Wrought aluminum

【China Aluminum Network】The external force is applied to the metal blank (not including the plate) to cause plastic deformation, change in size, shape, and improvement of performance. It is used to form the machining method of mechanical parts, workpieces, tools, or blanks.

Types and characteristics of forging When the temperature exceeds 300-400°C (blue brittle zone of steel) and reaches 700-800°C, the deformation resistance will decrease sharply and the deformation energy will also be greatly improved. According to the forging performed in different temperature regions, according to the different forging quality and forging process requirements, can be divided into cold forging, warm forging, hot forging three molding temperature regions. There is no strict limit to the division of such a temperature region. In general, forging in a temperature range where recrystallization has occurred is called hot forging, and forging without heating at room temperature is called cold forging.

At cold forging, the size of the forging varies little. Forging at temperatures below 700°C results in less scale formation and no surface decarburization. Therefore, as long as the deformation energy is within the forming energy range, the cold forging easily obtains good dimensional accuracy and surface finish. As long as the control of temperature and lubrication cooling, warm forging below 700 °C can also get good precision. When hot forging, large forgings with complex shapes can be forged due to small deformation energy and deformation resistance. Forgings with high dimensional accuracy can be hot forged in the 900-1000°C temperature range. In addition, attention should be paid to improving the working environment for hot forging, and the life of the forging dies (2 to 5,000 for hot forging, 1 to 20 for warm forging, and 2 to 50,000 for cold forging) is shorter than that of other forgings. However, its degree of freedom is large and its cost is low.

The blank is subject to deformation and work hardening during cold forging, and the forging die is subjected to a high load. Therefore, a high-strength forging die and a hard lubricating film treatment method for preventing wear and adhesion are required. In addition, in order to prevent cracking of the blank, intermediate annealing is performed when necessary to ensure the required deformability. In order to maintain a good lubrication condition, the billet can be phosphatized. In the continuous processing with bar stock and wire rods, no lubrication treatment is currently available for the section, and the possibility of using phosphating lubrication methods is being investigated.

According to the movement of the blank, forging can be divided into free forging, upsetting, extrusion, die forging, closed die forging, closed upsetting. Closed and closed upsets have high material utilization due to the lack of flash. It is possible to complete the finishing of complex forgings in one operation or several operations. Because there is no flash, the forging area is reduced and the required load is reduced. However, it should be noted that the blank cannot be completely constrained. For this purpose, the volume of the blank must be strictly controlled, the relative position of the forging die must be controlled, and the forging should be measured in an effort to reduce the wear of the forging die.

According to the movement mode of the forging dies, forging can be further divided into pendulum enthalpy, pendulum rotary forging, roll forging, cross wedge rolling, stumbling ring and oblique rolling. Pendulum, swing swaged and ring can also be used precision forging processing. In order to increase the utilization of materials, roll forging and cross rolling can be used as a pre-processing process for elongated materials. Rotary forging like free forging is also partially formed, which has the advantage that the forging force can also be achieved when the forging force is smaller than the size of the forging. This type of forging method, including free forging, causes the material to spread from the vicinity of the die surface toward the free surface during the machining. Therefore, it is difficult to ensure accuracy. Therefore, the direction of movement of the forging die and the rotary forging process can be controlled by a computer and can be used low. The forging force obtains products with complex shapes and high precision, such as the production of forgings such as steam turbine blades with large variety and large size.