Quality Characteristics of Basic Hand Tools Sold in Nigeria

2009 ◽  
Vol 62-64 ◽  
pp. 708-714
Author(s):  
F.A. Oyawale ◽  
M.A. Ogunmolati
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Impact Energy ◽  
Quality Characteristics ◽  
Alloying Elements ◽  
Manufacturing Processes ◽  
Hand Tools ◽  
Three Samples ◽  
Major Property

Hand tools sold in Nigeria have become increasingly unreliable due to critical failures during use. The objective of this study is to test samples of these tools vis-à-vis manufacturer’s claims. A total of fifteen (15) hand tools from six (6) different countries available on the Nigerian market were tested for their quality characteristics. The tested tools included spanners, hammers, screwdrivers, pliers and chisels. Three samples of each of the groups of hand tools were ranked in accordance to their impact energy which is a major property of percussion tools. The results showed that built-in mechanical properties of these hand tools were largely controlled by their alloying elements, manufacturing processes and heat-treatment. Five (5) of the fifteen (15) selected hand tools conformed to BS 876, 1981 and were adjudged safe and reliable.

The Influence of Austenisation Temperature and Holding Time on Mechanical Properties, Scale Thickness, and Microstructure in Alloy Steel

2015 ◽  
Vol 776 ◽  
pp. 239-245
Author(s):  
Abdul Aziz ◽  
Maulud Hidayat ◽  
Indah Hardiyanti
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Tensile Strength ◽  
Alloy Steel ◽  
Impact Energy ◽  
Holding Time ◽  
Micro Structure ◽  
Scale Thickness ◽  
Alloy Steels ◽  
Steel Weight

The application of steel products have been widely used and various research have been developed to find a good and appropriate quality of steel and can be produced in the country without have to be imported, for example alloy steels. One of the alloy steels that have been constantly developed is Ni-Cr-Mo alloy steel with additional nickel, chromium and molybdenum which can increase hardness, tensile strength, ductility and toughness. The effect during the production process is at the heating process that causes the formation of iron oxide layer (scale) and the loss of steel weight. Therefore, the selection of heat treatment methods and techniques are required to increase the mechanical properties of steel, such as hardness, tensile strength, and toughness, with the scale is about <5% of steel weight. In this research, the heat treatment was carried out at austenisation temperature of 800°, 850°, 900°C and at holding time of 20, 40, 60 minutes, then followed by a rapid cooling (quenching) to improve the mechanical properties of hardness. This research also tested the mechanical properties of steel that consist of hardness test and impact test, and metallographic observation that consist of micro structure observation and scale thickness observation. The micro structure from heat treatment process is martensite, it is due to a rapid cooling (quenching) that rapidly change the austenite phase into martensite. The data showed the highest hardness is 588.35 HVN at 850°C of temperature and 60 minutes of holding time, 8.5 Joules of impact energy, and 91.5 μm of scale thickness. While the lowest hardness is 539.34 HVN at 800°C of temperature, 5 Joules of impact energy, and 47.81 μm of scale thickness.

Effect of Different Heat Treatments on Microstructure and Mechanical Properties of the Martensitic Gx12CrMoVNbN9-1 Cast Steel / Wpływ Parametrów Obróbki Cieplnej Na Mikrostrukture I Własciwosci Mechaniczne Martenzytycznego Staliwa Gx12CrMoVNbn9-1

2013 ◽  
Vol 58 (1) ◽  
pp. 25-30 ◽  
Author(s):  
G. Golanski ◽  
J. Słania
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Impact Energy ◽  
Cast Steel ◽  
Lath Martensite ◽  
High Strength ◽  
Strength Properties ◽  
Microstructure And Mechanical Properties ◽  
Quenching And Tempering ◽  
Very High

The paper presents a research on the influence of multistage heat treatment with the assumed parameters of temperature and time on the microstructure and mechanical properties of high-chromium martensitic GX12CrMoVNbN9-1 (GP91) cast steel. In the as-cast state GP91 cast steel was characterized by a microstructure of lath martensite with numerous precipitations of carbides of the M23C6, M3C and NbC type, with its properties higher than the required minimum. Hardening of the examined cast steel contributes to obtaining a microstructure of partly auto-tempered martensite of very high strength properties and impact strength KV on the level of 9-15 J. Quenching and tempering with subsequent stress relief annealing of GP91 cast steel contributed to obtaining the microstructure of high-tempered lath martensite with numerous precipitations of the M23C6 and MX type of diverse size. The microstructure of GP91 cast steel received after heat treatment was characterized by strength properties (yield strength, tensile strength) higher than the required minimum and a very high impact energy KV. It has been proved that GP91 cast steel subject to heat treatment No. 2 as a result of two-time heating above the Ac3 temperature is characterized by the highest impact energy.

