STUDY ON THE INFLUENCE OF WEDM PROCESSING REGIMES ON THE QUALITY OF ARMOR STEEL

The aim of the current paper is to analyze the influence of process parameters on the dimensional accuracy of parts manufactured by Ramor 550 and Ramor 400 armored steel, using the wire electrical discharge machining (WEDM). Two working regimes were used and the processing quality were quantified by measuring the dimensional accuracy of four parameters (three lengths, an angle and a radius). The obtained results emphasized that working regime 002 leaded to larger dimensional deviations compared to working regime 001. Related to the material, the dimensional deviations were larger in case of Ramor 550 armored steel

STUDY ON THE INFLUENCE OF WEDM PROCESSING REGIMES ON THE QUALITY OF ARMOR STEEL

The aim of the current paper is to analyze the influence of process parameters on the dimensional accuracy of parts manufactured by Ramor 550 and Ramor 400 armored steel, using the wire electrical discharge machining (WEDM). Two working regimes were used and the processing quality were quantified by measuring the dimensional accuracy of four parameters (three lengths, an angle and a radius). The obtained results emphasized that working regime 002 leaded to larger dimensional deviations compared to working regime 001. Related to the material, the dimensional deviations were larger in case of Ramor 550 armored steel

STUDY ON THE INFLUENCE OF WELDER’S FATIGUE ON THE QUALITY OF WELD LINES

In this paper a case study is presented, based on certain exercises applied to different welders, to evaluate the influence of welder’s fatigue on the quality of welding. The performed test was aimed at evaluating the technical performance (the welding act) of subjects, as well as the accuracy of weld lines. Five modules of exercises were applied. The exercises of each module were various, they were of medium level, so that they were neither overburdened, nor unsolicited, because both situations could lead to accidents due to fatigue. A weld line was performed after each exercises’ module. The visual quality of welding was appreciated according to the EN ISO 17637:2011 standard

OBTAINING NEW THIN WALLED TUBULAR STRUCTURES THROUGH MATRIX MORPHOLOGICAL RESEARCH

New products based on a structure that represents a combination of known elements in a higher quality set, as well as products that refer to new shapes, new curves, new surfaces can be obtained logically - analytically - deductively or by methods specific to the optimal calculation. The present paper focuses on the method of analyzing tridimensional morphology, some possible solutions being evaluated on value criteria. Of course, these methods can be applied in the field of engineering with very good results. The focus of this study is to obtain new thin walled tubular structures - such as car crash members - which in the case of axial shock loads have a higher predictable behavior compared to those already used in various technical fields. Following the study, it can be said that depending on the amount of absorbed energy in the case of axial collisions and the absorption of kinetic energy developed at the time of impact, the optimal crashworthiness solution could be tubular structures with a circular support base and rectangular deformable area for impact

STUDY ON THE INFLUENCE OF WELDER’S FATIGUE ON THE QUALITY OF WELD LINES

In this paper a case study is presented, based on certain exercises applied to different welders, to evaluate the influence of welder’s fatigue on the quality of welding. The performed test was aimed at evaluating the technical performance (the welding act) of subjects, as well as the accuracy of weld lines. Five modules of exercises were applied. The exercises of each module were various, they were of medium level, so that they were neither overburdened, nor unsolicited, because both situations could lead to accidents due to fatigue. A weld line was performed after each exercises’ module. The visual quality of welding was appreciated according to the EN ISO 17637:2011 standard

NEW CHALLENGES IN ABRASIVE WATER JET MACHINING

Abrasive water jet machining (AWJM) is one of the most important method used in cutting different types of materials: alloy sheet, marble, glass, rocks. This process is used in the aeronautic, automotive, metallurgy industries and even in some art techniques and textile industry. The method consists in transforming the kinetic energy of a solid particle directed with water jet at a high pressure to remove material through erosion and abrasion. AWJM is low cost equipment compared to other conventional cutting technologies. This paper is an attempt to review the achievements made in AWJM technology for different hardness materials

NEW CHALLENGES IN ABRASIVE WATER JET MACHINING

Abrasive water jet machining (AWJM) is one of the most important method used in cutting different types of materials: alloy sheet, marble, glass, rocks. This process is used in the aeronautic, automotive, metallurgy industries and even in some art techniques and textile industry. The method consists in transforming the kinetic energy of a solid particle directed with water jet at a high pressure to remove material through erosion and abrasion. AWJM is low cost equipment compared to other conventional cutting technologies. This paper is an attempt to review the achievements made in AWJM technology for different hardness materials

STRETCH FORMING USING HEATED DIE

The stretch forming process implies stretching and drawing into shape a sheet of material onto a die. This method is used, among other sectors, in the construction of aeroplane fuselage, as significant, complex parts can be obtained in one piece. In essence, stretch forming implies working with materials that have medium to high spring back effects, such as aluminium or magnesium alloys. Different approaches are used in manufacturing due to this phenomenon, ranging from incremental processes to multipoint dies. Another critical aspect of this process is to know how the material behaves under severe plastic deformation, as different alloys require different approaches that vary from step by step forming to in-process chemical treatments to manual pounding the metal sheet. However, all these alloys have in common that, when heated, their machinability properties improve. In this experimental study, a heated die approach was taken into consideration. 6x60 mm 100W heating elements along with temperature sensors were fitted into the die. The USB/OC326009 metal sheet is in direct contact with the die, thus assuring the heat transfer, as the temperatures reach 200 °C. The die temperature is software controlled so that maximum temperature and thermal inertia could be controlled with ease. The data indicate that this method offers significantly improved results compared to a normal room-temperature process

Azimuthal anisotropy of charged jet production in root s(NN)=2.76 TeV Pb-Pb collisions

We present measurements of the azimuthal dependence of charged jet production in central and semi-central root s(NN) = 2.76 TeV Pb-Pb collisions with respect to the second harmonic event plane, quantified as nu(ch)(2) (jet). Jet finding is performed employing the anti-k(T) algorithm with a resolution parameter R = 0.2 using charged tracks from the ALICE tracking system. The contribution of the azimuthal anisotropy of the underlying event is taken into account event-by-event. The remaining (statistical) region-to-region fluctuations are removed on an ensemble basis by unfolding the jet spectra for different event plane orientations independently. Significant non-zero nu(ch)(2) (jet) is observed in semi-central collisions (30-50% centrality) for 20 <p(T)(ch) (jet) <90 GeV/c. The azimuthal dependence of the charged jet production is similar to the dependence observed for jets comprising both charged and neutral fragments, and compatible with measurements of the nu(2) of single charged particles at high p(T). Good agreement between the data and predictions from JEWEL, an event generator simulating parton shower evolution in the presence of a dense QCD medium, is found in semi-central collisions. (C) 2015 CERN for the benefit of the ALICE Collaboration. Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).Peer reviewe