COMPARATIVE STUDY OF CASE-HARDENING AND WATER-QUENCHING OF MILD STEEL ROD ON ITS MECHANICAL PROPERTIES

Mild steel is easily available and affordable having all material properties that are acceptable for many applications. It has carbon content up to 0.15%. While case-hardening and water-quenching are carried out on mild steel to improve toughness, strength and hardness, ductility declines as a result of internal stress developed in the material. This research work evaluated the effect of case-hardening and water-quenching on the mechanical properties of mild steel rod. Fifteen samples of mild steel rod of diameter 50 mm were prepared and heat treated in all, 12 of which were tensile samples. The other materials used for the project work were; powdered charcoal (4.44 g), barium carbonate (250 g), venier caliper, optical microscope, heating furnace and the material testing equipment. The water quenched specimens were heated to 950 oC and soaked for 40 minutes, after which the specimens were quenched in water. The case-hardened specimens were heated to 950 oC and for a period of 40 minutes and then quenched in salt solution. Various tests were carried out on the heated samples such as; tensile strength test, hardness test, microstructural analysis and chemical analysis were all carried out. The results showed that the case-hardened specimens had more ductility than the water-quenched. The hardness test revealed that the water-quenched samples were the hardest, followed by the case-hardened samples. The case-hardened specimens had higher value than water-quenched specimens for strain at break. Various microstructures which were product of austenite were got such as, martensite (BCT, fine grains), Bainites and Pearlite

Impacts of Carburizing Temperature and Holding Time on Wear of High Speed Steel Cutting Tools.

The paper presents a report on effects of variation in carburizing temperature and time on cutting tool to enhance its use in engineering applications. 30 pieces of HSS cutting tools (200 x 14 x 14 mm) sizes were used for the project and its composition was analyzed with the UV-VIS spectrometer before carburization. The tools were carburized with pulverized carbon (Palm Kernel Shell) using 25 % Barium trioxocarbonate (V) as an energizer in a muffle treatment furnace of about 1500oC. The performance evaluation of the tool was done by measuring its wear volume, wear resistance, weight loss and wear rate on all the samples (treated and untreated) using Rotopol –V. Minimum wear rate of the tool was 1.095 X 10 -8 cm2/N at carburizing temperature with time of 950oC and 120 minutes, 2.190 X 10 -8 cm2/N at 800oC and 60 minutes while those of the control sample ( untreated) was 1.127 X 10 -8 cm2/N. It can be concluded that the carburized tool has a lower wear rate at high carburizing temperature with time over at low carburizing temperature with time and control (untreated sample) in the tests carried out. The result of the performance evaluation tests corroborated the higher qualities of the carburized cutting tool at high temperature with time over others

Computational Modelling of Chromium Steel in High Temperature Applications

Modern martensitic 9-12% Cr steels are alloys with excellent mechanical properties even at elevated temperatures. The high temperature strength of these materials is inevitably related to their complex microstructure. Due to diffusional processes however, this microstructure changes during high temperature service, which leads to a decrease in strength. This work was aimed at modeling the 9-12% Cr steels with tailor-made microstructures for applications such as fossil fuel fired power plants, internal combustion engines etc. The investigations concentrated in the design and characterization of heat resistant steels for applications in high oxidizing atmospheres. A microstructure-property link is formulated with focus on the precipitate and solid solution hardening effect. For different heat treatments, the numerical results are compared with other samples. The numerical simulation showed excellent agreement in the case when all operative strengthening mechanisms are duly considered. The experimental results can be reproduced in a comprehensive and consistent manner by the numerical simulations using the software as MatCalc and ThermoCalc. From the result of the simulation, the observed phases after creep (M23C6 carbides, V-MX and Nb-MX particles and Laves phase) are in good agreement with the MatCalc and ThermoCalc calculations except for the Z-phase phase. The volume fraction of precipitated M23C6 carbides is directly related to the carbon content of the alloys

Impacts of Carburizing Temperature and Holding Time on Wear of High Speed Steel Cutting Tools.

