What are the common cooling methods for wheel forgings?

2024-08-14 15:24:06

The cooling of wheel forgings refers to the cooling of forgings from the final forging temperature to room temperature. Improper selection of cooling method may cause cracks, network carbides, and white spots due to excessive stress, which can affect product quality and even lead to the scrapping of forgings. So we need to choose corresponding cooling methods for different forgings. The following are several cooling methods for wheel forgings:

Spray cooling. Use a fan to atomize the water flowing out of the water pipe and blow it onto the forging for cooling. Air cooling. Forged parts are cooled by blowing air.

Air cold. The forging is evenly placed on the ground and cooled in still air. Be careful not to place it on damp ground or metal plates, and do not place it in areas with ventilation to prevent defects caused by rapid local cooling of forgings.

Pile cold. The forgings are stacked in the material basket and cooled in the air. The pit (box) is cold. The forgings are cooled in a pit or iron box.

Grey sand is cold. The forgings are cooled in slag, ash, or sand. The ash and sand used must be dry. The temperature for general forgings to be filled with ash and sand should not be lower than 500 ℃, and the thickness of the surrounding ash and sand should not be less than 80mm.

Furnace cold. The forgings are slowly cooled in a heating furnace with a temperature of 500-700 ℃, and the cooling rate can be adjusted according to the specified speed. The temperature of the forging entering the furnace is generally not lower than 600-650 ℃. After the forging temperature is consistent with the furnace temperature, it is cooled with the furnace. Cold air should be avoided from entering the furnace. Generally, the furnace temperature should not exceed 100-150 ℃.

Control cooling. Control the cooling rate of the forging after final forging to achieve a certain goal. The cooling method for forgings after final forging generally means that smaller forgings have a smaller temperature difference between the surface and inside, and the cooling rate can be faster, while larger forgings should have a slower cooling rate. Carbon steel and low-alloy structural steel have good thermal conductivity, with a small temperature difference between the surface and interior, and can cool faster. High alloy structural steel has poor thermal conductivity and slower cooling speed. So the cooling specifications for different forgings should be selected based on factors such as the chemical composition of the material and the maximum heat dissipation size of the forging.

Isothermal annealing. The correct cooling process after smelting and casting of white spot sensitive steel ingots is a prerequisite for ensuring quality, and the first cooling after forging is also a key factor. It is generally believed that hydrogen expansion isothermal annealing is carried out directly after stopping forging.