A. Gontarz

Numerical Modeling of Cross — Wedge Rolling of Hollowed Shafts

In this article, the results of numerical calculations and experimental work of the cross‐wedge rolling (CWR) processes of hollowed shafts, realized with mandrels and without them, are presented. The results of numerical calculations for the CWR process of three rolls were also provided. On the basis of the calculations it was stated that the method of forming with the use of three rolls is the most appropriate for forming of hollowed shafts. This because in this process there is no excessive and irremovable ovalization of the normal cut, often observed in the process of rolling with two tools.

Cross rolling of parts with non-circular cross section

The aim of this paper is to present the possibilities of forming by means of cross rolling method (CR) of the parts with cross section different from circular one. In the paper the methodology of profiled tools forming is provided. These tools application allows for obtaining of parts with cross section in the shape of square, hexagon, oval, etc. The correctness of the worked out forming conception was confirmed by the results of numerical calculations and experimental research. Experiments were made in laboratory rolling mill LUW-2, parts from steel C45 type were rolled in hot forming conditions. Uniquely, it was stated that using profiled tools, parts in the form of stepped axles and shafts which have steps of non – circular cross section can be formed with satisfactory precision. The application in industrial conditions of profiled tools will allow for enlarging scope of CR technological possibilities and decreasing of material consumption.

Forming of flat parts with ribs from magnesium alloy

Purpose – The purpose of this research is working out of a new forming technology of flat parts with ribs from magnesium alloys with the application of a three-slide forging press (TSFP) for the aircraft industry. Design/methodology/approach – New possibilities of forming aviation parts with ribs gives the application of a prototype TSFP. This press consists of three moveable tools and has wider technological possibilities than typical forging machines. It was assumed that this machine (press) application would allow for obtaining ribbed flat forgings from magnesium alloys of good functional and resistance qualities. A characteristic feature of such forgings forming is the working movement of two side tools, which upset the billet in the form of a plate; the result of their action is forming of one or more ribs in the plane central part. It is possible to use the upper punch to form appropriate rib outline. Theoretical research works based on simulations by means of finite element method were conducted fo...

A new technology for producing AZ31 magnesium alloy aircraft brackets with a triangular outline

Purpose This paper aims at working out an innovative technology of aircraft brackets with a rib of a triangular outline manufacturing from magnesium alloy AZ31 based on forging process. Design/methodology/approach Theoretical analysis of the assumed forming process of brackets with a rib of a triangular outline was made on the basis of computer simulations in software Deform 3D, basing on finite-element method. Research works were conducted for a magnesium plate from magnesium AZ31 alloy. Considering calculations, the scope of technological parameters guaranteeing the process proper course and good quality of the product was determined. Theoretical results were verified using a three-slide forging press. Findings The experiment’s results confirmed the effectiveness of the worked-out technology and the rightness of its application at manufacturing of brackets from non-ferrous metals used in the aircraft industry. Practical Implications The main aim of the worked-out method is manufacturing of aircraft brackets from light metals alloys, e.g. magnesium alloys. This technology can be applied for plastic forming of flat parts with ribs of a triangular outline. Manufacturing of aircraft brackets, basing on that worked out by the author’s technology, will allow for the improvement of products’ quality and reduction of their manufacturing costs. Originality/value The originality of this paper is based on the presentation of a new, innovative manufacturing technology of brackets with a rib of a triangular outline. The presented method is a unique one at a national (Poland) and global scale, and its assumptions underwent patent protection.

THE FORMING OF MAGNESIUM ALLOY FORGINGS FOR AIRCRAFT AND AUTOMOTIVE APPLICATIONS

The paper presents the theoretical and technological aspects of forming magnesium alloy parts for aircraft and automotive applications. The main applications of magnesium alloys in the aircraft and automotive industries are discussed. In addition, the forging technology for magnesium alloys is generally described, with a particular emphasis on wrought alloys. A brief outline of the state of the art in the forging of magnesium alloys is given based on a survey of the specialist literature and the results of previous research by the authors.

