Shaped spring decision valve opening pressure, disc stroke and seal stability. If there is a problem with this spring, the entire valve will be difficult to work properly.

On this basis, the failure of the valve spring is summarized in order to pay attention to and prevent in the future operation.

The reasons for frequent failure of valve spring are summarized as follows:

1, high pressure - spring load can be divided into static load, impact load and vibration load according to the form of external force. The key cause of spring failure is high stress caused by large deformation and high load. High stress is only applicable to static load spring, low stress fatigue life is longer.

Step 2. Hydrogen embrittlement - Spring will fail due to brittleness if proper hydrogen solution is not developed after electroplating or pickling, but non-ferrous valve springs are not affected by this. In electroplating solutions, the necessary number of hydrogen ions is always present in the electrolysis of water molecules. One part of the hydrogen ion causes hydrogen to overflow, while the other part penetrates into the coating and the metal body in the state of hydrogen, making the metal body and the coating less tough and brittle, i.e. hydrogen embrittlement. Therefore, after electroplating or pickling should be dehydrogenated in an oven or resistance furnace. The temperature and time shall be determined according to the spring size and coating thickness. The normal temperature should be between 150-250 degrees Celsius and the holding time should be between 0.5-5 hours.

3, leaf springs, grooving or scratches caused by severe bending and notching stretch, deformation and severe bending, can cause higher stress concentration and damage, so bending radius should be as large as possible, to prevent imprinting.

4. Fatigue - Repeated spring deformations, especially in excess of 106 cycles, will cause fatigue damage even under moderate stresses. When operating conditions are bad, low stress should be selected to enhance the spring fatigue. Under the condition of reasonable selection of raw materials, shot peening not only makes the surface layer of spring smooth, but also improves the anti-fatigue property of spring and extends the service life of spring. And can alleviate and even prevent surface decarburization, pit, indentation, cracks and other defects.