Types of steels used in Industries Steel Types of Steel API Industries Usage of steel with different composition in different area

2. Steel
•It is an alloy of iron with typically a few percent of carbon to
improve its strength and fracture resistance compared to iron.
•Many other elements may be present or added.
•Used in Various sectors like
in buildings, infrastructure, tools, ships, trains, cars, machines, elect
rical appliances and weapons. Iron is the base metal of steel and it
can take on two crystalline forms (allotropic forms): body-centred
cubic and face-centred cubic.

3. Types of Steel
Mainly there are four types of Steel Used for various purposes:
•Carbon Steel
•Alloy Steel
•Stainless Steel
•Austenitic Steel
•Ferritic Steel
•Martensitic Steel
•Tool Steel

4. Types of Steel
Carbon Steel
Dull Appearance & vulnerable to corrosion.
Carbon steel or plain-carbon steel, is a metal alloy.
It is a combination of two elements, iron and carbon. Other elements are present in
quantities too small to affect its properties.
The only other elements allowed in plain-carbon steel are: manganese (1.65%
max), silicon (0.60% max), and copper (0.60% max).
Steel with a low carbon content has the same properties as iron, soft but easily formed.
With more carbon the metal gains hardness and
strength but becomes less ductile and more difficult
to weld.
Higher carbon content lowers steel's melting point and
its temperature resistance in general.

5. Types of Steel
Carbon Steel
Typical compositions of carbon Steel are:
Mild (low carbon) steel: approximately 0.020% to 0.25% carbon content with
up to 0.4% manganese content.
Less strong but cheap and easy to shape;
surface hardness can be increased through carburizing.
Medium carbon steel: approximately 0.14% to 0.84% carbon content with 0.60
to 1.65% manganese content.
Balances ductility and strength and has good wear resistance; used for large
parts, forging and car parts.
High carbon steel: approximately 0.59% to 0.65% carbon content with 0.30 to
0.90% manganese content.
Very strong, used for springs and high-strength wires.
Very high carbon steel: approximately 0.96% to 2.1% carbon content, specially
processed to produce specific atomic and molecular micro structures.

6. Types of Steel
However, the term "alloy steel" is the standard term
referring to steels with other alloying elements added
deliberately in addition to the carbon.
Common alloyants include manganese (the most
common
one), nickel, chromium, molybdenum, vanadium, silic
on, and boron.
Alloy Steel
Alloy Steel is steel that is alloyed with a variety of elements in total amounts
between 1.0% and 50% by weight to improve its mechanical properties.
 Alloy steels are found into two groups: low alloy steels and high alloy steels.
Strictly speaking, every steel is an alloy, but not all steels are called "alloy steels".
 The simplest steels are iron (Fe) alloyed with carbon (C) (about 0.1% to 1%,
depending on type).

7. Types of Steel
Alloy Steel
Less common alloyants
include aluminium, cobalt, copper, cerium, niobium, titanium, tungsten, tin
, zinc, lead, and zirconium.
The following is a range of improved properties in alloy steels (as
compared to carbon steels): strength, hardness, toughness, wear
resistance, corrosion resistance, hardenability, and hot hardness.
To achieve some of these improved properties the metal may
require heat treating.
Some of these find uses in exotic and highly-demanding applications,
such as in the turbine blades of jet engines, and in nuclear reactors.
Because of the ferromagnetic properties of iron, some steel alloys find
important applications where their responses to magnetism are very
important, including in electric motors and in transformers.

8. Types of Steel
Stainless steel's resistance to ferric oxide
formation results from the presence of chromium in
the alloy, which forms a passive film that protects the
underlying material from corrosion attack, and
can self-heal in the presence of oxygen.
Stainless Steel
It is a group of iron-based alloys that contain a minimum of approximately
11% chromium.
A composition that prevents the iron from rusting as well as providing heat-
resistant properties.
Different types of stainless steel include the elements carbon (from 0.03% to
greater
than1.00%), nitrogen, aluminium, silicon, sulfur, titanium, nickel, copper, selenium,
niobium, and molybdenum.

9. Types of Steel
Stainless Steel
Corrosion resistance can be increased further, by: increasing the chromium
content to levels above 11%; addition of 8% or higher amounts of nickel and
addition of molybdenum (which also improves resistance to "pitting corrosion").
The addition of nitrogen also improves resistance to pitting corrosion and
increases mechanical strength.
Thus, there are numerous grades of stainless steel with varying chromium and
molybdenum contents to suit the environment the alloy must endure.
Resistance to corrosion and staining, low maintenance, and familiar luster make
stainless steel an ideal material for many applications where both the strength of
steel and corrosion resistance are required.
Moreover, stainless steel can be rolled into sheets, plates, bars, wire, and tubing.

