A grey-based Taguchi method was applied to investigate the optimal operating conditions in shielded metal arc welding (SMAW) to join SS316 and ASTM A36. This work aims to set optimal parameters for the mechanical properties of the weld joint. The effects of various welding factors on electrode type, welding current, arc welding, and welding speed have to be characterized and optimized to achieve an optimum condition. An L9 orthogonal array was used to group the various components. The mechanical properties of a dissimilar weld joints were described through hardness, tensile and flexural strength tests. The optimum welding parameters were obtained simultaneously as an electrode type E309, a welding current of 100 A, an arc voltage of 14 V, and a welding speed of 4 cm/min, which predicted improve 23.0% in its performance.

This paper presents the failure analysis of AISI304 stainless steel pipeline that was fabricated by welding and used for CO₂ transmission in a petrochemical plant. After a years of satisfactory operation, significant cracking was observed adjacent to the weld joints of valve and pipeline. The failure investigation was carried out on welded pipe samples using optical and fractography, micro hardness measurements, XRF and XRD testing. The hardness test results show faults occur in the HAZ region. Fractured surface macrostructure and morphology analysis shows inter-granular brittle fracture mode. The inter-granular fault begins with the presence of very intensive inter-granular corrosion, especially on the outer metal surface and progressively propagates to the inside of the metal. The results of XRD found peak of carbide from the secondary phase of SS 304 austenite steel. The material experienced sensitization that is indicated by the presence of carbides at the grain boundary.

This study focuses on the synthesis of hydroxyapatite (HA) from bovine bones through calcination and subsequent combination with Polyvinyl Alcohol (PVA) using the Cold Sintering Process (CSP). The CSP, operating at lower temperatures than conventional methods, aims to preserve the bioactivity and biocompatibility of HA, crucial for biomedical applications. The research investigates the influence of HA composition, sintering temperature, and PVA content on the porosity and compressive strength of the HA-PVA composite. The Hydroxyapatite powder, obtained from calcinated bovine bones, exhibits irregular shapes and sizes with a maximum grain size of 10µm, confirmed by SEM analysis. XRD analysis validates the successful production of Hydroxyapatite, showcasing characteristic peaks. The HA/PVA composite's XRD pattern indicates the dominance of HA, with PVA present as well. The study produces 27 specimens through the CSP, varying HA composition and sintering temperature. Porosity increases with higher HA content and sintering temperature, attributed to the role of PVA in binding HA particles. Compressive strength rises with increased HA content, emphasizing HA's role in enhancing mechanical strength. The presence of porosity is mitigated by a strong bond between HA and PVA, contributing to structural integrity. This research provides insights into tailoring HA-PVA materials for biomedical applications, considering controlled porosity and mechanical strength. The CSP, with its unique advantages, emerges as a promising method for developing customized materials to meet diverse biomedical needs.

This study explores the effect of preheating on the toughness of dissimilar welded joints between AISI 1037 and AISI 304 steels, using Shielded Metal Arc Welding (SMAW) and E309-16 electrodes. The innovation of this approach lies in assessing how preheating temperatures influence the mechanical properties of such welds. Preheating temperatures ranged from 150 °C to 300 °C, with impact testing revealing a notable increase in toughness, from 6.01 Joules at 150 °C to 19.57 Joules at 300 °C. Hardness tests indicated a maximum hardness of 313 VHN in the fusion zone and a minimum of 185 VHN in the AISI 304 area. Compared to non-preheated joints, preheating significantly enhanced impact strength and altered the fracture mode from brittle to ductile. Macrostructural and microstructural analyses with optical microscopy and SEM showcased changes in fracture surfaces and microstructural evolution, highlighting the improvement in mechanical properties due to preheating. These findings demonstrate that preheating critically enhances the toughness and overall performance of dissimilar metal welds, making it a valuable technique in industrial applications where enhanced joint toughness is crucial.

Synthetic hydroxyapatite is a material that has a chemical composition and molecular structure similar to bones and teeth, generally this material is widely used for medical applications including as an implant material. Non-medical applications of porous HA include as catalyst in chemical reaction, packing media for column chromatography, and as probe for gas sensors. The study aims to develop porous material based HA/Al₂O₃ composites. HA/Al₂O₃ composites prepared with three variations of latex space holder weight fractions namely 10%, 20%, and 30% and using the unidirectional compaction method to produce composites. Two step holding process sintering process applied on the green body specimens. Firstly, hold for 60 minutes at temperature of 600°C and secondly 3 hours at final temperature of 1200°C with 5°C/min heating rate. The apparent density test was performed based on the Archimedes’ principle. Porosity characteristics of the sample show that density of the composite decreased with increased space holder. Compressive strength results show that the addition of SH weight fraction decreased the compressive strength of porous hydroxyapatite-Al₂O₃ composites. The morphology observation via SEM showed pore formation due to burning of space holder and interconnecting porous formed.