Crane performance and boom length are the most important concerns of crane friends.，The length of the arm is increasing，As a result, the Vehicle weight is getting heavier and heavier.，Restricted by road laws，Vehicle structure lightweight will become the key breakthrough point of crane。At present，Single-cylinder five-section arm technology independently developed by SANY，Under the condition that the performance is not reduced，Achieve the effect of saving time and labor and reducing weight.，Fully adapt to the development trend。