Extrusion: a pressure processing method in which a punch or a terrace die is used to pressurize the blank placed in a concave mold to produce a plastic flow, so as to obtain the parts corresponding to the shape of die hole or concave convex die. When extruding, the billet generates three-way compressive stress, and even the billet with lower plasticity can be extruded and shaped. So, what materials can be used for extrusion? How to classify extrusion by blanks? As a professtional one of the best extrusion machine manufacturers, let Kailite Machinery give you a brief introduction.
Extrusion, especially cold extrusion, has high material utilization. The structure and mechanical properties of the material are improved, the operation is simple, and the productivity is high. It can produce parts with long rods, deep holes, thin wall and special-cross section of special shape. It is an important cutting process.
Extrusion is mainly used for metal forming, and can also be used for plastic, rubber, graphite clay blanks, and other non-metal forming.
In the 17th century, the French used a manual screw press to extrude the lead pipe and used it as a water pipe, which was the beginning of cold extrusion.
At the end of the 19th century, cold extrusion of zinc, copper, and copper alloys was realized.
In the early 20th century, it expanded to aluminum and aluminum alloy extrusion.
In the 1930s, the Germans invented phosphating and saponification surface antifriction lubrication treatment technology, which made the cold extrusion of steel successful and was initially used to extrude steel bullet casings.
After the Second World War, the cold extrusion of steel was extended to other countries and the scope of application was expanded.
The molten glass lubrication method was adopted in the 1950s, and the hot extrusion of steel was applied and developed in the metallurgical and mechanical industries.
According to the temperature of the blank, there are three types of extrusion: hot extrusion, cold extrusion, and warm extrusion. When the metal billet is above the recrystallization temperature (see plastic deformation), it is hot extrusion; when the metal billet is at room temperature, it is cold extrusion; when the metal billet is above the recrystallization temperature but does not exceed the recrystallization temperature, it is warm extrusion.
According to the plastic flow direction of the blank, extrusion can be divided into three types, namely, forward extrusion with the same flow direction as the pressure direction, and reverse extrusion with the flow direction opposite to the pressure direction, and compound extrusion in which the blank flows in both directions.