ALEXANDRIA UNIVERSITY

FACULTY OF ENGINEERING
NAVEL ARCHITECTURE AND MARINE ENGINEERING
Course title: Material Engineering
NAM 161

STAINLESS
STEEL
PREPAERD BY:
 FATMA AL-ZAHRAA LABIB
 FATMA WASIM HELAL
 MOHAMED FATHY KANDIL
 AHMED ABDELSALAM
ELBDWY
 MOHAMED MAHMOUD
ESSA

2020 / 2021
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Table of contents:
1- Introduction……………………………………………………………….2
2- Types of stainless steel………………………………………………....3
3- Properties of Stainless Steel…………………………………………....6
4- Stainless steel applications……………………………………...…….12
5- Stainless steel welding………………………………………………….14
6- Stainless steel in ship manufacturing………………………………….16
7- References……………………………………………………………….18

List of figures:

Figure 1 Austenitic stainless steels…………………………………………………3

Figure 2 Ferritic stainless steels…………………………………………………….3
Figure 3 Martensitic stainless steels………………………………………………..4
Figure 4 Stainless steel welding…………………………………………………….13
Figure 5 LNG carrier………………………………………………………………….16
Figure 6 pipes at -162 °C…………………………………………………………….16

List of tables:
Table 1 Typical strength for annealed stainless steel from different families……..7
Table 2 physical Properties……………………………………………………………10
Table 3 mechanical Properties………………….….………………………………....10
Table 4 Electrical Properties…………………………………………………………..10
Table 5 Thermal Properties……………………………………………………………10

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Introduction

History of stainless steel:

The series of invention of steel began in 1798, when chromium was first introduced to
the French Academy by “Louis Fauqulin”, and many observations were subsequently
recorded on the resistance of chromium and iron alloys. 1861 Robert Forster obtained a
patent for chrome steel, and many attempts to discover steel took place over the years
and at the hands of many scientists until 1912, when the scientist “Harry Brierley” He
was experimenting with steel alloys – combinations of metals – that would be suitable
for making gun barrels.
A few months later he noticed that while most of his rejected specimens had rusted,
one containing 14 per cent chromium had not. The discovery led to the development of
stainless steel.

stainless steel composition:

It is an iron metallic alloy consisting of a mixture of elements where the percentage of
iron in it is not less than 50% and the percentage of chromium ranges between 5% to
30% and nickel and molybdenum is about 8.5% and the maximum percentage of
carbon has a maximum of 2% and as a result the formation of a thin coherent and
invisible layer of oxide Chromium, it acquires its resistance to rust, and this layer is
sufficiently protective whenever the proportion of chromium in steel is high, so this name
is considered to stem from the fact that stainless steel does not rust with that ease with
which ordinary carbon steel rusts, but in fact it is corrosive and rust in certain conditions.
Its resistance to rust varies according to its proportion of chromium, so it is important to
choose the correct type of stainless steel

Types of stainless steel:

Stainless steel family:

There are more than 100 grades of stainless steel, but the majority are classified as
main five groups; austenitic, ferritic, martenistic, duplex and precipitation-hardening.

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1- Austenitic stainless steels:

are considered the largest family, the most

frequently used types, they have a cubic crystal
structure, they contain 16 to 26 percent chromium
and up to 35 percent nickel, characterized by:

-They have the highest corrosion resistance.

-They tend to be non-magnetic, though they may
become magnetic after cold working.
-They have good formability and weld ability.

Common types of austenitic stainless steel:

-Grade 304 stainless steel.

