1. CUTTING
&
EDGE PLANNING

2. PROCEDURE FOR MARKING, CUTTING AND CHECKING OF
SHELL PLATES
SHELL
PLATE
4 UNITS
K2
TS
NI
ROLLING DIR.
5U
W
SA 516 GR
70 24357
9262 /
3
K1
3 UNITS
L
TOLERANCE
• L - + 1 mm / M, Max. 3 mm., &
• K1 - K2 = + 1 mm / M,
W - + 1 mm / M, Max. 3 mm
Max. + 5 mm
• IDENTIFICATION MARKING
TO ROLLING DIRECTION.
• L - NOMINAL CIRCUMFERENCE = MEAN DIA. X
π
π
=
3.1415926535897932384626433832792………...

3. GENERAL WEP
WHEN JOINING PLATES OF DIFFERENT THICKNESS
X
T1
T2

4. FORMING

5. ROLLING DEPENDS
Provide necessary allowance ( 1.5 to 2 times the
thickness)
•
Gas cut
•
Wastage of the material
•
increased cycle time
Edge breaking to remove out peak out
Not feasible for all the thickness
Pressure required is more

6. ROLLING
THE PROCESS OF STRETCHING BEYOND THE YIELD
POINT OF THE METAL
METHODS
PINCH ROLLING
PYRAMID ROLLING
COLD ROLLING
WARM ROLLING
HOT ROLLING
NORMAL ROLLING

7. PINCH ROLLING
BENDING AT THE PLATE ENDS
BOTTOM ROLLER SHIFTED FROM CENTRE TO EITHER
LEFT OR RIGHT
PRESSURE APPLIED > NORMAL ROLLING PRESSURE

9. PYRAMID ROLLING
NORMAL ROLLING
TOP
ROLLER
BOTTOM
ROLLER
BOTTOM
ROLLER

11. COLD ROLLING
ROLLING AT NORMAL ROOM TEMPERATURE
WARM ROLLING
PLATE HEATED BELOW ITS CRITICAL TEMPERATURE
BEFORE ROLLING .
WHY?
PLATE THICKER THAN THE CAPACITY OF THE ROLLING M/C
PLATE MATERIAL HAS HIGHER YIELD POINT

13. HOT ROLLING
PLATE HEATED BEYOND UPPER CRITICAL TEMP.
BEFORE ROLLING .
WHY?
PLATE THICKER THAN THE CAPACITY OF THE ROLLING M/C
PLATE MATERIAL HAS HIGHER YIELD POINT

14. NORMAL ROLLING
PLATE PLACED BETWEEN TOP AND BOTTOM
ROLLERS AND PRESSURE APPLIED SLOWLY ON
TOP ROLLER TO ROLL THE REQUIRED DIAMETER.

15. CHECKING SHELL OVALITY AND
CIRCUMFERENCE
OVALITY
ACTUAL THK.
= ID max - ID min
= 0.5 % of Nominal ID
M
TE
P
D/
4
4
D/
PEAK OUT
TE
M
P
I/D CHECK IN HP PLANE
PEAK IN

16. TEMPLATES
TO CHECK THE INSIDE DIAMETER
MADE OUT OF 3-4MM THICKNESS PLATES
D/4 TO D/8 TEMPLATES
R
D/4

17. PEAK IN / PEAK OUT
ID
WHY?
OVER / UNDER BENDING DURING
EDGE BREAKING OPERATION
PRECAUTIONS
PROPER CARE
RE ROLLING
< 152
MM
457
MM
914
Allowed gap
Pick in /
out
0.8 MM
< 305
1.2
<
1.6 MM
< 610
2.4
<
3.2 MM
< 1219
4.0 MM
< 1524
4.8
MM
<
1905
5.6 MM
< 2133

18. SKEW
Rollers not aligned
Plate edges not kept parallel to roller axis plate
diagonals not checked

19. SKEW
15 TO 20MM AND LOW THICKNESS

20. SKEW
HIGH THICKNESS

21. SKEW
TURN BUCKLES

22. PRECAUTIONS
PROPER DEVELOPMENT & MARKING OF CONE
CHECK THE DIAGONALS
EDGE BREAKING WITH CARE ( D/4 LENGTH )
KEEP SUITABLE RADIUS GAUGE (HANDY)
ENSURE THE GENERATOR LINE OF THE CONE IS
PARALLEL TO THE TOP ROLLER
TO AVOID FLARE, INCREASE PREISURE SLOWLY

23. GOOD ENGINEERING PRACTICES
( FOR ROLLING )
Check diagonals of the plates to be rolled.
Stamp identification mark on the outer surface of
the width so that, when the plate is rolled in to a
shell the identification mark can be seen from
outside.
Identification mark should be stamped parallel to
the width of the plate

24. GOOD ENGINEERING PRACTICES
( FOR ROLLING )
Always pain rolling direction with an arrow on the
plate to be rolled
Remove burrs, dust, dirt from the edges of the plate
before it is fed in to rolling machine
While edge breaking a very long plate, hold one
end of such plate with crane while other end is
being edge broken
While edge breaking a very long plate, hold one end
of such plate with crane while other end is being
edge broken.

25. GOOD ENGINEERING PRACTICES
( FOR ROLLING )
Always refer capacity chart of a particular rolling
machine before attempting any bending/rolling on
that machine
Check alignment of the rollers, before rolling is
attempted.
Ensure that required templates are available before
rolling is taken up.
Before taking up s.s plate for rolling, the rollers
must be thoroughly cleaned with wire brush.

26. TOLERANCES ON CIRC. OF SHELLS, D’ENDS , CONES &
BELLOWS
• THE REQUIRED CIRCUMFERENCE SHALL BE COMPUTED
BY THE FOLLOWING METHOD.
REQUIRED CIRCUMFERENCE = ( ID + 2T ) * PIE
WHERE,I.D = INSIDE DIA. AS SPECIFIED IN DRAWINGS
T
= ACTUAL THICKNESS MEASURED AT ENDS
PIE = VALUE OBTAINED FROM CALCULATOR
• MEASURE THE ACTUAL CIRCUMFERENCE ON THE JOB.
• ONLY CALIBRATED TAPES SHOULD BE USED FOR MEASUREMENT.
• COMPARE THESE TWO VALUES OF CIRCUMFERENCE AND CHECK THE
ACCEPTABILITY BASED ON BELOW GIVEN TOLERANCE CHART.