GB/T 39249-2020 in English
VALIDRubber and plastics hoses and tubing-Textile-reinforced types- Sub-ambient temperature crush test
- Issued on:2020-11-19
- Implemented on:2021-10-01
- File Format:PDF
- Delivery:Via email within 1~3 business days
$78.00
《GB/T 39249-2020橡胶和塑料软管及非增强软管 织物增强型 低温压扁试验》由TC35（全国橡胶与橡胶制品标准化技术委员会）归口，TC35SC1（全国橡胶与橡胶制品标准化技术委员会软管分会）执行，主管部门为中国石油和化学工业联合会。
Introduction
Interpretation of the core content of the standard
This standard is equivalent to the ISO28702:2008 international standard, which specifically establishes a unified test method for the anti-flattening performance of fabric reinforced rubber hose and plastic hose in low temperature environments. The test is to flatten the hose to 50% of the inner diameter at a specific low temperature to test its crack resistance and structural integrity.
Key technical elements
| Elements | Specific requirements | Technical significance |
|---|---|---|
| Scope of application | Nominal inner diameter ≤100mm | Ensure the adaptability of the test device |
| Test temperature | 0℃ to -55℃ (±2℃) | Covering typical low temperature conditions |
| Flattening degree | 50% of the inner diameter | Simulate extreme deformation conditions |
| Adjustment time | 24h+30min | Ensure uniform temperature penetration |
Key requirements of the test device
The compression fixture must meet the following requirements:
- Parallel plate structure, area ≥ 150% of the sample contact surface
- Flattening speed controlled within 5±2 seconds
- Adjustment room equipped with temperature monitoring device
Typical application case: A hydraulic hose was judged to be unqualified due to cracks at the seams of the fabric layer during a -40℃ test. It passed the verification after improving the weaving process.
Recommendations for the implementation of the standard
- For special medium hoses, it is recommended to add additional temperature points specified in the product standard
- When cutting the sample, the hose connection should be avoided by at least 50mm
- It is recommended to use a conditioning room with an observation window for real-time monitoring
- The environmental temperature and humidity data need to be recorded during the recovery phase after the test
Analysis of technological evolution
Compared with the old version of the standard, GB/T39249-2020 has the following major improvements:
- Explicitly allow the use of equivalent mechanical test devices
- Add a 15-second transfer time limit clause
- Refine the magnification requirements for sample inspection
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