1) The document discusses different steelmaking processes including the Bessemer converter process, open hearth furnace process, and basic oxygen converter process.
2) The Bessemer converter process was the first major steelmaking technique but has been replaced by basic oxygen converters. It used hot metal and an oxygen blast to oxidize impurities.
3) The basic oxygen converter process is now the dominant steelmaking method. It uses a pear-shaped vessel, oxygen lancing, and produces steel in 40-60 minutes by oxidizing impurities into slag.
Non - Ferrous Extraction of Metals Lecture NotesFellowBuddy.com
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various types of steel basically low carbon steels and alloy steels and how the alloying elements alter the various properties of steels , a detailed study & analysis
Introduction to Physical Metallurgy Lecture NotesFellowBuddy.com
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various types of steel basically low carbon steels and alloy steels and how the alloying elements alter the various properties of steels , a detailed study & analysis
Introduction to Physical Metallurgy Lecture NotesFellowBuddy.com
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The challenges that confront Steel industry in the age of globalization are complex in nature. The secret of sustainable turnaround lies in how steel industry faces the challenges and develops combative and anticipatory process. Most of the Problem can be solved by adopting and modifying their Operational Management strategy.
Steelmaking, Shaping, Treating and Processing, Steel and Steel Products (Fast...Ajjay Kumar Gupta
Steel is one of the most important and widely used products in the world. Currently, the steel industry is undergoing a process of change. As a result of ongoing technical and economic developments, the production and use of electric arc furnace steel is, beneath the steel production in a blast furnace, becoming increasingly important, continuously gaining share of world-wide steel production over the past 30 years.
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Presentation on bokaro steel plant, a SAIL subsidiary unit situated in bokaro steel city, jharkhand. I complied it at the end of my training there in my 2nd year.
Steel is an alloy of iron and a number of other elements, mainly carbon, that has a high tensile strength and relatively low cost.
Steel is one of the most sustainable construction materials. Its strength and durability coupled to its ability to be recycled, again and again, without ever losing quality make it truly compatible with long term sustainable development.
The versatility of steel gives architects the freedom to achieve their most ambitious visions.
High carbon steel
Mild steel
Medium carbon steel
Stainless steel
high steel
Cobalt steel
Nickel chromium
Aluminium steel
Chromium steel
At its narrow upper end it has an opening through which the iron to be treated is introduced and the finished product is poured out
The wide end, or bottom, has a number of perforations through which the air is forced upward into the converter during operation.
As the air passes upward through the molten pig iron, impurities such as silicon, manganese, and carbon unite with the oxygen in the air to form oxides; the carbon monoxide burns off with a blue flame and the other impurities form slag.
Quality defects in TMT Bars, Possible causes and Potential Solutions.PrashantGoswami42
Maintaining high-quality standards in the production of TMT bars is crucial for ensuring structural integrity in construction. Addressing common defects through careful monitoring, standardized processes, and advanced technology can significantly improve the quality of TMT bars. Continuous training and adherence to quality control measures will also play a pivotal role in minimizing these defects.
Courier management system project report.pdfKamal Acharya
It is now-a-days very important for the people to send or receive articles like imported furniture, electronic items, gifts, business goods and the like. People depend vastly on different transport systems which mostly use the manual way of receiving and delivering the articles. There is no way to track the articles till they are received and there is no way to let the customer know what happened in transit, once he booked some articles. In such a situation, we need a system which completely computerizes the cargo activities including time to time tracking of the articles sent. This need is fulfilled by Courier Management System software which is online software for the cargo management people that enables them to receive the goods from a source and send them to a required destination and track their status from time to time.
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.
CFD Simulation of By-pass Flow in a HRSG module by R&R Consult.pptxR&R Consult
CFD analysis is incredibly effective at solving mysteries and improving the performance of complex systems!
Here's a great example: At a large natural gas-fired power plant, where they use waste heat to generate steam and energy, they were puzzled that their boiler wasn't producing as much steam as expected.
R&R and Tetra Engineering Group Inc. were asked to solve the issue with reduced steam production.
An inspection had shown that a significant amount of hot flue gas was bypassing the boiler tubes, where the heat was supposed to be transferred.
