Reduction of Induced Central Damage in Cold Extrusion of Dual-Phase Steel DP800 Using Double-Pass Dies

Abstract

Advanced High Strength Steels (AHSS) are a promising family of materials for applications where a high strength-to-weight ratio is required. Central burst is a typical defect commonly found in parts formed by extrusion and it can be a serious problem for the in-service performance of the extrudate. The finite element method is a very useful tool to predict this type of internal defect. In this work, the software DEFORM-F2 has been used to choose the best configurations of multiple-pass dies, proposed as an alternative to single-pass extrusions in order to minimize the central damage that can lead to central burst in extruded parts of AHSS, particularly, the dual-phase steel DP800. It has been demonstrated that some geometrical configurations in double-pass dies lead to a minimum value of the central damage, much lower than the one obtained in single-pass extrusion. As a general rule, the position of the minimum damage leads to choosing higher values of the contacting length between partial reductions (L) for high die semiangles (α) and to lower values of the reduction in the first pass (R A ) for low total reductions (R T ). This methodology could be extended to find the best configurations for other outstanding materials.

Revisiting Formability and Failure of AISI304 Sheets in SPIF: Experimental Approach and Numerical Validation

“…Is it a powerful numerical tool that has been mainly used recently for modelling manufacturing processes such as cutting [19] and bulk forming of metals [20], but it has been also used for simulating sheet metal-forming processes [21,22].…”

Guidelines for Selecting Plugs Used in Thin-Walled Tube Drawing Processes of Metallic Alloys

“…The finite element software used in this analysis is DEFORM (Scientific Forming Technologies Corporation, v11.0, Columbus, OH, USA) [42]. This program is a specific purpose code that is especially designed to simulate both bulk [43] and sheet metal forming processes [44]. The design of the tools (die and mandrel) has been previously developed in AutoCAD (Autodesk Developer Network, 2013, San Rafael, CA, USA) and subsequently imported into DEFORM™-F2.…”

The Prediction of the Mechanical Properties for Dual-Phase High Strength Steel Grades Based on Microstructure Characteristics

“…To meet the oftentimes contradictory demands of the automotive industry on the utility properties, the steel industry is constantly developing new concepts of high-strength steel grades (DP-dual phase steel, CP-complex phase steel, TRIP-transformation induced plasticity steel, TWIP-twining induced plasticity steel, and so forth). It appears that thanks to a wide variety of combinations of strength, plasticity properties (yield strength R p0.2 = 280-700 MPa, ultimate tensile strength R m = 600-1000 MPa, ductility A = 12-34%, strain-hardening exponent n = 0.09-0.21, and normal anisotropy ratio r = 0.9-1), and cost from all the known high-strength steel sheets used in the construction of motor vehicles, dual phase steel grades take the largest share [6,7].…”