Influence of Annealing Temperature and Time on the Mechanical Properties of Selected Steels for Heavy Forgings

2015 ◽  
Vol 647 ◽  
pp. 38-46
Author(s):  
Jakub Horník ◽  
Petr Zuna ◽  
Jaroslav Malek ◽  
Tomáš Jetmar ◽  
Josef Kasl ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Grain Boundary ◽  
Impact Energy ◽  
Experimental Evaluation ◽  
Annealing Temperature ◽  
Elevated Temperatures ◽  
Long Time ◽  
Grain Boundary Embrittlement ◽  
Boundary Embrittlement

Two types of steels used for production of heavy forgings were selected for the experimental evaluation of the effect of long time dwell at elevated temperatures and cooling during heat treatment on their mechanical properties in order avoid the possibility of grain boundary embrittlement. Samples from evaluated steels 26NiCrMoV14-5 and 22CrNiMoWV8-8 were austenitized for 2 hours at temperature of 1200°C and oil quenched. Subsequently the annealing at temperatures (200 - 700)°C for 1 hour and 100 hours was applied. Selected mechanical properties, especially hardness and impact energy, were monitored. It was found that for steels 26NiCrMoV14‑5 and 22CrMoNiWV8-8 exist the temperature intervals (300 - 400)°C and (500 ‑ 600)°C respectively with the possible potential for toughness decreasing.

Enhancement of the Gray Cast Iron Properties by Adding Chromium Element

2017 ◽  
Vol 753 ◽  
pp. 218-221
Author(s):  
Awad Eisa Gaib Alla Mohamed ◽  
Khairi Abdulsalam
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Cast Iron ◽  
Gray Cast Iron ◽  
Chromium Content ◽  
Gray Cast ◽  
Three Samples ◽  
Before And After ◽  
Different Temperatures

In this paper the effect of chromium element on some mechanical properties of gray cast iron is studied .The work was divided in to four categories, each category has three samples; each sample has three different chromium content 0.0%, 1.7%, 3.7%. The mechanical properties were investigated (hardness and impact) before and after the heat treatment. The heat treatment was carried out for period of 12 minutes at two different temperatures. The results confirmed that durability, toughness, and hardness are proportional to the chromium content. The ultimate aim of this research is to enhance the mechanical properties of gray cast iron by adding chromium element.

The effect of heat treatment on mechanical properties of 42CrMo4 steel

2020 ◽  
Vol 1 (98) ◽  
pp. 5-10
Author(s):  
A. Çalık ◽  
O. Dokuzlar ◽  
N. Uçar
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Tensile Stress ◽  
Yield Stress ◽  
Impact Energy ◽  
Ultimate Tensile Stress ◽  
Tempering Temperature ◽  
Heat Treated ◽  
Quenching Process ◽  
42Crmo4 Steel

Purpose: In this study, the effect of heat treatment on the microstructure and mechanical properties of 42CrMo4 steel were investigated. Design/methodology/approach: The samples were annealed at 860°C for 120 min. followed by oil quenching and then tempered at temperatures between 480 and 570°C for 120 min. The microstructure of untreated 42CrMo4 steel mainly consists of pearlite and ferrite whereas the microstructure was found to be as a martensitic structure with a quenching process. Findings: The results showed that there is an increase in yield stress, ultimate tensile stress, hardness and impact energy, while elongation decreases at the end of the quenching process. Conversely, yield stress, ultimate tensile stress and hardness decrease slightly with the increasing of tempering temperature, while elongation and impact energy increase. Research limitations/implications: Other types of steels can be heat treated in a wider temperature range and the results can be compared. Practical implications: It is a highly effective method for improving the mechanical properties of heat treatment materials. Originality/value: A relationship between the mechanical properties and the microstructure of materials can be developed. The heat treatment is an effective method for this process.

Mechanical Properties of G17CrMoV5 – 10 Cast Steel after Regenerative Heat Treatment

2009 ◽  
Vol 147-149 ◽  
pp. 732-737 ◽  
Author(s):  
Grzegorz Golański
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Impact Energy ◽  
Cast Steel ◽  
Negative Influence ◽  
Optimum Combination ◽  
Structure And Properties ◽  
Tempering Temperature ◽  
Regenerative Heat ◽  
Bainitic Structure

The paper presents results of research on the influence of regenerative heat treatment on structure and properties of G17CrMoV5 – 10 cast steel. Investigated material was taken out from a turbine frame serviced for over 250 000 hours (total service time) at the temperature of 535 oC. The cast steel after service revealed degraded bainitic-ferritic structure and was characterized by mechanical properties ranging below norm requirements. It has been proved that high tempering temperature in the case of cast steel with bainitic structure ensures optimum combination of mechanical properties and impact energy. It has also been shown that ferrite has a negative influence on impact energy of the cast steel with bainitic-ferritic structure.

