Gear castings are also called cast steel gears.
This is because most gears are made of cast steel.
Here, I share some information about the production of gear castings and related heat treatment.
The weight of gear castings usually ranges from a few kilograms to several tons.
Gear castings usually use high-carbon cast steel, and some alloy steels containing chromium, nickel, and molybdenum are used to achieve high tensile strength.
Generally, large gears have lower physical requirements than small gears.
Regarding the casting process, usually the floor molding process is suitable and can meet the normal requirements.
As for cast steel gears, such as driven gears, gears and idlers, the floor molding process using quartz sand is a good choice. Why, because most parts of the gear need to be processed.
Therefore, you do not need to use a higher casting process. In addition, for medium and large steel castings, the floor molding process using quartz sand is almost the only option.
Regarding heat treatment, of course, all steel castings must be standardized to eliminate internal pressure.
Some parts of the gear casting can be welded. If the foundry welds castings, the welding position must be annealed.
If the hardness is extremely high after hobbing, you can re-anneal to reduce the hardness and eliminate internal hard spots.
After machining and hobbing, the gear is quenched or called hardening treatment to increase the surface hardness of the gear teeth.
For small gears, you can do carburizing treatment. For large driven gears, you can do surface hardening treatment.
The gear life without hardening treatment is very short, only a few weeks to a few months.
Because gear castings have higher requirements for materials, defects, processing and heat treatment.
Moreover, the number of orders for gear castings is relatively small. Therefore, many steel foundries are unwilling to manufacture.
Some gears are manufactured by the forging process. The internal structure of the forged gear has better density and higher strength.
Forged gears can be used in stricter working conditions. Cast gears have low strength, but are widely used in general working conditions.
The cost of forging gears is high, while the cost of casting gears is relatively low. The buyer should choose the appropriate manufacturing process according to the cost and use conditions.
