Direct Metal Deposition Of Waspaloy Wire Using Laser And Arc Heat Sources

In the manufacture and repair of parts by direct metal deposition (DMD) it is common to inject powder into a molten pool formed by laser heating. However, a wire feedstock offers potential advantages and was employed in the present study of multilayer deposition of Waspaloy, in the form of walls using a high power diode laser (HPDL) or gas tungsten arc weld method (GTAW). Understanding the microstructure and mechanical properties of the materiaL especially one such as Waspaloy which is used in aerospace engines, is crucial to ensure its performance. Building parts layer-by-layer causes dynamic changes in the underlying substrate and the previously deposited layers due to the thermal cycling experienced. The heating and cooling rates during the deposition process affect the microstructure of the alloy which has an important impact on the mechanical properties of the material. Solidification of Waspaloy during the DMD process leads to dendritic segregation and interdendrtic carbide formation which can strongly influence the mechanical properties of the deposited structure. Heat treatment can be the principal means of altering the microstructure and optimising the mechanical properties. Hence, solution treatment and ageing was performed on the deposited structure. In this thesis, the macro- and microstructural evolution were investigated and the deposits were characterized by optical microscopy, scanning electron microscopy, x-ray diffraction, differential scanning calorimetry, microhardness testing and tensile testing. Results from the microstructural and mechanical properties are then related to the thermal cycles arising from layer deposition

Review on effect of repetitive rework on dissimilar austenistic stainless steel pipes by using GMAW orbital welding

Dissimilar metal welding is widely applied to meet the rquirement of transition in mechanical properties and/or difference in working conditions. For instance, even though AISI 304 and AISI 316L are both belong to austenitic stainless steels, but they are applied in different working environment. AISI 304 is used at high temperature applications, whereas AISI 316L is used at low temperature. Repair welding is able to return a part back to its normal service life if weld failure happened due to service deterioration or defects during fabrication stage. However, repetitive heat input due to repair welding will cause changes in welded structure and properties. In this article, the effect of repetitive repair welding of dissimilar austenitic stainless steel pipes to the microhardness, tensile strength, microstructure and quality of the weldment has been reviewed

Microstructure formation in Waspaloy multilayer builds following direct metal deposition with laser and wire

In the manufacture of parts by direct metal deposition it is common to inject powder into a molten pool formed by laser heating. However, a wire feedstock offers potential advantages and was employed in the present study of multilayer deposition of Waspaloy in the form of walls approximately 6 mm thick using a high power diode laser. The macro- and microstructural evolution was investigated and the deposits were characterized by optical microscopy, scanning electron microscopy (SEM), differential scanning calorimetry (DSC) and microhardness testing. A columnar-dendritic solidification structure forms with the dendrites growing approximately in the plane of the wall and at an angle of around 30◦ to the build direction. Layer bands were observed, corresponding to the depth of remelting in each successive pass and are due to localized dendrite arm coarsening. The microhardness of multilayer walls decreases from bottom to top, i.e. along the build direction and also depends on the number of layers in the wall. Although the Ni3(Al,Ti) precipitate phase (y')could not be detected by SEM, DSC thermograms of samples from different positions in the multilayer deposits exhibit different characteristics which are ascribed to variations y' in precipitation. The DSC data are used to interpret the microhardness variations in terms of the complex thermal histories affecting y'formation in the alloy

Mechanical properties comparison of stainless steel 304L and carbon steel BS1387 prior to orbital welding

Dissimilar metal joint (DMJ) is one of many joining methods for welding processes which is common in the power plant, chemical and petrochemical industries. Stainless steel pipe and carbon steel pipe are the most widely used in this technique. In order to perform DMJ to these metals, it is important to understand the mechanical properties of both base materials. In this study, the characterizations of stainless steel (SS) 304L and carbon steel (CS) BS1387 were made. The SS304L and CS BS1387 were cut out from pipes according to ASTM E 8M-04, before their tensile and microhardness properties were measured and evaluated. The results show that the SS 304L has better mechanical properties compared to the CS BS1387 pipe in terms of tensile strength and hardness. Due to the higher mechanical properties, SS 304L was selected to conduct higher temperature water, while CS BS1387 was selected to conduct room temperature water

The Impact Of Worker Experience And Health Level To Vibration Absorbed By Hand

This study was set to identify how working environment affected workers' stress level and to determine the differences of vibration absorbed by hand in both good and bad health conditions. To achieve the first aim, a survey method was employed to gather data from the workers who were involved in the composite cutting job. Meanwhile, to achieve the second aim, an experiment to investigate the effects of performing cutting job using hand tools was conducted on five participants with different health conditions. The results of the study revealed that the workers felt that their working environment was stressful. The workers who had bad health condition as average would absorb 237.8% (for 5mm thickness) and 17.46% (for 3mm thickness) more vibration from the hand tools while performing the cutting job than the others. The paper discusses whether workplace stress and vibration absorption from using hand tools will finally lead or contribute to health problems especially the hand arm vibration disease