The paper presents a report on effects of variation in carburizing temperature and time on cutting tool to enhance its use in engineering applications. 30 pieces of HSS cutting tools (200 x 14 x 14 mm) sizes were used for the project and its composition was analyzed with the UV-VIS spectrometer before carburization. The tools were carburized with pulverized carbon (Palm Kernel Shell) using 25 % Barium trioxocarbonate (V) as an energizer in a muffle treatment furnace of about 1500oC. The performance evaluation of the tool was done by measuring its wear volume, wear resistance, weight loss and wear rate on all the samples (treated and untreated) using Rotopol –V. Minimum wear rate of the tool was 1.095 X 10 -8 cm2/N at carburizing temperature with time of 950oC and 120 minutes, 2.190 X 10 -8 cm2/N at 800oC and 60 minutes while those of the control sample ( untreated) was 1.127 X 10 -8 cm2/N. It can be concluded that the carburized tool has a lower wear rate at high carburizing temperature with time over at low carburizing temperature with time and control (untreated sample) in the tests carried out. The result of the performance evaluation tests corroborated the higher qualities of the carburized cutting tool at high temperature with time over others

EFFECTS OF CARBURIZATION ON MECHANICAL PROPERTIES OF RECYCLED STEEL WITH PERM KERNEL SHELL (PKS) AS CARBON ADDITIVES.

The prediction and control of wear is one of the most essential problems emerging in the design of cutting operations which has to be checked through local production. This work therefore studies the effects of carburization on mechanical properties of recycled steel with Perm Kernel Shell (PKS) as carbon additives. 40 pieces of recycled Steel tools were used for the project. The tools were carburized with 40 kg of pulverized carbon of Perm Kernel Shell using 30 % Barium trioxocarbonate (V) as an energizer in a muffle treatment furnace of about 1500oC. Each sample was held at temperature of 800oC, 850oC, 900oC and 950oC for 60, 90 and 120 minutes holding time. The performance evaluation of the tool was done by using the tools (carburized and un-carburized) to machining low and medium carbon work piece on the lathe machine and also measured its impact/toughness using impact tester. The results shown best cutting performances and toughness in carburized tool of higher impact/ toughness value of 24 J over control sample of 17 J. The result of the performance evaluation tests corroborated the higher qualities of the carburized cutting tool over un-carburized type

Production of Cutting Tools from Recycled Steel with Palm Kernel Shell as Carbon Additives

Machining is an integral and indispensable part of production technology with cutting tool playing key roles in its operations. This work therefore developed cutting tool from scrapped crank shaft, connecting rod, alloy additives and palm kernel shell. These materials were chosen due to their hardness and availability. The scrapped crankshaft and rod (100 kg) containing 0.560 % carbon were charged into electric induction furnace with maximum temperature 3000oC. The composition of the charged materials was analyzed with the UV-VIS spectrometer before and after melting. In order to raise the carbon content of the melt to 0.65% target (HSS) and upgrade relevant elements, alloy additives were added. Annealing was the first treatment carried out in muffle treatment furnace at temperature at 900oC for 9 hrs then cooled to 300oC. The annealed materials were machined into 20 pieces of long (199 x 12 x 12 mm) and short (20x 12 x12 mm) sizes. Further treatments of hardening, normalizing and tempering were also carried out on the cutting tools. The tools were then carburized with pulverized carbon using 20 % Barium trioxocarbonate (V) as an energizer in a muffle treatment furnace. Each of the samples was soaked at temperature of 800oC, 850oC, 900oC and 950oC for 60, 90 and 120 minutes holding time. Microhardness and surface hardness of the tool were 47.9 and 76.8HR, while for control sample were 46.1 and 76.3HR respectively

Investigation of Wear Land and Rate of Locally Made HSS Cutting Tool

Production technology and machining are inseparable with cutting operation playing important roles. Investigation of wear land and rate of cutting tool developed locally (C=0.56%) with an HSS cutting tool (C=0.65%) as a control was carried out. Wear rate test was carried out using Rotopol –V and Impact tester. The samples (12) of locally made cutting tools and one (1) sample of a control HSS cutting tool were weighed to get the initial weight and grit was fixed at a point for the sample to revolve at a specific time of 10 mins interval. Approach of macro transfer particles that involved mechanism of abrasion and adhesion which was termed as mechanical wear to handle abrasion adhesion processes was used in developing equation for growth wear at flank. It was observed from the wear test that best minimum wear rate of 1.09 x10-8 and 2.053x10-8 for the tools developed and control were measured. MATLAB was used to simulate the wear land and rate under different conditions. Validated results of both the experimental and modeling showed that cutting speed has effect on wear rate while cutting time has predicted measure on wear land. Both experimental and modeling result showed best performances of tools developed over the control

