How do hydraulic valve parts of hydraulic presses become damaged and fail? The damage to the hydraulic valve parts during daily production and use of hydraulic presses is usually caused by the following reasons: 1. Deformation of physical structures due to long-term fatigue and overload. When the stress during work and external load stress during use exceed the yield strength of the part material, physical deformation of the external structure occurs, especially the bending deformation of the valve core of the overflow valve and the spring deformation, the reciprocating operation is inflexible, resulting in unstable system pressure or slow state transition process. 2. The valve core and valve body are seriously worn, and the gap is too large. The valve core and valve body (shelves), etc. are constantly friction during movement and use, causing changes in the size, shape and surface quality of the parts to change, and the quality is reduced and the effect is ineffective. The solenoid reversing valve core is worn and deformed, causing the valve to leak internally, resulting in reduced efficiency or unstable pressure, causing the system to not work normally. 3. The oil is not clean and causes the hairpin to wear, which will cause the hydraulic valve parts to not work normally, and may even cause hydraulic pressure.