Based on the simulation of the valve body casting process, a hydraulic valve body model with casting defects is established for a single hydraulic valve body. The stress values of the valve body with shrinkage cavity under different pressures are calculated by using workbench. The strength of the valve body with defects and the ideal valve body are analyzed and compared, and the weakening law of the casting defects on the strength of the valve body is revealed. The following conclusions are drawn:
(1) The existence of shrinkage cavity will cause stress concentration, which makes the maximum stress of the valve body with shrinkage cavity greater than the maximum stress of the ideal valve body; at the same time, shrinkage cavity will change the structure of the valve body, reduce the local effective wall thickness, reduce the effective pressure bearing area, reduce the bearing capacity of the valve body, weaken the strength of the valve body, and increase the stress of the valve body, and the stress of the valve body changes with the The pressure increases.
(2) When the pressure is 25MPa, although the maximum stress value of the valve body with shrinkage cavity before improvement is less than the yield limit, the fatigue safety factor is less than 1, which does not meet the fatigue strength; therefore, both the yield limit and the fatigue safety factor need to be considered when analyzing the valve body strength.
(3) When the valve body structure is improved, the volume of defects in the valve body is reduced, and the strength of the valve body is weakened by defects. When the pressure is 30MPa, the improved valve body with shrinkage cavity can still meet the strength requirements.