Influence of Post Weld Heat Treatment on the HAZ of Low Alloy Steel Weldments

The heterogeneous nature of weldments demands an additional processing to retain and/or improve the joint properties. Heat Affected Zone, the zone Adjacent to the weld metal zone is critically affected by the sudden dissipation of heat from weld metal during welding. Toughness of this zone becomes weak as the grains get coarsened and the interface between the two regions is more prone to fracture. Post weld heat treatment is thus generally carried out on the weldments to relive the thermal residual stresses and to enhance the properties of welded joints. This paper discusses about the influence of post weld heat treatment on the fracture toughness of low alloy steel weldments. Fracture toughness of heat treated weldments was determined using standard CTOD test and the results were correlated

Material Characterization of 316L Stainless Steel After Being Subjected To Cryogenic Treatment

Post processing of materials is necessary to suit them for the intended requirements. The properties of stainless steel of grade 316L cannot be influenced with further processing such as hot working [1]. Thus the current study aims at investigating the properties of stainless steel of grade 316L after being subjected to deep cryogenic treatment. The specimens from both cryogenically treated and untreated conditions were subjected to Tensile Test, Charpy Impact Test, Rockwell Hardness Test, Microstructure and Percentage Shear Area Analysis and the results thus obtained are discussed in this paper. The results have shown that cryogenic treatment has improved the hardness and strength

Simulation Study on Hypervelocity Penetration of Lab Scaled Shape Charge Mechanism

Shaped charge (SC) is a mechanism used by defence industries as anti-armored weapon to penetrate armored plates.  Numerous studies have been conducted on the shaped charged effects.  However, experimental studies are limited due to great safety requirement and limited access to high grade explosive.  Due to these limitations, an experimental study on a small-scale shaped charge mechanism (SCM) penetration blast test was conducted against five (5) types of target materials.  The experimental data is then verified by simulation to proof that it can be used to predict the SC penetration data. This paper intent to present a comparative study on the effect of shaped charge blast conducted by simulation with the actual experimental results. In order to conduct this study, a 2D AUTODYN software were used to develop the SC blast model against five (5) types of target materials.  This study concludes that the 2D AUTODYN simulations results can predict the hypervelocity penetration for all target materials compared to the experimental test with an average difference of 9.1 %

Simulation Study on Hypervelocity Penetration of Lab Scaled Shape Charge Mechanism

Shaped charge (SC) is a mechanism used by defence industries as anti-armored weapon to penetrate armored plates.  Numerous studies have been conducted on the shaped charged effects.  However, experimental studies are limited due to great safety requirement and limited access to high grade explosive.  Due to these limitations, an experimental study on a small-scale shaped charge mechanism (SCM) penetration blast test was conducted against five (5) types of target materials.  The experimental data is then verified by simulation to proof that it can be used to predict the SC penetration data. This paper intent to present a comparative study on the effect of shaped charge blast conducted by simulation with the actual experimental results. In order to conduct this study, a 2D AUTODYN software were used to develop the SC blast model against five (5) types of target materials.  This study concludes that the 2D AUTODYN simulations results can predict the hypervelocity penetration for all target materials compared to the experimental test with an average difference of 9.1 %

Advanced structural fibre material for single link robotic manipulator simulation analysis with flexibility

The aim of this article is to investigate the characteristics of a composite fibre advanced materials used as a robotic link manipulator for replacement of rigid one. The composite material is combination of two and more fibre processed and bonded with epoxy, resulting hybrid form of material component with required properties which are to be analyzed for suitability with respect to its function, reliability, durability, safety and cost-effectiveness. The composites generally have high-strength, high-stiffness (graphite, kevlar, etc.) low-density (epoxy, polyvinyl) strong and stiff with lightweight. In this investigation, five different composite structural fibres are taken as a flexible link with joint flexibility for case study analysis. The rotating structural fibre link, loaded and tested different types of joint stiffness coefficients (kc). The numerical evaluations are conducted for structural fibre material for replacement rigid manipulator. The modeling of structural fibre single flexible link on the basis of Euler-Bernoulli beam theory and Lagrange’s equations of motion is studied and accurate modes of the system are obtained

A comparative study on X-ray peak broadening analysis of mechanically alloyed Al2O3 particles dispersion strengthened Al 7017 alloy

AA7017 + x vol. % Al2O3 (x = 5, 10, 20) nanocomposites powders were synthesized by HEBM process with milling time of 0 h and 20 h. The synthesized nanocomposite powders were characterized using XRD (Bruker USA D8 Advance, Davinci) with CuKα (1.5406 Aͦ), 2θ range (30°-90°), and Scan Speed (1°/min) for examining the crystalline nature of the powder samples. The size and shape of the powder particle were identified by HR-SEM (FEI Quanta FEG 200F) with 30 KV voltage, wide magnification range (12x-105 x) and secondary electron mode, and HR-TEM (JEOL Japan, JEM-2100 Plus) with voltage (200 kV), and magnification range (below 50 nm). Powder particles were measured by laser scattering technique using zeta analyzer (Laser Particle size Analyser, M/s Microtrac),and finally, the melting point and peak shift variation of composite powder samples were analyzed using TG-DSC (Netzsch TG-DSC) with temperature range (25–1400 °C), and heating rate (10 °C/min)under argon atmosphere. Furthermore, the particle sizes evaluated from different models of diffraction analysis (Scherrer, Williamson-Hall, and size-strain plot, SSP, methods) were compared with the results from PSA, HR-SEM, and HR-TEM analyses. The obtained mechanical properties explained that 20h milled AA7017 + x vol. % Al2O3 (x = 5, 10, and 20) samples produced higher values; and the properties improvement in all the samples were correlated theoretically by various strengthening mechanisms

Study on Sound Absorption Properties of Coconut Coir Fibre Reinforced Composite with Added Recycled Rubber

Sound pollutions have become worsen and creating concerns for many peoples. Conventionally, expensive sound absorption materials are employed to control noise disturbances. However, recent developments on natural fibres have created interest for researchers especially for acoustics application purposes. This paper investigates the viability of coconut coir added with recycled rubber to be implemented as sound absorption panel. The composite is constructed at prescribed percentages of fillers and polyurethane as resin. The two-microphone method was applied to obtain the acoustic properties of the samples. The samples were also tested for physical properties such as density and porosity, as well as the microstructures. The results demonstrate good acoustics performances and highlight the potential of the coconut coir reinforced with recycled rubber as the sound absorption panel