This paper analyzes pitting corrosion at the weld zone and at the heat affected zone (HAZ) in AISI 304 rolled stainless steel welds. As the aforementioned material is one of the most frequently used types of stainless steel, it is needful to be aware of the mechanisms that lead to its deterioration, like corrosion, since it can cause failures or malfunction in a wide variety of products and facilities. For the experimental tests 1.5 mm thick AISI 304 stainless steel plates were welded and rolled to different thicknesses and after, the samples were subjected to mechanical and corrosion tests and to a micrograph study. Deformation stresses and other intrinsic metallurgic and physic-chemical transformations that occur during cold rolling and welding, and that are key factors in the anti-corrosion behavior of AISI 304 rolled stainless steel, have been observed and analyzed. A correlation has been found between cold work levels in test samples and number of pits after corrosion tests.

This article examines the weldability of ductile cast iron when the root weld is applied with a tungsten inert gas (TIG) welding process employing an Inconel 625 source rod, and when the filler welds are applied with electrodes coated with 97.6% Ni. The welds were performed on ductile cast iron specimen test plates sized 300 mm × 90 mm × 10 mm with edges tapered at angles of 60°. The plates were subjected to two heat treatments. This article analyzes the influence on weldability of the various types of electrodes and the effect of preheat treatments. Finally, a microstructure analysis is made of the material next to the weld in the metal-weld interface and in the weld itself. The microstructure produced is correlated with the strength of the welds. We treat an alloy with 97.6% Ni, which prevents the formation of carbides. With a heat treatment at 900 °C and 97.6% Ni, there is a dissolution of all carbides, forming nodules in ferritic matrix graphite.

The design of the formative and summative assessment processes is of paramount importance to help students avoid procrastination and guide them towards the achievement of the learning objectives that are described in the course syllabus. If the assessment processes are poorly designed the outcome can be disappointing, including high grades but poor learning. In this paper, we describe the unexpected and undesirable effects that an on-demand formative assessment and the timetable of a summative assessment that left the most cognitively demanding part, problem-solving, to the end of the course, had on the behavior of students and on both grading and learning. As the formative assessment was voluntary, students procrastinated till the last minute. However, the real problem was that due to the design of the summative assessment, they focused their efforts mainly on the easiest parts of the summative assessment, passing the course with ease, but achieving a low learning level, as evidenced by the low scores of the problem-solving part of the summative assessment.

The electrodeposition of cuprous oxide (Cu₂O) onto FTO-coated glass substrate was studied by using a statistical approach in order to control the Cu₂O morphology and optical properties. The factorial design considered four electrodeposition conditions at two representative levels as input variables (electrolyte temperature and pH, deposition potential and duration) and the deposition charge and morphology of obtained Cu₂O as the output variables. The morphology analysis showed the highest influence on crystal shape was exhibited by electrolyte temperature and pH, reaching significance levels of 95 and 98%, respectively. Temperature as low as 35°C and pH 12.2 results in cubic morphology, while other parameters result in octahedron shape. The highest absorbance was exhibited by the Cu₂O with cubic morphology.

This article investigates the effect of low-level ionizing radiation, namely X-rays, on the micro structural characteristics, resistance, and corrosion resistance of TIG-welded joints of AISI 304 austenitic stainless steel made using AISI 316L filler rods. The welds were made in two different environments: natural atmospheric conditions and a closed chamber filled with inert argon gas. The influence of different doses of radiation on the resistance and corrosion characteristics of the welds is analyzed. Welded material from inert Ar gas chamber TIG showed better characteristics and lesser irradiation damage effects.

Este artículo estudia el efecto de la soldadura de raíz (GTAW) con ERNiCrMo-3 sobre la microestructura y propiedades mecánicas de una unión de fundición nodular cuando las pasadas de la cubierta se realizan con la técnica SMAW con electrodos de Ni. Para tener una mejor comprensión de los resultados, se comparan con las características de una soldadura completa de Ni SMAW. Esto se hizo antes y después de un recocido a 900 °C con el fin de evaluar las influencias y los posibles beneficios de este tratamiento térmico. Los resultados muestran que la presencia de una soldadura de raíz de GTAW ERNiCrMo-3, a pesar de la mejora de la penetración, conduce a una pérdida de propiedades mecánicas en la soldadura de raíz que, incluso con un recocido, no es posible eliminar.