R&R Consult conducted a CFD analysis, which revealed that 6.3% of the flue gas was bypassing the boiler tubes without transferring heat. The analysis also showed that the flue gas was instead being directed along the sides of the boiler and between the modules that were supposed to capture the heat. This was the cause of the reduced performance.
Based on our results, Tetra Engineering installed covering plates to reduce the bypass flow. This improved the boiler's performance and increased electricity production.
It is always satisfying when we can help solve complex challenges like this. Do your systems also need a check-up or optimization? Give us a call!
Work done in cooperation with James Malloy and David Moelling from Tetra Engineering.
More examples of our work https://www.r-r-consult.dk/en/cases-en/
Cosmetic shop management system project report.pdfKamal Acharya
Buying new cosmetic products is difficult. It can even be scary for those who have sensitive skin and are prone to skin trouble. The information needed to alleviate this problem is on the back of each product, but it's thought to interpret those ingredient lists unless you have a background in chemistry.
Instead of buying and hoping for the best, we can use data science to help us predict which products may be good fits for us. It includes various function programs to do the above mentioned tasks.
Data file handling has been effectively used in the program.
The automated cosmetic shop management system should deal with the automation of general workflow and administration process of the shop. The main processes of the system focus on customer's request where the system is able to search the most appropriate products and deliver it to the customers. It should help the employees to quickly identify the list of cosmetic product that have reached the minimum quantity and also keep a track of expired date for each cosmetic product. It should help the employees to find the rack number in which the product is placed.It is also Faster and more efficient way.
Automobile Management System Project Report.pdfKamal Acharya
The proposed project is developed to manage the automobile in the automobile dealer company. The main module in this project is login, automobile management, customer management, sales, complaints and reports. The first module is the login. The automobile showroom owner should login to the project for usage. The username and password are verified and if it is correct, next form opens. If the username and password are not correct, it shows the error message.
When a customer search for a automobile, if the automobile is available, they will be taken to a page that shows the details of the automobile including automobile name, automobile ID, quantity, price etc. “Automobile Management System” is useful for maintaining automobiles, customers effectively and hence helps for establishing good relation between customer and automobile organization. It contains various customized modules for effectively maintaining automobiles and stock information accurately and safely.
When the automobile is sold to the customer, stock will be reduced automatically. When a new purchase is made, stock will be increased automatically. While selecting automobiles for sale, the proposed software will automatically check for total number of available stock of that particular item, if the total stock of that particular item is less than 5, software will notify the user to purchase the particular item.
Also when the user tries to sale items which are not in stock, the system will prompt the user that the stock is not enough. Customers of this system can search for a automobile; can purchase a automobile easily by selecting fast. On the other hand the stock of automobiles can be maintained perfectly by the automobile shop manager overcoming the drawbacks of existing system.
Immunizing Image Classifiers Against Localized Adversary Attacksgerogepatton
This paper addresses the vulnerability of deep learning models, particularly convolutional neural networks
(CNN)s, to adversarial attacks and presents a proactive training technique designed to counter them. We
introduce a novel volumization algorithm, which transforms 2D images into 3D volumetric representations.
When combined with 3D convolution and deep curriculum learning optimization (CLO), itsignificantly improves
the immunity of models against localized universal attacks by up to 40%. We evaluate our proposed approach
using contemporary CNN architectures and the modified Canadian Institute for Advanced Research (CIFAR-10
and CIFAR-100) and ImageNet Large Scale Visual Recognition Challenge (ILSVRC12) datasets, showcasing
accuracy improvements over previous techniques. The results indicate that the combination of the volumetric
input and curriculum learning holds significant promise for mitigating adversarial attacks without necessitating
adversary training.
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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.
2. Steel classifications
What is steel?
Steel is an alloy of basically iron & carbon
ranging from 0.025-2%. Other alloying elements
are occasionally added to improve different
properties in the ultimate steel.
