Structure type and design method of thermal power

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Structural types and design methods of Electrodeposited bellows

structural types of Electrodeposited bellows

according to the structure of the mating parts at both ends, electrodeposited bellows can be divided into three types: both ends are internally matched; Both ends are externally matched; One end is an internal fit and the other end is an external fit. The waveform of Electrodeposited bellows can be divided into "U" type and "V" type

material of Electrodeposited bellows

nickel material is generally used for electrodeposited bellows. The properties of nickel layer obtained by different electrodeposition processes are different, which can be generally divided into two types

1. Conventional nickel

this metal is brighter and has higher yield strength. The deposition layer contains a certain amount of sulfur, which will cause the embrittlement of bellows at higher temperature. Therefore, the service temperature of bellows made of this material cannot exceed 180 ℃

2. Sulfur free nickel

this metal has Satin luster, its yield strength is slightly lower than that of conventional nickel, its corrosion resistance is better than that of conventional nickel, and the sulfur content in the nickel layer is less than 0.003%. The maximum service temperature of bellows made of this material can reach 250 ℃

performance analysis of Electrodeposited bellows

1. displacement of bellows

the rated displacement of Electrodeposited bellows is related to factors such as outer diameter, inner diameter, wall thickness and number of corrugations of bellows. At the same time, the compression bellows is stretched, which requires special calculation

2. Pressure resistance of bellows

the maximum pressure that does not cause plastic deformation of the waveform of the bellows is called the pressure resistance of the bellows

3. Stiffness of bellows

because bellows can bear concentrated force, uniformly distributed force and bending moment, its stiffness can be divided into concentrated force stiffness, uniformly distributed force stiffness and bending stiffness according to the force category. The most commonly used one is the concentrated force stiffness, which is called the stiffness of bellows

4. Effective area of bellows (2) strive to improve the effective area of a batch of advanced basic materials

bellows represents the ability of bellows to convert pressure into concentrated force. Due to the complex structure of bellows and different electrodeposition processes, the properties of bellows are different. Even under the same process conditions, if the electrolyte composition or process parameters change, the properties of bellows will also change. Therefore, when selecting bellows, the actual test parameters should prevail

design limit of Electrodeposited bellows

in the process of design and manufacture, electrodeposited bellows should meet not only the requirements of its mechanical properties, but also the requirements of electrodeposition process. Mainly manifested in:

1. Outer diameter limit

the outer diameter of Electrodeposited bellows generally cannot exceed 35m. If the ripple depth is limited to meet the needs of the electrodeposition process, the outer diameter of the bellows can be appropriately increased

2. Ratio of inner diameter to outer diameter

in order to meet the needs of electrodeposition process, the ratio of inner diameter to outer diameter must be greater than or equal to 0.6, and the best value is 0.65. The larger the ratio is, the more uniform the wall thickness of the bellows is, but too large the internal and external diameter ratio will reduce the elasticity of the bellows

3. The wall thickness of bellows

the wall thickness of Electrodeposited bellows of different sizes is generally greater than a certain value

the manufacturing tolerance of Electrodeposited bellows is due to its excellent waterproof performance

1 When the inner diameter of the bellows is greater than 6.35mm, the manufacturing tolerance is +/- 0.125mm. When the inner diameter is less than 6.35mm

outer diameter

the outer diameter tolerance changes with the wall thickness and the size of the bellows


the length tolerance of the corrugated part is +/- 0.25mm

the opening of the end pipe

the inner diameter tolerance of the opening of the end pipe is +/- 0.04mm

the end pipe joint

the length tolerance of the end pipe joint is +/- 0.125mm

2. Stiffness tolerance

the length tolerance of the bellows.The stiffness tolerance is generally +/- of the nominal value, which is made into automobile components The shell of the flashlight is 30%, and the special can reach +/-5%

3. The wall thickness tolerance

the wall thickness of the bellows is variable, and its tolerance is generally +/-5% of the average wall thickness (end)

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