How to Test the Stiffness of Bellows Ring

Ring stiffness is a key indicator to measure the compression resistance of HDPE double-wall corrugated pipes. The test process needs to simulate the actual stress scene through professional equipment. The following is the popular version of the guide for ring stiffness testing of double-wall corrugated pipes: 1. Test principle Core logic: By slowly compressing the pipe, measure its pressure value at 3% deformation, and then convert it to the pressure per square meter (kN/m ²). Key formula: Ring stiffness (SN) = pressure value (N) Pipe length (m)/deformation amount (m) ² 2. Test steps (super easy-to-understand version) Cut pipe Take a sample with a length of 300mm from the whole corrugated pipe (both ends need to be cut flat). Example: If the total length of the pipe is 6 meters, saw off 30cm for inspection. The device places the sample horizontally between the two flat clamps of the electronic universal testing machine. Make sure that the axis of the pipe is aligned with the center of the fixture (clamp the pipe like a hamburger). Press the pipe to start the testing machine, and let the upper pressure plate slowly press down at a speed of 10mm/min (slower than a turtle crawl). Observe the deformation of the pipe. When the diameter is compressed by ** 3% ** (such as the original diameter of 200mm, pressed to 194mm), stop immediately. The screen of the reading data testing machine shows the pressure value at this time (unit: N). Example: The pressure shows 5000N. The calculation result is substituted into the formula to calculate the ring stiffness: plaintextSN = 5000N 0.3m/(0.03200mm) ² = 50000.3/(6mm) ² = 1500/0.000036 = 41666667N/m ² 41.67kN/m ² (ie SN41.67) Practical application: According to the industry standard rounding, SN41.67 may be marked as SN40 or SN42.5. 3. Precautions (the secret of accurate measurement) Samples should be "regular" The cutting surface must be perpendicular to the axis, otherwise it will lead to uneven force. There can be no scratches or depressions on the inner and outer walls of the pipe (pick smooth ones like selecting watermelons). Environmental stability testing The room temperature needs to be controlled at 232 ° C (too cold or too hot will affect the performance of plastics). Avoid people walking or vibrating equipment during the test (like being quiet when measuring blood pressure). The operation should be "Buddhist". The pressure speed must be strictly carried out according to the standard. If it is fast, the result will be high, and if it is slow, the result will be low. 4. Test Standards and Qualifications National Standard: GB/T 9647-2015 "Thermoplastic Pipes, Determination of Ring Stiffness" Authoritative Certification: The pipes of regular manufacturers (such as Hubei AD Building Materials) will be accompanied by a third-party test report, which can be scanned to verify the authenticity. 5. Why choose AD HDPE double-wall corrugated pipes? Precise Quality Control: Random sampling and testing of each batch of pipes, the qualified rate of ring stiffness is 99.8%. Scene Adaptation: Provide a full range of SN4 to SN16 products to meet the different needs of municipal, industrial, agricultural, etc. Professional services: free to provide ring stiffness testing guidance to assist customers to complete the acceptance.

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One-sentence summary: Measuring ring stiffness is like giving a pipe a "physical examination", when pressed to 3% deformation to see how much force it can bear, the larger the value, the more pressure!