Experimental Analysis of the Wear Properties of Carburized HSS (ASTM A600) Cutting Tool

Prediction and control of undesirable deterioration of cutting tools are the most essential challenges emanating in the design of tool which has to be checked. As a result of an increase in wear rate of HSS cutting tools, so has the need for wear resistant. The result has been a progression of carburizing the tools for better performance. Based on the theoretical analysis and study of tool wear and parameters that mitigates against wear resistance of cutting tools, this research work presents an experimental investigation and analysis of the wear properties of carburized HSS cutting tools. Twelve Samples under consideration were carburized HSS (ASTM A600) tools (0.65% C) treated at 800,850,900 and 950oC with holding time of 60, 90 and 120 minutes respectively. The wear properties of weight loss, wear volume, wear resistance and wear rate were carried out using Rotopol –V, impact tester, polisher, grinder and weight scale. It was found from the experiment carried out that cutting tool(sample 5) carburized at holding temperature and time of 800 oC and 90 minutes has the lowest cutting weight loss, volume and wear rate of 0.002 g, 0.00026 cm3 and 5.476 X10-10 cm2 with maximum wear resistance of 1.83X109 . This showed that sample 5 has the best wear properties which undermined the general believe that the sample with highest holding temperature and time should have the highest wear properties. This experiment has further established carburization as one of the heat treatment methods that involved carbon penetration to the depth that improved wear rate and resistance of a material

Cost of Corrosion of Metallic Products in Federal University of Agriculture, Abeokuta

The cost of corrosion has been increasing drastically due to the degradation of the metallic materials. This study was carried out to estimate the “Cost of Corrosion of Metallic Products in Federal University of Agriculture, Abeokuta (FUNAAB)”. Questionnaires were administered and interviews were also conducted to gather necessary information. The cost of corrosion from 2013-2015 was estimated and analysed with the aid of engineering economy method and statistical analysis method. For the cost of corrosion prevention methods, cleaning gave the highest cost contribution (69%), followed by the use of oil (30%), use of grease (1%), and painting gave zero percent of the total cost. While on the cost of corrosion maintenance methods, repair gave the highest cost contributions (66%), and prevention gave (34%) of the total cost. The overall cost of corrosion from (2013-2015) gave an upward trend, but a downward trend in future value and the annualized value. While the forecast cost from (2013-2016) at (95%) confidence level and (5%) significance level gave an upward trend. The present value, future value, and annualized value from (2013-2016) increased by (66%, 43%, and 75%) respectively. The total cost and the total annualized value of corrosion from (2013-2015) were estimated to be N 166,955,641 and N 93,791,024, and with the forecast (2013-2016) were found to be N 277,650,388 and N 163,672,460 respectively. Under the corrosion prevention methods and corrosion maintenance methods, cleaning and repair gave highest cost contribution respectively. Corrosion prevention methods need to be added to bring down the repair cost of those facilities for saving cost

Potentiodynamic Polarization of Brass, Stainless and Coated Mild Steel in 1M Sodium Chloride Solution

Enormous funds are spent on the protection of engineering components and structures annually as a result of corrosion. Degradation sets in, dueto electrochemical reaction that takes place between materials and the environment leading to reduced performance. The associated downtime caused by replacement and maintenance of vessels, pipes, valves and other equipment necessitated seeking for techniques and method to efficiently combat corrosion. This study evaluated the potentiodynamic polarization of brass, Coated Mild Steel (CMS) and Stainless Steel (SS) in sodium chloride (NaCl). The samples (1 x 30 x 30 mm3) were used as working electrodes for Potentiodynamic Polarization Experiment (PPE). The samples were cleaned, and soaked in 1M NaCl solution. Open circuit potentials and current densities of the samples were obtained from PPE which were used to evaluate their corrosion rates. The pH of the media was recorded before and after each experiment. The results obtained using PPE in NaCl (in mm/y) were 0.209, 0.0053 and 0.0046; for brass, MSC and SS respectively. The pH of the medium was measured as 10.9.The results revealed that brass had highest corrosion rate in the medium. The least corrosion rate was obtained for Stainless Steel in 1M NaCl followed by Coated Mild Steel