The activity of reworked magnesium oxide should be tested for each batch to ensure that each batch of reworked parts meets ≥60% of the industry standard (HG/T 3928-2012), avoiding insulation failure or early faults due to batch fluctuations.
1. Testing Frequency Principle: Every batch must be tested.
Sampling Requirements: At least 3 samples should be taken from each reworked batch for testing to ensure representativeness.
Testing Timing: Samples should be taken and sent for testing within 24 hours after sintering is completed and cooled to room temperature to prevent moisture absorption from affecting activity.
Testing Basis: The hydration method as specified in the national standard HG/T 3928-2012 is used for determination, performed by a CNAS-certified laboratory.
Batch testing can effectively identify potential risks such as raw material changes and process deviations, and is a core link in quality closed-loop management.
2. When is it necessary to increase the testing frequency?
Scenario Testing Strategies
Raw Material Batch Change: The first piece of new raw material must be tested; two consecutive batches are tested to confirm stability.
Sintering Process Adjustment: The first three batches after process change are fully tested to verify parameter compatibility.
Equipment Overhaul or Restart After Shutdown: The first batch after restart is subjected to stricter testing to rule out contamination or parameter drift.
Abnormal Returned Parts: Trace back and retest the same batches to prevent batch-related risks.
Practice shows that dynamically adjusting the testing frequency can improve problem response speed and reduce quality risks.
3. Recommended Testing Institutions (CNAS Certified)
To ensure authoritative and traceable results, it is recommended to send samples to the following institutions:
Zhongxi Testing (Nationwide coverage, supports 22+ tests)
Wuhan Kehai Inspection Co., Ltd. (Localized service, fast report generation)
Guangfen Testing & Certification Co., Ltd. (Wuhan Branch) (Focusing on high-purity material analysis)
The test report must bear the CMA/CNAS mark as the legal basis for quality release.
