Janina Adamus

Stamping of Titanium Sheets

In this paper, some technological problems (e.g. low drawability, high susceptibility to galling, spring-back) occurring in the sheet-titanium forming process are discussed. A numerical simulation of the stamping process was carried out with the Adina System v.8.3 based on the finite element method. The effects of friction, the holding-down force and tool geometry on the course of the stamping process were analysed. The mechanical and technological material data needed for the calculations were determined experimentally. The friction coefficients for the frictional pair: ”titanium – tool steel” for different lubricants and antiadhesive layers determined in the “strip drawing” test were found. The role played by lubrication and antiadhesive layers in preventing titanium “build-ups” on the tools is presented. The calculated results were then confirmed experimentally.

Possibility of the Increase in Titanium Sheets' Drawability

Forming of titanium sheets, especially titanium alloy sheets, is very difficult due to low drawability caused by a high ratio of the yield point to the tensile strength Re/Rm, usually more than 90%. Although drawability of titanium sheets can be enhanced by forming at elevated temperatures it is avoided due to the high costs and difficulties associated with the operation of the process. Therefore the authors have developed an unconventional stamping method allowing for forming of almost unworkable materials at ambient temperature, such as Ti6Al4V titanium alloy. The paper presents both numerical simulation and experimental results of the stamping process using a device specially designed for this purpose.

The Influence of Cutting Methods on the Cut-Surface Quality of Titanium Sheets

In this paper, the influence of the cutting method on the cut-surface quality is analysed. A WT1-0 titanium sheet was cut in three different ways: using a guillotine, a laser and an abrasivewaterjet. The cut-surface’s appearance, microstructure, microhardness and the roughness of the cutsurface were tested. Moreover, a numerical simulation of the banking process of a titanium disk was carried out with the ADINA System v.8.3 based on the finite element method. The influence of the radius of the cutting edge and the clearance on the surface quality was analysed.

Analysis of Tensile Test of Titanium EBW Sheet

The continuous pursuit of vehicle weight reduction forces the industry to look for alternative materials to steel. Light alloys such as aluminium or titanium are materials that provide a decrease in weight using conventional technologies. Additional weight reduction results from using tailor-welded blanks (TWB). While the joining and forming steel or even aluminium TWBs is quite well known and described in the technical literature, joining and forming titanium TWBs still poses a significant problem. In the paper, experimental tests carried out with welded samples manufactured from commercially pure titanium Gr 2 and titanium alloy Gr 5 sheets are presented. The samples were joined by electron beam welding. Mechanical testing and optical microscopy were used to characterise the welds and the base metal of the samples. The samples were subjected to uniaxial tension up to final failure. The 3‑D Digital Image Correlation system ARAMIS was used for monitoring the whole deformation process. This makes it possible for real-time observation of sample deformation. The test results and the numerical analysis of the tensile tests are compared. The numerical simulations were carried out with the ADINA System based on the Finite Element Method (FEM). The mechanical analysis leads to calculation of the strain state after sample deformation in uniaxial tension (mechanical model).

Analysis of SCM Sill Beam Reinforced with Steel or Titanium Profile

Minimization of the demand for energy which is needed to heat a building is an important issue of a sustainable development policy, therefore mutual exchange of heat between the interior of the building and its external environment through a window as well as its mounting parts is one of the most important issues of energy calculations.In the paper, the SCM (Quick Warm Mounting) sill beam used as a support for a window installed in a thermal insulation layer is analyzed. Due to the fact that titanium has a more favorable specific strength, lower coefficient of thermal conductivity and much higher resistance to corrosion than steel, the currently used steel reinforcement of the SCM beam was replaced by a titanium one. Numerical calculations were performed using the ADINA System, which is based on the finite element method (FEM). The process of heat exchange between the interior with the constant temperature of 20°C and the external environment with the constant temperature of -20°C is analysed. The temperature distribution in the wall, the dew point temperature as well as corrosion and economical aspects associated with the use of titanium profiles are discussed.

Modelling of Fine Blanking Process of the Aluminium Sheets

The required technological quality of the blanked products can be achieved through operations of fine blanking. This allows for obtaining products with improved dimensional accuracy and good quality cut-surface. In order to cut products from soft materials, including aluminium and its alloys, the methods of fine blanking with upsetting and fine blanking with reduced clearance are typically employed. The study presents the results of numerical modelling of the fine blanking process for a disk made of 1-millimetre sheet aluminium EN AW-1070A. The goal of the numerical simulations was to evaluate the effect of clearance between blanking die and the punch, and the impact of V-ring indenter on stress and strain distribution in the shearing zone.

Numerical Simulation of Forming Titanium Thin-wall Panels with Stiffeners

Due to the increase in the application of titanium components made of thin titanium sheets, in the work titanium panels made of 4 mm thick sheets are analysed. To increase the rigidity of the panels, some cross-shaped stiffeners were made. Such panels enable a reduction in weight while maintaining the existing strength of the drawn parts. Three kinds of commercially pure titanium are considered: Grade 1, 2 and 3. Numerical calculations were performed with PamStamp 2G based on the finite element method. The basic mechanical and technological properties of the analysed sheets, which are necessary for numerical modelling, were determined by static tensile testing. The friction coefficient was assumed based on the literature. On the basis of the performed numerical analyses, it was stated that the proper forming of panels with stiffeners depends not only on the drawability of the sheets but also on the technological parameters such as blank holder force and frictional conditions.

Lubricants Based on Vegetable Oils as Effective Lubricating Agents in Sheet-Titanium Forming

Sheet metal forming processes allow for production of lightweight and durable goods. For this reason, drawing operations have been widely used across the automotive, aviation and construction industries and for production of various components of machines. Despite the popularity of deep-drawing steel sheet metal, non-ferrous materials, such as aluminium, magnesium and titanium are also used for such purposes. Titanium materials seem to be particularly attractive due to a beneficial ratio of strength to density and excellent corrosion resistance in the most of technological environments. However, titanium and its alloys belong to a group of materials with low tribological properties and tendencies for galling and build-up of layers of the deformed material on the tool surface. Therefore, this study will discuss the results of the investigations concerning selection of technological lubricants based on vegetable oils used for the operation of forming of sheet metal made of commercially pure titanium (Grade 2). The focus of the experiment is on lubricants based on vegetable oils i.e. rapeseed oil, sunflower oil and olive oil. The main lubricating additive was boric acid and stearic acid. The study presents the results of the determination of friction coefficient during a strip drawing test.