Chapter 3: Metal Works, Casting & Heat Treatmentsyar 2604
This topic explains the processes of metal works and casting. It also describes the types and purpose of heat treatment for steels and the effects of heat treatment on mechanical properties of steels.
Chapter 3: Metal Works, Casting & Heat Treatmentsyar 2604
This topic explains the processes of metal works and casting. It also describes the types and purpose of heat treatment for steels and the effects of heat treatment on mechanical properties of steels.
Recrystallization is the process in which deformed grains of the crystal structure are replaced by a new set of stress-free grains that nucleate and grow until all the original grains have been consumed. The process is accomplished by heating the material to temperatures above that of crystallization.
Concepts of rolling, annealing, quenching, drawing, cold working, hot working...Talha Saleem
pictorial Concepts of rolling, annealing, quenching, drawing, cold working, hot working and forging by simple diagrams.
its just basics. (no explanation )
Study and Analysis on Heat Treatment Process and Microstructure of Low Carbon...IJARTES
Low carbon steel is easily available and cheap
having all material properties that are acceptable for many
applications. Heat treatment on low carbon steel is to improve
ductility, to improve toughness, strength, hardness and tensile
strength and to relive internal stress developed in the material.
Here basically the experiment of harness and ultimate tensile
strength is done to get idea about heat treated low carbon steel,
which has extensive uses in all industrial and scientific fields
Recrystallization is the process in which deformed grains of the crystal structure are replaced by a new set of stress-free grains that nucleate and grow until all the original grains have been consumed. The process is accomplished by heating the material to temperatures above that of crystallization.
Concepts of rolling, annealing, quenching, drawing, cold working, hot working...Talha Saleem
pictorial Concepts of rolling, annealing, quenching, drawing, cold working, hot working and forging by simple diagrams.
its just basics. (no explanation )
Study and Analysis on Heat Treatment Process and Microstructure of Low Carbon...IJARTES
Low carbon steel is easily available and cheap
having all material properties that are acceptable for many
applications. Heat treatment on low carbon steel is to improve
ductility, to improve toughness, strength, hardness and tensile
strength and to relive internal stress developed in the material.
Here basically the experiment of harness and ultimate tensile
strength is done to get idea about heat treated low carbon steel,
which has extensive uses in all industrial and scientific fields
EXPERIMENT 8 PRECIPITATION HARDENING IN 2024 ALUMINUM .docxSANSKAR20
EXPERIMENT 8
PRECIPITATION HARDENING IN 2024 ALUMINUM
Objective
To study the time and temperature variations in the hardness of Al-4% Cu alloy on
isothermal aging.
Introduction
Materials can be hardened by inhibiting the motion of crystal defects called dislocations. In
pure metals, the presence of defects (such as vacancies, interstitials, dislocations and grain
boundaries) can enhance the strength. In single phase alloys, additional resistance to
deformation may arise from the presence of foreign atoms. In two-phase alloys, additional
stress is needed to enable the dislocation to intersect the second-phase particles. A finely
dispersed precipitate may, therefore, strengthen the material. This phenomenon is termed
precipitation hardening.
The thermodynamics of precipitation in 2024 Al can best be understood by referring to the
binary phase diagram of Aluminum-Copper in the aluminum-rich region in Figure 8-1.
When the aluminum-copper alloy of less than 5 wt% copper is heated to a temperature just
above the solvus line, only one phase (kappa, ) is thermodynamically stable. Other solid
phases dissolve (disappear). This process is called solution treatment. The only requirement
is that the specimen must be kept at this temperature for a long enough time. To solution
treat a sample of 2024 Al (4 wt% Cu), the sample should be heated to 930°F (500°C) and held
for 30 minutes.
When a solution treated sample is rapidly cooled (quenched) to below the solvus line (Figure
8-1), two phases are thermodynamically stable (kappa and theta). These phases are two
different solids, physically distinct, and separated by a phase boundary. The process is
similar to precipitation of salt in supersaturated brine.
The process of precipitation is not instantaneous, as is often the case in liquid-solid
precipitation. The process involves the formation of embryos of theta through thermal
fluctuations and their subsequent growth, once they achieve stability. With time, more and
more precipitates form. This process is called aging. Once the solution achieves an
equilibrium composition given by the solvus line for the aging temperature, precipitation
stops. For example, the precipitation of the copper-rich theta phase depletes the kappa phase
of copper to approximately 1-1/2 wt% Cu at 715°F (380°C).
