Selection of flat washers and spring washers

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Flat washers: How to choose flat washers? Flat washers are components used to prevent bolts and nuts from locking together. Flat washers are used wherever fasteners are employed. How should one choose the appropriate flat washer? A flat washer is a type of washer that serves primarily to increase the contact area between screws and large equipment, as well as to aid in tightening. When using flat washers, they are often used in combination with nuts. When storing flat washers, it is important to do so within an appropriate sealing period; they possess the following key characteristics: 1. In harsh environments, flat washers should be sealed so that leakage does not occur under the effects of certain temperatures and pressures during operation. 2. When connecting the flat gasket and the contact surface, it is necessary to ensure better sealing, to achieve an optimal result. 3. When the gasket is under pressure, it should have good wrinkle resistance due to the influence of temperature; otherwise, the screws may be damaged, leading to air leakage. 4. Be careful not to get infected when using flat washers. 5. Using flat washers allows for easy disassembly; this is the main advantage of choosing flat washers. 6. Remember to ensure that flat washers are used under appropriate temperature conditions for proper functioning. To make better use of flat washers, it is advisable to choose those coated with rust- and corrosion-resistant materials when selecting them; this not only saves time and effort but also ensures that the washers can perform their functions effectively. When used in conjunction with bolts and nuts, the selection criteria for flat washers are as follows: 1. When choosing the material for the washer, attention should be paid to the issue of electrochemical corrosion that occurs when different metals come into contact. The material of the flat washer is generally the same as that of the components being connected, usually steel, alloy steel, stainless steel, aluminum alloy, etc. When electrical conductivity is required, copper and copper alloys can be used. 2. The inner diameter of the flat washer should be chosen based on the larger value of the thread or screw diameter; if the materials to be connected are soft (such as composite materials), or if it is to be used in conjunction with a spring washer, its outer diameter should be set at a larger value. 3. When choosing to place a W washer under the head of a bolt or screw, in order to avoid interference between the radius at the bottom of the head and the washer, a flat washer with chamfers on its inner hole can be used. 4. For important bolts with larger diameters, or to enhance resistance to crushing forces, steel washers should be used. Steel washers shall be used for tension bolts or tension-shear composite bolt connections. 5. Special washers are used in areas with specific requirements; copper washers can be used when conductivity is required ； For applications requiring airtightness, gaskets and the like can be used. Functions of flat washers: 1. Increase the contact area between the screw and the machine. 2. Eliminate damage to the machine surface caused by the spring washer when removing screws. When in use, it must be: a spring washer followed by a flat washer, with the flat washer against the machine surface and the spring washer located between the flat washer and the nut. Flat washers are used to increase the area over which the screw is subjected to force. Spring washers serve to prevent screws from loosening, providing a certain degree of cushioning protection when stress is applied. Although flat washers can be used as sacrificial washers. 3. But more often, it is used as a supplementary cushion or flattening pad. Advantages: ① By increasing the contact area, it can protect components from damage ； ②By increasing the contact area, the pressure between the nut and the equipment is reduced, thereby providing protection. Disadvantages: ① Flat washers cannot provide seismic resistance ； ②Flat washers also do not have a loosening-prevention function. Spring washer: Functions of the spring washer. 1. The function of a spring washer is to provide elastic force to the nut after it has been tightened, thereby pressing the nut in place and preventing it from coming loose. The basic function of the spring is to apply a force to the nut after it is tightened, thereby increasing the friction between the nut and the bolt. 2. Spring washers are generally used instead of flat washers (flat and spring washers are considered only when it is necessary to protect the surfaces of the fasteners and the mounting surface). 3. Flat washers are generally used in connectors; one type is soft in texture while the other is hard and brittle. Their main function is to increase the contact area, distribute pressure, and prevent the softer material from being damaged. Advantages: ① Spring washers provide excellent anti-loosening effects ； ②Spring washers provide good seismic resistance ； ③Low manufacturing cost ； ④It’s easy to install. Disadvantages: Spring washers are greatly affected by the material and manufacturing process; if the material is of poor quality, the heat treatment is not done properly, or other aspects of the manufacturing process are not up to standard, cracking can easily occur. Therefore, it is essential to choose a reliable manufacturer. When to use flat shims and when to use spring shims? 1. Under normal circumstances, flat washers can be used alone when the load is relatively small and there is no vibration load. 2. In cases of high loads or exposure to vibration-induced loads, a combination of flat washers and spring washers must be used. 3. Spring washers are basically not used alone; they are always used in combination. In actual use, due to the different functions of flat washers and spring washers, in many cases they are used together in combination; this approach offers the advantages of protecting components, preventing nuts from loosening, and reducing vibrations, making it an excellent choice.