A new method for producing magnesium alloy twin-rib aircraft brackets

Purpose – The purpose of the present paper is to develop a new technology for producing magnesium alloy twin-rib aircraft brackets by the forging method. Design/methodology/approach – An overall description of magnesium alloys is given, with particular emphasis placed on magnesium wrought alloys that are used in the aircraft industry. Methods for producing ribbed brackets are discussed and the location of these parts in aircraft structure is described. The forging process for producing AZ31 magnesium alloy twin-rib brackets was modelled numerically, and selected results of the simulations performed are presented. The simulation results were then verified under laboratory conditions using a three-slide forging press equipped with three movable working tools. It was assumed that the use of this machine would allow for obtaining twin-rib aircraft brackets with improved both functional and strength properties compared to the production methods used so far. Findings – The results demonstrate that the method de...

Theoretical and Experimental Research on a Method for Producing a Triangular Rosette-Shaped Flange

The paper presents a new method for forming a hollow shaft with a triangular rosette-shaped flange on its end. The part being investigated is used as a propeller shaft in helicopters. The product must be monolithic, therefore it cannot be produced by methods which consist in joining a flange with a tube. Up till now, such shafts have been produced by machining from solid barstock, the process which generates material losses exceeding 90%. The application of the proposed flanging method results in a significant reduction in both material and labour consumption, which leads to lower production costs. Due to beneficial texture of the shaft flange, shafts produced by this method exhibit better strength properties than shafts produced by machining. The paper presents the results of a numerical analysis of the flanging process, performed using DEFORM-3D software. Also, experimental tests were conducted using a three-slide forging press. Theoretical and experimental results obtained confirm the effectiveness of the new method for forming this part.

GEOMETRICAL PHENOMENA IN TUBE BENDING WITH LOCAL INDUCTION HEATING

A theoretical and experimental analysis of heat induction bending for tubes used in the power industry is performed. First, the design of the heat induction bending process for tubes is described and industrial application areas for this technology are presented. Next, the main methods for tube bending with local induction heating are discussed and the effect of the technology on geometrical parameters of bends formed is presented. Then, the heat induction bending process for tubes is modeled using numerical techniques (FEM). The simulations are performed in a three-dimensional strain state, where thermal phenomena are taken into account, using the commercial software package Simufact Forming v. 11.0. In the simulations, the changes in workpiece geometry in the region of the bend being made (cross section ovalization, darkening and thickening of walls, neutral axis position) are examined. Also, potential phenomena that could limit the stability of the bending process and cause shape defects are predicted. The results of the numerical modeling are then compared to those obtained under industrial conditions.

A study of a new screw press forging process for producing aircraft drop forgings made of magnesium alloy AZ61A

Purpose The aim of this study was to develop a die forging process for producing aircraft components made of magnesium alloy AZ61A using a screw press. Design/methodology/approach The proposed forging technique was developed based on the results of numerical and experimental research. The required forging temperature was determined by upsetting cylindrical specimens on a screw press in order to examine both plasticity of the alloy and quality of its microstructure. The next stage involved performing numerical simulations of the designed forging processes for producing forgings of a door handle and a bracket, both made of magnesium alloy AZ61A. The numerical modelling was performed using the finite element method-based on simulation programme, Deform 3D. The numerical results revealed that the forgings are free from material overheating and shape defects. In addition to this, the results also helped determine the regions which are most prone to cracking. The final stage of the research involved performing ...

New Method for Forming Brackets with a Triangular Rib

This paper presents the experimental research results concerning a new method of forming of brackets with a triangular rib. The forging process of products with ribs was conducted applying a three-slide forging press (TSFP) on material model in the form of lead plates. During the experiment, the influence of the process particular parameters on the obtained products quality was analyzed. On the basis of the research results the main failure modes of the material during processing were determined. The limiting value of the plate upsetting coefficient depending on its length was given. Considering conducted research works, it was stated that it is possible to form such brackets forgings in TSFP in accordance with the worked out method.