The distribution of precipitates affects the hardness and yield strength. The hardness and
yield strength are greater when the precipitates are small and finely dispersed in the kappa
matrix than when the precipitates are large and not finely scattered. Therefore, to gain
hardness in 2024 Al, the specimen should be heat treated to produce a fine dispersion of
small precipitates.
Unfortunately, there is a tendency when thermodynamic equilibrium is reached for large
precipitates to grow and small precipitates to shrink. This will lower the surface to volume
ratio of the precip ...
Cold Work and Annealing: Recovery, Recrystallization and Grain GrowthMANICKAVASAHAM G
Cold Working and Annealing.
Cold working is deformation carried out under conditions where recovery processes are not effective.
Structural changes during cold working of polycrystalline
metals and alloys.
Effect of cold work on properties.
Annealing.
Recovery
EFFECT OF SCANDIUM ON THE SOFTENING BEHAVIOUR OF DIFFERENT DEGREE OF COLD ROL...msejjournal
The softening behavior of different cold rolled Al-6Mg alloys containing scandium 0.2 wt% and 0.6 wt% have been investigated by means of microscopy, hardness and electrical conductivity measurements. It is found that the scandium added alloys attend the higher hardness at every state of cold rolling at higher
annealed temperature due to the precipitation of scandium aluminides. Electrical resistivity of the scandium added alloys show higher than base alloy due to grain refining. It is seen from the microstructure that scandium refine the grain structure and inhibit recrystallization.
Effect of Scandium on the Softening Behaviour of Different Degree of Cold Rol...msejjournal
The softening behavior of different cold rolled Al-6Mg alloys containing scandium 0.2 wt% and 0.6 wt% have been investigated by means of microscopy, hardness and electrical conductivity measurements. It is found that the scandium added alloys attend the higher hardness at every state of cold rolling at higher annealed temperature due to the precipitation of scandium aluminides. Electrical resistivity of the scandium added alloys show higher than base alloy due to grain refining. It is seen from the microstructure that scandium refine the grain structure and inhibit recrystallization.
International Journal of Engineering and Science Invention (IJESI) is an international journal intended for professionals and researchers in all fields of computer science and electronics. IJESI publishes research articles and reviews within the whole field Engineering Science and Technology, new teaching methods, assessment, validation and the impact of new technologies and it will continue to provide information on the latest trends and developments in this ever-expanding subject. The publications of papers are selected through double peer reviewed to ensure originality, relevance, and readability. The articles published in our journal can be accessed online.
Welcome to WIPAC Monthly the magazine brought to you by the LinkedIn Group Water Industry Process Automation & Control.
In this month's edition, along with this month's industry news to celebrate the 13 years since the group was created we have articles including
A case study of the used of Advanced Process Control at the Wastewater Treatment works at Lleida in Spain
A look back on an article on smart wastewater networks in order to see how the industry has measured up in the interim around the adoption of Digital Transformation in the Water Industry.
Water scarcity is the lack of fresh water resources to meet the standard water demand. There are two type of water scarcity. One is physical. The other is economic water scarcity.
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Indigenized remote control interface card suitable for MAFI system CCR equipment. Compatible for IDM8000 CCR. Backplane mounted serial and TCP/Ethernet communication module for CCR remote access. IDM 8000 CCR remote control on serial and TCP protocol.
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Indigenized remote control interface card suitable for MAFI system CCR equipment. Compatible for IDM8000 CCR. Backplane mounted serial and TCP/Ethernet communication module for CCR remote access. IDM 8000 CCR remote control on serial and TCP protocol.
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• Compatible with MAFI CCR system
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• Compatible with Backplane mount serial communication.
• Compatible with commercial and Defence aviation CCR system.
• Remote control system for accessing CCR and allied system over serial or TCP.
• Indigenized local Support/presence in India.
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• Remote control: Parallel or serial interface.
• Compatible with MAFI CCR system.
• Compatible with IDM8000 CCR.
• Compatible with Backplane mount serial communication.
• Compatible with commercial and Defence aviation CCR system.
• Remote control system for accessing CCR and allied system over serial or TCP.
• Indigenized local Support/presence in India.
• Easy in configuration using DIP switches.
Overview of the fundamental roles in Hydropower generation and the components involved in wider Electrical Engineering.
This paper presents the design and construction of hydroelectric dams from the hydrologist’s survey of the valley before construction, all aspects and involved disciplines, fluid dynamics, structural engineering, generation and mains frequency regulation to the very transmission of power through the network in the United Kingdom.
Author: Robbie Edward Sayers
Collaborators and co editors: Charlie Sims and Connor Healey.