-Grade 316 stainless steel
Figure 1

2- Ferritic stainless steels:

have a ferrite microstructure like carbon steel,

they have a cubic crystal structure also, they
consist of 10.5: 27 percent of chromium with very
little or no nickel, characterized by:

-This microstructure at all temperature is present

due to the chromium addition; so that they aren't
harden able by heat treatment.
-They cannot be strengthened by cold work to the
same degree as austenitic stainless steels.
-They are magnetic.
-They are cheaper than austenitic steels

Figure 2

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3- Martensitic stainless steels:

possess a body-centered cubic (bcc), or body-

centered tetragonal (bct), martensitic crystal structure
in the hardened condition contain 11.5 to 18 percent
chromium and 0.15: 0.63 percent carbon with nickel
sometimes added, characterized by:
- they are strengthened by heat treatment.
- they are magnetic.
- they have modest corrosion resistance.
- they are low in toughness and therefore brittle.
their types:
-grade 410
-grade 414
-grade 416 Figure3

4- Duplex stainless steels:

have a mixed of austenitic and ferritic in equal amounts, they consist of 21 to 27 percent
chromium, 1.35 to 8 percent nickel, 0.05 to 3 percent copper and 0.05 to 5 percent
molybdenum, they are stronger and magnetic and more resistance than ferritic and
austenitic stainless steels.
Duplex grades are usually divided into three sub-groups based on their corrosion
resistance:

-Lean duplex
-Standard duplex
-Super duplex.

5- Precipitation hardening stainless steels:

provide remarkable levels of high strength and hardness in a very wide range, contain
15 to 17.5 percent chromium, 3 to 5 percent nickel and 3 to 5 percent copper, they
develop their high strength and hardness by heat treatment

There are three types of precipitation hardening stainless steels

-low carbon martensitic.
-semi austenitic.

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Properties of Stainless Steel:

Mechanical Properties of Stainless Steel

 Yield Strength
 Ductility
 Hardness
 Tensile Strength

Physical Properties of Stainless Steel

 Corrosion Resistance
 Extreme temperature resistance
 Ease of fabrication
 High Strength
 Aesthetic appeal
 Hygiene and ease of cleaning
 Long life cycle
 Recyclable
 Low magnetic permeability

Mechanical Properties of Stainless Steel

The required mechanical properties are usually given in stainless steel purchase
specifications. Minimum mechanical properties are also given by the various standards
relevant to the material and product form. Meeting these standard mechanical
properties indicates that the material has been properly manufactured to an appropriate
quality system. Engineers can then confidently utilize the material in structures that
meet safe working loads and pressures.

Mechanical properties specified for flat rolled products are normally tensile strength,
yield stress (or proof stress), elongation and Brinell or Rockwell hardness. Property
requirements for bar, tube, pipe and fittings typically state tensile strength and yield
stress.

1) Yield Strength of Stainless Steel

the yield strength of annealed austenitic stainless steel is a very low proportion of the
tensile strength unlike mild steels. The yield strength of mild steel is usually 65-70% of

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the tensile strength. This number tends to be only 40-45% in the austenitic family of
stainless.

Cold working rapidly and greatly increases the yield strength. Some forms of stainless
steel can be cold worked to lift the yield strength to 80-95% of the tensile strength.

2) Ductility of Stainless Steel

The combination of high work hardening rates and high ductility makes stainless steel
very easy to fabricate. With this combination of properties, stainless steels can be
severely tarnished in processes such as deep drawing.

Ductility is usually measured as the percentage of elongation before a fracture during a

tensile test. Hardened austenitic stainless steels contain exceptionally high elongations.
Typical numbers are 60-70%

3) Hardness of Stainless Steel

Hardness is the resistance to penetration of the material surface. Hardness testers
measure the depth that a very hard indenter can be pushed into the surface of a
material. Brinell, Rockwell and Vickers machines are used. Each of these has a different
shaped indenter and method of applying the known force. Conversions between the
different scales are therefore only approximate.

Martensitic and precipitation hardening grades can be hardened by heat treatment.

Others can be hardened through cold working.

4) Tensile Strength of Stainless Steel

Tensile strength is generally the only mechanical property required for fixing rod and
wire rod products. Identical material grades in different tensile strengths can be used for
completely different applications. The tensile strength provided for rod and wire
products is directly related to the end use after fabrication. Spring wire tends to have the
highest tensile strength after fabrication. The high strength is transmitted through cold

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work in coil springs. Without this high force, the wire will not function properly as a
spring.

This high tensile strength is not required for wires to be used in molding or weaving
processes. The wire or rod used as the raw material for fasteners, such as bolts and
screws, must be soft enough to form a head and thread but still strong enough to
perform an adequately service.

