What are the main characteristics of metal drawn automotive stamping parts in auto parts industry?

2020-02-20 09:59:26

Metal stretch stamping is a kind of forming processing method to produce plastic deformation or separation of sheet, strip, tube and profile by using press and die, so as to obtain the required shape and size of workpiece (stamping part). Stamping and forging belong to plastic processing (or pressure processing), collectively known as forging. The billets for stamping are mainly hot-rolled and cold-rolled steel plates and strips.

Drawing stamping parts are mainly formed by stamping metal or non-metal plates with the help of the pressure of the press through the stamping die. Automobile stamping parts mainly have the following characteristics:

(1) Drawing stamping parts are made by stamping on the premise of little material consumption. The parts are light in weight and good in rigidity. After plastic deformation, the internal structure of metal is improved, and the strength of stamping parts is improved.

(2) In the process of drawing and stamping, because the surface of the material is not damaged, it has better surface quality and smooth appearance, which provides convenient conditions for surface painting, electroplating, phosphating and other surface treatment.

Compared with castings and forgings, drawing stamping parts are thin, uniform, light and strong. Stamping can produce workpieces with stiffeners, ribs, undulations or flanging which are difficult to manufacture by other methods, so as to improve their rigidity. Due to the use of precision die, the precision of workpiece can reach micron level, and the repeat precision is high.

Structural technology of drawing parts:

1. The shape of the drawing part shall be as simple and symmetrical as possible, and it shall be drawn once as much as possible;

2. For the parts that need to be deep drawn for many times, under the premise of ensuring the necessary surface quality, the inner and outer surfaces shall be allowed to have traces that may occur in the process of deep drawing;

3. On the premise of ensuring the assembly requirements, it is allowed that the side wall of the drawing part has a certain slope;

4. The distance from the hole edge on the bottom or flange of the drawing part to the side wall shall be appropriate;

5. The fillet radius of the bottom and wall, flange and wall, and rectangle corner of the deep drawing part shall be appropriate. Take the fillet radius of the bottom and wall of the deep drawing part as 1pr = 1.5mm, mm5.1r2p =, the fillet radius of the flange and wall of the deep drawing part as mm2rd1 =, mm5.1r2d =;

6. For the dimension marking of drawing parts, the vehicle parts shall be marked with the guaranteed external dimension or internal dimension, and the internal and external dimensions cannot be marked at the same time.

For the drawing parts with steps, the dimension of height direction shall be based on the bottom generally. If the above part is based, the height dimension is not easy to guarantee.

Tolerance of drawing parts

The dimensional accuracy of deep drawing parts shall be below T13 and not higher than it11. According to the table, the precision grade of this drawing part is it12 ~ it13, and the blank thickness of the drawing part is t = 0.5mm.

Generally, the wall thickness tolerance of drawing parts should not exceed the variation rule of wall thickness in drawing process.

Material of drawing parts

The materials used for deep drawing are generally required to have good plasticity, low yield ratio, large plate thickness directivity and small plate plane directivity. The material of the parts processed by the drawing die has been determined as 08 steel.