Potential defects of large die forgings

Hammer die forging is a forging production method developed on the basis of free forging and tire die forging. Although hammer die forging has aging characteristics, it still occupies a very important position in the forging industry at home and abroad. This is because compared with other forging equipment, forging hammer has the advantages of wide process adaptability, high production efficiency and low cost of equipment.

The strike energy of the die forging hammer can be adjusted in operation, and can achieve the priority of strike. The blank is hammered by multiple hammers with different energy. After upsetting, flattening, drawing, rolling, bending, clamping, forming, pre-forging and final forging, forgings of various shapes can be formed. Therefore, forging factories (workshops) with a certain scale are equipped with forging hammers of different tonnages.

Surface blistering: Flattened air holes under the skin of the workpiece. When the workpiece is demoulded or heated by heat treatment, the surface will be bubbled up due to thermal expansion. The causes are as follows:

1. There are too many non-burnt and non-volatile coatings in the die, or the exhaust of the die chamber is not good, which makes the gas produced in the pouring immerse into the liquid metal.

2. Extrusion speed is too fast, which causes eddy current when liquid metal fills the mold chamber and coils a large amount of gas.

3. The liquid metal contains too much gas, so the bubbles that precipitate before pressurization can not escape and are flattened under the skin.

Improvement measures:

1. Properly raise the mould temperature and adopt spraying method to make the coating dry before pouring.

2. Pressure should be slow and steady.

3. Pay attention to liquid metal degassing operation;

4. Exhaust measures should be considered in die design.

Forging manufacturer, truck front axle, large die forgings selection Linyi Hongsen Rail Transit Material Co., Ltd.