Different families of stainless steels tend to have different tensile strengths. These
typical strengths of solids are illustrated in Table 1.

Table 1. Typical strength for annealed stainless steel from different families

Tensile Strength Yield Strength

Austenitic 600 250

Duplex 700 450

Ferritic 500 280

Martensitic 650 350

Precipitation Hardening 1100 1000

Physical Properties of Stainless Steel

The reason for choosing stainless steel is usually due to the advantages provided by
physical properties such as:

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 corrosion resistance.
 Extreme temperature resistance
 Ease of fabrication
 High Strength
 Aesthetic appeal
 Hygiene and ease of cleaning
 Long life cycle
 Recyclable
 Low magnetic permeability

1) Corrosion Resistance of Stainless Steel

Good corrosion resistance is considered as a feature of all stainless steels.
Low alloys can resist corrosion under normal conditions while high alloys resist
corrosion by most acids, alkaline solutions and chloride environments.

Corrosion resistance of stainless steel is due to its chromium content. In general,

stainless steel contains at least 10.5% chromium. The chromium in the alloy forms a
transparent, self-healing protective oxide layer that spontaneously forms in air. The self-
healing nature of the oxide layer means that the wear resistance remains intact
regardless of the manufacturing method. Even if the material surface is cut or damaged,
it will self-heal and will still be wear resistant.

2) Extreme Temperature Resistance

Some stainless steel alloys can resist scaling and retain high strength at very high
temperatures. Others retain high mechanical properties at extremely cold temperatures.

3) Simple Fabrication of Stainless Steel

Most stainless steel grades can be cut, welded, formed, machined and fabricated while
using standard methods and equipment used for other types of steel.

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4) High Strength
Manufacturing methods and component designs can be changed to get the advantage
of the work hardening of stainless steel that occurs when cold work is done. The
resulting higher strengths can allow for thinner material to be used, resulting in lower
weights and costs.
Other stainless steels can be treated by heat to increase strength.

5) Aesthetic Appeal
stainless steel can be supplied with a surface finishes. Stainless steel can also be
polished after fabrication to give the desired finish. The finish of stainless steel is easy
to clean and maintain.

6) Hygiene and Ease of Cleaning

Stainless steel is non-toxic and can be cleaned easily. This makes stainless steel the
preferred material for use in hospitals, kitchens, food and beverages, and drug
processing plants.

7) Long Life Cycle

Stainless steel's durability and resistance to corrosion mean it will withstand many
competitive products. The lower maintenance properties also add to the stainless steel
which is often the least expensive option in the life cycle cost comparison.

8) Recyclable
Stainless steel is completely recyclable. New stainless steels typically contain between
50 and 80% recycled material. Stainless steel scrap can be stored without deteriorating
its value as raw material.

9) Magnetic Permeability of Stainless Steel

Magnetic permeability is the ability of a material to attract a magnet. Austenitic grades
are the only non-magnetic stainless steel grades. Cold work can lead to a limited
degree of magnetism in austenitic grades other than 310 and 316 stainless steels.

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Type 304 Stainless Steel Properties: Table (2,3,4,5)

physical Properties Metric English Comments

Density 8 g/cc 0.289 lb/in³

mechanical Properties
Hardness, Brinell 123 123 Converted from
Rockwell B hardness.
Hardness, Knoop 138 138 Converted from
Rockwell B hardness.
Hardness, Rockwell B 70 70
Hardness, Vickers 129 129 Converted from
Rockwell B hardness.
Tensile Strength, Ultimate 505 MPa 73200 psi
Tensile Strength, Yield 215 MPa 31200 psi at 0.2% offset
Elongation at Break 70 % 70 % in 50 mm
Modulus of Elasticity 193 - 200 GPa 28000 - 29000 ksi
Poisson's Ratio 0.29 0.29
Charpy Impact 325 J 240 ft-lb
Shear Modulus 86 GPa 12500 ksi

Electrical Properties
Electrical Resistivity 7.2e-005 ohm-cm 7.2e-005 ohm-cm at 20°C (68°F); 1.16E-
04 at 650°C (1200°F)
Magnetic Permeability 1.008 1.008 at RT

