Design of different types of forging parts

I. Final forging design:


The final forgings are the basis of the design of preforgings and blanks. The final forging room mainly refers to the hot forging drawing for design, manufacture and inspection. Two aspects should be considered in the design of the final forging:



1. Thermal shrinkage rate:



For low alloy steel and low carbon steel in the hot die forging process, the heat shrinkage of all dimensions on the hot forging drawing is usually 15, take 1.5%. However, for long, thin bars and forgings with more die forging steps, the shrinkage can be 1.2%-1.6%. However, for non-ferrous metals, the shrinkage rate can be set at 0.8%-1.2%. For the same forging, the thermal shrinkage is different due to the different structural shape.



2. Flyside design:



The shape and dimensions of the final forging drawings correspond to those of the cold forging drawings. The local dimensions of the cold forgings can be trimmed according to the die forging conditions and a suitable fly-edge type can be selected.



2. Basis for the design of billet parts and the selection of work steps:



The blank manufacturing design of long shaft die forging parts is mainly determined according to the calculated blank drawing, including the calculation of the blank section and the blank diameter. The main idea is: if the blank is deformed, the metal flow will not change in the length direction, the plane deformation will occur in the plane in the height and width direction, and the blank cross-sectional area along the axis is equal to the sum of the forging cross-sectional area and the blank area in the corresponding length direction, the blank is calculated as the ideal blank. The main functions of calculating blank drawing are:



(1) The volume and mass of the blank can be calculated according to the blank section diagram;



(2) It is possible to rationally choose the manufacturing steps of long-shaft forgings;



(3) It provides a reasonable design basis for making damaged groove.



For the selection of long shaft forging blank manufacturing step, the initial parameter is determined: 1 ratio α=Dmax/d average value. If the proportion is large, the preparation steps with high aggregate effect should be selected. 2. The ratio β=L m/day is the average. If the ratio is large, the billet preparation steps with high drawing efficiency should be selected. 3. Taper k= (dk-d smaller value) /l rod. If the value of K is large, the horizontal component acting on the metal in the cavity will increase correspondingly. 4. The forging quality is g forging. If the G forging is large, it indicates an increase in the volume of metal flowing through the die hole. According to these four factors (aβ, K.G forging), the blank manufacturing process of long shaft forging can be determined.



Forging raw materials with the same cross section into calculated rough shapes with different cross sections requires more reasonable damage manufacturing steps before the excess metal in the rod can be transferred to the large cross section. And refer to the relevant chart to choose the appropriate blank production steps. In addition, we should choose the best blank manufacturing process according to the actual production situation.