Residual stresses are locked stresses present in steel prior to applied loads. They are unintended and can cause premature failure. Residual stresses typically range from 10-15ksi and increase with member thickness. The 1967 collapse of the Silver Bridge was attributed to high residual stresses in eye-bar members. Residual stresses form from manufacturing processes like rolling, welding, flame cutting and straightening due to uneven cooling and restraint. Measurement techniques include contour method, ring core, and x-ray diffraction. Residual stresses can be reduced through processes like quenching and tempering steel.

1. RESIDUAL STRESSES IN
STEEL
Abhishek Koppolu

2. CONTENTS
 Definition
 Causes
 Measurement techniques
 Remedial measures
 References

3. DEFINITION:
 Locked stresses in steel which are present prior to the
application of stress are called “Residual stresses.”
 These stresses are unintended and undesirable in
structural steel which cause it to fail prematurely.
 Research shows that residual stresses are typically
ranging from 10ksi to 15ksi.
 Thicker the section higher will be the residual stresses.

4. Collapse of silver bridge:
 Silver bridge of West Virginia collapsed in December
1967.
 Eye-bar crack growth was encouraged by the high levels
of residual stresses in the steel.

5. CAUSES:
Residual stresses occur mostly of the following cases:
1. Manufacturing of rolled steel members.
2. Welding in steel members
3. Cold straightening
4. Flame cutting

6. 1. Rolled members as they cool:
 Molten steel members as the cool the flange tips cool
and contract and gain stiffness
 As the adjacent fibers cool they contract and pull on the
previously cooled portions putting them into
compression.
 Cooled portions restrain inner portions from shortening
so the inner portion undergoes a tensile stress as they
cool.

9. 2. Residual stresses in welding
 Residual stresses in welded joints primarily develop due
to differential weld thermal cycle (heating, peak
temperature and cooling at the any moment during
welding)
 localized heating and cooling leading to differential
volumetric expansion and contraction of metal around
the weld zone.

10. 3. Cold straightening:
 An initially curved column member can be straightened by
an application of load which causes the same amount of
permanent deformations in the reverse direction.
4. Flame cutting:
The difference in temperature occurs during cutting
of steel sections imparts residual stresses for steel

11. Measurement of Residual stresses:
Destructive
Techniques
• Contour
Method
• Sach's
Boring
• Slitting
Semi destructive
Techniques
• Deep Hole
drilling
• Ring core
Non
destructive
Techniques
• Neutron
Diffraction
• X-Ray
Diffraction
• Ultrasonic

12.  Quenching and Tempering
• Quenching is the act of rapidly cooling the hot steel to
harden the steel.
• Quenched steel is hard and brittle.
• Often it is just too brittle and must be made more
malleable, This is achieved by a process known as
tempering.
Remedial measures for Residual stresses

13. • The quenched steel is heated again but this time to a
temperature between 200 °C and 300 °C.
• When the metal reaches the tempering temperature, it is
quenched again in cold water or oil. The result is a steel
that is still hard but is more malleable and ductile.
• Because they are quenched and tempered, rolled steel
shapes are partially stress-relieved, so residual stresses
are small.

14. References:
 https://en.wikipedia.org/wiki/Residual_stress
 Handbook of Residual stress and deformation of steel by
G. Totten, M. Howes, T. Inoue.
 Effects of initial condition of steel plate on welding
deformation and residual stress due to welding by
Park.J.U , Lee H. W

15. Thank you