The composition of steel broadly divides it into,
i) Plain carbon steel
ii) Alloy steels
3. The plain carbon steels are of three major types:
i) Low carbon or mild steels upto 0.25%C
ii) Medium carbon steels 0.25-0.65%C
iii) High carbon steels 0.65-1.70%C
Alloy steels are broadly divided into three different
types:
i) Low alloy steels total alloy content < ~5%
ii) Medium alloy steels ‘’ 5-10%
iii) High alloy steels ‘’ >10%
4. Steelmaking is a process of selective oxidation of
impurities i.e. reverse of iron making. During
steelmaking impurities like C, Si, Mn, P are
oxidized to their respective oxides and
eliminated either as gas or as liquid slag. Other
impurity ‘S’ can be minimized in reducing
condition by a slag-metal interface reaction.
6. Bessemer Converter Process
The Bessemer Converter Process was first developed in
1856. the original process was suitable for only low
‘P’ iron as it used acidic refractory lining. The basic
bessemer process, suitable for high ‘P’ hot metal was
developed later by Thomas Gilchrist and is known as
Thomas process.
The Bessemer converter process has now been
completely replaced by basic oxygen converters.
7. The converter & operational
practice
The bessemer converter is a pear shaped vessel with a
detachable bottom. It is mounted on a trunnion and
can be rotated through 360⁰. After charging the hot
metal blowing is started through the bottom tuyeres.
At the end of the blow, the converter is again tilted
upside down and the metal and slag are tapped out.
The Bessemer converter process is completely
autogeneous, i.e. no external heat supply is needed.
The energy requirement for steelmaking is provided
by the exothermic chemical reaction of the bath.
8.
9. Silicon oxidation occurs first, then Mn and ‘C’
oxidation peaks only after ‘Si’ and ‘Mn’.
Carbon oxidation is indicated by appearance
of the long flame over the mouth of the
converter. It drops after the completion of C-O
reaction.
‘P’ oxidation reaction continues for another 3-4
mins. This period is known as after-blow
period.
10. Composition of suitable hot metal
Element% Acidic process Basic process
C 3.5-4.0 3-3.6
Si 2.0-2.5 0.6-1.0
S 0.04max. 0.08-0.10
P 0.04max. 1.8-2.5
Mn 0.75-1.0 1.0-2.5
11. Decline of the Bessemer Process
In spite of the basic simplicity, the Bessemer steel
suffered from several limitations:
• A large part of the heat generated through
exothermic reactions is lost in the form of sensible
heat of the N2 gas. So, the scrap melting ability of
this process is very limited.
• The ‘N’ content in the Bessemer steel is high-of the
order of 0.012%. This is not desired with extremely
low level (50-60ppm) required in most commercial
steels.
12. • The need to change the bottom section
frequently was a severe problem.
• The Bessemer process could not refine high
‘Si’ medium ‘P’ iron in one single stage. In
Indian condition, a duplex or triplex process
became necessary to treat this type of hot
metal.
13. Open hearth furnace steelmaking
The process was originally developed by
Siemens in Germany and Martin in France in
late nineteenth century. The ability of OH
furnaces to melt both light & heavy scraps to
produce liquid steel of any ‘C’ content and any
desired chemical compositions had saved this
process till eighties.
14. Construction of OH Furnace
It is basically a reverberatory furnace in which
hot metal and molten steel scraps are refined
in a shallow basic lined hearth. The fuel
burners heat up the bath through the
intermediate slag layer. The hot exhaust gases
are conducted through a set of regenerators.
The sensible heat of hot gases preheat the
refractory checker works. The regenerators
preheat the air and fuel.
16. Operation of the basic OH furnace
There is usually a wide choice of raw materials in basic OH
furnace. In Indian plants , usually steel scrap + hot metal mix
constitutes the basic charge materials. The ‘Si’ content of the
hot metal was maintained as low as possible usually ≤ 1.0%,
to ensure optimum basicity of the slag. The ‘P’ content ranged
from 0.22-0.30%. The formation of basic oxidising slag
required addition of iron ore + limestone.
In integrated steel plants the usual practice was to charge steel
scrap, lime/limestone and iron ore first. The charge was
heated upto a state of incipient fusion. Then hot metal was
charged.
17. Reasons for decline of OH process
• OH steelmaking is a very slow process. It cannot
match the productivity of modern BOF where the tap
to tap time is of the order of 40-60mins.
• The dependence of external fuel supply is a serious
constraint of the process.