Thermal Properties
CTE, linear 20°C 17.3 µm/m-°C 9.61 µin/in-°F from from 0-100°C
CTE, linear 250°C 17.8 µm/m-°C 9.89 µin/in-°F at 0-315°C (32-600°F)
CTE, linear 500°C 18.7 µm/m-°C 10.4 µin/in-°F at 0-650°C
Specific Heat Capacity 0.5 J/g-°C 0.12 BTU/lb-°F from 0-100°C (32-
212°F)
Thermal Conductivity 16.2 W/m-K 112 BTU-in/hr-ft²-°F at 0-100°C, 21.5 W/m°C
at 500°C
Melting Point 1400 - 1455 °C 2550 - 2650 °F
Solidus 1400 °C 2550 °F
Liquids 1455 °C 2650 °F

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Stainless steel applications

• Cars and transportation

Ford introduced stainless steel into cars in the 1930s to manufacture its model cars.
After that, it has been used to produce a wide variety of auto parts such as exhaust
systems, grills and trims. As technology advances, manufacturers prefer stainless
steel to make structural components.
It is also widely seen in other transportation fields such as shipping to make shipping
containers, road carriers and garbage vehicles. Its corrosion resistance makes it
ideal for transporting chemicals, liquids, and food products. And the low
maintenance stainless steel makes it easy and cost effective to clean and sustain.

• Medical technology
Stainless steel is preferred in clean and sterile environments as it is easy to clean
and does not corrode easily. Stainless steel is used in the production of a wide
range of medical equipment, including surgical and dental instruments.
They can be used to build operating tables, kidney dishes, MRI machines, cannulas,
and steam sterilizers.
Most surgical implants, such as prosthetic joints and prosthetic hips, are made of
stainless steel, and so are some joint equipment such as screws and stainless steel
plates to fix broken bones.

• Construction trade
Due to its strength, resistance and flexibility, the use of stainless steel has become a
vital component in the construction trade. Commonly displayed in the interior on
countertops, backsplashes, and handrails, it is also used externally in the cladding of
high impact buildings.
It is a popular feature in modern architecture due to its weldability, ease of
maintenance and attractive finishing, which are used on the Eurostar station in
London and the Helix Bridge in Singapore.
With the move toward sustainable construction, stainless steel, a highly recyclable
metal, is becoming increasingly preferred for use in construction. With a polished or
granular finish, it has properties that are aesthetically pleasing and can help improve
the natural lighting in a building.

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• Aircraft industry
The aviation industry also prefers stainless steel. It is used in many applications
including aircraft tires due to its strength and ability to withstand extreme
temperatures. It can be used in jet engines as it can help prevent rust too.
Stainless steel is an mean part of the landing gear. Its strength and stiffness can
handle the weight of the landing plane.

• Food and restaurant industry

In the food and restaurant industry, stainless steel is used to make kitchen
accessories, cooking utensils, and tableware. Utensils like knives are manufactured
using lower grades of stainless steel. The more flexible ductile grades are used for
making grills, stoves, pans and sinks.
Stainless steel can also be used to finish freezers, dishwashers, refrigerators, and
work surfaces. In food production, stainless steel is ideal as it does not affect the
flavor of the food. It is also resistant to corrosion and thus is able to retain acidic
drinks including orange juice. The ease of cleaning stainless steel makes it difficult
to harbor bacteria, which increases its utility for food storage.
• Tanker manufacturing
• Ship manufacturing

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Stainless steel welding:

 Difficulty of welding stainless steel:

Welding stainless steel is a difficult challenge for beginners and you must have
extensive experience in welding to deal with it. This is due to the high-efficiency
thermoplastic stainless steel. Stainless steel can be deformed from high
temperatures or during the cooling process. The difficulty in welding of stainless
steel is that it shows all the signs of impurity and scratches that are left.

