Industry Information

Inventory and Summary of Automotive Parts Processing Technology

A car is composed of numerous components, each of which plays a different role and needs to be processed through different processing techniques before it can be installed on the car for use. What are the processes for processing automotive components?
1、 Forging and processing of automotive parts
In the automotive manufacturing process, forging is widely used as a processing method. The forging method is divided into free forging and model forging. Free forging is a processing method of forming metal blanks by placing them on an anvil to withstand impact or pressure (commonly known as “forging”). The rough parts of automotive gears and shafts are processed using the method of free forging.
Model forging is a processing method in which metal billets are placed in the cavity of a forging die and subjected to impact or pressure to form. Model forging is a bit like the process of pressing dough into the shape of a biscuit in a mold. Compared to free forging, the shape of the workpiece produced by die forging is more complex and the size is more accurate. Typical examples of automotive die forgings are: engine connecting rods and crankshafts, steering knuckles, front axles, etc.
2、 Casting and processing of automotive parts
Casting is the production method of obtaining products by pouring molten metal into the cavity of the mold, cooling and solidification. In the process of processing and manufacturing automotive parts, many parts are made of cast iron into blanks, accounting for about 10% of the total weight of the vehicle, such as the cylinder body, transmission case, steering case, rear axle case, brake drum, various brackets, etc.
Sand molds are usually used to manufacture cast iron parts. The raw material for sand molds is mainly sand, which is mixed with binders, water, etc. The sand mold material must have a certain adhesive strength in order to be molded into the desired shape and be able to resist the erosion of high-temperature molten iron without collapse. In order to create a cavity in the sand mold that matches the shape of the casting, it is necessary to first make a model out of wood, called a wooden mold. After the hot molten iron cools down, its volume will decrease. Therefore, the size of the wooden mold needs to be increased according to the shrinkage rate based on the original size of the casting, and the surface that needs to be machined should be correspondingly thickened.
The heat treatment process includes annealing, normalizing, quenching, and tempering. Annealing is the process of heating steel parts, holding them for a certain period of time, and then slowly cooling them together with the furnace to obtain a finer and uniform structure, reduce hardness, and facilitate cutting processing. Normalizing is the process of heating steel parts, holding them warm, removing them from the furnace, and then cooling them in air, suitable for refining low-carbon steel. Quenching is the process of heating steel parts, holding them warm, and then rapidly cooling them in water or oil to improve their hardness. Tempering is usually the subsequent process of quenching, where the quenched steel parts are reheated, insulated, and cooled to stabilize the structure and eliminate brittleness. Many automotive parts require surface high-frequency quenching, carburization, cyanidation, and other heat treatment processes to preserve the toughness of the core while changing the surface structure to improve hardness.