Stern Cover Metal Die Castings
The stern cover is a critical metal structural component located at the rear of the ship, typically made by aluminum or magnesium alloy die casting. It is used to cover and protect underwater parts such as the propeller, rudder actuator, and stern shaft. It plays multiple roles including streamlining, corrosion prevention, and vibration damping. Due to its long-term underwater working environment, airtightness is crucial. Even minor leakage could lead to water ingress into the internal motor, transmission mechanism, or bearing lubrication system, seriously affecting vessel safety.
| Issue | Consequence |
|---|---|
| Prevent water ingress and corrosion: | Undetected micro-pores in castings can allow seawater to seep in, corroding internal equipment. |
| Ensure vacuum/pressure chamber stability: | Some stern covers contain cooling or lubrication pipelines that must remain leak-free. |
| Avoid costly post-installation repairs: | Once embedded in the vessel, repairs are difficult. Leak detection before delivery helps eliminate hidden issues. |
| Enhance product grade and delivery standards: | Meet sealing requirements for classification societies or military-grade projects (e.g., IP68, 10m water pressure). |
A marine propulsion system manufacturer once experienced water ingress and short circuit failures shortly after delivery due to undetected micro-sand holes in aluminum alloy stern covers. These products had not undergone precise leak testing before shipping. After adopting WaFu Brothers' leak testing instruments, they implemented differential pressure testing to ensure airtightness of every product, successfully filtering out potential defects. This reduced their repair rate from over 5% to just 0.3%, significantly improving product quality and customer trust. This case fully demonstrates that leak testing of key castings is not only about quality assurance, but also a protective moat for brand reputation and market entry.
Detailed Professional Testing Solutions:
| Pressure Decay Leak Testing | Detection Sensitivity: ±0.8 mmHg | Test Pressure Range: 0–200 mmHg | Application: Overall seal performance of the stern cover |
| Differential Pressure Micro-Leak Detection | Detection Sensitivity: ±0.3 mmHg | Ideal for identifying tiny gaps or micro-leaks | Application: Key sealing joints and interfaces |
| Quantitative Air Flow Detection | Accurately quantifies leakage rate (mL/min) | Application: Pressure chambers and gas channels |
Typical Leak Testing Process for Stern Cover Die Castings
Taking stern cover casting leak detection as an example:
| Testing Phase | Detailed Steps |
|---|---|
| Pre-treatment Phase | Calibration of testing equipment and confirmation of environmental parameters |
| Prepare and install dedicated fixtures to secure the casting | |
| Connection Phase | Connect the air source to the casting's test interface |
| System automatically identifies test program and prepares for testing | |
| Testing Phase | Apply preset test pressure (typically 150 mmHg) |
| Maintain pressure for 10 seconds to ensure sealing | |
| Record pressure decay and flow data for 60 seconds | |
| Evaluation Phase | Compare test data with threshold standards |
| Automatically generate test report and quality rating | |
| Visual and audible alerts indicate pass or failure |
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