Wyniki wyszukiwania - BazTech

1

Finite element analysis of material deformation behaviour during DRECE: the sheet metal SPD process

Tkocz Marek, Kowalczyk Karolina, Bulzak Tomasz, Jabłońska Magdalena B., Hawryluk Marek

Archives of Civil and Mechanical Engineering

|

2023

|

Vol. 23, no. 3

art. no. e145, 2023

EN

The material deformation behaviour during the innovative SPD process called DRECE (Dual Rolls Equal Channel Extrusion) has been analysed by FEM simulations. In the process, a workpiece in the form of a strip is subjected to plastic deformation by passing through the angular channel; however, the workpiece dimensions remain the same after a pass is finished. Performing consecutive passes allow for increasing the effective strain in the material to a required level. In the conducted simulations two various channel angles (108° and 113°) have been taken into consideration, as well as two processing routes, A and C (without and with turning the strip upside-down between consecutive passes, respectively). The analysis of simulation results has revealed that significant strain and stress inhomogeneities across the strip thickness are generated in a single DRECE pass. The die design (the inner and outer corner radius) and friction conditions affect the material flow, reducing significantly the shear strain in the near-surface regions of the strip. The strain inhomogeneity can be effectively reduced by choosing the processing route C. The strain distributions and the corresponding tensile test results have confirmed that the smaller channel die angle allows to generate larger strain and higher strength of the strip but also reduces its ductility more than the die setup with the larger channel die angle.

2

Weldability of carbon steel processed by multiple plastic deformation

Ochodek V., Boxan P.

Archives of Materials Science and Engineering

|

2014

|

Vol. 69, nr 2

88--93

EN

Purpose: The paper is focused on experimental verification of weldability of high-carbon steel C55E processed by the SPD DRECE (Dual Rolling Equal Channel Extrusion) process. Design/methodology/approach: A test of basic mechanical properties, metallographic examination and an analysis of residual stresses were performed on these joints. Findings: Acquired results show that the choice of an appropriate technology and the optimization of welding parameters allow to achieve solid welds even in the case of materials rather difficult to weld. The optimized welding process does not significantly degrade the properties acquired by SPD. Research limitations/implications: Mastering a proper coupling technology, welding materials after plastic deformation in particular, is one of key parameters for a successful application of given materials in technical practice. Within experimental works, test welded joints were made from the C55E steel with the use of 141-GTAW pulse welding technologies. Originality/value: The methods of intensive plastic deformation SPD (Severe Plastic Deformation) belong to a group of very attractive means of increasing utility properties of metallic materials (strength and structural characteristics).

3

New type of device for achievement of grain refinement in metal strip

Rusz S., Cizek L., Michenka V., Dutkiewicz J., Salajka M., Hilser O., Tylsar S., Kedron J., Klos M.

Archives of Materials Science and Engineering

|

2014

|

Vol. 69, nr 1

38--44

EN

Purpose: The main goal of the paper is a review of current achieved results obtained by processing of Cu based materials by DRECE technology, the prototype equipment of which was put in service towards the end of 2008 at the Department of mechanical technology, Faculty of Mechanical Engineering, VSB - Technical University of Ostrava. Design/methodology/approach: Device „DRECE - Dual Rolls Equal Channel Extrusion” (dual rolls pressure combined with equal channel extrusion) is used for production of metallic materials with very fine grain size (hereinafter referred to as UFG structure - Ultrafine Grain Size). Findings: The results reached after heat treatment show the necessity of next experiments with changing conditions of heat treatment parameters. Research limitations/implications: This method is used for various types of metallic materials, non-ferrous metals and their alloys. Forming process is based on extrusion technology with zero reduction of thickness of the sheet metal with the ultimate aim - achieving a high degree of deformation in the formed material. The DRECE device is also being verified from the viewpoint of achievement of a UFG structure in a blank of circular cross-section (wire) with diameter of ø 7 mm × 1000 mm (length).Originality/value: Article shows new type of device for achievement of grain refinement in metal strip.

4

Evaluation of the deep-drawing steel sheets processed by DRECE device

Hilser O., Rusz S., Salajka M., Cizek L.

Archives of Materials Science and Engineering

|

2014

|

Vol. 68, nr 1

31--35

EN

Purpose: The article describes a new developed method for producing fine-grained materials, such as DRECE (DRECE, Dual Rolling Equal Channel Extrusion). Design/methodology/approach: The process of forming of material using the DRECE technique is based on making use of the material’s intensive plastic deformation, i.e. that process is a combination of two known technologies, ECAP and CONFORM. Findings: The article presents the results of both exams, including photographs of cracks. Mechanical properties of the steel grade11 321 before and after extrusion by DRECE tool are described as well. Research limitations/implications: The article describes the process of forming of metal sheets made of steel grade 11 321. It further describes two methods for detection of deep drawing - Erichsen and Fukui. Originality/value: The article describes the process of forming of metal sheets made of steel grade11 321. It further describes two methods for detection of deep drawing - Erichsen and Fukui. These methods were applied to the extruded metal sheet by DRECE tools.