how balls of ball bearing is made?

Question

my meaning is how spherical shape of balls are given

Answer 1

Ball bearings are manufactured in a 5-step process:

1. Heading
First, a wire or rod made of steel is cut into slugs and "headed", or cold-formed, into spherical blanks on high-speed automatic machines.

2. Flashing
The flashing operation removes the "belt" and small protrusions from the surface by rolling them between two hard plates under very high pressure. This brings the balls to their "rough" size and sphericity.

3. Heat Treat
The balls are then heat-treated, or hardened, in a controlled atmosphere furnace. The balls are then inspected for
grain size and metallurgical structure.

4. Grinding
The hardened balls are then precision ground by rolling them between a fixed iron plate and a very hard fine-grit grinding wheel to bring them to their finished size.

5. Lapping and Polishing
To ensure the balls meet diameter and sphericity tolerances the balls are then rolled between two iron plates: one of which is fixed and the other which rotates and at a very low speed. A polishing operation creates a high shine to the ball.

Answer 2

Normally they are made from 2 hemispheres (half-spheres) and then joined together, similar to forming dough balls.

See link...
http://www.wisegeek.com/what-are-ball-bearings.htm

New techniques such as laser sintering can also be used, but this would make the process very expensive.