Plastic Flow Instability Under Compressive Loading During Shear Spinning Process

Abstract

The sudden appearance of a material bulge beneath the roller during tube spinning operation (referred to as “plastic instability”) is considered experimentally and examined quantitatively via an upper bound analysis. The phenomenon is explained by a sudden transfer of flow from one admissible mode to its competing mode when an external condition (or few conditions) is changed in a certain way to be discussed (e.g., increasing the roller angle of attack, increasing the initial tube thickness, etc.). As a by-product, the interrelation between the dominant variables of the process emerges. The associated formulation with its inherent idealizations enables one to mark the line between favorable and unfavorable working conditions of the spinning process. Experimental evidence demonstrates the utility of the proposed approach.

A Review of Flow Forming Processes and Mechanisms

“…[6] explore the effect of flow forming on steel using Vickers and Rockwell hardness evaluation. They also map the relationship between axial contact and circumferential contact, which are evaluated using the axial on circumferential contact methodology developed by [8]. The microstructure is investigated in order to detect the grade of grain elongation, in comparison with thickness reduction.…”

The journal of materials processing technology 2018

“…Gur and Tirosh (1982) developed the formulation of a planar contact area in each of the primary rolling and extrusion deformation directions in backwards flow forming. Singhal et al (1995) Nomenclaturę the entry angle from workpiece to the roller, also known as the attack angle ( • ) (Fig.…”

Investigation of effective parameters on surface roughness in thermomechanical tube spinning process

“…Hayama [4] analyzed the deformation mechanism and load in tube spinning, based on the observation of experimental metal flow. Tirosh [5] used the upper-bound method in order to analyze the instability of plastic flow under shearing load and extrusion in the tube spinning process. Hasimoto [6] studied experimentally the deformation mechanism of the tube spinning with a model material (plasticine) and particularly inspected the strain distribution using a flow function under the assumption of plane deformation in the circumferential direction.…”