How to test the tear strength of stainless steel plate protective film

Tear Strength Testing Protocol for Stainless Steel Plate Protective Film

Select 10 representative samples from different positions of the same batch

Cut samples to 150mm × 25mm rectangles according to GB/T 1040.3 standard

Prefabricate a 20mm long incision in the middle (depth = 1/2 width)

Ensure incision is smooth and burr-free

				Conditioning: Place samples at 23℃±2℃ and 50%±5% RH for ≥4 hours to reach stable state
			

Use universal material testing machine with 100mm clamping distance

Align sample longitudinally with clamp center line to prevent skew

Set test speed to 500mm/min

Record maximum force value during tearing process

				Testing Repeats: Perform 3 tests per sample, use average value as tear strength data (in kN/m)
			

If deviation exceeds 15%, require re-sampling

				Acceptance Criteria:

• General protective film: ≥2.5kN/m

• Heavy processing scenarios: ≥4.0kN/m

Prevent fixture slippage (use rubber pads to enhance friction)

Discard data if sample breaks at clamping point (retest required)

Inspect glue layer at incision for detachment after testing

Important Note:

If material stratification is observed at incision, analyze its impact on test results