ROLLING
Thread Rating:
  • 0 Vote(s) - 0 Average
  • 1
  • 2
  • 3
  • 4
  • 5
seminar surveyer
Active In SP
**

Posts: 3,541
Joined: Sep 2010
#1
31-12-2010, 04:55 PM





.doc   6 mnths.doc (Size: 302 KB / Downloads: 74)

WHAT EXACTLY IS ROLLING?
The majority of steel products start their life by being converted from the ingot or continuous cast form by a process of rolling. To the steel supplied in the ingot form, the preliminary treatment, given is reduced in its section by rolling. Rolling consists of passing a metal between two rolls which grip the sheet and so reduced it in size, and after each pass the rolls are brought closer together and the metal passed through until required reduction in its section has been attained.


FACTS TO REMEMBER :

1. Volume entering ==== Volume leaving
A1×F1 ==== A2×F2

2. Speed increased develops between ‘A’ and ‘C’ on roll surfa- ce. Therefore, since roll surface travels at constant speed, there must be slippage between roll and steel. Theoretically, this slippage of the roll on the steel is forward between ‘A’ and ‘B’, and backward between ‘B’ and ‘C’. ‘B’ is the neutral point.

3. Increase in the speed can be explained by starting that the longitudinal pull in the direction of the ‘BP’ is the result of many tangential pulls at the roll surface introduced immedia- ly at the point of contact with the steel at ‘A’ until the bar leaves at ‘C’. These tangential forces are equal to the force of friction.

4. Therefore, as the pressure of the rolls increases, friction incre- ses. Tangential pulls and subsequent longitudinal pull along ‘CP’ increases, and the bar leaves faster. Thus the increased speed compensates for the decreases area of the bar.


CONTENTS


 H.R. SLITTER SECTION

 PICKLING LINE SECTION

 ROLLING MILL

 ANNEALING SECTION

 QUALITY CONTROL

 C.R.SLITTER SECTION

 C.T.L. SECTION

 MAINTAINENCE SECTION

 UTILITY


SALENT FEATURES OF COLD ROLLING


• Metal is fed to the rolls when it is below its recrystallisation
temperature.

• The metal shows the work hardening effect after being cold
rolled.

• Coefficient or friction between the rolls and the stock is com-
pearatively lower.

• Theoretical analysis can be easily carried out extensively de-
veloped theory is available.

• Experimental measurements can be easily carried out in cold rolling.

• Heavy reduction is not possible.

• Hardness increases. Excessive cold working generates cracks. Ductility of the metal reduces. Cold rolling increases the tensile strength and yield strength of steel.

• Roll radius is smaller.

• The cold rolled surface is smooth and oxide-free.



Reply

Important Note..!

If you are not satisfied with above reply ,..Please

ASK HERE

So that we will collect data for you and will made reply to the request....OR try below "QUICK REPLY" box to add a reply to this page

Quick Reply
Message
Type your reply to this message here.


Image Verification
Please enter the text contained within the image into the text box below it. This process is used to prevent automated spam bots.
Image Verification
(case insensitive)