Method to produce a plug chamber for cascade drawing of tubes and device for carrying out the method.

摘要

Use is made of a device (15) with a clamping and denting unit (16) and with an end-expansion and ironing unit (17). A starting tube (1) is first of all fixed locally by means of the clamping and denting unit (16). An ironing ring (30) is then moved along a freely projecting end section (31) of the starting tube (1) with the aid of an ironing cylinder (22) of the end-expansion and ironing unit (17), and a mandrel (26) is then driven into the end section (31) with the aid of a mandrel cylinder (21) of the end-expansion and ironing unit (17). Once the mandrel (26) has reached its end position, in which the inside diameter and the outside diameter of the end section (31) are enlarged, the ironing ring (30) is drawn over the end section (31), the outside diameter being reduced to the original outside diameter of the starting tube (1). Following this, the mandrel (26) too is withdrawn from the end section (31) and two dents are produced on the outer circumference of the end section (31) of the starting tube (1) with the aid of the clamping and denting unit (16). Together with a drawing point produced by forming the free end of the starting tube (1), these dents form a plug chamber into which are embedded a plurality of drawing plugs that interact with drawing dies during the cascade drawing.