How to choose sealing gasket (2)

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This post was last edited by Xin Ruifang Xiao on 2025-6-13 08:54 Last time we shared with you how to select sealing gaskets based on temperature, pressure, medium, gasket thickness and gasket stress. In this issue we introduce several aspects related to fasteners, including the material properties of bolts/studs, nuts and washers. 1. Bolts/studs The reliability of bolt flange connections depends largely on threaded fasteners. They are not only one of the key components in the connection, but also one of the most neglected components. They act like a spring to control internal and external forces to maintain the required sealing stress on the gasket. Although threaded fasteners are generally considered a mature technology, there are still significant problems with their use. Problems with threaded fasteners are due to insufficient preload, self-loosening, tensile overload, fatigue, wear and stripping. Bolted design provides reliable connection ； In practice, fastener-related failures are not uncommon. Critical problems often arise in practical applications due to force uncertainty, the size of the preload during the tightening process, inappropriate materials and, most notably, human errors. Any problems with fasteners can have serious consequences. Sometimes such failures can have disastrous consequences. 2. Steel washers are added to the washer fastener system to improve the conversion of torque input to bolt pretightening force. The gasket protects the flange contact surface from the turning nut and provides a smooth bearing surface to reduce friction between the nut and flange. Dramatically reduces friction between the turning nut and joint assembly. This improves the consistency of torque operation, thereby improving accuracy and repeatability while reducing the torque required ； Reduces fatigue problems by spreading the load exerted by fasteners on the joint ； Improves gasket performance by making interfacial forces more uniform between joint components ； Bridge slotted or oversized holes to facilitate assembly of poorly fitting parts ； Prevent damage to joint surfaces ； Reduces the amount of embedment between joint components, thereby reducing slack after tightening ； 3. Nuts Nuts generate tension in the fastener (and compressive pressure on the washers) by tightening along the bolt threads. The bolt and nut materials are well matched, the physical condition is correct, the surface is lubricated, and the hardness is good. This is the end of this sharing. See you in the next one!