Preforging design of circular mechanical forgings related principles

Preforging design of circular mechanical forgings related principles
In this paper, we briefly describe the pre-forging design principles of circular mechanical forgings, with specific reference as follows:

(1) For such forgings, the volume distribution of each part of the pre-forging should be strictly controlled, so that the excess metal can flow reasonably in the mold cavity, and the folding and reflux of the excess metal can be avoided. If the cross section of the final forging is circular, the cross section of the neck forging should be designed to be oval, and the ellipticity should be 4%-5% of the cross section diameter of the corresponding final forging.

In order to make the pre-forging easy to put into the final forging cavity, the internal size of the pre-forging is about 0.5 mm, and the external size is 0.5 to 1.0 mm smaller than the final forging. For the transition part from the spoke to the rim, although the part is internal, the pre-forged size is 0.5 to 2mm smaller than the final forged size. When the spoke is thin and the thickness difference between the spoke and the rim is more than twice, special attention should be paid to this principle to prevent cracks and folding defects. For stamped connection forgings with preforgings, when the larger connection thickness of the preforgings is 1.5 to 2 times that of the terminal mechanical forgings, that is, when Spre=(1.5 to 2)s final, the radius of the connection fillet is 5 to 30 mm, and the value can be calculated according to the larger connection thickness.

(2) spoke thickness size: pre-forging and final forging size equal or slightly smaller, generally 0.5~1 mm difference...

(3) Hub parts: the volume of the pre-forged hub is 1%-6% larger than the volume of the terminal forged hub. If the spokes are thin and wide, the design should adopt a smaller value of 1%.

(4) Height direction: the pre-forging size should be 2~6mm larger than the final forging size. The depth of the pre-forging hole is less than the depth of the final forging hole, but the range should not exceed 5~6mm. Otherwise, during the final forging process of mechanical forgings, a large amount of excess metal in the inner hole will flow radially, resulting in backflow and folding defects. If the aperture is large, the pre-forging should be designed to connect the skin and the warehouse to accommodate excess flowing metal and skin. Through the above feature design points, we can apply "forging feature based pre-forging design" to design the driven gear's pre-forging reasonably.

This is a continuous heat treatment furnace of Tong Xin Precision Forging Co., LTD