Characterization of compact heat exchangers manufactured by laser powder bed fusion technology

This study presents the material characterization of compact heat exchanger manufactured by laser powder bed fusion. Twelve tensile specimens were manufactured, six horizontally and six vertically, to evaluate the material properties. The mechanical properties of the samples manufactured horizontally resulted in yield strength and ultimate tensile strength higher than the samples produced in the vertical orientation. A pressure vessel specimen was manufactured for hydrostatic test, which was submitted and approved in leak tests, with a leakage rate below 10-7\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${10}^{-7}$$\end{document} mbar/s. The hydrostatic pressure tests demonstrated that the core was suitable for application with pressure up to 700 bar. The average surface roughness was 9.28 µm, measured on the lateral face and 5.84 µm on the upper face, a difference justified by the staircase and remelting effects. Finally, a complete heat exchanger prototype was manufactured and tested. Rectangular samples were produced alongside with the heat exchanger and it was observed that the manufacturing parameters were adequate to obtain a dense part with 99.8% of apparent density, obtained by the image analysis method. Also, the average roughness on the core was 14.38 µm.