various properties of steel

1. Sanjivani Rural Education Society’s
Sanjivani College of Engineering, Kopargaon-423 603
( An Autonomous Institute Affiliated to Savitribai Phule Pune University, Pune)
NAAC ‘A’ Grade, NBA Accredited, ISO 9001:2015 Certified
Unit I : Properties of Steel
By
Prof V M Mahajan (Asst. Professor)
Department of Civil Engineering
Email Id: mahajanvalmik@sanjivani.org.in

2. Properties of structural steel:
2
 Classified by BIS based on it’s ultimate or yield strength
 For example: Fe415, steel has 415 N/mm2 tensile strength,
Fe500, Fe500D etc.
 Mechanical properties depends upon chemical composition,
rolling method, rolling thickness, heat treatment.
1. Chemical composition: ferrous/iron = 95-98%
Carbon, C Manganese, Mn Sulphur, S Phosphorous, P Silicon, Si
Upto 2% is carbon
steel or
> 2% is cast steel
1.5 0.050 0.0050 0.4
Increases is C %,
increases tensile
strength, reduces
ductility

3. 3
2. Cast iron- low carbon %
3. Wrought iron- high carbon %
4. steel- medium or average of above
5. Rolling method-
Hot rolling- if temperature of metal is above its recrystallization
temperature while if temperature is below termed known as cold
working.
Flat rolling- foil-ring-controlled
6. Heat treatment- process of controlled heating and cooling of
metals to alter physical and mechanical properties without
changing shape.
Softening – hardening – material modification
Properties of structural steel:

4. 4
 Modulus of elasticity, E = 2x105 N/mm2
 Steel section obeys Hooks law in linear range. It remains elastic
& can recover its original shape after removal of loading.
 Shear modulus, G = 0.769x105 N/mm2
 Shear stress directly proportional to shear strain
 Poisson's ratio, (u) = 0.3, lateral strain/linear strain =constant
 Coefficient of thermal expansion,
change in volume due to temperature changes
 Ultimate tensile strength is ratio of ultimate tensile load to the
original area of c/s.
e
E 
 u
E
G


12
Cx o
t /1012 6

Other properties of structural steel:

5. 5
 As per Indian standard,
 IS:800-2007: General construction in steel structure
 IS:808-1989: Dimensions of hot rolled sections
 IS:875 part I to III: Panel load calculation other than earthquake
 SP: 6(1): structural shapes and other steel product
 SP: 6(6): plastic analysis and flexural beam
 IS:4000- 1992: High strength bolt in steel structures
 Grade of steel:
Fe415, Fe500, Fe500D etc.
Relevant IS specifications

6. 6
Stress strain curve for mild steel bar
OAB - straight line-obeys hooks law,
strain directly proportional to stress
A - limit of proportionality
B - Elastic limit
C', C - upper & lower yield point
OC' - material is elastic E = 2x105mpa
CD - plastic yielding
DE - strain hardening region
E - ultimate stress- reduction of c/s, necking formation
EF - post ultimate stress, stress falls rapidly with increase in
strain and specimen breaks.
F - breaking stress.