Aspects of the piercing of shells made of hypereutectoid silumins on a universal 20–60 rotary rolling mill

Abstract

The world’s first technology has been introduced for piecing hollows (tubes) of hard-to-deform hypereutectic silumin alloys (01390 and 01392). The tubes have the dimensions 80 mm diameter × 13.5 mm wall thickness and 74 mm diameter × 15 mm wall thickness. The are obtained on universal rotary rolling mill 20–60. The technology was developed by modeling the rotary rolling operation, studying the rheological properties of hypereutectic alloys, finding scientifically sound parameters (rolling scheme, feed angles, temperature-speed parameters) for an intermediate rotary-rolling operation performed to obtain bars with a crystalline structure and ductility properties 3–4 times better than those of the initial ingots, and the developing and introducing a piercing process that employs special spherical mandrels with a conical nose.