Description
ABSTRACT
In this study, steels are generally selected, first, on the basis of their resistance to corrosion and, second, on the basis of their mechanical properties. As the temperatures of operating environments increase, however, elevated-temperature properties quickly become the primary concern. The family of medium carbon steel and stainless steels is most versatile in its ability to meet the requirements of high-temperature service. In the present work, high temperature tensile properties and abrasive wear performance of a medium carbon and stainless steel has been examined. properties of medium carbon and stainless steel were based on their wear rate and tensile properties were carried out an was found that those properties were affected by tampering temperature and immersion rate.
TABLE OF CONTENTS
COVER PAGE
TITLE PAGE
APPROVAL PAGE
DEDICATION
ACKNOWELDGEMENT
ABSTRACT
CHAPTER ONE
- INTRODUCTION
- BACKGROUND OF THE PROJECT
- AIM AND OBJECTIVES OF THE PROJECT
- SCOPE OF THE STUDY
- SIGNIFICANCE OF THE STUDY
- PROJECT ORGANISATION
CHAPTER TWO
LITERATURE REVIEW
- OVERVIEW OF THE STUDY
- MICROSTRUCTURAL CHANGES INDUCED BY HIGH TEMPERATURE EXPOSURE
- HOT DEFORMATION
- HIGH TEMPERATURE BEHAVIOUR IN THE PRESENCE OF LOADING/TEMPERATURE
- THERMAL PROPERTIES OF MEDIUM CARBON STEEL AND STAINLESS STEEL
- REVIEW OF RELATED STUDIES
- ELEVATED TEMPERATURE MATERIAL MODELLING TECHNIQUES
- STRENGTH AND STIFFNESS REDUCTION FACTORS AT ELEVATED TEMPERATURES
- BASIS FOR DERIVATION OF STRENGTH REDUCTION FACTORS
- REDUCTION FACTORS FOR 2% PROOF STRENGTH AND ULTIMATE TENSILE STRENGTH.
- REDUCTION FACTORS FOR STRESS AT 2% TOTAL STRAIN
- REDUCTION FACTORS FOR YOUNG’S MODULUS
CHAPTER THREE
METHODOLOGY
- MATERIAL SELECTION AND PREPARATION
- SAMPLE PREPARATION TECHNIQUES
- MECHANICAL TESTS
- HIGH-TEMPERATURE DEFORMATION EXPERIMENTS
- EXPERIMENTAL SETUP AND CONDITIONS
- DEFORMATION PARAMETERS
- MICROSTRUCTURAL ANALYSIS TECHNIQUES
- OPTICAL MICROSCOPY
- TENSILE AND HARDNESS TESTING
CHAPTER FOUR
4.0 RESULT AND DISCUSSION
CHAPTER FIVE
- CONCLUSION
- REFERENCES
CHAPTER ONE
1.0 INTRODUCTION
1.1 Background of the study
Medium carbon steel is easily available and relatively cheap having all material properties that are acceptable for many applications. Heat treatment on medium carbon steel is to improve ductility, to improve toughness, strength, hardness and tensile strength and to relive internal stress developed in the material (Sanji et al., 2018).The possible applications of medium carbon steel are very wide. Some popular uses of medium carbon steel for various engineering application are for Flywheel, Ball bearing, Railway wheels. Crankshaft, Bevel wheel, Hydraulic clutch on diesel engine for heavy vehicle etc (lning, 2014). Quenching refers to the process of rapidly cooling metal parts from the austenitizing or solution treating temperature. Successful hardening usually means achieving the require microstructure, hardness, strength, or toughness while minimizing residual stress, distortion, and the possibility of cracking. The most common quenchant media are either liquids or gases. The liquid quenchants commonly used include Oil, Water and Aqueous polymer solutions.
Quenching effectiveness is dependent on the steel composition, type of quenchant, or the quenchant use conditions. Tampering of steel is a process in which previously hardened or normalized steel is usually heated to a temperature below the lower critical temperature and cooled at a suitable rate, primarily to increase ductility and toughness, but also to increase the grain size of the matrix. So the main purpose of tempering is to reduce the brittleness imparted by hardening and to produce definite physical properties within the steel. Principal Variables associated with tempering that affect the microstructure and the mechanical properties of tempered steel include tempering temperature, time at temperature and cooling rate from the tempering temperature (Rafael, 2011).
