Quality Control
Measured at every stage, from sand to shipment.
PT Tri Sinar Purnama operates in-process quality control across the full malleable iron production sequence — raw material preparation, casting, annealing, galvanizing, machining and final packing. The checks below are the procedures applied in our Semarang plants, with their measurable acceptance criteria and inspection frequency.
In-process and final inspection procedures
| Inspection | Method & acceptance criteria | Frequency |
|---|---|---|
| Sand inspection | Compactibility testing of moulding sand | Every 30 minutes |
| Hit test | Fracture surface visually observed | Three periods per operator, per day |
| Tensile & elongation | Minimum tensile strength 350 N/mm²; minimum elongation 6% | Every unloading process |
| Spectrometer | Chemical composition, minimum 5 surface test points | Four times per day |
| Pressure test | Sample strength testing — applied in particular to other casting products | Early casting process |
| QC sorting | 100% visual inspection | After production |
| Zinc coating thickness | Elcometer, 10 spots per sample, minimum 65 µm | During process |
| Dimensional test | Calibrated vernier caliper and thickness tester, against the required standard | According to order instruction |
| Alignment | Maximum deviation 1.5 mm per 300 mm, or 1 mm per 200 mm | 3 pcs from each machine, every 30 minutes |
| Thread test | Plug gauge and ring gauge | 3 pcs from each machine, every 30 minutes |
| Leakage test | Minimum 7 bar, held over 3 seconds | 100% of products, before packing |
| AQL inspection | Visual, gauge, alignment and packaging accuracy | Before shipment |
Criteria and frequencies above are TSP's own in-process procedures. Applicability varies by product family and by customer order specification — the pressure test in particular applies chiefly to casting products rather than to every threaded fitting.
The zinc coating check above applies to hot-dip galvanized fittings. See black vs galvanized malleable iron pipe fittings for how the two finishes differ.
Inspection methods and acceptance criteria shown here are based on PT Tri Sinar Purnama production and quality-control information.