7 quality inspection criteria to identify high-quality rubber seals
As a key component in the industrial field, the quality of rubber seals directly affects the tightness, durability, and safety of equipment. However, the quality of products in the market is uneven, how can you quickly identify high-quality rubber seals? Based on international industry standards (such as ASTM and ISO) and 20 years of industry experience, this article summarizes 7 key quality inspection standards to help you accurately select cost-effective products and reduce procurement risks.
Rubber Material Performance Testing: The Basics of the Basics
The core of high-quality rubber seals lies in the raw materials. Focus on:
Hardness test (Shore hardness tester): select the appropriate hardness (usually 50-90 Shore A) according to the application scenario, the hardness is too low and easy to deform, and too high is inelastic.
Tensile strength and elongation at break: in accordance with ASTM D412 standard, tensile strength ≥ 10MPa, elongation ≥ 200% is qualified.
Density detection: verify the purity of the material by drainage method, and the abnormal density may be doped with reclaimed rubber or filler.
Temperature Resistance Verification: Stability in Extreme Environments
Rubber seals need to be adapted to operating temperatures from -40°C to 200°C (depending on the material):
High-temperature aging test: After 70 hours of 150°C hot air aging, the hardness changes by ≤±15% and the tensile strength retention rate is≥ 70%.
Low-temperature brittleness test: The sample is frozen in liquid nitrogen to see if cracks or fractures occur.
Oil and chemical resistance testing: against complex media
1. Select the corresponding material according to the contact medium (such as NBR oil resistance, EPDM acid, and alkali resistance):
2. Volume change rate test: Soak in the specified liquid (such as ASTM oil #3) for 70 hours, the volume expansion rate should be ≤ 30%.
3. Quality loss rate test: 5% of the mass loss ≤ after chemical corrosion is qualified.
Compression set testing: a key indicator of long-term sealing
(Solve the user's pain point "seal deformation leakage")
Tested according to ISO 815:
After compressing the sample by 25%, it was kept at the indicated temperature for 22 hours.
Measure the deformation after 30 minutes of recovery, and the deformation rate of high-quality products should be ≤ 20%.
Dimensional accuracy control: millimeter-level error determines success or failure
Detected by a CMM:
Inner diameter/outer diameter tolerance: usually controlled within ±0.1mm (0.05mm for medical/aerospace ±applications).
Cross-sectional dimensional consistency: the thickness fluctuation of the same batch of products ≤ 0.05mm.
Surface defect troubleshooting: quality control details visible to the naked eye
Visual inspection: no bubbles, impurities, lack of glue, or burrs (with the aid of 10x magnification).
Surface roughness test: Ra value ≤ 3.2μm to ensure a tight fit with the contact surface.
Simulated Life Testing: The Ultimate Quality Verification
Dynamic fatigue test: Simulate the actual working frequency (such as 1000 times/min) to run 100,000 times, and the leakage ≤ 0.1ml/min.
Pressure cycle test: continuous pressurization for 1000 times at 1.5 times working pressure without rupture or permanent deformation.
Why Choose Our Rubber Seals?
✅ Triple quality inspection system: raw material incoming inspection→ SPC control in the production process→ 100% full inspection of finished products
✅ Comply with international certifications: ISO 9001, FDA, RoHS, REACH compliance
✅ Customized service: provide free sample testing and working condition adaptation solutions
