Advanced Materials Research Vol. 1157

Abstract: Structural integrity and life of welded joints made of a micro-alloyed low-carbon fine-grained normalised high strength pressure vessel steel, P460NL1 is presented [1]. The researach performed within the scope of this topic involved a large number of experiments, including tensile and bending tests, hardness and toughness, as well as metallography and fractography tests, in order to determine the mechanical properties of the materials and the welded joints in detail, along with their microstructures and their influence on the obtained test results. Specimens cut out of a welded plate with dimensions of 500x500x14 mm were used for the experiments, whereas certain tests required the making of notches in the specimens, inside the heat affected zone, and this welded joint region was the focus of the research. Fatigue experimental tests were based on the assumption that fatigue crack growth rate changes depending on the regions through which the crack passed during its propagation. For this purpose, specimens used in toughness and fatigue tests were divided into four groups, depending on the part of the plate from which they were taken. Numerical calculations were performed using the extended finite element method (XFEM) [2]. Simulations were based on the experimentally determined values of Paris law coefficients, C i m [3-5], for every region through which the crack propagated during each test. Obtained results have indicated good agreement with the experimental ones, which verified the application of extended finite element method in this case.

Abstract: The paper presents studies carried out in order to determine the causes of destruction, by cracking, of a crankshaft from the composition of a tractor used to process soil.Experiments were carried out in two directions, namely a step by step study on the degraded area and a investigation into the operating conditions of the machine, on that specific work cycle.The degraded shaft was investigated visually at a magnification of 10x and by hardness tests on the areas with embrittlement cracking.Hardness test enfolded large variations (in hardness), of up to 40%, leading to a high sensitivity to cracking by mechanical fatigue, induced by the structural tension concentrators. However, hardness examination did not reveal areas of shaft degradation due to fatigue, which determined us to study the operating conditions. The shaft cracking occurred during soil processing, using a multilayered plow and in difficult exploitation conditions.Variations of mechanical characteristics of soils in the area of ​​operation of the machine, is relatively large, fact which corroborated with the lack of safety elements when overloaded, of the endowment of the tractor-plow system, led to the overcoming of the permissible load, which on a background of high hardness material, determined the embrittlement cracking of the crankshaft. Research performed highlighted, for the area in which the machine activates, the necessity of introducing in the power-generating system of safety and protection elements to prevent the destruction of components.

Abstract: Research conducted aimed to compare the hybrid ultrasonic-thermal cutting technology with the classic thermal cutting one. The experimental program was carried out on the ISIM designed hybrid equipment, operating at a frequency of 35 KHz, with a cutting geometry of the ultrasonic horn - sonotrode and the thermal anvil designed specifically for the task at hand; the first phase of the experimental program was developed on the thermal cutting module, the second one was performed on the US-thermal hybrid module, both modules being part of the hybrid cutting equipment designed and patented by ISIM Timisoara. The research performed in this present paper, intends to highlight the benefits of the hybrid cutting technology when compared to classical thermal cutting, in order to process two types of materials with different specifications and dimensions. After visually inspection cut materials have been then compared with automotive seatbelt quality standard IATF - International Automotive Task Force 16949. Experiments highlighted that hybrid ultrasonic-thermal cutting process has a significant influence on the quality of processed materials when compared to classic thermal cutting process, which in some cases makes the materials unsuitable for use in the automotive industry. The paper further presents two types of technology data sets suitable for 2 types of materials and up to automotive industry requirements.

Abstract: A grapple is a device that includes at least one gripping arrangement. The gripping arrangement is configured to grip and traverse objects so as to reach a desired location on site and to anchor it, therefore allowing the work to be carried out. [1] A method for controlling the fill volume of a grapple, such as a bulk-material crane grapple which includes at least one hoist-and-closure unit, may include adjusting the fill volume of the grapple is during the grapple closure process by adjusting/controlling the grapple hoist height. The grapple hoist speed and/or grapple hoist height may be the controlling parameter for the adjustment of the fill volume of the grapple. [2]Grapples geometric configuration is established by calculating the useful load mass. In the experiments performed in the present paper the load mass was 3000 kg. In exploitation, in cases where relatively low density materials, if compared to standard materials, are being moved/processed, changes to the volume capacity must be done; [3] changes that need to be correlated with the new materials and the exploitation conditions.The tractor attachment is a grapple assembly, and the grapple assembly kit includes a mounting assembly, a plurality of clamping units, and a plurality of support units. [4] A connection system for coupling an claw to a work vehicle includes a receiver assembly that needs to be implement and configured to a connector assembly of an arm of the work vehicle. [5]The solution developed by the authors consists in prolonging and consolidating the active elements of the grapple, by equipping it with additional elements that take and process load tensions, in the present case hard wood logs; and a consolidation and protection system that protects it from wear, that mostly appears when the hook crane repeatedly hits the ground in order to collect the deposited logs.The additional elements for handling and processing logs are made out of low alloyed steel, thus by configuring the tips we assure the good gliding of processed materials on the active/used surfaces. The self-protection system to wear is made out of boron micro-alloyed steel sheets that have hardness values up to 500 HB. Joining the grapple ensemble with specialized elements was performed through welding.

Abstract: The paper presents technologies for the manufacturing of modulated bi-metal elements, used as interchangeable reinforcement, according to patent RO129865. The bi-metal was developed by surface build-up of functional layers that have increased hardness, on a low alloyed steel substrate, so as to ensure maximum lifespan in exploitation. Welded layers deposited on active areas has a thickness of 3 mm and have high hardness (about 50-60 HRC) in order to ensure a good resistance to wear by abrasion, possibly combined with fatigue, erosion or corrosion. The modulated elements sizes are equal to or higher than the wear additions, up to 10%, being dimensioned on the principles of preventive-repetitive maintenance. The interchangeable bi-metal elements are welded on the steel components of machines, used for hot or cold processing of parts and semi-finished products manufactured in series.