Effect of Brazing Conditions on the Microstructure and Mechanical Properties of Duplex Stainless Steels to Cr-Cu Alloy with Cu-Base Insert Metal

摘要

The brazing of a copper-chromium alloy and DSS (Duplex stainless steel) was conducted under various conditions to investigate the bonding phenomena, microstructures and mechanical properties. The reactions of liquid insert metal with dissimilar base metals, a Cu-Cr alloy and DSS produced various phases in the bond zone. The chemical composition and the volume fraction of the phases varied as a function of the brazing conditions. The Cu phase for the DSS and piece of stainless steel separated from the DSS was produced from the reaction of the insert metal and the DSS. In addition, the Cr-Mn phase, Mn-Fe phase and Fe-Cr phase were formed by the reaction between the insert metal and each base metal. As the brazing temperature and time increased; the amounts of the Cu phase and the number of stainless steel pieces increased. In addition, the Mn-Fe phase varied compared to the Fe-Cr phase after brazing at 1273 K at 0 min. The Cr-Mn phase initially increased but eventually decreased after holding times of 15 min at 1273 K and 7 min at 1303 K.