El ensayo micro abrasivo por esfera rotativa libre en la caracterización de materiales de ingenieria y depósitos de recargue superficial
Fecha
2018
Autores
Galvan Martin, José Alejandro
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Editor
Universidad Central ‘‘Marta Abreu’’ de Las Villas. Facultad de Ingeniería Mecánica e Industrial. Departamento de Ingeniería Mecánica
Resumen
En el presente trabajo se realiza un estudio teórico del desgaste abrasivo, los modos en que se manifiesta y su forma de actuación a nivel microestructural en las aleaciones de alto empleo en el recargue superficial por soldadura. Vinculado a lo anterior se describen las variables que afectan los resultados de desgaste abrasivo en determinado ambiente tribológico particularizando en las fundiciones blancas aleadas empleadas en el recargue superficial. Se detallan los métodos de ensayos de desgaste abrasivo de mayor empleo en la evaluación de depósitos de recargue, exponiendo sus características fundamentales, además de las ventajas y desventajas de su aplicación, demostrándose la limitada precisión de los resultados de los ensayos tradicionales, debido a las características de los materiales de recargue de alta aleación, a lo que se suman las dificultades y costos relacionadas con la elaboración de las probetas. Se realiza un estudio de las características del equipamiento del ensayo de desgaste micro abrasivo con esfera rotativa, los parámetros de ensayo y las demás variables de entrada que determinan los resultados de pérdida de material. Posteriormente se estudian varias experiencias de aplicación del ensayo micro abrasivo en aleaciones ferrosas, donde se plantean los rangos de variación de los parámetros de ensayo y su efecto en los resultados de desgaste, basado en lo cual se concluye que no se cuenta con una unidad de criterios en cuanto a la selección de estos parámetros, del tipo de material abrasivo, sus características y concentración, a pesar del determinante efecto de estos en los resultados de desgaste. Se realiza el diseño de un equipo de ensayo de desgaste micro abrasivo con esfera rotativa libre, se elaboran las tecnologías de fabricación de cada una de sus partes y se establecen los criterios de selección de sus componentes. Finalmente se realiza un cálculo económico de la fabricación de una máquina para este tipo de ensayo, demostrándose así la factibilidad económica de esta tarea, en las condiciones de una empresa nacional.
In the present work a theoretical study of the abrasive wear, the ways in which it manifests and its form of action at the microstructural level in the widely used alloys in the hardfacing, is made. Related to the above, the variables affecting the abrasive wear results, in a given tribological environment, are described, particularizing in the alloyed white iron. The most widely used abrasive wear testing methods in the evaluation of hardfacing welds are detailed, explaining their fundamental characteristics, as well as the advantages and disadvantages of their application, demonstrating the limited precision of the results with this traditional tests, due to the characteristics of the high alloy hardfacing materials, to which are added the difficulties and costs related to the preparation of the specimens. A study of the characteristics of the micro abrasive wear test equipment with rotating sphere, the test parameters and the other input variables that determine the results of loss of material, is made. Subsequently, several experiences of application of the micro abrasive wear test, in ferrous alloys, are studied, where the ranges of variation of the test parameters and their effect on the wear results are considered, based on which it is concluded that there is not a unit of criteria regarding the selection of these parameters, the type of abrasive material, its characteristics and concentration, despite the determining effect of these on the wear results. The design of a micro abrasive wear test equipment, with free rotating sphere, is carried out. The manufacturing technologies of each of its parts are elaborated and the selection criteria of its components are established. Finally, an economic calculation of the manufacture of a machine is carried out, demonstrating the economic feasibility of this task, under the conditions of a national enterprise.
In the present work a theoretical study of the abrasive wear, the ways in which it manifests and its form of action at the microstructural level in the widely used alloys in the hardfacing, is made. Related to the above, the variables affecting the abrasive wear results, in a given tribological environment, are described, particularizing in the alloyed white iron. The most widely used abrasive wear testing methods in the evaluation of hardfacing welds are detailed, explaining their fundamental characteristics, as well as the advantages and disadvantages of their application, demonstrating the limited precision of the results with this traditional tests, due to the characteristics of the high alloy hardfacing materials, to which are added the difficulties and costs related to the preparation of the specimens. A study of the characteristics of the micro abrasive wear test equipment with rotating sphere, the test parameters and the other input variables that determine the results of loss of material, is made. Subsequently, several experiences of application of the micro abrasive wear test, in ferrous alloys, are studied, where the ranges of variation of the test parameters and their effect on the wear results are considered, based on which it is concluded that there is not a unit of criteria regarding the selection of these parameters, the type of abrasive material, its characteristics and concentration, despite the determining effect of these on the wear results. The design of a micro abrasive wear test equipment, with free rotating sphere, is carried out. The manufacturing technologies of each of its parts are elaborated and the selection criteria of its components are established. Finally, an economic calculation of the manufacture of a machine is carried out, demonstrating the economic feasibility of this task, under the conditions of a national enterprise.
Descripción
Palabras clave
Desgaste Abrasivo, Diseño Mecánico, Soldadura