Cm352 Corrosion Inhibitor
CM352 is a Hartzell Propeller part number for a specialized corrosion inhibitor
. It is primarily used to protect bolt-on steel counterweights and mounting hardware on various propeller models from oxidation and environmental degradation. Purpose and Application Protection
: Applied to prevent corrosion on steel counterweights, which are critical for the mechanical balance and operation of the propeller assembly. Target Areas : Specific application points include bolt heads spring pins bolt wells Service Intervals
: Hartzell recommends re-applying CM352 at regularly scheduled maintenance intervals, typically aligned with the lubrication schedule found in the Propeller Owner’s Manuals Application Instructions For detailed procedures, technicians should refer to Hartzell Service Letter HC-SL-61-364 Standard Practices Manual 202A Preparation cm352 corrosion inhibitor
: Clean surfaces using a solvent like Stoddard solvent (CM23) and an abrasive pad if existing corrosion is present.
: Spray the inhibitor into a small container and apply it precisely with a soft-bristled brush : The material must cure for a minimum of three hours before flight. Safety and Cautions Ice Protection Hazard Do not apply
CM352 to de-ice/ice protection components such as terminal strips, boots, or harnesses, as it may damage these systems. CM352 is a Hartzell Propeller part number for
: According to safety standards, avoid skin and eye contact. Use safety glasses and resistant gloves during application.
: Keep the container tightly closed in a cool, well-ventilated area away from heat or open flames. Hartzell Recommended Service Facility near you to assist with this application? Hartzell Propeller Counterweight Bolt Update | PDF | Screw
Refer to Figure 3. * Be sure the bolt heads, spring pins, and bolt wells are completely. covered with corrosion inhibitor CM352. * HC-SL-61-364 - SERVICE LETTER CM352 vs
CM352 vs. Traditional Corrosion Inhibitors
| Feature | CM352 | Sodium Nitrite | Molybdate | Phosphates | | :--- | :--- | :--- | :--- | :--- | | Metal Protection | Multi-metal (Steel, Cu, Al, Brass) | Steel only | Steel & Al | Steel & Zn | | Environmental Toxicity | Low (Biodegradable) | Moderate (Nitrosamine risk) | Low (Molybdenum limits) | High (Eutrophication) | | Temperature Limit | Up to 180°C | < 80°C | < 95°C | < 90°C | | Microbial Support | No nutrient value | Potential nitrifier food | None | High algal nutrient | | Critical Dosage | 500–1500 ppm | 800–2000 ppm | 2000–5000 ppm | 1000–3000 ppm |
Verdict: CM352 offers superior high-temperature stability and multi-metal compatibility, making it the preferred choice for modern mixed-metallurgy systems.
9.1 Recommended Dosage by Environment
| Environment | Initial dose | Maintenance dose | Notes | |-------------|--------------|------------------|-------| | Acidizing (15% HCl, 90°C) | 0.3% v/v | – | Add KI 0.03% for synergy | | Cooling water (pH 7.5, 40°C) | 50 ppm | 20 ppm weekly | Monitor biocide compatibility | | Sour brine (200 ppm H₂S) | 100 ppm | 50 ppm every 3 days | For batch treatment | | Pipeline pigging | 0.1% in batch volume | – | Use with MEG for hydrate control |
5. Performance Data & Testing
The Economic Impact: Cost-Benefit Analysis
Is CM352 worth the investment compared to cheaper inhibitors like sodium nitrite? Consider the following scenario:
- System: 500-ton chilled water loop with 200,000 gallons volume.
- Metals: Steel piping, 3 copper heat exchangers, 2 aluminum pumps.
- Corrosion rate with nitrite: 12 MPY (mils per year) on copper; 8 MPY on steel.
- Corrosion rate with CM352: <2 MPY on all metals.
Annual Savings:
- Reduced heat exchanger replacement: $15,000
- Lower pump maintenance (shaft seals, impellers): $6,000
- Decreased water and chemical blowdown: $3,500
- Total ROI: CM352 pays for itself within 4 months of installation.
