Adapt to working pressure and temperature. Not only to consider the peak pressure and temperature, but also to consider their fluctuations and rate of change. Seal gasket is necessary to withstand pressure and temperature, but also because of pressure and temperature changes and leakage
Consider the chemical corrosion and electrochemical corrosion of the medium. If the reaction tank, should consider the corrosion of raw materials, finished products, corrosive and corrosive reaction process. foam gaskets If the medium is a solvent, consideration should be given to the dissolution of the gasket.
The media can not leak from the gasket and the flange surface (interface leak), can not leak out from the gasket itself (osmotic leakage), which depends on the extent of the flange tightening, but also depends on the nature of the gasket itself, so To seriously consider, foam gaskets especially for toxic gases, foam gaskets vacuum, radioactive media, flammable and explosive materials more attention. Not only requires the initial state of the gasket sealing is good, but also requires long-term operation is not fatigue, no relaxation.
Flange sealing surface with a plane, bump, tongue and groove and other forms, foam gaskets the gasket should be the corresponding. Flange sealing surface surface finish, foam gaskets hardness is different, there are different requirements on the gasket, gasket should also be the corresponding. If the flange is not large, it is necessary to use not often strong gasket.
Take care of special requirements. If a medium does not allow the amount of fiber mixed, foam gaskets do not use asbestos rubber sheet and other fibrous washers. Some parts of the vibration is very large, we must use strong anti-vibration gasket. For difficult to repair the place, foam gaskets on the use of durable gaskets. And so on, all need to use the brains.
Y, m value is small. In the premise of ensuring the seal should be used y, foam gaskets m value of the small gasket, the installation of labor saving labor, when the replacement is also convenient
Economically cheap. Several can meet the requirements of the gasket, of course, to choose the economy cheap. But how to be considered cheap broker, can not just look at the price of a gasket, foam gaskets but also consider the purchase of easy, how much freight, life and other factors, and then make conclusions.
A device area, a workshop, and even a factory, gasket specifications and material varieties, the less easy to manage, so the choice of gaskets, in addition to the above should consider the above, foam gaskets but also try to merge specifications and materials, avoid unnecessary diversification The
The microstructure, chemical composition, foam gaskets surface discontinuity, mechanical properties, core hardness and so on of the broken bolts were all in line with the standard requirements. The microstructure of the section shows that there is a large area fatigue zone in the section, which is characterized by fatigue fracture. The fatigue source area is located at the end of the thread. The fatigue extension area is about 4/5, the fatigue strip spacing is narrow, Small, it can be concluded that the fracture properties of the bolts are typical low stress high cycle fatigue fracture, and the ultimate stress is smaller. The metal structure of the gasket shows that the material is low carbon steel and is not heat treated, and the surface is completely decarburized, foam gaskets resulting in a lower hardness of the gasket, especially the surface hardness.
The friction coefficient of the bolt washer assembly was tested. The results showed that the friction coefficient between the bolt head and the washer was large. When the test torque was 100 Nm, foam gaskets the axial clamping force of the bolt was only 45.4 kN. In general, the bolt installation preload force of the appropriate range of 70% to 80% of the yield strength of the bolt, after conversion to the specifications for the M12, the performance level of 10.9 Bolt theoretical best preload of 55.4 ~ 63.3 k N The Experiments show that: the bolt preload is significantly less than the recommended preload. Washer hardness is too low, resulting in the role of pre-tightening plastic deformation occurs, which is caused by increased friction under the head of the reasons for the bolt. foam gaskets Due to the large friction coefficient, the applied installation torque is mostly used to overcome the friction under the head of the bolt, resulting in insufficient actual preload. The test results show that under the same conditions, the fasteners with smaller preload are more easily loosened and induce fatigue damage. At the same time, foam gaskets when the gasket stiffness or strength is insufficient, the bolts are also subjected to alternating loads. Will lead to increased load on the bolt to increase the load or the bucket creep caused by loose bolts, more likely to induce fatigue fracture of the bolt. foam gaskets In addition, according to GB / T 97.1-2002 regulations, foam gaskets and 10.9 bolts supporting the use of flat washers recommended for the 300 HV level, that is, the gasket hardness range of 300 HV ~ 370 HV, and the test of the combined test results with the standard does not match the standard.