Selection of aluminum forging blanks

Forging blank processing is the first process of forging production. The quality and productivity of forging blank will have an important impact on the quality, performance, life and economic benefits of the enterprise. The processing technology, equipment precision and performance of the forging blank determine the blank quality. The quality of forging blank directly affects the turning accuracy, while the quality of turning affects the grinding accuracy and efficiency. Therefore, the selection of forging blanks plays a very important role in the whole forging process. The principle of the selection of forging blanks should reduce the production cost as much as possible on the premise of meeting the requirements of use, so that the products can compete in the market.

The use requirements of forgings determine the blank shape characteristics. Different use requirements and shape characteristics form the corresponding blank forming process requirements. The use requirements of forgings are specifically reflected in the external quality requirements such as shape, size, machining accuracy and surface roughness, and the internal quality requirements such as chemical composition, metal structure, mechanical properties, physical properties and chemical properties.

For the use requirements of different forgings, the process characteristics of forging materials (such as forging performance, welding performance, etc.) must be considered to determine which blank forming method is used. When selecting the blank forming method, the machinability of subsequent machining should also be considered. For some workblanks with complex structure that are difficult to be formed by a single forming method, it is necessary to consider the possibility of combining various forming schemes and whether these combinations will affect the machinability of machining.

In the selection of blank forming scheme, the principle of adaptability should also be considered. The suitable blank scheme shall be selected according to the structural shape, overall dimension and working conditions of forgings. For example, for stepped shaft parts, when the diameter difference of each step is small, bar stock can be used; If the difference is large, forging blanks should be used. The type of blank selected varies with the working conditions of forgings.

The forging blank forming scheme shall be selected according to the on-site production conditions. The on-site production conditions mainly include the actual process level, equipment status, and the possibility and economy of outsourcing of on-site blank manufacturing, but also consider the use of more advanced blank manufacturing methods due to production development. For this reason, when selecting the blank, the existing production conditions of the enterprise, such as equipment capacity and staff technical level, should be analyzed, and the existing production conditions should be used as much as possible to complete the blank manufacturing task. If the existing production conditions are difficult to meet the requirements, the forging materials and (or) blank forming method shall be considered to be changed, which can also be solved through outsourcing processing or purchasing.

The principle of economy is to minimize the cost of materials, energy and wages for forging. When selecting the type and specific manufacturing method of forging blanks, several pre selection schemes shall be compared economically on the premise of meeting the requirements of parts, and the scheme with low overall production cost shall be selected. Generally, when selecting the type and manufacturing method of forging blanks, the size and shape of the blanks should be as close as possible to the finished parts, so as to reduce the machining allowance, improve the utilization of materials and reduce the workload of machining. But the more accurate the blank is, the more difficult it is to manufacture and the higher the cost is.

Therefore, when the production program is large, the blank manufacturing method with high precision and productivity should be adopted. Although the one-time investment is large, the increased blank manufacturing cost can be compensated by the reduced material consumption and machining cost. The general rule is that free forging, manual arc welding, sheet metal fitter and other forming methods can be used in small batch production of single piece, and machine modeling, die forging, submerged arc automatic welding or other methods can be used in batch production.