ABSTRACT
Este texto apresenta uma conversa-entrevista entre um grupo de pesquisa sobre as práticas de profissionais de saúde atuantes na Atenção Básica em Saúde e a Dra em filosofia Ilze Zirbel, pesquisadora do campo das Teorias do Cuidado. A conversa ocorreu durante um encontro do grupo de pesquisa, na cidade de Santos, no dia 29.11.2019 e foi registrada em áudio sendo, em seguida, transcrita e editada na forma de entrevista. Nela são abordadas questões de gênero, classe e raça envolvidas nas atividades e relações de cuidado, o que toca nas temáticas do privilégio e da exploração, do autossacrifício e da coerção, bem como da autonomia e da interdependência de seres humanos. O pano de fundo é o da necessidade de políticas públicas visando o cuidado da população e desenvolvimento do senso de cuidado tanto em homens quanto em mulheres.
This text presents a conversation-interview between a research group on the practices of health professionals working in Primary Health Care and a researcher in the field of Care Theories. It addresses issues of gender, class and race involved in care activities and relationships, which touches on the themes of privilege and exploitation, self-sacrifice and coercion, as well as autonomy and interdependence. The background is the need for public policies aimed at the care of the population and the development of a sense of care for both men and women.
Este texto presenta una conversación-entrevista entre un grupo de investigación sobre las prácticas de los profesionales de la salud que trabajan en Atención Primaria y un investigador en el campo de las Teorías de la Atención. Aborda temas de género, clase y raza involucrados en las actividades y relaciones de cuidado, que toca los temas de privilegio y explotación, autossacrificio y coacción, así como autonomía e interdependencia. El trasfondo es la necesidad de políticas públicas orientadas al cuidado de la población y al desarrollo de un sentido de cuidado tanto para hombres como para mujeres.
ABSTRACT
INTRODUCTION: The mechanical properties and corrosion resistance of a material are dependent on its microstructure and can be modified by phase transformation. When a phase transformation occurs in a material it usually forms at least one new phase, with physical-chemical characteristics that differ from the original phase. Moreover, most phase transformations do not occur instantly. This paper presents an evaluation of the phase transformation of martensitic stainless steels ASTM 420A and ASTM 440C when submitted to different thermal processes. METHODS: Dilatometry tests were performed with several continuous heating and cooling rates in order to obtain the profiles of the continuous heating transformation (CHT) and continuous cooling transformation (CCT) diagrams for these two types of steel. Also, the temperature ranges for the formation of the different phases (ferrite and carbides; ferrite; austenite and carbides; non-homogeneous and homogeneous austenite phases) were identified. Rockwell hardness (HRC) tests were performed on all thermally treated steels. Anodic and cathodic potential dynamic polarization measurements were carried out through immersion in enzymatic detergent as an electrolyte for different samples submitted to the thermal processes in order to select the best routes for the heat treatment and to recommend steels for the manufacture of surgical tools. RESULTS: The martensitic transformation temperature tends to increase with increasing temperature for the initiation of cooling. The 440C steel had a higher hardness value than the 420A steel at the austenitizing temperature of 1100 °C. Above the austenitizing temperature of 1100 °C, the material does not form martensite at the cooling rate used, which explains the sharp decline in the hardness values. CONCLUSION: The study reported herein achieved its proposed objectives, successfully investigating the issues and indicating solutions to the industrial problems addressed, which are frequently encountered in the manufacture of surgical instruments.
ABSTRACT
This research consisted of implementing and evaluating an empirical mathematical model to reproduce analytically the dilatometric behavior of ASTM 420A and ASTM 440C martensitic stainless steels, widely used for manufacturing surgical tools. Martensitic stainless steels can be subdivided into three subgroups: low-carbon, medium-carbon and high-carbon steels. The microstructure of each group is also characteristic as needlelike martensitic; very fine martensitic; and ultra-fine martensitic containing carbides. The proposed method was based on experimental data obtained from the dilatometric testing of the steel samples applying low heating rates. It was possible to determine the formation of phase fields near the equilibrium conditions. The method, being based on empirical data, ensured a greater approximation to the experimental values, verifying that it can be applied as a useful tool in the evaluation of industrial heat treatments for surgical tools.
O presente trabalho consistiu em implementar e avaliar um modelo matemático empírico que reproduz analiticamente o comportamento dilatométrico dos aços inoxidáveis martensíticos ASTM 420A e ASTM 440C, utilizados em ferramental cirúrgico. Aços inoxidáveis martensíticos podem ser subdivididos em três subgrupos, ou seja, baixo carbono; médio carbono e alto carbono. A microestrutura de cada grupo é caracterizada por martensita em forma de agulha; martensita fina e martensita ultra-fina contendo carbetos. A elaboração do método matemático se baseou em dados extraídos de ensaios dilatométricos sob baixas taxas de aquecimento. Foi possível determinar a formação dos campos de fase próximos às condições de equilíbrio. Os resultados obtidos garantiram boa aproximação com os valores experimentais, evidenciando que o modelo aplicado é um instrumento útil na avaliação dos tratamentos térmicos industriais para ferramental cirúrgico.