gear material

What will the gear be used for? unless it's some type of toy, I wouldn't even think of aluminum bronze, too soft.

Cast iron, do you mean gray iron or ductile?

have you looked at steel? I think SAE 8620 or 4140 would heat treat well to a nice hard material for most heavy duty applications.

yes

you are right. original driver gear is aluminium bronze and mating driven gear is steel material.

please advice me. because al bronze one is getting worn out earlier.

<helical gear,>

1. "Helical gear" is Spur Gear with enhanced teeth load bearing capability.Never manufactured from Cast Iron . Too expensive to be made from Al-Bronze.
2. Do you mean WORM-WHEEL pair.Here Worm will be Hardened Steel.Wheel can be Bronze or Cast Iron.What isthe speed ratio and duty?
3. Do you have your own gear generating machine setup?
4. If not, it is better you buy a new Gear box -professionally manufactured.
5. Please let me know.