Daramola et al (2010), studied the effect of heat treatment on the mechanical properties of rolled medium carbon steel. The steel was heated to the austenizing temperature of 830ᵒC and then quenching by water ; It was reheated to the ferrite – austenite two phase region at a temperature of 745ᵒC below the effective Ac3 point. The steel was then rapidly quenched in water and tempered at 480ᵒC to provide an alloy containing strong, tough, lath martensite (fibers) in a ductile soft ferrite matrix. The result shows that the steel developed has excellent combination of tensile strength, impact strength and ductility which is very attractive for structural use [4].
Hani et al (2011) Investigated the wear rate for different materials (Steel, Aluminum and brass) under the effect of sliding speed, time and different loads, where the apparatus pin on disc has been used to study the specification of the adhesion wear. A mathematical models have been made for all cases and from the results, It will showed that the rate of adhesion wear will be direct proportional with (time, sliding speed and load) , and the low carbon steel has less wear rate than the other materials. Heat treatments like annealing, normalizing and tempering have been done for medium carbon steel. Two different grades of Steel (one with copper and another without copper) have been used in this study. The samples are tempered at 200°C, 400°C and 600°C for 1 hr. Heat treated samples were then mechanically tested for hardness (Rockwell) ,tensile properties (ultimate strength, ductility) and the microstructure. The results revealed that steel with copper has high hardness, ultimate tensile strength and low ductility (Motagi et al., 2012).
Samples of medium carbon steel were examined after heating between 900ºC980ºC and soaked for 45 minutes in a muffle furnace before quenching in palm oil and water separately. The mechanical behavior of the samples was investigated using universal tensile testing machine for tensile test and Vickers pyramid method for hardness testing. The microstructure of the quenched samples was studied using optical microscope. The tensile strength and hardness values of the quenched samples were relatively higher than those of the as-cast samples. Samples quenched in palm oil displayed better properties compared with that of water-quenched samples. This behavior was traced to the fact that the carbon particles in palm oil quenched samples were more uniform and evenly distributed, indicating the formation of more pearlite structure, than those quenched in water and the as- received samples (Jamiu et al., 2012). An investigation of suitability the adequate material properties and structure for agricultural industries. The En 8 is a medium carbon steel, En 19 and En 24 is a plain medium carbon low alloy steels containing molybdenum and chromium in different amount (up to 5% in total). The selected steels were heat treated and their mechanical and Tribological properties have been accessed for their suitability for agro machinery industries. The Tribological properties have been quantitatively estimated by three body abrasion test set-up which is Flex make as per standard specifications of American society of testing materials (ASTM), where the wear caused by abrasive trapped between the two moving surfaces [8]. The influence of heat treatment on mechanical behavior of AISI1040 has been investigated. Result shows that the ultimate tensile strength and the yield strength decrease while the elongation increases with an increase in tempering temperature and tempering time of different tempered specimen. The hardness of quenched/hardened specimen decreases with an increase in tempering temperature and tempering time. Furthermore, increasing temperature and lowering time produces approximately same result as decreasing temperature and increasing time (AshishVermaa et al., 2013).
In the case of stainless steel, At both room temperature and increased temperature, the material characteristics of stainless steel differ from those of carbon steel due to the high alloy content. At room temperature, stainless steel displays a more rounded stress-strain response than carbon steel and no sharply defined yield point, together with a higher ratio of ultimate-to-yield stress and greater ductility. At elevated temperatures stainless steel generally exhibits better retention of strength and stiffness in comparison to carbon steel. For a structure under fire conditions, these material properties are beneficial. Austenitic stainless steel, in particular, shows the best combination of strength, oxidation resistance and elevated temperature properties for long service, high temperature industrial applications and has been successfully employed for such purposes (with operating temperatures of around 550°C) for many years (Davies, 2019). Recent research (Ala-Outinen et al., 2017) has examined the suitability of employing stainless steel for fire resistant structural applications, where the demands are very different from those in long service industrial applications. For instance, for structures in fire, the duration of exposure to high temperatures will be relatively short, while the temperatures reached may exceed 1000°C. Additionally, owing to the low probability of occurrence of fire, large plastic deformations are tolerable in the structural members, provided overall structural collapse can be avoided. General background information related to the behaviour of steel structures at elevated temperatures and guidance on design for fire safety according to Wang (2019).
