Projeto, construção e teste de um aparato Jominy para ensaios de temperabilidade

Abstract

This project is based in constructing a device for temperature testing, according to ABNT NBR 6339 and ASTM A 255 standards, to provide UNIPAMPA (Federal University of the Pampa) Alegrete campus’ laboratories, a mean of measuring temperability or hardenability in steels, ie the ability to measure hardening as a function of depth in high and low alloy materials. It consists of a metal plunger with approximately 101 mm in length and 25.4 mm in diameter which will be heated to the austenitizing zone. Then one of it’s ends is subjected to a sudden cooling by a constant water jet, while the ends are exposed to ambient temperature. This method allows for a hardening progression from the end which has been cooled. For the cooling to be analyzed, Rockwell hardness testing are performed, by this means we obtain axial hardness alongside it's body. By following aforementioned standards we plot Jominy’s temperability curve. The device consists of valves controlling water flow, a bracket for test specimens, a standard following nozzle, water storage and pumping system, everything fastened to a metal structure with height adjustment. The working of the apparatus has already been tested and validated, and the same, is already working in the class of Thermal and Surface Treatments in UNIPAMPA laboratories.