 Preparing for welding:

It is very important to clean the stainless steel before welding and it is very
important not to use stainless steel welding tools to weld any other metals
Such as stainless brushes, hammers, and clips due to their sensitivity to the
presence of any carbon steel. This is because small amounts of carbon steel can
be combined with stainless steel, causing rust.
Carbon steel and stainless steel must be completely separated so that the
carbon steel dust suspended in the air does not descend on the stainless steel
and lead again to rust.
Make sure you have the right filler material.

Figure 4

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 Methods for welding stainless steel:

There are 3 common methods of welding:

1. (TIG) welding or gas tungsten arc welding.

The most common welding process produces high quality, versatile and
long-lasting products. It produces low temperatures making it suitable for
delicate materials. Argon gas is often mixed with other gases such as
helium, hydrogen and nitrogen, depending on the type of project. Gases
are mixed to prevent oxidation and to increase corrosion resistance.

2. Resistance or spot welding:

It is one of the most money-saving types of welding. The equipment of this
type of welding is versatile and can be used in large and small projects. It
can be adjusted to prevent metal deformation.

3. (MIG) welding or gas metal as welding:

It is a semi-automatic process that provides a correct and robust
connection of two stainless steel parts. This process uses a shielding
gas rich in argon and a solid wire electrode. This welding is considered
pulsed, which makes it easier to weld hard to reach places. To improve
the welding quality, a mixture of gases is added, including those
containing oxygen and helium.

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Stainless steel in ship manufacturing:

Natural gas transportation methods: More than 90 percent of the natural gas
produced worldwide is distributed via pipelines. The easiest and most economical
alternative to this is transportation by ship it via LNG tankers that have thermally
insulated tanks, that have been specially designed to maintain the natural gas in a liquid
form. With this mode, the natural gas is liquefied at -162 °C (−260 °F) at atmospheric
pressure and (thus reduced to one 600th of its original volume). and then it is
‘regasified’ and then distributed as pipeline natural gas.

LNG pipe requirements: The quality of LNG pipe is the most important factor that
affects the LNG transportation. This places extreme demands on the pipes used for this
purpose, the specialist materials used to transport LNG have to be reliable and have the
ability to maintain the extremely low temperatures required. because If LNG is
vaporized, then it potentially could become explosive or emit thermal radiation hazards.

LNG pipe is often made of stainless steel pipe. The main reasons are:
 Stainless steel has the ability to maintain the extremely low temperatures
required.

 Stainless steel pipe is a kind of widely used pipe in water and oil transportation
because of high corrosion resistance.

 the efficiency of the transportation will be high because the stainless steel LNG
pipe has smooth surface.

 Stainless steel LNG pipe has high strength and there will not be any leakage.

 Stainless steel LNG pipe is not hard to maintain and clean. We only need some
clean agent to clean the pipe after using a period of time.

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Figure 5: LNG carrier

Figure 6: pipes at -162 °C

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References:

 Jonathan Beddoes , J. Gordon Parr “Introduction to Stainless Steels” July

1, 1999
 D. Feron “Marine Corrosion of Stainless Steels, EFC 33 (European
Federation of Corrosion Publications) Hardcover” November 4, 2001
 Philip D. Harvey “Engineering Properties of Steels” American Society for
Metals, Metals Park, OH, (1982).
 Donald Peckner, I. M. “Bernstein Handbook of Stainless Steels” McGraw-
Hill Book Company, New York, NY, (1977)
 Metals Handbook, Howard E. Boyer and Timothy L. Gall, Eds., American
Society for Metals, Materials Park, OH, 1985.
 Metals Handbook, 10th ed., vol. 1, ASM International Handbook Committee.,
ASM International, Materials Park, OH, (1990)
 https://eagletube.com/about-us/news/stainless-steel-characteristics/
 https://www.thyssenkrupp-materials.co.uk/properties-of-stainless-steel
 Frank Marlow “Welding Fabrication and Repair” (Volume 1) 1st Edition
January 7, 2002
 https://www.britannica.com/technology/stainless-steel
 http://www.marlinwire.com/blog/what-are-the-common-types-of-stainless-
steel
 https://www.specialpipingmaterials.com/industries/lng/

 Supertanker movie “Richard Hammond”

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