1、 Forged aluminum alloy oil seal folding
Oil seal folding is a kind of forming defect encountered during the commissioning of oil seal flange crankshaft, including closing and incomplete closing. Its composition mechanism is mainly to form local shape at the initial stage of forming, and then because of the large axial movement, the local shape formed has obvious axial deviation. Folding defects occur in the supplementary process at the late stage of molding.
The pre forging forming process can change the pre forging shape of forged aluminum alloy here, weaken the steps, coordinate the forming application rate of back-end data, and deal with folding defects. In the forming process without pre forging, these problems can be solved by appropriately extending the local blank length of the rear end. In mass consumption, attention should also be paid to the positioning of blanks to avoid one end of these problems.
2、 Forged aluminum alloy connecting rod journal folding
The folding of connecting rod journal is a common forming defect in the direct and final forging process of die forging hammer. It is generated on the upper part of the mold surface inside the opening gear. The shape is horizontal one word or eight word, and there are also vertical one word or non overlapping groove shapes. In the forming process of forging compressor, these defects rarely occur due to the pre forging step. When the pre forging is opened and stored, and the material separation structure is unreasonable, the final forging will produce vertical slot or non overlapping groove defects.
As for the die forging hammer process, the main reason for the folding of the connecting rod journal is that there is no pre forging step. When the crankshaft die forging starts to deform, the protrusion of the die is first formed at the opening of the connecting rod journal, and the blank will form a concave shape. Then, the pit is offset horizontally, and the metal backflow of adjacent parts fills the unfilled pit. When the pit is obvious, a fold is formed at this pit. The processing method is to control the striking weight at different forming stages, but the operation requirements are high, or form a large round corner at the protruding local corners at the opening of the mold connecting rod neck, and increase the thickness of the connecting skin at the opening to improve the metal activity. The latter is a commonly used method. Due to the existence of pre forging steps, the crankshaft consumed by the forging press usually does not produce such defects, but when the pre forging structure and parameters are unreasonable, grooves or fold lines will be generated. Generally, the stored connecting skin is too thick or the thickness difference between the upper and lower connecting skin is too large. In the final forging process, it is easy to correct the causes of excessive deviation or dislocation of upper and lower blanks.
3、 Wrought aluminum alloy burr pressing folding
Folding formed by pressing the high vertical burr into the forging body after subsequent correction. The crankshaft formed by twisting is more prone to such folding during the straightening process. After trimming, the burr on the parting surface turns to the upper and lower die grooves of the correction die after twisting. After thermal correction, long burrs are pressed into the forging body to form folds. Timely replace or repair the aging trimming die to prevent pulling out high vertical burrs and prevent such defects.
4、 Folding of parting surface of forged aluminum alloy equalizing block
For the forging that is not fully formed, the folding of the deepening forging body has been generated on the parting surface of the balance block, and the residual local folding of the local forging body will be in the process of fully forming. The main reason is that the blank size is small. For the easily formed crankshaft, although the blank size is small, it can be completely overflowed for forming, but it is easy to produce the folding fold of the balancing block parting surface. Micro folding can increase the angle of adjacent dies to stop improvement. Deep folding can be designed through the pre forging structure. Without the pre forging process, the blank size is often increased or the semi closed process may be used.