Effect of Heat Treatment on Microstructure Evolution and Mechanical Behavior of SKLB3 Alloy

2017 ◽  
Vol 898 ◽  
pp. 380-386
Author(s):  
Wei Yuan ◽  
Dong Mei Liu ◽  
Qiang Song Wang ◽  
Guo Liang Xie
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Impact Energy ◽  
Hot Forging ◽  
Charpy Impact ◽  
Aging Treatment ◽  
Ni Alloy ◽  
Before And After ◽  
Different Temperatures ◽  
The Impact

In this paper, the effect of heat treatment on the microstructure and mechanical properties of hot forging Cu-Ni alloy was studied. Specimens of hot forged Cu-Ni alloy were subjected to first solution treated at 900oC for 2hrs and then aged at different temperatures for 2hrs. The mechanical properties including tensile performance and impact energy, and the microstructure were measured for specimens before and after heat treatment. The results show that both solution and aging treatment have an influence on the grain growth. After heat treatment, the tensile strength decreases very slightly but the yield strength decreases seriously from 235.96MPa to 136.12MPa, while the elongation increases sharply from 36% to 48%. It was also observed that hardness values of the heat-treated alloys are all lower than that of the hot forged alloy. The measurement of Charpy impact energy with V-type notch was performed at 298K and 77K for different specimens. At both temperatures, the impact energies of the specimens are higher than 200J. The microstructure results show that at both temperatures, the alloys are fractured in a ductile mode.

The effect of heat treatment on the mechanical properties of a low carbon steel (0.1%) for offshore structural application

2012 ◽  
Vol 226 (3) ◽  
pp. 242-251 ◽  
Author(s):  
Sung S Kang ◽  
Amir Bolouri ◽  
Chung-Gil Kang
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Grain Size ◽  
Cooling Rate ◽  
Impact Energy ◽  
Cast Steel ◽  
Low Carbon ◽  
Austenite Grain Size ◽  
Tempering Temperature ◽  
Austenite Grain

In this study, a low carbon cast steel (0.1% C) alloy designed for offshore structures, and the mechanical properties of the alloy under different heat treatment cycles have been evaluated. The effect of austenitizing time on the austenite grain size was studied. Subsequently, the quenched samples with minimum austenite grain size subjected to tempering experiments at different tempering temperatures (450 °C, 550 °C, and 650 °C) and cooling rates (0.23, 36, and 50 °C/s) from the temperature. The results showed that by increasing the austenitizing time, the austenite grain size initially decreased and reached the minimum value with ASTM number of 6.35 and then followed by an increase. When the tempering temperature increased, yield and tensile strengths decreased, whereas the ductility properties improved. In addition, yield and tensile strengths were not affected by cooling rate from tempering temperature, whereas the ductility properties were slightly affected. The increase in tempering temperature significantly led to improvement in the toughness to fracture of the alloy. The effect of cooling rate on impact energy for the samples tempered at 450 °C and 550 °C was negligible. By the contrast, impact energy for the samples tempered at 650 °C was markedly affected by cooling rate, in which the highest value was achieved for a cooling rate of 50 °C/s.

scholarly journals Estimation of Austenitizing and Multiple Tempering Temperatures from the Mechanical Properties of AISI 410 using Artificial Neural Network

2018 ◽  
Vol 7 (4.19) ◽  
pp. 778
Author(s):  
Abdul Kareem F. Hassan ◽  
Qahtan A. Jawad
Keyword(s):  
Neural Network ◽  
Mechanical Properties ◽  
Heat Treatment ◽  
Artificial Neural Network ◽  
Tensile Strength ◽  
Regression Analysis ◽  
Impact Energy ◽  
Ann Model ◽  
Artificial Neural ◽  
Quenching And Tempering

This research involved a study of the heat treatment conditions effect on the mechanical properties of martensitic stainless steel type AISI 410. Heat treatment process was hardening of the metal by quenching at different temperature 900°C, 950°C, 1000°C, 1050°C and 1100°C, followed by double tempering at 200°C, 250°C, 300°C, 350°C, 400°C, 450°C, 500°C, 550°C, 600°C, 650°C and 700°C, were evaluated and study of some mechanical properties such as hardness, impact energy and properties of tensile test such as yield and tensile strength is carried out. Multiple outputs Artificial Neural Network model was built with a Matlab package to predict the quenching and tempering temperatures. Also, linear and nonlinear regression analyses (using Data fit package) were used to estimate the mathematical relationship between quenching and tempering temperatures with hardness, impact energy, yield, and tensile strength. A comparison between experimental, regression analysis and ANN model show that the multiple outputs ANN model is more accurate and closer to the experimental results than the regression analysis results. 

Effect of Alloying Elements on Mechanical Properties of Al-Si-Cu-Mg Cast Alloys

2015 ◽  
Vol 817 ◽  
pp. 127-131
Author(s):  
Yan Peng Pan ◽  
Zhi Feng Zhang ◽  
Bao Li ◽  
Bi Cheng Yang ◽  
Jun Xu
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
High Performance ◽  
Cast Alloy ◽  
Experimental Results ◽  
Alloying Elements ◽  
Mg Alloy ◽  
T6 Heat Treatment ◽  
Specific Composition ◽  
Cast Alloys

To develop Al-Si cast alloys with high performance is important for lightweighting vehicles. In this study, the effects of the alloying elements such as Si, Cu, Mg contents (5%-7% Si, 1%-3%Cu, 0.3%-0.9%Mg) on mechanical properties of a test Al-Si-Cu-Mg cast alloy was studied to achieve a specific composition. The experimental results show that the Al-6%Si-3%Cu-0.3%Mg alloy has better comprehensive mechanical properties after T6 heat treatment, which indicates a remarkable interaction of the alloying elements for improving performance.

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