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.

Efficiency in the management of integrated product and processes development is a basic requisite to guarantee competitiveness and success for manufacturing companies. This means that operational management of activities and human and material resources is extremely important, especially in virtual OKP (one-of-a-kind production) systems, and must cover related aspects of their capabilities and social character as well as assignment criteria. In this context, and to facilitate collaborative resources management, an ontology focused on resources and capabilities is proposed in this work. This ontology supports the necessary knowledge for generic and collaborative process planning, providing a shared common semantic for all the members of the virtual company. This work differs from other proposed ontologies in the area of process planning where the resources considered are all those elements that participate in the execution of the different activity types involved in this wide and complex process. The ontology directly covers the shared, social nature of the resources, the agentive behaviour of many of them and a characterisation of their capabilities, thus providing specific solutions to the needs of the collaborative integrated development of products, processes and resources (CIDP²R) process.

The search for and assignment of resources is extremely important for the efficient planning of any process in a distributed environment, such as the collaborative product integrated development process. These environments require a degree of semantic interoperability, which currently can only be provided by ontological models. However, the ontological proposals centred on Resources for Machining and Inspection Process Planning have a limited reach, do not adopt a unified view of machining and inspection, and fail to express knowledge in the manner required by some of the planning tasks, as is the case with those concerned with resource assignment and plan validation. With the aim of providing a solution to these shortcomings the manufacturing and inspection resource capability (MIRC) ontology has been developed, as a specialist offshoot of the product and processes development resources capability ontology. This ontology considers resource capabilities to be a characteristic of the resource executing any activity present in an integrated process plan. Special attention is given to resource preparation activities, due to their influence on the quality of the final product. After describing the MIRC ontology, a case study demonstrates how the ontology supports the process planning for any level, approach or plan strategy.

In this work, an ontological model for welding processes is proposed and the need to manage the information and knowledge associated with such complex discipline is justified. First, an overview of the meaning and use of the models for this purpose and the concept of interoperability applied to the information contained in the welding standards is given. Next, an approach to the concept of ontology is made, the ontology applications for engineering, basic functionalities of ontologies and the way in which they are implemented. The work concludes showing some entities of the proposed ontology, focusing on the definition and classification of welding processes and knowledge inference based on the information contained in the ontology.

En el presente trabajo se analizan las variaciones resistentes y microestructurales de la fundición dúctil soldada mediante la técnica tungsten inert gas (TIG), sin tratamientos térmicos y utilizando diferentes materiales de aporte (fundición maleable perlítica, aleación Fe-Ni y aleación de bronce y manganeso). A partir de cada cupón soldado de dimensiones 100x100x6 mm, se obtienen las probetas para los ensayos mecánicos y microestructurales. Con el análisis cualitativo de las micrografías y el análisis cuantitativo de los resultados de los ensayos mecánicos, que han sido realizados en zonas bien diferenciadas de las uniones soldadas (metal base, interfase y cordón de soldadura), se concluye la idoneidad de este tipo de soldaduras y de la introducción nuevas variables como los tratamientos térmicos previos y/o posteriores a la soldadura. Se han correlacionando las características mecánicas y resistentes con las microestructuras obtenidas en las placas (probetas) para poder evaluar sus ventajas e inconvenientes, así como elaborar conclusiones.

Welding of carbon steels induces significant microstructural modifications within the heat-affected zone (HAZ), which influence the material’s performance during service. These changes are typically associated with increased hardness and reduced toughness. Although often remaining within acceptable limits, they must still be considered, especially when the weld is part of a highly demanding application. Continuous Cooling Transformation (CCT) diagrams, which are typically used to describe heattreatment behaviour, are not fully suitable for welding applications. This is because welding heat cycles differ substantially from quenching: they reach much higher temperatures and include no soaking time. As a result, HAZ hardness depends not only on the cooling rate but also on the heating rate and the peak temperature reached at each point within the HAZ. These parameters govern the transformation of pearlite into austenite and the homogenization of the austenitic phase. This paper investigates the influence of the peak temperature within the HAZ on the hardness of three different steels (S355, C45, and S700MC) under conditions of relatively slow cooling. Samples were heated in a furnace to predefined maximum temperatures and then immediately cooled in an air stream. The results indicate that, beyond a certain temperature, a sharp transition from low to high hardness occurs. This transition is associated with grain coarsening and completion of the austenitization process. Compared to oil quenching, additional features such as the formation of Widmanstätten microstructures were also observed.