EFFICIENT NEAR NET SHAPE PRECISION FORMING METHOD OF HOLLOW VALVE BLANK FOR ENGINE

摘要

Disclosed is an efficient near net shape precision forming method of a hollow valve blank for an engine. Cross wedge rolling precision blank forming is realized via a cross wedge rolling die (1), a valve metal pipe material (3) deforms under the rolling action of the cross wedge rolling die (1) to be recessed in the middle and elongated at two ends, a rod portion (41) of a hollow valve is formed in the middle, plate portions (44 and 45) to be processed are formed at two ends, connecting segments between the plate portions (44 and 45) and the rod portion (41) form necks (42 and 43) with arc-shaped concave faces and cone frustum side face structures, and thus the consistency of the shape and size of the obtained hollow valve blank is good; and a die forging forming die (2) matching the structure of the prepared hollow valve plate portion is utilized to process the plate portions of the obtained hollow valve blank preform, and the hollow valve blank preform is directly put in a cavity of the die forging forming die to be forged, so that the rod portion, the necks and the plate portions of the prepared hollow valve are rational in overall streamline distribution, and the texture is fine, thereby meeting the performance requirements, avoiding material waste, and increasing the production efficiency and material utilization.