Desenvolvimento do sistema de instrumentação e controle de um Macroindentador portátil para avaliação de propriedades mecânicas de dutos

Abstract

Automated bali indentation is a non-destructive technique to obtain some important mechanical properties of metallic structures. Those properties can be used, for instance, to establish the correct operating setpoint under specific conditions. This work describes the development of a dedicated apparatus capable of performing in-situ macroindentation tests. The system is divided into three major blocks: mechanical structure, hardware and software. A number of hardware units are used to control and monitor the indentation process. The software acts as a general manager and should define the correct operating condition for the hardware units. Besides, the software is responsible for data acquisition and processing to obtain the following mechanical properties: hardness, yield strength, ultimate tensile strength, work hardening exponent, stress coefficient and flow curve. This work depicts the development of the hardware and software units necessary for controlling the various devices, data acquisition and processing. In order to evaluate the prototype, a number of macroindentation experiments were develop in laboratory. The experiments were based on tests with two types of steel: X42 and X60. Those materiais were also evaluated by conventional tensile and hardness tests. The mechanical properties obtained by macroindentation showed excellent correlation with those obtained by conventional tests (error below 10%).