Current Research Trends In Wire Electrical Discharge Machining (WEDM): A Review

Wire Electrical Discharge Machine (WEDM) is a ‘non-traditional machining process’ and becoming more important in providing a non-contact machining process which is suitable for machining geometrically complex and hard advanced material which impossible to machine by conventional machine. This paper reviews the experimental investigation results on performance evaluation of machining parameters which effect machining performance which will reflect the machining factors and responses. In addition, the method in analyzing, modelling, development and tool steel in WEDM were also discussed. Last but not least, some recommendations and future WEDM research were propos

Transforming Linear Laser Cutting machine Into Laser Lathing – An Empirical Investigation & Evaluation of Roundness Quality

Lasers are widely used in industries as cutting tools due to ultra-flexibility cutting capabilities in obtaining high quality end product while posing advantage of quick set up, non-mechanical contact mechanics, and small region of heat affected zone. This paper presents the laser lathing performance of 2D CO2 flatbed laser cutting machine by investigating the roundness quality. A specially designed mechanism was developed to clamp and spin a steel rod of 10mm diameter cylindrical workpiece on X to Y sacrificial table. Three significant cutting parameters were controlled in this experiment namely; cutting speed, spinning speed and depth of cut. The experiments were carried out based on DOE full factorial matrix design. The results were realistic, promising and efficient as compared to manual lathes within the same range of workpiece properties and dimension

Influence of ceramic particles size on the incorporation of SiC into stainless steel material using 480 J/mm heat input for tribological applications

The objective of the present study is to deposit highly wear resistant silicon carbide (SiC) ceramic particles on Duplex-2205 using tungsten inert gas (TIG) torch arc cladding at a heat input of 480 J/mm. The influence of various SiC ceramic particles size ranging from 20 µm to 100 µm on microstructure, hardness and linear motion reciprocating wear test was studied. Scanning electron microscopy (SEM) and microhardness tester were used to characterize the influence of SiC particle size on duplex stainless steel (DSS). The tribological properties of the cladding layer was examined using a ball-on-disc tribometer. It was found that the hardness properties for 60 µm and 100 µm samples were generally higher than 20 µm and this was believed owing to the presence of the dendrite microstructure. Furthermore, it was found that wear rate and friction coefficient of larger particle size produced better wear resistance. The tribological properties of the clad layer were increased further due to the well dispersion of the dendrites structure in the SiC-DSS layer. The strongest clad layer consisted of 100 µm SiC particle size and had a hardness value of 750 Hv, wear rate of 4.13 mm3/Nm and friction coeficient of 0.49

Tensile Properties Of Ternary Blends For HDPE/PP/Recycle HDPE In Blow Moulding Process

Increasing the environmental concern among peoples have increased the recycling activities, especially for high-density polyethylene (HDPE) bottles. Therefore, recycled HDPE needs to be mixed with other plastic materials to improve their mechanical properties. In this study, recycled HDPE was mixed with virgin HDPE and polypropylene (PP). The ratio of virgin HDPE and PP were set at 10/90, 30/70 and 50/50, meanwhile recycled HDPE was set at 20%, 35% and 50%. The blended materials were extruded into the parison and was blown using extruded blow-moulding machine to produce a 5-litre bottle. The tensile strength and elongation at break of the blended materials were measured using universal testing machine (UTM). Miscibility of the blended materials was also evaluated using differential scanning calorimetry (DSC). The result shows that decreasing the recycled HDPE in the blended materials increases the tensile strength. Meanwhile, increasing the recycled HDPE content in the blended materials increases the elongation at break of the blended materials. DSC curve shows that blended materials are immiscible

Optimization Parameters of Injection Moulding Machine For Reducing Warpage of Dog Bone Plastic Part

The optimization of processing parameters on warpage of polypropylene (PP) in the application of injection moulding machine was studied. The appropriate parameters were adjusted to reduce the warpage defect on the tensile test specimen of dog bone. The type of injection moulding machine used in this research is Arburg 420C 800-250C. Four parameters that have been investigated; injection pressure, clamping pressure, back pressure and holding pressure.A concept of design of experiment (DOE) has been applied using Taguchi method to determine the suitable parameters.To measure the warpage of the dog bone, digital height gauge was used to measure the flatness of the part surface.According the analysis of variance (ANOVA), the most significant factor that effect the warpage was holding pressure by 57.82%, followed with back pressure by 25.75%, clamping pressure by 16.27% and injection pressure by 0.16%. Itis found that the optimum parameters setting that have been obtained were injection pressure at 950 bar, clamping pressure at 600 kN, holding pressure at 700 bar and back pressure at 75 bar. The depreciation value of warpage minimum index in this experiment was decreased by 4.6% after confirmation run