Cracks Cause excavator boom side cracks reasons: including the original weld itself bubble, slag and small cracks, the work overload excavator, used excavator manufacturers Which is good, original weld produces micro-cracks and slowly expand: when welding electrode and the plate does not match the performance and cracks: a large excavator boom due to volume, large-scale second-hand excavator manufacturers, difficult to employ reliable and effective heat insulation measures, failed to complete after welding removing the hardened base material surrounding the weld zone, resulting in weld strength decline: Excavators greater impact vibration during operation, so that the weld seam at the uneven stress cracking. System check the relevant parameters of the hydraulic pump large hydraulic excavator control two main ways: ultimate load regulator with pressure shut-off function (ie CUT-OFF function) (GLR) and load sensing regulator (LS) mode. The role of CUT-OFF function, when system pressure reaches the setting value, the swash plate angle variable pump is reduced, the pump can only be maintained at the pressure required to maintain the "residual" flow state, Beijing second-hand excavator manufacturers, in order to avoid overflow relief valve overheating. To achieve this purpose, the system parameters to match the technical requirements so that the setting value is lower than the CUT-OFF valve set-value of the primary circuit pressure valve; otherwise, the primary pressure relief valve open will result in overheating. Used excavator manufacturers sale, Jin Hao used excavators, used excavators vendors Yunnan Jin Hao from Shanghai Used Construction Machinery Co. Shanghai Jin Hao Used Construction Machinery Co. (www.jinhaosh.cn) is the Shanghai Minhang District, mining machinery leaders, over the years, the company is implementing the scientific management, innovation and development, the principle of honesty and trustworthiness, and satisfy customer needs. Kim Ho used excavators in leadership with the staff warmly welcome all inquiries negotiations to create jinhao used excavators better future.