Effect of Cu Content on Microstructure and Mechanical Properties for High-Strength Deposited Metals Strengthened by Nano-Precipitation

With the rapid development of low-carbon high strength steel, higher requirements are put forward for matching welding consumables. The deposited metals with 0.62–2.32% Cu addition was prepared by tungsten inert gas via metal cored wire. effect element on microstructure and mechanical properties were investigated. multiphase consists bainite, martensite, residual austenite, martensite-austenite constituents. It is found that decreases start temperature martensite (Ms) enlarges range bainite from 372 K to 416 K, improving formation bainite. increase content, fraction shape M-A constituents changes strip into granular. There BCC FCC precipitates in metals. diameter 14–28 nm, volume it increases content. Meanwhile, 1.79% can achieve a 10% enhancement (yield strength, 873–961 MPa, ultimate tensile 1173–1286 MPa) at little expense impact toughness (64.56–56.39 J ?20 °C). precipitation effectively improve metals, but degrades because lower crack initiation energy. shows an excellent strength-toughness balance.