Rolling process is defined as a process used to reduced the thickness and to make the thickness uniform.
If the temperature of metal is above its re crystallization temperature then the process is known as hot
If the temperature of metal is below re crystallization temperature then it is known as a cold rolling process.
HOT ROLLING PROCESS:
It is a metal working process that occurs above re crystallization which maintain equal microstructure
And prevents the metal from work hardening.
Casting is defined as a manufacturing process in which a liquid material is poured into a mould which contains a hollow cavity of desired shape and then allow to solidify.
The solidify part is also known as a casting, which is ejected or broken out of the mould to complete the process.
TYPES OF CASTING :
- METAL CASTING
- PLASTER,CONCRETE OR PLASTIC RESIN.
In hot rolling process the starting point is usually large pieces of metals like semi finished casting products such as slabs ,blooms and billets.
Semi finished casting products are intermediate casting produced in a foundry that required further processing before being a finished products.
TYPES OF PRODUCTS :
If these products came from a continuous casting operation the products are directly fed into the
Rolling mills at proper temperature.
As the material is worked the temperature must be monitored to make sure it remain above
re crystallization temp.
To maintain a safety factor a finishing temperature is defined above re crystallization temperature.
If the temperature does drop below this temperature the material must reheated before more hot rolling.
Hot rolled mild steel seems to have a wider tolerance for amount of included carbon than cold rolled steel.
Also hot rolled products seems to be less costly than cold rolling ones.
Hot rolling is used mainly to produce sheet metal or simple cross section such as rail tracks.
It is the process where molten metal is solidified into semi finished billets, blooms, slabs for rolling in finishing mills.