Effect of Chromium,Niobium and Vanadium Contents on 9Cr-1Mo Tempered Weld Metal Microstructure and Tensile Properties

Mechanical property test,TEM and optical microscope were carried out on the the deposited metals of three 9Cr-1Mo electrodes,provided by the ESAB Company in Sweden,to have a better understanding of their high temperature performance after the tempering of 710℃ or 740℃ for 5 hour.The as tempered weld metals show distribution of Cr carbides,such as Cr₂₃C₆ and Cr₇C₃,precipating along the grain or martensite phase boundary.A comparison of the chemical content of the weld metals indicates that the contents of V and Nb are responsible for the better performance to keep the high temperature when the weld metals were served under high temperature for a long time.