The three main performance indicators of metal bellows are ring stiffness, impact resistance and ring flexibility

Ring stiffness
The ring stiffness represents the ability of the pipe to resist external pressure. The unit is kN / m2. The greater the value of the ring stiffness, the stronger the pipe's ability to resist external pressure and the thicker the wall thickness of the corresponding pipe.

Impact resistance
Using the method of falling weight impact, under the environment of 0 ± 1 ℃, the true impact rate (TIR) ​​≤ 10% (it can be understood that 10 are allowed to break one, but they are not completely equivalent).
的 The factors that affect impact resistance are similar to those that affect ring stiffness.

Loop flexibility
The ring flexibility testing equipment has the same stiffness as the ring, but the compression is greater. The specimen is immediately unloaded when the outer diameter deformation of the specimen in the vertical direction is 30% of the original outer diameter. Observe whether the inner wall of the specimen remains smooth and has no reverse bending. Whether it is cracked and whether the two walls are disengaged.
The loop flexibility reflects the ability of the pipe to resist deformation.

In addition to the ring stiffness, ring flexibility, and impact resistance of the metal bellows, national standards also include creep ratios (reflecting the creep of the bellows after deformation under external force and affecting the product's service life) and oven tests (reflecting double Whether the wall-to-wall corrugated tube has sufficient internal and external bonding strength and structural stability) are required.