• Construction and maintenance of the roof and
substructure of the OH furnace is more difficult than
the overall maintenance of a basic oxygen converter.
18. Top-blown Basic Oxygen Converter
Process
The easy availability of oxygen gas in the post Second World War
period facilitated research on oxygen lancing through the
throat of the converter. As a result the top-blown basic
oxygen converter process, popularly known as LD process was
developed. LD stands for Linz and Donawitz towns in Austria,
where the developmental work was carried out. In course of
time the process also came to be known as Basic Oxygen
Furnace (BOF) process.
Because of its flexibility, it can refine hot metal of varying
compositions to produce low ‘C’, high ‘C’ and low alloy steels.
19. A basic oxygen converter is a pear-shaped vessel with a
concentrically positioned oxygen lance. The steel
shell is suitably lined with basic refractories. O2
(99.9%) is blown through a water cooled lance fitted
with a copper nozzle. The position of the lance w.r.to
the bath and the flow rate of O2 are automatically
controlled. The capacity of a modern converter
ranges from 100T-400T.
20. BOF Steelmaking practice
1. Scrap Charging
• Scrap Iron and Steel are tipped into the Furnace. The Iron and
Steel comes from old or scraped cars, bridges, buildings, etc.
Also used is Iron or Steel that when manufactured into a
product was not of good enough quality to be used for its
intended purpose.
2. Molten Iron Charging
• Molten Iron, which comes straight from the Blast Furnace is
then tipped into the Furnace. The Furnace is now ready for
the blow. The hot metal to scrap ratio ranges70:30 to 100:1.
22. 3. The Blow
• The Gas Offtake Hood is lowered onto the Furnace. The water
cooled Oxygen Lance is then lowered. This carries the hot
Oxygen to the surface of the hot metal, increasing the
temperature in the Furnace and melting all of the metal. The
Oxygen combines with the impurities to form oxides in the
form of gases and slag.
4. Sampling
• During the Blow the temperature of the Furnace is monitored,
and at regular intervals samples of the molten metal are taken
to be analysed. When the Steel is of the right composition,
then the Steel workers can move onto the next stage.
24. 5. Pouring
• When the Steel is of the right composition the Gas Offtake
Hood and the Oxygen Lance are removed. The molten Steel is
then poured out the Top-hole by turning the Furnace to one
side. The Steel is then cast into ingots, or processed by
continuous casting.
6. Slagging
• When all of the Steel has been poured out, the Furnace is
turned upside down, in the opposite direction to that when
pouring, and the Slag is removed.
26. Oxygen jet characteristics
• In BOF process, O2 is blown at a pressure of 8-10atm. through
a convergent –divergent nozzle. The O2 jet is supersonic and
has a speed of 1.5-2.2 times the speed of sound. A supersonic
jet is characterized by a supersonic core in which the jet
velocity is higher than the speed of sound.
• As the jet travels away from the nozzle, it is retarded by the
converter atmosphere so that the supersonic core shrinks
radially and the axial velocity gradually decreases until at
some distance away from the nozzle, the jet becomes fully
subsonic. This point marks the end of supersonic core.
27. • The jet ultimately impinges on the liquid metal surface to
form a cavity. The impingement of the jet and the dissipation
of the jet momentum causes circulation of the liquid bath in
the upward direction at the vessel central axis. The intensity
of the jet-bath interaction is expressed in terms of ‘Jet Force
No.’ (JFN) and is defined as,
JFN = Gas pressure x Nozzle dia./ Lance height
28. • At low JFN, dimpling with a slight surface depression
is observed.
• At medium to high JFN, splashing with a shallow
depression.
• At very high JFN, penetrating mode of cavity with
reduction in splashing.
Only the last two types of behavior are encountered in
BOF. Metal droplets are formed on the lip of the
cavity and get ejected in both modes.
29. Mechanism of refining
• During refining, controlled oxidation of the impurities takes
place once O2 is blown at supersonic speed. The interaction
of the O2 jet with the bath produces crater on the surface,
from the outer lips of which a large number of tiny metal
droplets get splashed. These droplets reside for a short time
in the slag above the bath.