Appropriate assessment of the fire resistance of stainless steel structures depends largely on the ability to accurately predict the material response at elevated temperature. This paper presents an overview and reappraisal of existing pertinent research, proposes strength and stiffness reduction factors at elevated temperatures for a range of grades of stainless steel, some of which are not covered in existing design guidance, and describes a modified compound Ramberg-Osgood material model suitable for elevated temperatures. Use of the compound Ramberg-Osgood material model is now commonplace for modelling the nonlinear response of stainless steel at room temperature. At elevated temperatures, although the degree of nonlinearity changes, the basic rounded form of the stress-strain curve remains the same. The proposed modified material model utilises the material strength parameters currently employed for fire design in Eurocode 3, namely the elevated temperature 0.2% proof strength s0.2,q and the strength at 2% total strain st2.0,q.
Steel that has been heat treatment using quenching is hard but brittle. Tempering was done to remove the agility caused by the residual stress. The effect of heat treatments on microstructure and mechanical properties of medium carbon steel and stainless steel materials is carried out in this work.
1.2 Aim and objectives of the study
The aim of this study is to study the effects of high temperature on the properties of medium carbon steel and stainless steel materials. The objectives of the study are:
- To study how high temperature affect the properties of medium carbon steel and stainless steel materials
- To carry out an experiment regarding the effect of temperature.
- To study different properties of medium carbon steel and stainless steel materials
1.3 Scope of the study
The scope of this work covers studying the effects of high temperature on the properties of medium carbon steel and stainless steel materials. Further both steels are compared on the basis of their mechanical properties as well as the rate of corrosion, then the hardness of both the carbon steel are noted before and after the heat treatment processes. The heat treatment processes i.e. Annealing, Tempering & Oil quenching (hardening) are done. The mechanical properties such as the hardness and tensile strength among three process, the oil quenching sample possess highest hardness and the annealed sample possess highest elongation. That is how heat treatment plays an important role in the mechanical properties and corrosion resistance of the experimental steel. The mechanical properties of the two materials can be enhance by controlling the temperature of heating and cooling (KhushalKhera et al., 2014).
1.4 SIGNIFICANCE OF THE STUDY
- For the student: This study will provide an understanding on how high-temperature influences the behavior of medium carbon and stainless steel.
- In manufacturing industries: Both medium carbon and stainless steel are used in various manufacturing processes, and its behavior under high-temperature deformation is crucial for optimizing heat treatment and manufacturing procedures. Insights gained from this research can contribute to more efficient and cost-effective production methods.
- For designing materials: Investigating the effects of high-temperature deformation in medium carbon and stainless steel is essential for designing materials capable of withstanding extreme conditions, leading to increased reliability and durability.
- Contribute to the broader field of materials engineering: The findings from this study will contribute to the broader field of materials engineering, offering new insights into the behavior of medium carbon and stainless steel at increased temperatures. This knowledge can be applied to the development of advanced materials with tailored properties.
- Economic and Environmental Impact: By optimizing materials processing, the research can contribute to cost savings in manufacturing processes and reduce environmental impact. Improved efficiency in materials usage and processing aligns with sustainable and eco-friendly practices.
1.5 PROJECT ORGANISATION
The work is organized as follows: chapter one discuss the introductory part of the work, chapter two presents the literature review of the study, chapter three describes the methods applied, chapter four discusses the results of the work, chapter five summarizes the research outcomes and the recommendations.
CHAPTER FIVE
5.1 CONCLUSION
In this research work, Investigation the effect of high temperatures on the properties of medium carbon and stainless steel has been studied. The main results obtained are as follows:
- Wear rate for tempered medium carbon and stainless steel is higher than hardened
- As tempering temperatures of medium carbon and stainless steel increased the wear rate
- Hardness and brittleness of the medium carbon and stainless steel are decreased with increasing the tempering
- Ductility and percentage of elongation of medium carbon and stainless steel increased with increasing the tempering
5.2 RECOOMENDATION
In this work, properties of medium carbon and stainless steel were based on their wear rate and tensile properties; I recommend that the future work should base on all the properties of medium carbon and stainless steel.
I also recommend that higher temperature and higher Immersion Rate should be used in the future work.
