the cooling curves of Cassava Liquid Effluent, SAE 40 engine oil and water.
1.4 Scope of the Study
The carbon content of the medium carbon steel samples in this research work is 0.36%C. Mechanical properties and cooling rates were the parameters used to measure the effectiveness of Cassava Liquid Effluent as a quenching medium for medium carbon steel.
1.5 Justification
Cassava (Manihot escalenta) has been identified as an important root crop especially to the people living within West African sub-region. This is due to the numerous end products to which cassava can be processed. The different types of food obtainable from cassava range from garri, fufu, tapioca to starch.
Cassava also finds considerable use as a source of industrial starch, which is used mainly in the textile and adhesive industries. Although a major source of food, especially carbohydrate, processing cassava into food items usually generates a lot of waste. During the traditional processing of cassava root for garri production, the root is peeled and at the stage of hydraulic pressing of the grated cassava, a liquid effluent is generated. This waste if not properly disposed of, constitute a nuisance to the environment and the economy.
There is need to take advantage of abundance and availability of cassava and stop wastage of the effluent by harnessing its economic value. This liquid effluent from cassava could be used as a quenching medium to induce hardness in steel, producing severity lower than water but better than oil. With the use of Cassava Liquid Effluent as a quenching medium, a waste to wealth initiative would have been provided and an alternative quenching to water, oil and the expensive polymer quenchants would be developed.
Click “DOWNLOAD NOW” below to get the complete Projects
FOR QUICK HELP CHAT WITH US NOW!
+(234) 0814 780 1594
Login To Comment