FRACTURE OF A HYDRAULIC CYLINDER DUE TO OVERLAY WELDING

An hydraulic cylinder repaired by overlay welding fractured due to fat igue. The failure analysis showed that the crack weld repair was carri ed out without any preheating of the base metal. This results in a que nch crack in the transition zone between the deposit weld metal and th e base material. Therefore the damage must have been caused by an inco rrect weld repair. Additionally, further processing defects were detec ted, such as the omittance of necessary quenching and tempering, the u se of different filler metals as well as the presence of a coarse weld slag inclusion. This failure is typical of the accumulation of severa l processing defects.