• So, the existance of metal-slag- gas emulsion within the vessel
during the entire blowing period is an integral part of the BOF
steelmaking. This is the reason why slag-metal
(dephosphorization) and gas-metal (decarburization) reaction
proceed so rapidly in BOF steelmaking.
30. Bath conditions at various stages of
blow
0 min. 5 min. 7 min. 20 min.
GAS-SLAG-
METAL
EMULSION
32. • When the metal bath reacts with O2 jet
oxidation of iron occurs,
2[Fe] + {O2} = 2(FeO)
4(FeO) +{O2} = 2(Fe2O3)
An iron oxide rich slag forms in the early stage of
blowing due to oxidation of iron and addition
of iron ore/mill scale in the charge.
33. • The (FeO) reacts with the impurity elements in the metal &
slag.
(FeO) + [Si] = [Fe] + (SiO2)
(SiO2) + 2(FeO) = (2FeO.SiO2)
[Mn] + (FeO) = (MnO) + [Fe]
2(MnO) + (SiO2) = (2MnO.SiO2)
A (FeO) rich slag quickly dissolves lime, and the following
reactions proceed,
(2MnO.SiO2) + 2(CaO) = 2(CaO.SiO2)
34. Carbon removal
• The most important reaction in BOF is oxidation of
carbon. The rate decarburization is initially low, it
increases to a peak value in the middle of the blow
and then decreases again.
• In the initial period the (FeO) in slag may raise to 14-
16%. During peak period it decreases to 7-9%,
because during this period more O2 is consumed
than supplied. When the ‘C’ content of the bath
drops to <0.2% the decarburization kinetics drops
and (FeO) rises again.
35. Variation of rate of decarburization
during the blow
0
0.05
0.1
0.15
0.2
0.25
0.3
0.35
0 20 40 60 80 100 120
Carbonoxidationrate(%/min)
% of Blow time
C oxidation rate
36. Mn removal
• [Mn] from the bath is lost in the slag as (2MnO.SiO2),
so there is reduction in Mn% in the bath in the initial
period. As the slag basicity increases due to lime
dissolution, (MnO) is gradually released & is reduced
by carbon,
(MnO) + [C] = [Mn] + {CO}
So, the [Mn] content in the bath increases again. As the
intensity of C-O reaction decreases towards the end
of the blow, Mn is reoxidised from the bath. This
accounts the characteristic “Mn hump” in the
reaction diagram.
37. Phosphorus removal
• The early formation of a basic slag enables
dephosphorization to proceed simultaneously
with decarburization. The reactions are,
2[P] + 5 (FeO) = (P2O5) + 5 [Fe]
(P2O5) + 4 (CaO) = (4CaO.P2O5)
38. Sulphur removal
• Although the oxidizing slag in BOF is not suitable for desulphurization,
some ‘S’ removal may occur due to highly basic character of the slag and
high temperature (1680-1700⁰C).
The slag-metal desulphurization reactions are,
(FeS) + (MnO) = (MnS) + (FeO)
(FeS) + (MgO) = (MgS) + (FeO)
(FeS) + (CaO) = (CaS) + (FeO)
Part of the ‘S’ may be removed in the initial stage of the blow through the
reaction with Mn,
[Mn] + [S] = (MnS)
39. Production of High Carbon Steels in
BOF
• High carbon steels like rail steels(0.65- 0.74%C, 0.6-
1.0%Mn, 0.27-0.3%Si), Ball bearing steels (1.0%C,
1.2%Cr) etc. are manufactured in BOF converter by
“catch carbon technique”.
• In this technique, dephosphorization is accelerated
and completed before decarburization. Extra lime
and fluorspar are charged and the lance is raised to a
higher position for maintaining a soft blow condition
till ‘P’ removal is completed.
40. • Thereafter, decarburization is continued by a harder
blow till the bath carbon content drops to the
desired level.
• Alternatively, blowing may be continued to complete
both dephosphorization and decarburization.
Required amount of carburizer (petroleum coke
/graphite) is then added to the low carbon steel bath
to raise the ‘C’ content to the desired level. However,
this method involves risk of increasing the inclusion
& nitrogen % in steel, picked up from the carburizer.