10. Types of Steel
Stainless Steel
These can be used in cookware, cutlery, surgical instruments, major appliances,
construction material in large buildings, industrial equipment (e.g., in paper
mills, chemical (Pharma) plants, water treatment), and storage tanks and tankers for
chemicals and food products.
The material's corrosion resistance, the ease with which it can be steam-cleaned
and sterilized, and the absence of the need for surface coatings have prompted the
use of stainless steel in kitchens and food processing plants.
Stainless Steel:
Austenitic stainless steel
Ferritic stainless steels
Martensitic stainless steels

11. Types of Steel
Austenitic Stainless Steel:
It is achieved by alloying steel with sufficient nickel and/or manganese and nitrogen to
maintain an austenitic microstructure at all temperatures, ranging from the cryogenic region
to the melting point.
Thus, austenitic stainless steels are not hardenable by heat treatment since they possess
the same microstructure at all temperatures.
Austenitic stainless steels can be further subdivided into two sub-groups, 200 series and
300 series.
200 series are chromium-manganese-nickel alloys that maximize the use of manganese and
nitrogen to minimize the use of nickel. Due to their nitrogen addition, they possess
approximately 50% higher yield strength than 300 series stainless sheets of steel.
E.g. Type 201 is hardenable through cold working.
Type 202 is a general-purpose stainless steel. Decreasing nickel content and increasing
manganese results in weak corrosion resistance.

12. Types of Steel
Austenitic Stainless Steel:
300 series are chromium-nickel alloys that achieve their austenitic microstructure almost
exclusively by nickel alloying.
Some very highly-alloyed grades include some nitrogen to reduce nickel requirements.
300 series is the largest group and the most widely used.
e.g. Type 304: The best-known grade is Type 304, also known as 18/8 and 18/10 for its
composition of 18% chromium and 8%/10% nickel, respectively.
Type 316: The second most common austenitic stainless steel is Type 316. The addition
of 2% molybdenum provides greater resistance to acids and localized corrosion caused
by chloride ions. Low-carbon versions, such as 316L or 304L, have carbon contents below
0.03% and are used to avoid corrosion problems caused by welding.

13. Types of Steel
Ferritic Stainless Steel:
Ferritic stainless steels possess a ferrite microstructure like carbon steel, which is
a body-centered cubic crystal structure.
It contain between 10.5% and 27% chromium with very little or no nickel.
This microstructure is present at all temperatures due to the chromium addition,
so they are not hardenable by heat treatment.
They cannot be strengthened by cold work to the same degree as austenitic
stainless steels.
They are magnetic.
Additions of niobium (Nb), titanium (Ti), and zirconium (Zr) to Type 430 allow good
weldability.

14. Types of Steel
Ferritic Stainless Steel:
Due to the near-absence of nickel, they are cheaper than austenitic steels and are
present in many products, which include:
Automobile exhaust pipes (Type 409 and 409c) are used in North America;
stabilized grades Type 439 and 441 are used in Europe),
Architectural and structural applications (Type 430, which contains 17% Cr)
Building components, such as slate hooks, roofing, and chimney ducts

15. Types of Steel
Martensitic Stainless Steel:
Martensitic stainless steels offer a wide range of properties and are used as
stainless engineering steels, stainless tool steels, and creep-resistant steels.
They are magnetic, and not as corrosion-resistant as ferritic and austenitic
stainless steels due to their low chromium content.
They fall into four categories:
Fe-Cr-C grades: These were the first grades used and are still widely used in
engineering and wear-resistant applications.
Fe-Cr-Ni-C grades: Some carbon is replaced by nickel. They offer higher toughness
and higher corrosion resistance.
Grade EN 1.4303 (Casting grade CA6NM) with 13% Cr and 4% Ni is used for
most Pelton, Kaplan, and Francis turbines in hydroelectric power plants because it
has good casting properties, good weldability and good resistance
to cavitation erosion.

16. Types of Steel
Martensitic Stainless Steel:
Precipitation hardening grades: Grade EN 1.4542 , the best-known grade, combines
martensitic hardening and precipitation hardening.
It achieves high strength and good toughness and is used in aerospace among other
applications.
Creep-resisting grades: Small additions of niobium, vanadium, boron,
and cobalt increase the strength and creep resistance up to about 650 °C (1,202 °F).

17. Types of Steel
The four major alloying elements that form tool
steel:
tungsten, chromium, vanadium and molybdenum.
Tool Steel
Tool steel refers to a variety of carbon steel and alloy steel that are particularly
well-suited to be made into tools.
Their suitability comes from their distinctive hardness, resistance to abrasion and
deformation, and their ability to hold a cutting edge at elevated temperatures.
As a result, tool steels are suited for use in the shaping of other materials.
With a carbon content between 0.5% and 1.5%, tool steels are manufactured under
carefully controlled conditions to produce the required quality.

18. Types of Steel
Tool Steel
Proper heat treatment of these steels is important for adequate performance.
The manganese content is often kept low to minimize the possibility of cracking
during water quenching.
There are six groups of tool steels: water-hardening, cold-work, shock-resistant,
high-speed, hot-work, and special purpose.
The choice of group to select depends on cost, working temperature, required
surface hardness, strength, shock resistance, and toughness requirements.
Tool steels are used for cutting, pressing, extruding, and coining of metals and
other materials.