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The influence of laser beam welding parameters (power, welding rate, focusing, head oscillation, shielding gas) on the microstructure, mechanical properties and corrosion resistance of the super-duplex stainless steel SAF 2507 was studied in this paper. The presented results clearly report the effects of welding parameter changes on the character of the steel's microstructure. The presence of secondary phase M2N in weld metals has an important influence on their mechanical properties. Optimal mechanical properties, an acceptable ferrite/austenite ratio, and the minimum content of M2N nitride required in the weld metal were acquired in the case the following application: 1100 W power, welding speed of 10 mm/s, focusing of 4 mm, and pure nitrogen shielding gas (20 L/min). [ABSTRACT FROM AUTHOR]

This paper deals with the deformation of precision seamless tubes during the cold drawing process, using Finite Element Methods. The value of strain obtain by stereology measurement of degree grain boundaries deformation are compared with simulation result for each drawing pass. The material chosen was the E235 and E355 steel grade, which is drawn from the initial dimension of Φ 70 × 6.3 mm to the final dimension of Φ 50 × 3.75 mm by two passes. FEM Software DEFORM 2D with the Lagrangian method is used to numerical analyses of the cold drawing process.

Anisotropy of microstructure in case of forming of metal depends on technology parameters of processes. In case of deformation of metals grain boundaries orientation can be observed. In the polycrystalline material (metal, alloy) the main microstructural parameter is grain boundary -- surface interface between individual grains. In case of isotropic non deformed structure the grains have isometric dimension mean grain size or specific surface area of grain boundaries can be measured. In case of anisotropic plastically deformed structure the grains have anisometric dimension, it is necessary to describe their anisotropy. Application of stereology methods to statistic reconstruction of three-- dimensional plastic deformed material structure by bulk forming led to detail analysis of material structure changes. The microstructure of cold drawing tubes from STN 411353 steel was analysed. Grain boundaries orientation was measured on perpendicular and parallel section of tubes with different degree of deformation. The anisotropic microstructure was decomposed into isotropic, planar and/or linear oriented components -- specific surface area of grain boundaries and these parameters were measured using stereology. Degree of grain boundary orientation is estimated as ratio of oriented specific surface area to total specific surface area. So the degree of grain boundary orientation depends on grain deformation, these results can be used for estimation of local plastic deformation in arbitrary places in volume of tube drawing which is not the same. This analysis can leads to optimization of technology parameters of the process. [ABSTRACT FROM AUTHOR]

The aim of this paper is to develop a mathematical model to investigate the rheological characteristics of short fibre reinforced thermoplastics. The rheological properties of this polypropylene were investigated using a capillary rheometer. Rheological characteristics of the composite components influence the development of resultant microstructures; this in turn affects mechanical characteristics of composites. The main rheological characteristics of polymer materials are viscosity and shear rate. They are the ones with fibre ratio changed. From the viscosity of unfilled material and 10% filled material, we can calculate viscosity for other filled materials. This mathematical formula is discussed in this paper. [ABSTRACT FROM AUTHOR]

The models are validated by finite element simulation of the performed characterization tests. Finally, the methodology is applied to an injection moulded component with complex geometry. Fiber orientation data predicted with Moldflow software has been used to determine the local effective elastic stiffness and strength coefficients. A FE simulation of the functional behaviour of the component has been carried out. Results indicate that the degree of orientation in real samples approximately equals to degree of orientation in simulation software. [ABSTRACT FROM AUTHOR]

This paper deals with the mechanical properties and macroscopic deformation of precision seamless tubes during cold drawing, using two different methods in one technological sequence. The tubes were cold-drawn in five technological sequences, undergoing seven drawing passes in total. After each sequence the intermediate annealing took place. The main goal of the experiment was to evaluate the initial state of Ø 31.8 x 2.6 mm hot-rolled tube made of E235 steel grade that was subsequently cold-drawn to the final dimension of Ø 6 × 1 mm while using specified reductions according to technological standards. Finally, the influence of selected reductions and the drawing technology itself on mechanical properties and macroscopic deformation of the material was evaluated. (The experiment described in this paper is a part of the research project aimed at whether it is possible to determine input technological parameters so that the tube production process would be more effective.) [ABSTRACT FROM AUTHOR]

Applications of aluminium alloys for drop forgings production are permanently increasing especially in the automotive industry. Alloys AlCuMg type have an significant position due to their low density compared to structural steels. This contribution provides information about mechanical properties, plasticity and workability of aluminium alloy AlCu4Mg1 at hot forming temperatures and at recovery temperatures. Database and comparison of measured values is important for future development of warm forming. Warm forging of drop forgings represents a lucrative method of precise forgings production not only from the energy and time savings point of view, but also for obtaining of higher surface quality and dimension precision of forged pieces too. [ABSTRACT FROM AUTHOR]