Flange Tire Forging Process
The flange has an elliptical shape (Figure 1) and is a non-machined surface. To ensure its appearance, hot stamping is generally used. The process flow is plate cutting → heating → punching → leveling or bar cutting → heating → forging → punching → leveling. But this type of punching mold requires high manufacturing accuracy and low service life; The utilization rate of flange material is low, less than half. To improve material utilization, simplify molds, and reduce costs, through analysis and research, it was decided to abandon traditional processes and utilize the relatively simple appearance to develop a new process for hammering the tire mold section. After being put into use, the effect was very good.
1. Flange tire die forging process
The process flow of flange die forging is: cutting → heating → blank making → die forging. The schematic diagram of tire die forging is shown in Figure 2. Its mold is easy to make, and its accuracy is also easy to ensure. Moreover, due to the uniform force on the mold, the lifespan of the mold is greatly improved. Over the past two years, nearly a thousand flanges were produced using die forging, and the molds remain intact. The blank-making process of this process is quite important. We use a double fan buckle die (as shown in Figure 3) to make a blank that is close to the shape of the forging and place it into the sleeve for forging. If the anvil of the hammer used in this process is relatively flat, the lower mold pad can be removed, so the sleeve height should be subtracted from the corresponding lower mold pad height. The lower part of the sleeve cavity can be designed straight, making it more convenient to use. But when equipped with a lower mold pad, the requirements for the flat surface of the hammer and anvil are not very high.
Figure.2 Forging diagram of flange tire mold
Figure.3 Double leaf buckle mold
2. Comparative analysis
(1) In terms of mold production
The manufacturing of the original process (hot stamping method) mold is relatively complex,
The lifespan is low, while the new process (tire die forging) has a simple manufacturing process and a much longer lifespan. This alone greatly reduces the cost of using molds.
(2) Material utilization
The weight of the flange forging is 0.61kg, and the weight of the original process cutting is 1.46kg, with a yield of only 42%. After adopting the new process, the cutting weight is only 0.63kg, and the material yield reaches 97%, 2.3 times that of the original process. Each flange can save 0.83kg of material.
(3) Fibrous tissue
The metal fiber structure of the flange made by the original process is cut off; The fiber structure of the flange made by the new process remains intact (Figure 4). In this way, its mechanical properties are better than the actual process.
(4) In terms of surface quality
During hot stamping, due to the maximum stress on the periphery of the flange and the minimum stress in the middle, after stamping, there will be defects such as the periphery tilting upwards and the middle slightly concave downwards. Finally, leveling must be carried out. And its tire die forging is closed forging, as long as the mold size is well matched, there are almost no burrs, and the surface is very flat. Therefore, the surface quality is quite good after applying the new process.
Figure.4 After flange hot stamping: (a) After forging;(b) Schematic diagram of fiber organization.
In summary, the flange tire forging process has the advantages of saving materials, saving molds, improving surface quality and internal quality, and it is worth learning from peers.
Author: Wang Minyi
Source: China Forged Flanges Manufacturer – Yaang Pipe Industry (www.epowermetals.com)