WELDING CHARACTERISTICS OF CORROSION RESISTANT NI-BASED ALLOYS MONEL 400 AND HASTELLOY C-276 THIN FOIL WELDED BY PULSED ND:YAGLASER

摘要

In this paper a Nd:YAG pulsed laser beam was used to join Monel 400 and Hastelloy C-276 thin foils, and the effects of pulse energy on the quality of the welding joints characteristics were analyzed. Pulsed laser processing is expected to be the method of choice because it allows more precise heat control compared with arc and plasma processing. Welding thin foifs is very important in many industrial applications. The need for joints between different thicknesses often appears in complex components, especially the combination with a more corrosion resistant material. Due to differences in thermal conductivity, fusion temperature and solubility of the materials, brittle phases can appear and deteriorate the tensile strength of the joint. Pulsed laser systems have the capability to weld thin foils without filler metal (autogenous welding), high energy density and low heat-input. The pulse energy was varied from 1.0 J to 2.25 J at an increment of 0.25 J and a 4 ms pulse duration. The macro and microstructures of the welds were analyzed by optical microscopy. Sound laser welds without discontinuities were obtained with 1.5 J and 1.75 J pulse energy. Results indicate that using a precise control of the pulse energy, and so a control of the dilution rate, is possible to weld Monel 400 and Hastelloy C-276 thin foils by pulsed Nd:YAG laser]