Gear castings are also referred to as cast steel gears. This is because most gears are made of cast steel. Here, I share some information about the production of gears, castings and related heat treatment. The weight of a gear casting usually varies from a few kilograms to several tons. The material used for gear castings is usually made of high carbon cast steel, and some alloy steels, such as chromium, nickel and molybdenum, are used to achieve very high tensile strength. In general, large gears have lower physical requirements than pinions.
About casting process, usually floor forming process is applicable, and can meet the normal demand. As for cast steel gears, such as driven gears, gears and idler wheels, the floor forming process using quartz sand is a good choice. Why? Because most parts of the gear need to be machined. So you don't need to use a higher casting process. In addition, for the medium and large steel castings, the use of quartz sand flooring molding process is almost the only option.
With regard to heat treatment, of course, all steel castings must be standardized to eliminate internal pressure. Some parts of the gear castings can be welded. If the casting factory welds the casting, it must be annealed in the welding position. If the tooth is extremely stiff, you can anneal it again to reduce the hardness and eliminate the internal hard points. After machining and hobbing, gear hardening, or hardening, is used to increase the surface hardness of the gear teeth. For the pinion, you can do carburizing. For large driven gears, you can do surface hardening. Gears without hardened gears have a short lifespan, only a few weeks to a few months. Because gear castings require more material, defects, processing and heat treatment. In addition, the orders for gear castings are relatively small. As a result, many steel foundries are reluctant to make them. Some gears are made by forging process. The internal density of the forging gear is better and the strength is higher. Forged gears can be used for more stringent working conditions. Cast gears are of 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 shall choose the right manufacturing process according to cost and conditions of use.http://www.shinehe.com/