(C) 2024 Robbie E. Sayers
Explore the innovative world of trenchless pipe repair with our comprehensive guide, "The Benefits and Techniques of Trenchless Pipe Repair." This document delves into the modern methods of repairing underground pipes without the need for extensive excavation, highlighting the numerous advantages and the latest techniques used in the industry.
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Hierarchical Digital Twin of a Naval Power SystemKerry Sado
A hierarchical digital twin of a Naval DC power system has been developed and experimentally verified. Similar to other state-of-the-art digital twins, this technology creates a digital replica of the physical system executed in real-time or faster, which can modify hardware controls. However, its advantage stems from distributing computational efforts by utilizing a hierarchical structure composed of lower-level digital twin blocks and a higher-level system digital twin. Each digital twin block is associated with a physical subsystem of the hardware and communicates with a singular system digital twin, which creates a system-level response. By extracting information from each level of the hierarchy, power system controls of the hardware were reconfigured autonomously. This hierarchical digital twin development offers several advantages over other digital twins, particularly in the field of naval power systems. The hierarchical structure allows for greater computational efficiency and scalability while the ability to autonomously reconfigure hardware controls offers increased flexibility and responsiveness. The hierarchical decomposition and models utilized were well aligned with the physical twin, as indicated by the maximum deviations between the developed digital twin hierarchy and the hardware.
Industrial Training at Shahjalal Fertilizer Company Limited (SFCL)MdTanvirMahtab2
This presentation is about the working procedure of Shahjalal Fertilizer Company Limited (SFCL). A Govt. owned Company of Bangladesh Chemical Industries Corporation under Ministry of Industries.
Sachpazis:Terzaghi Bearing Capacity Estimation in simple terms with Calculati...Dr.Costas Sachpazis
Terzaghi's soil bearing capacity theory, developed by Karl Terzaghi, is a fundamental principle in geotechnical engineering used to determine the bearing capacity of shallow foundations. This theory provides a method to calculate the ultimate bearing capacity of soil, which is the maximum load per unit area that the soil can support without undergoing shear failure. The Calculation HTML Code included.
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1. NAME OF EXPERIMENT: ANNEALING
OBJECTIVE OF EXPERIMENT: STUDY THE EFFECT OF
ANNEALING ON THE MICROSTRUCTURE AND THE
MECHANICAL PROPERTIES
Devices used:
1. Light microscope
2. Brass specimens that have undergone annealing at different
time periods and temperatures
Theory ANNEALING STEPS:
»Recrystallization: nucleation and growth of new grains
»Driving force: difference in internal energy between strained
And Unstrained
»Grain growth: -- short-range diffusion Extent of recrystallization
depends on temperature and time.
»Recrystallization is slower on alloys
2. 1. How does annealing effect grains?
During a recrystallization anneal, new grains form in a cold-worked metal.
These new grains have a greatly reduced number of dislocations compared to
the cold-worked metal. This change returns the metal to its pre-cold-worked
state, with lower strength and increased ductility.
With continued time at the annealing temperature, some of the newly formed
grains grow at the expense of neighboring grains. There is some further
decrease in strength and increase in ductility as the average grain size
increases during the grain growth phase of the annealing process.
The final grain size depends on the annealing temperature and annealing
time. For a particular annealing temperature, as the time at the temperature
increases the grain size increases. For a particular annealing time, as the
temperature increases the grain size increases. A piece of metal with large
grains has lower strength and more ductility than a piece of metal of the same
alloy with smaller grains.
3. The figure shows micrographs of a brass alloy that was cold-rolled to 50% of
its original thickness and annealed at two different temperatures. Figure (a)
shows the microstructure of the cold rolled sample. Figure (b) shows the
microstructure of a sample that was cold rolled and then annealed at 1022 °F
(550 °C) for 1 hour. Figure (c) shows the microstructure of a sample that was
cold rolled and then annealed at 1202 °F (650 °C) for 1 hour.
The cold-rolled sample had a yield strength of 80 ksi (550 MPa). The sample
that was annealed at 1022 °F (550 °C) for 1 hour had yield strength of 11 ksi
(75 MPa). Many small grains are present in this sample. The sample that was
annealed at 1202 °F (650 °C) for 1 hour had yield strength of 9 ksi (60 MPa).
Fewer, large grains were present in this sample compared to the sample in
Figure (b).
4. 2. Is it possible to predict the recrystallization
temperature for a metal? If so then how?
