Forged aluminum alloy folding is a defect formed by the accumulation of oxidized surface metals in the process of metal deformation. After the oxide skin is cleared, ordinary folds can be identified with the naked eye. For folds that are not easy to detect with the naked eye, magnetic particle inspection or penetrant inspection can be used for inspection. When the fold is shallow, the grinding workload is increased, and when the fold is deep, the scrapping of the forging is formed.

1. Folding forged aluminum alloy oil seal

Folding of the oil seal is a forming defect encountered in the debugging of the crankshaft with the oil seal flange, and there are two forms of closed and incomplete closed. Its structure mechanism is mainly that the local shape is formed in the early stage of forming, and the subsequent forming has a large axial movement, so that the formed local shape has a significant axial deviation. Overfeeding at the later stage of forming produces folding defects.

The pre-forging forming process can change the shape of the forged aluminum alloy pre-forging here, weaken the steps, and can coordinate the material forming application rate at the back end and deal with folding defects. In the forming process without pre-forging, such problems can be solved by properly lengthening the local billet length at the rear end. Pay attention to the positioning of the blanks when mass production, so as to avoid such problems caused by tending to one end.

2. Forged aluminum alloy connecting rod neck folding

The pin fold is a common forming defect in the direct final forging process of the die forging hammer. It occurs in the upper part of the parting surface inside the opening. The shape is horizontal "one" or "eight", and there are also vertical "one" or non-overlapping grooves. In the forming process of the forging press, due to the pre-forging step, there are few such defects. When the pre-forging open file storage and material distribution structure is unreasonable, the longitudinal "one" word or no gap will be generated during the final forging. Coincident groove defects.

Regarding the die forging hammer process, the main reason for the collapse of the connecting rod neck is that there is no pre-forging step. When the crankshaft is initially deformed, the protruding part of the mold at the opening of the connecting rod neck is formed first, and the blank will form the shape of the pit. Then the pit is shifted laterally, and finally the metal in the adjacent part reflows to fill the unfilled pit. When the pit is obvious, a fold is finally formed at the pit. The treatment method is to control the severity of the blows in different forming stages, but the operation requirements are higher, or make larger rounded corners at the protruding local edges and corners of the connecting rod neck of the mold at the opening, and increase the opening at the opening. Thickness of the skin to improve the movement of the metal, the latter is a commonly used treatment. The crankshaft produced by the forging press usually does not have such defects due to the existence of pre-forging steps, but when the pre-forging structure and parameters are unreasonable, grooves or creases will occur. Too thick or the thickness difference between the upper and lower skins is too large. During the final forging, the billet in this part deviates too much or the upper and lower parts of the billet move up and down. Regarding the die forging process of the forging press, such defects only need to be corrected for the reasons. The mold is easy to handle.

3. Folding of forged aluminum alloy burrs pressed into

The higher longitudinal burr pulled out by the trimming is subsequently corrected and pressed into the fold formed by the body of the forging. The crankshaft formed by twisting is more likely to show such folds during correction. The burr at the level of the parting surface after trimming is twisted. Then turn to the position in the groove of the upper and lower dies of the calibration die, and the longer burrs are pressed into the forging body after thermal calibration to form a fold. Such defects can be prevented by timely replacement or repair of the aging cutting edge die to prevent pulling out higher longitudinal burrs.

Four, forged aluminum alloy balance block parting surface folding

For the incompletely formed forgings, the parting surface of the equalizer block has produced folds that deepen the forging body, and there will be partial folds remaining on the forging body after complete forming. The main reason is that the billet size is too small. For the easy-to-form crankshaft, although the blank size is small, it can be fully formed, but it is easy to produce equalizing block parting surface folds, fine folds can be improved by enlarging the adjacent mold fillets in this part, and deeper folds can be This problem is dealt with by the pre-forging structure's tendentious material distribution design. In the absence of pre-forging process, it is often dealt with by increasing the billet gauge or possibly using a semi-closed process.