This Presentation briefly covers the highlights of steel; manufacturing of steel by basic oxygen furnace and electric arc furnace method, types of steel their properties and composition, applications of steel, corrosion, heat treatment, effect of alloying element. topic suited for Ethiopian university engineering curriculum

1. STEEL
SHARANABASAPPA
Lecturer Mechanical Engineering
College of Engineering & Technology
Samara University Ethiopia
+251-985159136, +91-8904111870
sharanubhurke999@gmail.com

2. Contents
• Introduction
• Making of steel
• Classification
• Effect of alloying elements
• Corrosion
• Applications
• Heat treatment

3. Introduction
• Steel is an alloy of iron and carbon; that may
contain appreciable concentration of other
alloying elements.
• Alloy is a mixture of a metal with at least
one other element.

4. Making of steel

5. Blast furnace

6. Basic oxygen furnace
Charge: Molten Pig Iron + Scrap Steel
Capacity: 35Ton
Time: 20-30mimutes

7. Classifications of steel
Steel
Low alloy
Low carbon
Plain HSLA
Medium
carbon
Plain
Heat
Treatable
High
carbon
Plain Tool
High alloy
Tool Stainless

8. Effect of alloying elements
• Nickel:
- increase its strength and toughness
• Chromium:
-It improves corrosion resistance.
-It increases tensile strength, hardness, wear
resistance and heat resistance.
• Tungsten:
- It increases hardness, wear resistance,
shocks resistance & magnetic reluctance.
• Aluminium:
-It is used as a deoxidizer

9. • Vanadium:
- It improves tensile strength, elastic limit,
ductility, fatigue resistance, shock resistance and
response to heat treatment.
• Molybdenum:
-It increases hardness, wear resistance, thermal
resistance.
• Cobalt:
-it refines the graphite and pearlite and acts as a
grain refiner. It improves hardness, toughness,
tensile strength and thermal resistance.
• Titanium:
-It acts as a good deoxidizer and promotes grain
growth. It prevents formation of austenite in high
chromium steels.

10. • Copper:
-It improves resistance to corrosion
• Silicon:
-It improves magnetic permeability and
decreases hysteresis losses.
-It decreases weldability and forgeability.
• Manganese:
- It improves the strength of the steel.
• Carbon:
-It increases tensile strength and hardness.
-It decreases ductility and weldability.
-It affects the melting point.

11. Corrosion
• Corrosion is defined as deterioration of
material or its properties because of reaction
with its environment.
• Sometimes deterioration may be weight gain
or reduction in weight or loss of mechanical
properties.
• The cause of corrosion in metals is tendency
to returns to its original state. Eg: Ore
• Corrosion process are electrochemical in
nature: some are not.

12. Types of Corrosion
1. Uniform(all over)
2. Pitting(local damage,
producing cavity)
3. Crevice(local corrosion
between metal to metal or
metal to non metal)
4. Galvanic(two dissimilar metals
are electrically connected in
electrolyte)
5. Stress corrosion
cracking(cracking by combined
effect of environment and
tensile stress)
6. Intergranular attack(grain
boundaries in metals)
7. Dealloying(when one
constituent of an alloy is
removed)
8. Erosion(kind of wear)

13. Factors affecting corrosion
1. Environment
• Nature of corrodant
• Operating conditions
• Polarization effect
2. Material Properties
• Electrochemical activity
• Homogeneity
• Passivity
3. Physical conditions
• Design
• Stress
• Couples
• External energy
• Mechanical action

14. Corrosion control
1. Design
• Crevice control
• No metal mixes
• Corrosion allowance
• Anodic protection
• Cathodic protection
• Welding practice
• Stagnant areas
• Hot spots
2. Environmental
control
• pH
• Temperature
• Velocity
• Concentration
• Inhabitation
• Cleaning
• Aeration
3. Material selection
• Coatings
• Cladding
• Heat treatment
• Diffusion treatment
• Corrosion data
• Surface finish

15. Heat Treatment

16. None can destroy an Iron its own rust can !
Likewise None can destroy a person but his own mindset can.
-Ratan Tata