Study on damage of fatigue and creep on 1Cr11Ni2W2MoV steel welding joint at 422 °C

Fatigue crack propagating tests and creep tests of butt welds in 1Cr11Ni2W2MoV steel plate used on aerospace at 422°C were carried out. The tests results show that the weakness of the welding joint is the heat affect zone (HAZ).The data from the tests were fitted to get parameters. The damages due to creep and fatigue crack propagating in three main welds on the outer box of an airplane engine were calculated using Miner linear accumulating damage theory through FEM(finite element method) and the tests parameters. The calculation shows that the discontinuity in geometry in the structure is the main fact to increasing the creep and fatigue damage in their service life at high temperature.