Stainless Steel Gear Lubricating Oil Pump

I. Product Overview

Marine stainless steel gear lubricating oil pumps are designed based on the gear meshing transportation principle, using austenitic stainless steel (316/316L) or duplex stainless steel (2205). They provide efficient lubrication solutions for lubricating oil circulation systems of marine main engines, auxiliary engines, and deck machinery. The all-stainless-steel gears and pump body, combined with vibration-resistant structural design, integrate excellent resistance to lubricating oil aging corrosion, wear resistance, and adaptability to complex marine working conditions. They can operate stably in high-temperature lubricating oil (oil temperature ≤150℃) and lubricating media with trace metal debris, meeting the high-reliability lubrication requirements of classification societies (CCS/ABS/DNV) and marine power systems.

II. Core Materials and Characteristics

1.316 Stainless Steel (Mainstream Marine Material)

Characteristics: Contains 2-3% molybdenum, outstanding corrosion resistance to additives in lubricating oil (such as extreme pressure agents and antioxidants), tensile strength ≥520MPa, maintains gear meshing accuracy in oil temperatures of -20℃~120℃, surface hardness reaches HRC28-32, and wear resistance is 3 times higher than cast iron.

Applications: Core components such as pump bodies and gears, suitable for marine main engine lubricating oil systems and auxiliary engine lubrication circulation, resisting erosion from acidic substances generated by long-term high-temperature oxidation of lubricating oil.

2.316L Stainless Steel (Low-Carbon Wear-Resistant Type)

Characteristics: Carbon content ≤0.03%, excellent intergranular corrosion resistance after welding, gear surface nitrided (hardness HRC40-45), fatigue wear resistance increased by 50%, and stable operation in high-load (contact stress ≤1000MPa) lubrication scenarios.

Applications: High-speed gearbox lubricating oil pumps (speed ≥3000r/min), such as lubrication systems for marine steam turbines and gas turbines, reducing gear meshing wear.

3.Duplex Stainless Steel (2205)

Characteristics: Ferritic-austenitic duplex structure, tensile strength ≥620MPa, pitting corrosion resistance index (PREN) ≥32, 40% improved resistance to metal debris scouring in lubricating oil compared to 316 stainless steel, and can withstand impact loads of high-pressure lubrication systems (≤1.6MPa).

Applications: High-pressure lubricating oil pumps for large low-speed diesel engines (such as two-stroke main engines), resisting scouring from iron debris generated by cylinder liner wear, suitable for lubricating media with solid particles (≤50μm).

III. Technical Advantages and Limitations

Core Advantages

1. Lubricating Oil Corrosion Resistance and Wear-Resistant Design

316L stainless steel gears have a wear rate of only 0.002mm per thousand hours in lubricating oil with 1% sulfur content, with a service life exceeding 30,000 hours—6 times that of cast iron gears. The gear meshing clearance is controlled at 0.03-0.06mm to ensure stable flow during high-pressure lubrication (pulsation ≤±0.05MPa).

2. Vibration Resistance and Lubrication Efficiency

The duplex stainless steel pump body adopts an elastic support structure, maintaining gear meshing accuracy during continuous ship vibration (amplitude ≤0.05mm), with lubricating oil leakage ≤5mL/h. Volumetric efficiency reaches 90%-95%, 10% higher than vane pumps, ensuring sufficient lubrication for main engine friction pairs (such as crosshead bearing oil film pressure ≥0.8MPa).

3. Low Maintenance and Compliance

The stainless steel gear surface requires no additional coating, with maintenance costs 60% lower than cast iron pumps (cast iron requires regular anti-rust agent spraying). Certified by classification societies, it complies with IMO SOLAS convention requirements for the reliability of marine power plant lubrication systems, with gearbox oil contamination ≤NAS 8.

Main Limitations

1. High-Temperature and High-Viscosity Limitations

When the oil temperature of 316 stainless steel pumps >120℃, lubricating oil carbonization causes gear wear to increase by 20%, requiring a cooler to control oil temperature. When transporting lubricating oil with viscosity >300cSt, efficiency decreases by 15%, requiring preheating to reduce viscosity.

2. Cost and Weight Challenges

316L stainless steel costs 3-4 times more than cast iron, and the density of 7.9g/cm³ makes the pump body 3 times heavier than aluminum alloy (e.g., a 100mm diameter pump weighs about 25kg), requiring reinforced ship foundations. Noise ≥75dB during high-speed operation requires a soundproof cover (cost +15%).

3. Impurity Adaptability Limitations

Gear meshing is sensitive to solid particles >50μm (such as metal debris and carbon deposits), requiring high-precision filters (filtration accuracy ≤25μm). Lubricating oil with fiber impurities easily jams gears, requiring regular disassembly and cleaning (recommended every 500 hours).

IV. Marine Application Scenarios

1. Main Engine Lubricating Oil Systems

316L stainless steel pumps provide high-pressure lubricating oil (pressure 0.6-1.2MPa) for two-stroke/four-stroke main engines, lubricating key components such as crossheads and bearings, achieving continuous operation (annual operation exceeding 8000 hours) in 100,000 DWT cargo ship main engines.

2. Auxiliary Engine and Power Generation Equipment Lubrication

316 stainless steel pumps are used for bearing lubrication of marine generators and boiler feed pumps, transporting antioxidant-containing lubricating oil (oil temperature ≤80℃) to protect high-speed rotating components (speed ≤1500r/min).

3. Deck Machinery Hydraulic Lubrication

Duplex stainless steel pumps provide circulating lubrication (pressure ≤1.6MPa) for hydraulic gearboxes of anchor machines and cranes, resisting extreme pressure additive corrosion in hydraulic oil to ensure reliable operation of deck machinery in harsh sea conditions.

4. Emergency Lubrication Systems

Configured for key equipment such as marine emergency generators and rudders, 316 stainless steel pumps are driven by batteries when the main power fails, providing at least 30 minutes of emergency lubrication to meet SOLAS convention requirements for emergency systems.

V. Precautions

1. Lubricating Oil Working Condition Adaptation

316 stainless steel pumps are prohibited from transporting lubricating oil with chlorine additives (such as extreme pressure lithium-based grease); duplex stainless steel must be selected. When the oil temperature exceeds 120℃, add cooling coils (heat exchange area ≥2m²) to control temperature.

2. Maintenance and Detection

Daily: Monitor pump inlet and outlet pressure (deviation ≤±10%), bearing temperature (temperature rise ≤40℃), and record lubricating oil contamination (replace the filter element when the NAS grade ≥8).

Regular: Inspect gear meshing clearance every 1000 hours (allowable wear ≤0.02mm), and conduct pump body pressure tests every 5000 hours (1.5 times working pressure, holding for 15 minutes without leakage).

3. Compliance Requirements

Products must pass classification society certification (such as CCS Rules for the Statutory Survey of Ships and Offshore Installations), providing intergranular corrosion test reports for stainless steel materials and gear contact fatigue strength test reports.

Lubrication system design must comply with the energy-saving indicators of IMO MEPC.227(64) resolution, with pump efficiency ≥85% to reduce ship fuel consumption.