Investigation of the Mechanical Properties of the Weld by Flux-Cored Wire E91T1 After Post Welding Heat Treatment

摘要

E91T1 is a kind of flux-cored wire used widely for the low-alloys. It has a characteristics of high welding efficiency and good shape of the weld. The weld deposit has good mechanical properties in As-welded condition. But after 10 hours of the Post welding heat treatment (short for PWHT below), the impact toughness of the weld deposits drop sharply. The microstructures of the weld deposits are investigated by using the scanning electron microscope and optional microscope respectively. Results indicate that the oxygen, the alkalinity of the weld slag and oxide inclusion are very important factors to make the weld deposits brittle in toughness. And a modified E91T1 is gotten by adding some alkaline oxides in the E91T1 which mainly contains acidic oxides in the powder. The modified E91T1 that its weld slag is alkaline has a high impact values than those of E91T1.