The method of cross-wedge rolling allows producing articles from billets that have round, hexahedral or square section and also from tube. As a result of cross-wedge rolling initial profile is transformed into round profile.
By cross-wedge rolling it is possible to obtain the articles, which contain round section elements such as cylinders, cones and spheres, rectangular section such as flats and also tread segments. Separate elements of initial billet section may be preserved in them in the shape of a square or hexahedron.
The most widespread examples of such parts are 1. ball, 2. ball pin, 3. axle, 4. screw spike, 5. fishplate bolt.
Using the method of cross-wedge rolling it is possible to manufacture articles from structural steels, separate grades of tool and high-alloy steels, aluminium, brass, copper, titanium.
Metal utilization ratio during cross-wedge rolling is 70-97%, which, as a rule, is higher than by forging, foundry and cutting.
One of the advantages of the cross-wedge rolling process is high accuracy level of the parts, as compared to other hot deformation processes. The modern level of equipment and technology development allows to reach the accuracy of the diametral dimensions of the part at the H8 level, including tread elements. An example of such part is production of Spindle part..
Surface roughness of the part, which arises as a result of cross-wedge rolling, mostly depends on surface roughness of the die, shape and riffling size of the deforming edge of the die, material ductility of the part, temperature of deformation.
Surface roughness at the level of Ra = 0,35 - 0,65 is reached for the parts from ductile material, such as brass. For the parts from steel, during hot rolling, surface roughness is reached at the level of Ra = 1,5 – 2,5.
As a result of cross-wedge rolling the new macrostructure is formed in the part. The material fibres are continuous, axially symmetrical and compressed to the surface. Such macrostructure allows to increase operating characteristics of the parts, especially fatigue resistance.
MAIN APPLICATION AREAS OF THE CROSS-WEDGE ROLLING
Manufacturing of the preforms for further forging allows to increase material utilization ratio and capacity.
The most widespread example of cross-wedge rolling application for further forging is the manufacturing of the part “connecting rod”.
High accuracy level reached in the process of cross-wedge rolling allows to manufacture preforms for further forging with minimal fin or with no fin at all.
Manufacturing of the preforms for further fine turning allows to increase material utilization ratio and to decrease manufacturing content of the final item.
Manufacturing of the preforms for further smooth finishing allows to decrease manufacturing content of the final item.
Manufacturing of the completed products or preforms, which do not need further surface processing.
Cutter body is an example of such item, where required level of accuracy and roughness is provided by wedge rolling.