Production of a hollow cylinder with a bottom and at least one external protrusion extending over its entire length involves machining, heating and descaling of the blank before it is reverse-extruded by punch and die

摘要

An ingot segment is machined to required dimensions, heated to a forming temperature and descaled by high-pressure water jets. The resultant work-piece is placed into a die (6), and is reverse-extruded by means of a punch (7) to produce a cylinder (8) with a bottom (10) and external protrusions (9.1, 9.2). After the cylinder is ejected from the die, it cooled, descaled and finally completed by machining. Preferred Features: A first section of the ingot is machined to produce a cylindrical form, while a second section is machined to produce a conical form which converges towards the end of the ingot. Both sections are of the same length forming one half of the blank subjected to a reverse-extrusion process. Machining of the blank takes the form of turning with a surface roughness value Rz less than or equal to 80. The final length of the cylinder equals 1.5-2.5 the initial length of the blank. After ejection of the cylinder, the die (6) and the punch (7) are rapidly cooled down to their initial temperature. The lubricating agent used on the die and punch is mixture of glass powder and pure graphite in the ratio of 1:1 diluted by soluble glass (silicate of sodium). After ejection of the cylinder from the die, and before its descaling, it is subjected to heat treatment.