Recrystallization is the formation of a new set of strain-free and equiaxed grains
(i.e., having approximately equal dimensions in all directions) that have low
dislocation densities and are characteristic of the pre–cold-worked condition. The
driving force to produce this new grain structure is the difference in internal
energy between the strained and unstrained material. The new grains form as very
small nuclei and grow until they completely consume the parent material,
processes that involve shortrange diffusion. Several stages in the recrystallization
process are represented in Figures 8.21a to 8.21d; in these photomicrographs, the
small, speckled grains are those that have recrystallized. Thus, recrystallization of
cold-worked metals may be used to refine the grain structure. Also, during
recrystallization, the mechanical properties that were changed as a result of cold
working are restored to their pre–cold-worked values; that is, the metal becomes
softer and weaker, yet more ductile. Some heat treatments are designed to allow
recrystallization to occur with these modifications in the mechanical
characteristics The extent of recrystallization depends on both time and
temperature. The degree (or fraction) of recrystallization increases with time, as
may be noted in the photomicrographs shown in Figures 8.21a to 8.21d. The
explicit time dependence of recrystallization The influence of temperature is
demonstrated in Figure 8.22, which plots tensile strength and ductility (at room
temperature) of a brass alloy as a function of the temperature and for a constant
heat treatment time of 1 h. The grain structures found at the various stages of the
process are also presented schematically. The recrystallization behavior of a
particular metal alloy is sometimes specified in terms of a recrystallization
temperature, the temperature at which recrystallization just reaches completion
in 1 h. Thus, the recrystallization temperature for the brass alloy of Figure 8.22 is
about 450C (850F). Typically, it is between one-third and onehalf of the absolute
melting temperature of a metal or alloy and depends on several factors, including
the amount of prior cold work and the purity of the alloy. Increasing the
percentage of cold work enhances the rate of recrystallization, with the result that
the recrystallization temperature is lowered, and it approaches a constant or
limiting value at high deformations; this effect is shown in Figure 8.23.
Furthermore, it is this limiting or minimum recrystallization temperature that is
normally specified in the literature. There exists some critical degree of cold work
below which recrystallization cannot be made to occur, as shown in the figure;
typically, this is between 2% and 20% cold work. Recrystallization proceeds more
rapidly in pure metals than in alloys. During recrystallization, grain-boundary
motion occurs as the new grain nuclei form and then grow. It is believed that
impurity atoms preferentially segregate at and interact with these recrystallized
grain boundaries so as to diminish their (i.e., grain boundary) mobility's; this
results in a decrease of the recrystallization rate and raises the recrystallization
temperature, sometimes quite substantially. For pure metals, the recrystallization
temperature is normally 0.4Tm, where Tm is the absolute melting temperature; for
some commercial alloys it may run as high as 0.7Tm.
5.
6. 3. State how residual stresses are formed and how they are
relieve?
When work pieces are subjected to plastic deformation that is not uniform
throughout the part, they develop residual stresses.
These are stresses that remain within a part after it has been formed and all
the external forces (applied through tools and dies) are removed; a typical
example is the bending of a metal bar.
The bending moment first produces a linear elastic stress distribution As the
external moment is increased, the outer fibres in the bar reach a stress level
high enough to cause yielding. For a typical strain-hardening material, the
stress distribution shown in Figure is eventually reached, and the bar has
undergone permanent ending.
Let’s now remove the external bending moment on the bar. Note that this operation
is equivalent to applying an equal but opposite moment to the bar; consequently, the
moments of the areas oab and oac in Figure.
must be equal. Line oc,which represents the opposite bending moment, is linear,
because all unloading and recovery is elastic
7. The difference between the two stress distributions gives the residual stress pattern
within the bar, as is shown in Figure. Note the presence of compressive residual
stresses in layers ad and oe, and the tensile residual stresses in layers do and ef
Because there are no external forces applied, the internal forces resulting from these
residual stresses must be in static equilibrium. Although this example involves only
residual stresses in the longitudinal direction of the bar, in most cases these stresses
are three dimensional.
Residual stresses can be remove by a number of methods. One way is to heat
the material to a temperature at which the yield strength is diminished. Then
when the object cools, no stresses will remain above that thermally reduced
yield strength.
Another method used on rolled bar and plate stock is to stretch the material
using sufficiently large hydraulic cylinders so that the entire cross section goes
into yield at 1% - 3% strain. Then when the load is removed little or no
residual stresses remain. For example, when this is used on some solution
annealed aluminum alloys and then the material is age hardened, it is
designated T651 temper. This provides bar stock that will deform minimally as
material is removed from it by machining.