it is important to make sure that huge long reach excavator work safe and strong in project, usually below 50ton ecavator, we suggest general contruction equipment material Q345B to make long reach boom arm, yield strength of Q345B is around 350MPa, that is enough for small and medium excavator,

But for more than 50ton excavator, we recommend better quality steel, like Q690D which yield strength reach around 800MPa, the big long reach boom arm need to endure itself weight and working with excavator, general purpose material Q345B is not as good as Q690D performance, below is mechanical property of these two material