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A metal bellows is manufactured from thin tube, to provide the necessary flexibility in the bellows convolutions. The bellows tube may be only a few microns thick, and therefore the selection and manufacture of appropriate materials is critical to bellows performance and integrity.
Materials are selected to suit the application environment to take account of corrosion resistance, temperature, fatigue life and other parameters. They are specified and manufactured to the internationally recognised national standards relevant to our customers’ market sectors.
Thin-walled tubes for bellows are produced by seamless drawing from billet, deep drawing of flat sheet, or by rolling and butt-welding of weldable sheet materials. All tubing must be strictly uniform and homogeneous, not only in dimensions but in grain size, which should be closely controlled by suitable annealing of work-hardening materials at various stages of manufacture.
| Stainless Steel |
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Used in the main for its high resistance to corrosion and also because of its hygienic properties. Typical applications include Bellows Sealed Valves and covers for certain types of Load Cells and in the food industry where none contamination is essential. |
| Condition |
-Seamed
-Seamless |
| Type |
AISI 321
AISI 316L
AISI 316TI |
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| Phosphor Bronze |
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This material has excellent resistance to corrosion and is recommended for use in salt-laden air,sea water,crude oils and other corrosive conditions. It is relatively free from creep,drift and hysteresis. Typical applications include pressure sensitive devices and aneroid units |
| Type |
BS 2870 PB 102
ISO CuSn5
ISO CuSn6
ISO CuSn8 |
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| Brass |
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All sizes and types of bellows detailed in phosphor bronze are also offered in brass. Brass bellows exhibit similar characteristics to phosphor bronze bellows. In the smaller sizes these are identical but in the larger sizes spring rates and maximum pressures of brass bellows may be as much as 7% lower than for phosphor bronze equivalents. However, maximum deflections, flexibilities, lengths over convolutions and convolution pitches will be up to 5% more. Typical applications include liquid/gas filled thermostats and barometers. |
| Type |
BS 2870 CZ 103 - ISO CuZn20 |
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| Monel |
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A material with excellent corrosion and stress corrosion resistance in corrosive media. Typically used in harsh water environments. N.B. Please contact us for details of available range. |
| Type |
BS 3073:1977 NA 13 |
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